Organic Polymers in Energy-Environmental Applications E-Book
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Enables readers to understand core concepts behind organic polymers and their multifunctional applications, focusing on environmental and sustainable applications
Organic Polymers in Energy-Environmental Applications provides comprehensive coverage of polymerization and functionalization of organic polymers, followed by innovative approaches, sustainable technologies, and solutions for energy and environmental applications, including environmental remediation, energy storage, corrosion protection, and more.
Edited by five highly qualified academics with significant experience in the field, Organic Polymers in Energy-Environmental Applications includes discussion on:
- Characteristics and emerging trends of organic polymers, and organic polymers in imaging industries and curable coatings
- Antifouling technology based on organic polymers and wearable technology featuring multifunctional sensor arrays in biomedicine
- Organic bio-adhesive polymers in filter technology, nano-architectured organic polymers, and market dynamics of organic polymer-based technologies
- Organic and inorganic modifications of polymers, pollutant removal via organic polymers, and biodegradable organic polymers
- Life cycle assessment of organic polymers, applications of organic polymers in agriculture, and future outlooks of the field
With complete coverage of organic polymers, a topic of high interest due to their numerous practical applications ranging from membranes to super capacitors, Organic Polymers in Energy-Environmental Applications is an essential resource for polymer and environmental chemists, materials scientists, and all other related researchers and professionals interested in the subject.
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Veröffentlichungsjahr: 2024
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Table of Contents
Cover
Table of Contents
Title Page
Copyright
Preface
Acknowledgments
1 Organic Polymers: Past and the Present
1.1 Introduction and History of Polymers
1.2 Classification of Organic Polymers
1.3 Synthesis and Properties of Polymers
1.4 Conclusion and Future Scope
References
2 Basics of Polymerizations and Application Toward Organic Materials
2.1 Introduction
2.2 Preparation of Covalent Organic Framework (COF)
2.3 Application Toward Organic Materials
2.4 Conclusions
References
3 Organic Polymers Fabrication for Solar Cells
3.1 Introduction
3.2 Organic Solar Cells
3.3 The Role of Organic Polymers in Solar Cells and Their Recent Progress
3.4 Conclusion
References
4 Supercapacitor Energy Storage Incorporating Conjugated Microporous Polymer
4.1 Introduction
4.2 Microporous Polymer Material
4.3 Conclusion
Conflicts of Interest
References
5 Modification of Surface Properties of Polymeric Materials: Methodological Approaches and Applications
5.1 Introduction
5.2 Physical Treatment for Polymer Surface Modification
5.3 Chemical Treatment for Polymer Surface Modification
5.4 Plasma Treatment for Polymer Surface Modification
5.5 Corona Treatment for Polymer Surface Modification
5.6 UV Treatment for Polymer Surface Modification
5.7 Surface Patterning Treatment for Polymer Surface Modification
5.8 Thermal Annealing Treatment for Polymer Surface Modification
5.9 Conclusion
References
Note
6 Organic Polymers as Potential Catalysts
6.1 Introduction
6.2 Recent Development of Porous Organic Polymer (POP)
6.3 Metal–Organic Framework (MOF)-Based Heterogeneous Catalysis
6.4 Reversible Deactivation Radical Polymerization (RDRP)
6.5 Coordination Polymerization
6.6 Covalent Organic Frameworks (COFs)-Based Heterogeneous Catalysis
6.7 Polymer-Based Homogeneous Catalysis
6.8 Conclusion
References
7 Environmental Fate of Water-Soluble Cellulosic-Polymer-Based Composites
7.1 Introduction
7.2 Starch: A Widely Known Water-Soluble Polymer
7.3 Carboxymethyl Cellulose (CMC)
7.4 Properties of Water-Soluble Polymer-Based Composites
7.5 Conclusion and Future Prospects
References
8 Future Roadmap of Organic Polymers
8.1 Introduction
8.2 Polymers of Intrinsic Microporosity
8.3 Conclusion
References
9 Covalent–Organic Frameworks (COF): An Advanced Generation of Reticular Organic Polymers for Energy and Environmental Applications
9.1 Introduction
9.2 Synthesis
9.3 COFs as Thin Films
9.4 Polygon Skeletons
9.5 Pore Engineering
9.6 Thermal Stability
9.7 Advantages Over Conventional Polymers
9.8 Backbone Modifications
9.9 Functional Group Changes
9.10 COFs on Different Scales
9.11 Terracotta Process
9.12 Pyrolysis of COFs
9.13 COFs in Mitigation of Pollutants and Organic Dyes
9.14 COFs for Energy Applications
9.15 COFs in Batteries and Supercapacitors
9.16 Batteries
9.17 Supercapacitors
9.18 Electrochemical Sensors
9.19 Proton-Exchange Membrane Fuel Cells (PEMFC)
9.20 Conclusion
References
10 A Multifunctional Polymer – POLYOX – and Its Uses as a Novel Drug-Delivery System
10.1 Introduction
10.2 Advantages of Using POLYOX
10.3 Physical and Chemical Constituents
10.4 Release Mechanism
10.5 Ocular Drug Administration
10.6 Drug Delivery for the Gastroretentive System
10.7 Film with a Fast Turnaround Time
10.8 Extended Duration of Effect
10.9 Regulatory Aspects of POLYOX
10.10 The Consistency of POLYOX
10.11 Conclusion
References
11 Green Synthesis of Polymers and Its Application in Industry
11.1 Introduction
11.2 Polymer
11.3 The Difference Between Degradable and Biodegradable Polymer
References
12 Organic Polymers and Their Role in Pharmaceutical and Chemical Industries
12.1 Natural Polymers: Inorganic and Organic
12.2 Synthetic Organic Polymers
12.3 Synthetic Polymers in Everyday Use
12.4 Synthetic Polymers Types
12.5 Addition Reactions
12.6 Polymerization Method
12.7 Polymers and Their Uses in Pharmaceutical and Chemical Industry
12.8 Polymeric Hydrogels
12.9 Conclusion and Future Scope
12.10 Future Scope
References
13 Current Trends in Organic Polymers and Nutraceutical Delivery
13.1 Introduction
13.2 Current Advancements in the Polymeric Delivery System for Nutraceuticals
13.3 Scope of Developing New Polymeric Nutraceutical Delivery
13.4 Conclusion and Future Prospects
References
14 Conducting Organic Polymers Used in Biosensors for Diagnostic and Pharmaceutical Applications
14.1 Introduction
14.2 Processibility and Sensitivity Issues
14.3 Side Chain and π-Electron Backbone
14.4 Polarons, Bipolarons, and Solitons
14.5 Doping in CPs
14.6 CPs for Biosensing
14.7 Oxidation and Charge Transfer
14.8 Color Change in PDA Polymers
14.9 Ionic Detection
14.10 Conductometry
14.11 Enzyme Entrapment
14.12 DNA Sensing
14.13 Hydrogel-Based Biosensors
14.14 Urea and Melamine Detection
14.15 Summary
References
15 Organic-Polymer-Based Photodetectors: Mechanism and Device Fabrication
15.1 Introduction
15.2 Organic-Polymer-Based Photodetector
15.3 Conclusion
References
16 Organic-Solvent-Resistant Polymeric Membranes for Emerging Application in Separation Science
16.1 Introduction
16.2 Importance of Organic Polymers in Separation Science
16.3 OSR Membranes: Materials and Classifications
16.4 Types of Membrane Used for the Treatment of Organic Solvent
16.5 Modifications in Designing Membrane for Organic Solvent Purification
16.6 Application of OSR Polymeric Membranes in Different Industrial Processes
16.7 Commercial OSR membrane
16.8 Current Status of OSR Membrane
16.9 Conclusion
References
17 Biodegradable Organic Polymers for Environmental Protection and Remediation
17.1 Introduction
17.2 Role of Organic Biodegradable Polymers in Environmental Bioremediation
17.3 Conclusion
References
18 Application of Organic Polymers in Agriculture
18.1 Introduction
18.2 Organic Polymers as Soil Conditioners/Stabilizers
18.3 Organic Polymers and Agrochemicals Delivery
18.4 Organic Polymer and Heavy Metal Toxicity
18.5 Organic Polymers and Other Plant Stress
18.6 Superabsorbent Organic Polymer and Agriculture
18.7 Conclusion
References
19 Porous Organic Polymers as Potential Catalysts
19.1 Introduction
19.2 Synthesis of POP Catalyst
19.3 Advantageous Features of POPs
19.4 Principle
19.5 Properties and Functions
19.6 Porous Organic Polymer as the Catalyst
19.7 Conclusion
References
20 Developing Trend in Organic Polymer Science
20.1 Introduction
20.2 Applications of Organic Polymers
20.3 Purification of Drinking Water
20.4 Conclusion
References
21 Functionalization and Characterization of Organic Polymers
21.1 Introduction
21.2 Synthesis of Functionalized Organic Polymer
21.3 Transformation of Functional Group
21.4 Characterization of Functional Organic Polymer
References
22 Organic Polymers for Adhesive Applications: History, Progress, and the Future
22.1 Introduction
22.2 History and Developments
22.3 Classifications of Adhesives
22.4 Adhesive Characterization Techniques
22.5 Adhesive Efficiency and Strength Test
22.6 Applications of Adhesives
22.7 Commercial Aspects of Adhesives
22.8 Advanced Adhesive Formulations for Environment Sustainability and Applications in the Energy Sector
22.9 Disadvantages of Organic Adhesives
22.10 Conclusion
References
23 Remediation of Environmental Toxins with Porous Organic Molecules
23.1 Introduction
23.2 Parameters of Oxygen-Rich POPs in Dye Adsorption from Water Sources
23.3 TALPOPs Include Reversible Iodine Detection and Extraction
23.4 Sulfur- and Nitrogen-Rich Hierarchically POPs for Adsorptive Expulsion of Mercury
23.5 Novel N-Enriched Covalent Crystalline POPs for Efficient Removal of Cadmium
23.6 Novel Phenyl-Phosphate-Based POPs for the Elimination of Pharmaceutical Water Contaminants
23.7 Nano-architecture POPs in the Elimination of Toxic Metal Ions
23.8 PSM (Post-synthetic Modification)
23.9 POPs for Gas Extraction, Segregation, and Transformation
23.10 Hydrogen
23.11 Methane
23.12 Carbon Dioxide
23.13 Conclusion
References
24 Versatile Applications of Organic Polymer and Their Prospects
24.1 Introduction
24.2 Characteristics of Organic Polymer
24.3 Methods and Preparation
24.4 Properties and Characteristics of Organic Polymers
24.5 Types of Organic Polymers
24.6 Polymeric Co-delivery Systems in Cancer Treatment
24.7 Recent Clinical Research of Organic Polymers
24.8 Current Scenario of Organic Polymers
24.9 Future Perspectives of Organic Polymer
24.10 Conclusion
References
25 Transdermal Drug Delivery and Organic Polymers: Current Scenario and Future Prospects
25.1 Transdermal Drug Delivery System (TDDS) and Current Scenario
25.2 Navigating the Complexities of Transdermal Delivery
25.3 Structural Overview of Transdermal Delivery Systems
25.4 Exploring Different Organic and Synthetic Polymer-Based Strategies for Transdermal Drug Delivery
25.5 Conclusion and Future Prospects
References
Index
End User License Agreement
List of Tables
Chapter 1
Table 1.1 Some commercially important polymers and their uses.
Table 1.2 Major breakthroughs in the history and discovery of polymer scienc...
Chapter 3
Table 3.1 The photovoltaic performance of D–A polymers.
Chapter 7
Table 7.1 Mechanical properties of wood starch composites.
Chapter 8
Table 8.1 Porous organic polymers’ preparation and reaction.
Chapter 11
Table 11.1 Categories for green polymer chemistry.
Chapter 17
Table 17.1 Environmental applications of cellulose.
Table 17.2 Pros and cons of chitin and chitosan modification.
Chapter 18
Table 18.1 Studies depicting the use of organic polymers for the delivery of...
Table 18.2 Organic polymer in mitigation of heavy metal toxicity.
Table 18.3 Role of organic polymers in mitigation of abiotic and biotic stre...
Chapter 19
Table 19.1 List of other electrocatalytic processes using POP-based electroc...
Chapter 20
Table 20.1 Name and application of polymers.
Chapter 21
Table 21.1 Organic functional groups and their 1H NMR Chemical Shift Values ...
Table 21.2 Organic functional groups and their corresponding FTIR Bands (cm
−
...
Chapter 22
Table 22.1 ASTM methods for the analysis of adhesive strength, for different...
Chapter 24
Table 24.1 Classification of different types of POPs.
Table 24.2 Types of polymer dosage form.
Chapter 25
Table 25.1 Different approaches for transdermal delivery and potential drug ...
List of Illustrations
Chapter 1
Figure 1.1 Building blocks of a few natural polymers.
Figure 1.2 General classification of polymers (self-made).
Scheme 1.1 (a) Synthesis of adipic acid from benzene, (b) synthesis of hexam...
Scheme 1.2 (a) Synthesis of caprolactum and (b) synthesis of nylon 6.
Scheme 1.3 (a) Synthesis of PET by direct method and (b) synthesis of PET by...
Scheme 1.4 Synthesis of Lexan (Ghosh 2011).
Scheme 1.5 Synthesis of a polyurethane.
Scheme 1.6 Synthesis of an epoxy resin.
Scheme 1.7 Synthesis of phenol formaldehyde resin.
Scheme 1.8 Synthesis of polyethene.
Scheme 1.9 Synthesis of polyethylene by Ziegler–Natta catalysis.
Scheme 1.10 Mechanism of synthesis of polyethylene by coordination polymeriz...
Scheme 1.11 Synthesis of polyvinyl chloride.
Scheme 1.12 Synthesis of Teflon.
Figure 1.3 A flowchart of natural polymers (self-made).
Chapter 2
Figure 2.1 Condensation of various linkages for COF formation: (a) hydrazone...
Figure 2.2 Formation of CTF reproduced from Abuzeid et al. (2021).
Figure 2.3 (a) Friedel Crafts alkylation reaction for the formation of HCP (...
Figure 2.4 Schematic depiction of the synthesis of TPBCz-CMP films by electr...
Chapter 3
Figure 3.1 Examples of DPP-based organic-polymer-bearing aromatic substituen...
Figure 3.2 A general working mechanism of OSCs comprises the donor (D) and a...
Figure 3.3 Device architecture of the OSCs device.
Figure 3.4 Examples of reported polymers used in solar cells.
Figure 3.5 Examples of polymers used for the preparation of mesoporous TiO
2
....
Figure 3.6 Reported various types of polymer with their PCE values.
Chapter 4
Figure 4.1 (a) Graphical representation of synthetic route, (b) Galvanostati...
Figure 4.2 Synthesis of PT-Br
2
(b), TPE-PT-CMP (e), and P-PT-CMP (f) from PT...
Figure 4.3 Schematic strategies for the synthesis of BC-Py-CMP and BC-BF-CMP...
Figure 4.4 SNS reaction process and mechanism. (a) Chemical structures of th...
Figure 4.5 (a) Schematic of the ASC, positive (cathode) electrode: CMP-BT/CN...
Figure 4.6 Synthesis of CMPs, MWNT@CMPs and the corresponding porous carbon ...
Figure 4.7 (a) The schematic diagram of imide-based CMPs with different core...
Chapter 5
Figure 5.1 Pictorial illustration of injection molding process.
Figure 5.2 Pictorial illustration of lamination template techniques.
Figure 5.3 Pictorial illustration of extrusion process.
Figure 5.4 Halogenation mechanism in polyamide.
Figure 5.5 Hydrolysis of ester bond of poly(lactic acid) by alkali treatment...
Figure 5.6 Formation of carboxyl and amine groups due to enzymatic treatment...
Figure 5.7 Hydrolysis and condensation method involved in sol–gel method....
Figure 5.8 A schematic diagram of competitive polymerization–ablation techni...
Figure 5.9 Different plasma species interacting with a polymeric substance....
Figure 5.10 Formation of crosslinking due to plasma treatment.
Figure 5.11 Schematic diagram of corona discharge activator.
Figure 5.12 Schematic of (a) chemical phase reaction.and (b) set up of c...
Figure 5.13 Breakage of chemical bonds in the chain of polymer because of co...
Figure 5.14 UV light treatment for the modification of the surface of the po...
Figure 5.15 Schematic diagram of crosslinking of hydrogen bonded multilayers...
Figure 5.16 Surface morphologies of PMMA films/PS films/Si substrate after d...
Figure 5.17 Representation of the creation of an evaporation pattern over ti...
Figure 5.18 Schematic illustration of the patterning technique by electric g...
Figure 5.19 Pictorial illustration of different photolithographic systems: (...
Figure 5.20 llustration of the self-assembly of lamellar PS-
b
-PMMA (polystyr...
Figure 5.21 Schematic representation of the microcontact printing..
Figure 5.22 Schematic illustration of different
nanoimprint lithography
(
NIL
Figure 5.23 Schematic diagram for operating of laser surface texturing (LST)...
Figure 5.24 Schematic representation of laser-surface-texturing method (a) c...
Figure 5.25 Annealing leads to crosslinking in fluorinated polymer.
Chapter 6
Figure 6.1 Pictorial representation of the photocatalytic reaction.
Figure 6.2 Proposed mechanisms for Zr-MOFs-based hydrolysis of organophospho...
Figure 6.3 Esterification of lauric acid and benzyl alcohol using BSL2@HKUST...
Figure 6.4 Heterogeneous catalysis reaction using BF-CPFs.
Figure 6.5 Py-An COF-based catalytic Diels–Alder reaction between 9-hydroxym...
Figure 6.6 (A) Asymmetric Michael addition reactions catalyzed by Tfp2-COF, ...
Figure 6.7 The Michael addition reaction between β...
Figure 6.8 Suzuki–Miyaura cross-coupling reaction between
p
-nitrobromobenzen...
Figure 6.9 Heck coupling reaction between styrene and 1,4-dibromobenzene usi...
Chapter 7
Figure 7.1 Structure of amylose.
Figure 7.2 Structure of amylopectin.
Figure 7.3 Grafting of starch gluten blend and crosslinked with citric acid....
Figure 7.4 Structure of carbon nanotubes.
Figure 7.5 Synthesis of carboxymethyl cellulose.
Chapter 9
Figure 9.1 Scheme showing (a) different shapes of building blocks that make ...
Figure 9.2 Schematic representation of B–O, C–N, and C–C linkage formation f...
Figure 9.3 Structure of DTP-ANDI-COF with 2-e
−
redox step of an NDI ba...
Chapter 11
Figure 11.1 Schematic shows biodegradable polymers classification based on t...
Chapter 13
Figure 13.1 Classification of nutraceuticals.
Figure 13.2 Different types of liposomes depending on their vesicular arrang...
Figure 13.3 Structural difference in outer layer arrangements between the li...
Figure 13.4 The figure shows the presence of chitosan on the surface of nano...
Chapter 14
Figure 14.1 Conduction in polypyrrole (PPy).
Figure 14.2 Structure of conducting polymers used in biosensing.
Figure 14.3 Change of the double bond distribution during electrochemical re...
Figure 14.4 Absorption spectra of PDA (8, 9)/PVP10 nanocomposites measured u...
Chapter 15
Figure 15.1 Classification of optoelectronics.
Figure 15.2 Some examples of polymers and their molecular structures. (a) po...
Figure 15.3 Device architectures of (a) photoconductor, (b) photodiode, and ...
Figure 15.4 Schematic representation of the NPD device structure using syner...
Chapter 16
Figure 16.1 A typical membrane separation technique (flow of permeate throug...
Figure 16.2 Schematic representation of (a) pervaporation, (b) organic solve...
Figure 16.3 Membrane morphology for (a) integrally skinned asymmetric (ISA) ...
Chapter 17
Figure 17.1 Formation of keratin derivatives through chemical modifications:...
Figure 17.2 Applications of levan.
Chapter 18
Figure 18.1 General illustration of different plant stressors and applicatio...
Figure 18.2 General applications of organic polymers as soil conditioners.
Figure 18.3 Superabsorbent hydrogels and water retention.
Chapter 19
Figure 19.1 Example of POPs.
Figure 19.2 Mechanism for porous organic polymers for photocatalysis.
Figure 19.3 Photocatalytic hydrogen evolution process.
Chapter 20
Figure 20.1 An illustration of different types of polymers.
Figure 20.2 Different applications of organic polymers.
Chapter 21
Figure 21.1 Some examples of end-functionalized polymerization.
Figure 21.2 Some examples of monomers of functional polymers.
Figure 21.3 Example of condensation reactions used to form nanoporous polyme...
Figure 21.4 Metal-catalyzed reactions used to form nanoporous polymer networ...
Figure 21.5 Poly(methyl methacrylate) (PMMA) can exhibit different isotactic...
Figure 21.6 500-MHz 1H nuclear magnetic resonance spectrum of isotactic poly...
Figure 21.7 Here is the spectrum of polypropylene at 24-MHz 13C nuclear magn...
Figure 21.8 Here are the solid-state crosspolarization magic angle spinning ...
Figure 21.9 Atomic group vibrations are the vibrations of atoms within a mol...
Figure 21.10 Shows the infrared spectra of polyimide (—) and a model molecul...
Figure 21.11 Comparative research of trans-poly pentenamer IR and Raman spec...
Figure 21.12 Shows the IR spectrum (top) and Raman spectrum (bottom) of P3HT...
Figure 21.13 Synthesis of P3HT using Grignard metathesis reaction.
Figure 21.14 The absorption spectrum of 4-methyl-3-penten-2-one.
Figure 21.15 Effect of conjugation length on the
λ
max
and
ɛ
of org...
Figure 21.16 (a) DSC spectra of PLLA and poly(
L
-lactide-
co
-RS-
b
-benzyl malat...
Chapter 22
Figure 22.1 Applications of adhesives in different fields.
Figure 22.2 Applications of organic adhesives in medicals and pharmaceutical...
Figure 22.3 The adhesive market scenario as per their applications (as of 20...
Figure 22.4 Various means of obtaining adhesives for environmental sustainab...
Figure 22.5 The various applications of adhesives for energy conservation.
Chapter 23
Figure 23.1 POPs and their functions.
Figure 23.2 POPs including various methods of environmental remediation.
Figure 23.3 Artificial pathway for synthesis of the polymer POP-O. Adapted f...
Figure 23.4 Synthetic route for the preparation of the TALPOP.
Figure 23.5 Synthesis of N-enriched covalent crystalline POPs.
Figure 23.6 Synthesis route of phosphate-based POPs.
Figure 23.7 Artificial route for the formation of functionalized POPs.
Chapter 24
Figure 24.1 Organic polymer utilization in the formation of fuel.
Figure 24.2 Various types of nanomedicines in which organic polymers are uti...
Figure 24.3 The fields of biomedical, environmental, and chemical engineerin...
Figure 24.4 Discussion about the different Phases of clinical trials.
Chapter 25
Figure 25.1 Schematic view of skin.
Figure 25.2 Schematic representation of different TDDS.
Figure 25.3 (a) Describes different parts of TDDS. (b) Ideal properties of c...
Guide
Cover
Table of Contents
Title Page
Copyright
Preface
Acknowledgments
Begin Reading
Index
End User License Agreement
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Organic Polymers in Energy-Environmental Applications
Edited by Ramesh Oraon, Pardeep Singh, Sanchayita Rajkhowa, Sangita Agarwal, and Ravindra Pratap Singh
Editors
Dr. Ramesh Oraon
Central University of Jharkhand
Ratu-Lohardaga Road
Ranchi
Jharkhand 835205
India
Dr. Pardeep Singh
University of Delhi
PGDAV College
New Delhi
India
Dr. Sanchayita Rajkhowa
Haflong Government College
Haflong
Dima Hasao
Assam 788819
India
Dr. Sangita Agarwal
RCC Institute of Information Technology
Canal South Road
Kolkata
West Bengal 700015
India
Dr. Ravindra Pratap Singh
Government of India
New Delhi
India
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Preface
Polymers, natural or synthetic, have changed the lifestyle of each individual through their immense application in almost every field. The first polymer discovered (early nineteenth century) was completely natural and derived from “Rubber” plants. It was known to have been used by the indigenous people in South America for centuries. Then, in 1839, Charles Goodyear successfully vulcanized the rubber by cross-linking the polymeric chains that impart strength to it. The year 1907 marked a special achievement in producing the first synthetic polymer that was resistant to heat and electric current and used in various materials. It was named after the creator Leo Baekeland as “Bakelite.” Since then, there have been a series of remarkable discoveries in this budding field: polyethylene (1930s), nylon (1930s), polyester and PET (1940s), polypropylene (1950s), high-density polyethylene (HDPE) (1950s), and polycarbonate (1950s), to name a few. Since the mid-twentieth century, a significant advancement in polymer science and engineering has occurred, leading to novel and improved polymeric materials and applications. Although these polymers are of great use to humankind, they also have an adverse impact on the environment as they are not biodegradable and have been persistent for centuries. In the late twentieth century, the discovery of biodegradable polymers revolutionizes polymeric research and science. In recent years, research has focused on creating advanced polymers with unique properties, such as conducting polymers for electronics, smart polymers, biodegradable polymers, biopolymers advanced polymer blends and composites, 3D printing, polymeric nanoparticles, and polymers for energy storage that respond to environmental changes. The deployment of organic polymers has surpassed the traditional applications and can be seen in advances in imaging technology such as bioimaging, oil absorption, tissue engineering, and self-healing nanometer coatings in automobile and domestic housing. The recent advancements in organic polymers are expanding the range of applications and addressing important challenges, including environmental sustainability and improved performance across various industries.
The inception of this book was based on numerous applications and a plethora of research advancements in this field. The add-on factor of biodegradability to polymers has motivated us to dive into the depth of the knowledge. With this view, we attempted to comprehend the subject matter for our audience, including students, researchers, academicians, and scientists. The editors Dr. Ramesh Oraon (Central University of Jharkhand), Dr. Pardeep Singh (Delhi University), Dr. Sanchayita Rajkhowa (Haflong Govt. College, Assam, India), Dr. Sangita Agarwal (RCC Institute of Information Technology, Kolkata), and Dr. R.P. Singh (Central Public Works Dept., New Delhi) were keen to publish a handy material on this burning topic with elaborate details starting from its history, development, applications, and future aspects.
Chapter 1 starts with a basic introduction and history of organic polymers. It also offers a comprehensive summary of the basis of polymerization methodologies for synthesizing organic polymers, with recent developments describing the various applications of such materials. Functionalization and characterization of organic polymers demonstrate that the generation of hydrogels and their rheological properties were significantly influenced by the alteration of carboxylates in high molecular mass heparin (HMWH) with various maleimide groups and with thiol-derivatization of PEG crosslinker. In Chapter 2, the progress of porous organic polymers (POPs) as a potential catalyst in various applications like water splitting, CO2 capture, and degradation of organic pollutants, among others, along with the various synthetic processes of POP catalysts as well as their properties and potential applications, are broadly discussed. The subsequent chapters 3, 4, 10, 14 and 18 comprehensively understand organic polymers in photodetectors, energy storage and solar cells, agriculture, pharmaceuticals, drug delivery systems, etc. There is a great emphasis on green synthesis of organic polymers and their application in environmental remediation (Chapter 11). Another chapter (Chapter 22) provides information about the history, the current research scenario, and the future scope of organic polymer-based adhesives. Owing to their diverse functions and utility, there is a blossoming resurgence of modified polymers in science and technology. In this regard, the methods of polymeric surface modification and their applications, along with the prospects in the future, are also discussed (Chapter 5). A few chapters (Chapters 9, 13, 20, 21 and 24) discuss organic polymers’ current and developing trends in various fields, while another includes the future roadmap of POPs (Chapters 19 and 23). Organic polymers are a fundamental part of modern society, and their diverse properties and applications make them a crucial area of scientific and industrial research. Advances in polymer science continue to drive innovation in various industries, from materials engineering to medicine.
Through this journey, we hope to provide our readers with a deeper understanding of organic polymers, their applications, and recent trends that navigate to the future. We aim to make the content accessible, engaging, and relevant.
We extend our heartfelt thanks to the authors, researchers, educators, and all the contributors who have contributed their expertise to this endeavor.
So, dear readers, as you turn the pages of this book, I invite you to embark on this adventure with an open heart and a curious mind. Let us delve into the past, uncover its aspects and applications, and emerge with a deeper appreciation for the incredible journey of the future.
Thank you for joining us on this exploration.
Dr. Ramesh Oraon
Dr. Pardeep Singh
Dr. Sanchayita Rajkhowa
Dr. Sangita Agarwal
Dr. Ravindra Pratap Singh
Acknowledgments
We sincerely thank and appreciate everyone who helped make this book possible. We recognize the arduous labor, devotion, and support of the authors who helped make this project a reality with great pleasure and humility. The authors’ passion, creativity, and unwavering commitment to work have made this project an absolute joy to edit. Every page exhibited your talent as a writer, and we feel privileged to have contributed to realizing one’s dream.
We express our appreciation to Wiley and the publishing staff for their significant help and direction during the editorial process. This book has really benefited from your experience, professionalism, and unceasing effort.
The quality of a book depends to a large extent on proper reviewing. We gratefully acknowledge the time and expertise devoted to reviewing the manuscripts by a large group of reviewers.
We thank our colleagues and contributors for their invaluable collaboration, insights, and constructive feedback. Your input has been indispensable in refining the manuscripts and ensuring their quality. We also want to acknowledge the contributions of the proofreaders, copyeditors, and designers who worked diligently to make this book visually appealing and error-free. Your attention to detail and dedication to perfection have been truly exceptional.
A special thanks goes to the friends and family who provided emotional support during the long hours and deadlines. Your encouragement and understanding were crucial in helping me see this project through to completion.
Last but not least, we express our appreciation to the readers who will soon embark on this literary journey. Your interest in our work motivates us to continue creating, and we hope you find this book as rewarding to read as it was to edit.
Without the combined efforts of every member of the team, this book would not have been possible. We are incredibly appreciative of the chance to work upon this project and we are looking forward to engaging in many more imaginative partnerships in the futures.
Dr. Ramesh Oraon
Dr. Pardeep Singh
Dr. Sanchayita Rajkhowa
Dr. Sangita Agarwal
Dr. Ravindra Pratap Singh
1Organic Polymers: Past and the Present
Jyotirmoy Sarma1, Subhasish Roy1, Bhaskar Sharma1, Fredy A. Madukkakuzhy1, Monjumoni Das2, and Pallabi Borah1
1Assam Don Bosco University, Department of Chemistry, Tapesia Gardens, Sonapur, Assam 782402, India
2Sibsagar College, Department of Chemistry, Joysagar, Assam 785665, India
1.1 Introduction and History of Polymers
The word polymer is derived from the Greek word “polumeros” where “Polus” means “many” and “meros” means “units.” Henceforth polymers can be defined as the complex and giant molecules or “macromolecules” which are supposed to form by the combination of many small repeating molecules called monomers. Examples of some commercially important polymers and their practical applications have been highlighted in Table 1.1. The most practical distinguishing feature of polymer from its monomer is its huge difference in physical, chemical, and mechanical properties after the polymerization process occurs (Dorel 2008). For example, ethene is a gas but when they combine with each other via the polymerization process, a new class of compound, i.e., polyethene, is formed which differs from its monomer in terms of many physicochemical properties. Monomers being smaller have low molecular weight, while polymers being much larger have very high molecular weight. Compared to simple organic molecules, polymers aren’t composed of identical molecules; hence, a polymer sample generally comprises chains of different lengths, which is why their molecular weight is always expressed as an average molecular weight. For instance, the HDPE (high-density polyethylene) molecules are all long-chain carbon chains, but the lengths generally vary by thousands of monomer units. Depending on the type of monomeric units, polymers may be of different types such as homopolymers where all the repeating units (s) are same and co-polymers which can be made up of two or more monomer species. For example, in case of homopolymers such as polythene the monomer unit is ethylene, in polyvinylchloride (PVC) the monomer unit is vinyl chloride. Important examples of co-polymers include polyethylene-vinyl acetate (PEVA), nitrile rubber, and acrylonitrile butadiene styrene (ABS) which are formed by the combination of more than one monomer.
Table 1.1 Some commercially important polymers and their uses.
Name of polymer and structure
Monomer
Practical applications
Polythene
Ethene
Electrical insulators, packing of materials
Polystyrene
Styrene
As insulator, wrapping material, for construction of toys
Polyvinyl chloride
Vinyl chloride
In the manufacture of raincoats, handbags
Polytetrafluoroethylene (Teflon)
Tetrafluoroethene
As lubricant insulator in the manufacture of semiconductors, non-stick coating in kitchen cookware and medical devices
Polyacrylonitrile
(
PAN
)
Acrylonitrile
In construction of synthetic fibers and wools
Styrene butadiene rubber
(
SBS
) or Buna-S rubber
1,3-Butadiene and styrene
For making of automobile tires and footwear, etc.
Terylene (Dacron), polyester
Ethylene glycol and terephthalic acid
For making fibers, safety belts, plastic bottles, hard wear clothes like dresses
Nylon-6,6
Hexamethylenediamine and adipic acid
In making brushes, synthetic fibers, water-resistant machine parts
Nylon-6
Caprolactum
For manufacture of carpets, tire cords, seat belts, parachutes, ropes, etc.
Based on the type of backbone chain and composition, polymeric materials are classified into two types, viz. organic polymers and inorganic polymers (Currell and Frazer 1969; Gowarikar et al. 2022). Basically, organic polymers are made of carbon-carbon backbone skeleton (Peng et al. 2017), while inorganic polymers do not have carbon-carbon skeleton, rather they have a skeleton like Si–Si for polysilanes, Si–O for polysiloxanes, Si–N for polysilazanes, S–S for polysulfides, B–N for polyborazylenes, and S–N for polythiazyls (Seth 2020; Indra and Shrray 2015).
Cellulose is one of the most abundant organic polymers on Earth, and it is a linear polymer of as many as 10,000 dextro-glucose units joined with each other. Starch, belonging to carbohydrates, can be found in grains and potatoes. Starch is a polymer, also known as a polysaccharide because it is made from glucose as monosaccharide. Starch molecules include two types of glucose polymers, amylose and amylopectin. Amylopectin, being a major starch component, is found in many plants. Amylose belongs to a linear-chain polymer having around two hundred glucose molecules per molecule.
Based on the existence and method of formation, organic polymers may be further categorized as natural or synthetic, and interestingly both of them find equal attention in our day-to-day life. Natural organic polymers can be found in nature or living system and important examples of natural organic polymers include proteins or polypeptides, polynucleotides like DNA and RNA (DNA is a double-stranded polynucleotide chain, while RNA is a single-chain structure of polynucleotides), silk, wool, cellulose, natural rubber. Synthetic polymers are man-made polymers which are being synthesized in the industry or laboratory. Important examples of synthetic polymers include polyethylene (both low-density polyethylene – LDPE and high-density polyethylene – HDPE), polypropene (PP), polyacrylonitrile (PAN), polyaniline (PANI), polystyrene (PS), polyvinylchloride (PVC), tetrafluoroethene (Teflon), polyacetylene, nylon, thermoplastic polyurethane (TPU), and Bakelite. Most of the synthetic polymers possess enhanced lifetime and improved mechanical properties. However due to the absence of a functional group in most of them, they do not have some important physical and chemical properties which limit their synthetic utility in many practical applications. To address this problem post-synthetic functionalization and further modification of polymers have been done in recent times to achieve multinational properties.
During the fifteenth century, Christopher Columbus was involved in the discovery of rubber by isolating it from trees, and later Joseph Priestly observed that the material is helpful for erasing pencil marks on paper. This observation launched the rubber industry. Combining the latex of rubber tree with the morning glory plant juice in various proportions helped to achieve rubber’s distinct properties for designing selective products like bouncing balls, various kinds of rubber bands, etc. To gain the advantages and properties of both natural and synthetic polymers, researchers across the globe were always in search for the development of improved semi-synthetic organic polymers. For example, vulcanization of rubber was introduced for enhancing the quality of natural rubber where a small amount of sulfur is added as a cross-linking agent which can enhance the quality and stability of rubber. Vulcanized rubber is comparatively stronger, elastic, more resistant to abrasion and temperature change, and most importantly inert with respect to chemicals and electric current as compared to untreated natural rubber (Brown and Poon 2005).
Likewise, natural resources polymeric materials like cellulose and proteins have been extensively used for making improved polymers via copolymerization techniques.
Henri Braconnot’s Braconnot, Christian Schönbein, and coworkers in 1830s first developed the derivatives of cellulose for constructing novel semi-synthetic materials, known as celluloid and cellulose acetate. Later the term “polymer” was introduced in 1833 by Jöns Jakob Berzelius, even though Berzelius could not provide significant contribution for the development of modern polymer science.
In 1909, Leo Baekeland developed Bakelite from cheap and readily available chemicals such as phenol and formaldehyde which opened the door of emerging technology for designing many innovative polymeric products (Baekeland 1909; Wallace 1945).
In spite of the noteworthy developments in polymer synthesis, the molecular nature of polymers was not clear until the concept was introduced by Hermann Staudinger in the year 1922. Earlier formation of polymers was explained via aggregation theory proposed by Thomas Graham in 1861. According to Graham, cellulose and other polymers were supposed to have colloidal nature where aggregation of small molecules having smaller molecular masses was joined by some unknown intermolecular force. Later, Hermann Staudinger first anticipated that polymers consist of long chains of atoms held together by some covalent bonds. Staudinger, for his immense contribution in providing concepts to understand about polymeric structure, was awarded the Nobel Prize in Chemistry in the year 1953.
During the period of World War II there had been an increased demand of natural polymers such as silk and rubber. But due to their limited supply, alternative synthetic polymers such as nylon were introduced to meet the essential requirements. Then, the invention of advanced polymeric materials like Kevlar and Teflon became eye-catching to launch the robust polymer industry.
The most important properties of a reactant to be a monomer or to take part in polymerization reaction are (i) presence of reactive functional group and (ii) the minimum requirement of bifunctionality. Depending upon the nature of functionality, for example, bi- or tri-functionality, the polymers may be designed as chain polymers, blocked or cross-linked polymers, respectively. For the synthesis of polymers, various methods such as addition polymerization, condensation polymerization, and co-ordination polymerization have been employed. In most of the synthetic procedures use of catalyst, initiator, application of high pressure and temperatures are the important requirements to assist rapid polymerization process.
Due to the great demand of polymeric materials in day-to-day life, many researchers across the globe are working in this field, and hence Nobel Prize has been awarded to many scientists for the development of this particular field. Karl Ziegler (1898–1973) and Giulio Natta (1903–1979) independently developed catalysts which smoothly assist polymerization under ambient condition with high stereospecificity to furnish isotactic polypropylene (i-PP) and HDPE. In the year 1963, Giulio Natta and Karl Ziegler were jointly awarded Nobel Prize in Chemistry for their immense contributions in the area of polymer science. Next, Flory was awarded Nobel Prize in Chemistry in 1974 for his important contribution in both theoretical and experimental development of polymer science. In the year 2000, Alan G. MacDiarmid, Alan J. Heeger, and Hideki Shirakawa were jointly awarded Nobel Prize in Chemistry for their work on conductive polymers which provide significant contributions in the advancement of molecular electronics. John Bennett Fenn, Koichi Tanaka, and Kurt Wüthrich were awarded Nobel Prize in Chemistry in the year 2002 for their innovative methods in identification and structural analysis of biological macromolecules. Robert Grubbs, Richard Schrock, and Yves Chauvin were awarded Nobel Prize in Chemistry in the year 2005 for the development of olefin metathesis also known as ring-opening metathesis polymerization reaction (ROMP). The use of Ru-based Grub’s catalyst for polymerization gained significant popularity in recent past. Some of the major breakthroughs that evolved during the development of polymer science have been depicted in Table 1.2.
Even though polymeric materials have important applications, their non-biodegradability always poses a threat to the surroundings. For example, polyethene compounds cannot be broken down by the bacteria present in the soil, and due to constant accumulation of these materials soil and water pollution arises. To solve this particular problem, extensive study is going on around the world for the development of biodegradable polymers which are also considered as green polymers. One important example of biodegradable polymers is poly β-hydroxybutyrate-co-β-hydroxy valerate (PHBV) which can be prepared by the combination of 3-hydroxy butanoic acid and 3-hydroxy pentanoic acid.
Recently polymer matrix composites (PMCs) have been introduced which possess a wide range of potential applications (Tewatia et al. 2017; Ramakrishna et al. 2001). PMCs are polymers reinforced with additives such as glass fibers, carbon fibers, carbon nanofibers, graphene, and carbon nanotubes. They have been widely employed because of the magical enhancements of mechanical, thermal, and electrical properties associated with this special type of material. Presently, researchers are looking for intelligent polymers which are specially designed materials that can extend the scope of polymer science.
Table 1.2 Major breakthroughs in the history and discovery of polymer science.
Year
Name of the scientists and contribution
1833
Berzelius for the introduction of the polymer terminology
1839
Edward Simon for the synthesis of polystyrene
1859
A.V. Lourenço and Charles Adolphe Wurtz for the production of polyethylene glycol
1900
Hermann Staudinger (Father of Modern Polymer Science) for providing the idea about the structure of polymers (long-chain molecules), awarded Nobel Prize award in 1953
1938
W.H. Carothers for the synthesis of nylon which laid the foundation of the synthetic fiber industry
1963
Giulio Natta and Karl Ziegler awarded Nobel Prize in Chemistry for the metathesis ring-opening polymerization reaction
1974
Paul Flory awarded Nobel Prize in Chemistry for providing significant contributions in the area of experimental and theoretical polymer research
1984
Bruce Merrifield for the development of solid-phase protein synthesis awarded Nobel Prize in Chemistry
2000
Alan J. Heeger, Alan G. MacDiarmid, and Hideki Shirakawa awarded Nobel Prize in Chemistry for the discovery and development of electrically conductive polymers
2002
John Bennett Fenn, Koichi Tanaka, and Kurt Wüthrich for identification and structure analysis of biological macromolecules, awarded Nobel Prize in Chemistry
2005
Grubbs and coworkers awarded Nobel Prize in Chemistry for the introduction of metathesis tactics which provided significant advancement in synthetic chemistry
1.2 Classification of Organic Polymers
Polymers are divided primarily into organic polymers and inorganic polymers based on the nature of backbone chain. Primarily, organic polymers are made up of carbon backbone structures, while inorganic polymers do not have carbon atoms in their backbone. Organic polymers are suitable for several applications because of their simple structures and biodegradable nature, which make them environmentally friendly. Nevertheless hybrid polymers like “silicones,” which are organosilicon polymers or polysiloxanes, are also well known because of their potential industrial applicability. Silicones found wide applications because of the presence of strong carbon-silicon (C—Si) bonds. The formation takes place in a few steps, starting from the alkylation/arylation of a silicon tetrachloride and finally resulting in silicones, R2(SiO)n. Here “R” represents an alkyl/aryl group. Silicones found commercial applications mainly under three category namely fluids, elastomers, and resins (Zielecka et al. 2002).
It is well known that most of the polymers are built up via two organic-chemistry-based mechanisms. One is addition/chain and the another is condensation/step-growth polymerization mechanism. Both of these mechanisms involve a combination of small monomers or repeating units. The mechanism of polymer formation results in either addition or chain polymers. Apart from this, polymers are broadly classified based on their source, structure, molecular forces operating, and thermal behavior (Kariduraganavar et al. 2014).
Originally polymers were classified as either “natural or synthetic polymers.” Natural polymers occur naturally, whereas synthetic polymers can be synthesized artificially. Natural polymers are obtained from animals and plants. A few examples include
Proteins
: Wool and natural silk are protein-based products. Proteins are the building blocks of animal cells. The proteins are formed by the repetition of α-amino acids (
Figure 1.1
).
Carbohydrate polysaccharides
: Repetition of smaller monosaccharides like “glucose” leads to the formation of macromolecules like cellulose and starch, which constructs the plant cell. These biological molecules also supply energy to animal cells (
Figure 1.1
).
Nucleic acids
: “RNA” and “DNA” are the bio-polymers formed by the repetition of nucleotides. These are the primary constituents of all living cells (
Figure 1.1
).
Natural rubber
: This is a well-known plant-extracted component. It is present in the latex of rubber plant. It is also known as
cis
-polyisoprene, which is a polymer of isoprene. However the trans-isomer is known as “gutta-percha” (
Figure 1.1
).
On the other hand, most of the daily-use polymers are synthetic ones. This covers a series of polyvinyl-based chain polymers like “polyvinylchloride” and functional-group-based condensed polymers like “polyethyleneterephthalate.” A few examples are PVC, polyethylene, polystyrene, Teflon, synthetic rubber, nylon-6, and nylon-66. Most of these are organic polymers. Moreover “semi-synthetic polymers” also do exist. These are obtained by chemical modification of natural polymers. For example, one of the important materials, cellulose diacetate, is synthesized from cellulose by reacting with acetic anhydride in the presence of sulfuric acid (Kamide 2005). It is formed by the acetylation reaction. Some of the hydrogen atoms in cellulose are substituted by acetyl (–COCH3) groups.
Polymers are divided into three structural categories, namely, linear, branched, and cross-linked polymers.
Linear polymers are long straight-chain molecules with highly ordered structures. Importantly, the randomness is comparatively less as the monomers are linked together in linear fashion. Because of the linear arrangement their structure is densely packed. Some of the characteristics, like high densities, melting temperatures, and mechanical strengths, are the result of this. Polyester and polyethylene belong to this category.
Branched one possesses secondary polymer chains connected to a primary backbone, resulting in a branching-tree-like structure. The chains are less well packed due to branching, which results in much lower melting temperatures, densities, and mechanical strengths (Abuzreda
2023
). Branch-chain polymers can be created via condensation or addition polymerization methods. Examples include amylopectin, glycogen, LDPE, and any rubbers that have been vulcanized.
Network or more specifically the cross-linked polymers are formed by connecting two or more chains by cross-linking agents. The initially formed linear polymeric chains are joined together to form a three-dimensional network structure. The chain linkages give these polymers their hard, stiff, and brittle characteristics. Condensation polymers are invariably cross-linked polymers. A group of cross-linked polymers is known as resins.
Depending upon the mechanism of formation, polymers are classified into addition and condensation polymers. Addition or chain reaction polymers are formed by successive addition of monomers (small molecules). The linked monomers are called “repeating units” (RUs). The RUs are joined predominantly by covalent bonds. Their mechanism of formation is primarily dependent upon the three steps: initiation, propagation, and termination. The propagation step is responsible for getting high-molecular-weight polymers. The molecular weight is an important property in polymer characterization. “Polyethylene” is a chain polymer formed by the repetition of ethylene monomers.
Alternatively, condensation reaction between monomers bearing typical functional groups like hydroxyl (–OH), carboxyl (–COOH), ester (–COOR), and amide (–CONH2) results in the formation of condensed polymers. During condensation reaction some small molecules like water or mineral acids are released from the monomers by condensation. Polymerization proceeds by successive formation of dimers, trimers, and tetramers. However the extent of polymerization between them is important for having a high-molecular-weight condensation polymer (Kariduraganavar et al. 2014). Nylon-6,6 is a common example of condensation polymer. It is formed by the condensation of hexamethylene diamine, NH2–(CH2)6–NH2, and adipic acid, COOH–(CH2)4–COOH. The reaction takes place between a diamine and a dibasic acid. The two monomers are linked by a peptide bond as shown in Figure 1.1. One of the advantages here is that no initiator is required for the reaction.
Elastomers and fibers are two subcategories of polymers that are determined by the molecular forces between individual chains.
An elastomer is plastic and its polymeric chains are bounded by very weak van der Waal forces. Because of such weak operating molecular forces, these polymers are stretchable as well as compressible. They can be reverted back to their earlier form. It is a randomly oriented amorphous polymer. Vulcanized rubber is an elastomer that exhibits cross-linking by sulfur atoms. Such cross-linking prevents the chains from slipping over one another.
However, due to the highly organized geometry and potent intermolecular forces of attraction, fibers possess the highest tensile strength and negligible elasticity. Fibers have a high melting point and low solubility, and are crystalline in nature. Fibers include polymers like cellulose, nylon, wool, and silk (Abuzreda 2023).
Polymers are divided into thermoplastics and thermosetting plastics based on heat treatment. Interestingly most of organic macromolecules belong to these categories.
Thermoplastics are a type of polymer that softens when heated and may take on any shape when cooled. Thermoplastic polymers can undergo transition from hardness to softness and vice versa. At normal temperature conditions, they are hard. With increase in temperature, hardness decreases and they become soft and viscous. The polymeric chains can slip over one another during heating. When cooled, this material stiffens up after being soft and viscous. Hence depending on temperature, thermoplastic polymers can be molded into various shapes and products. Without affecting the chemical identity and mechanical merits of the plastic, the heating, softening, and cooling procedures can be performed as frequently as needed (Carothers 1929). They have highly ordered crystalline as well as less ordered amorphous regions. Polyethylene, polycarbonate, polypropylene, Teflon, and PVC are a few typical examples.
When thermosetting polymers are heated, they undergo chemical transformation and cross-linking takes place, and when they are cooled, they become permanently hard and infusible. Repeating heat treatment doesn’t cause them to soften; instead, they degrade. These polymers undergo setting to only one form during heat treatment. It cannot be converted back to the original form. They become hard on heating and turn into a solid that cannot be re-melted by changing the temperature (Carothers 1929). These polymers set into a solid structure because of the existence of cross-linking. With rise in the degree of cross-linking the rigidity also increases. Upon heating the hardness increases due to extensive cross-linking. Moreover, cross-linking reduces the mobility of the polymer chains, causing them to be relatively brittle. Common examples of thermosetting polymers are phenol-formaldehyde resin and urea-formaldehyde resin (Figure 1.2).
In addition to these, organic polymers also categorized as conducting polymers as they found promising applications in
organic light-emitting diode
(
OLED
), semiconductors, and superconductors. Interestingly, the first conducting polymer is an organic polymer, polypyrrole, as reported by Donald Weiss and coworkers in 1960. Polypyrrole is a heterocyclic polymer containing carbon and nitrogen atoms in its rings. Because of the conjugation of electrons in their rings, they can act as conducting polymers. Conducive polymers’ most important benefit is their processability, which is mostly attained through dispersion (Saldívar-Guerra and Vivaldo-Lima
2013
).
Conducting polymers can be further classified into intrinsically conducting polymers, extrinsically conducting polymers or doped polymers.
Intrinsically conducting polymers
: This class of polymers conducts electricity due to the presence of delocalized electron pairs or conjugated π–bonds in the structural frame. In a polymeric material with an electric field, the delocalized electrons can move across it. Coupled bands, valence bands, and conduction bands are produced as a result of overlapping orbitals.
Semiconducting or impure polymers
: Doping is a process by which conductivity of materials can be enhanced by adding or doping some impurity. Impurity means certain elements in their chemical form. Doping creates charge carriers in the polymer chain by either oxidation or reduction processes. The common doping processes are
p
-doping and
n
-doping. Both involve creation of positive holes and negative excess electrons by the redox processes.
Figure 1.1 Building blocks of a few natural polymers.
Source: Adapted from https://d1hj4to4g9ba46.cloudfront.net/questions/1536297_1144437_ans_9129a4f3e7f84e03932353ae379c21a0.png.
Figure 1.2 General classification of polymers (self-made).
1.3 Synthesis and Properties of Polymers
Polymer can be synthesized by two ways: (i) polymerization of the monomeric units and (ii) chemical modification of monomeric side chain of the polymer. Through the first method molecular weight can be increased, whereas the second method will change the structure of the molecule without molecular weight variation.
The chemical process which converts molecules into polymer macromolecules is known as polymerization. This process is the combination of different reactions which determine the features of the product. The properties of the obtained macromolecules are also dependent on the chemical composition of the starting materials. This chapter will mainly cover the synthesis of polymers by using different polymerization processes. Basically there are two types of polymerization processes: viz. step growth or condensation polymerization and addition polymerization.
Step Growth Polymerization is one type of polymerization process in which bi-functional or multifunctional monomers react to form first dimers, then trimers, longer oligomers, and eventually long-chain polymers. Through this step growth polymerization, many naturally occurring as well as synthetic polymers can be obtained. For example, polyamides, polyesters, polycarbonates, polyurethanes, epoxy resin, and phenol formaldehyde resin.
1.3.1 Polyamides
Nylon is a generic designation for a family of synthetic polyamides. Nylon, silk-like thermoplastics have significant applications in fabric, fibers, shapes, films, etc. Many synthetic polyamides, including nylon-6,6, nylon-6, nylon-6,10, and nylon-11, are well-known. The synthetic methods of some of the polyamides are discussed below.
1.3.2 Nylon-6,6
Hexamethylene diamine and adipic acid (Hexan-1,6-dioic acid) are co-polymers in it. Benzene, a byproduct of petroleum refining and cracking, is the primary raw material used in the manufacture of nylon-6,6. Adipic acid serves as the precursor once more in the creation of hexamethylene diamine. The synthesis of nylon-6,6 is shown in Scheme 1.1 (Gowarikar et al. 2022).
Scheme 1.1 (a) Synthesis of adipic acid from benzene, (b) synthesis of hexamethylenediamine from adipic acid, and (c) synthesis of nylon-6,6.
During fabrication, nylon fibers are cold-drawn to about four times their original length, which increases crystallinity, tensile strength, and stiffness.
1.3.3 Nylon-6
Nylon-6 or polycaprolactam, a semicrystalline polyamide, is synthesized from caprolactam. Fibers, brush bristles, high-impact moldings, and tire cords are all made from nylon-6. The synthesis of nylon-6 is depicted in the Scheme 1.2.
Scheme 1.2 (a) Synthesis of caprolactum and (b) synthesis of nylon 6.
Properties of nylon:
➢ With their parallel arrangement of molecules and hydrogen bonds holding them together, nylon fibers have a linear structure. Strong intermolecular forces give these fibers a more crystalline structure and provide them great strength, flexibility, and a high melting point.
➢ Nylons are chemically stable and resistant to abrasion.
➢ The yarn is smooth, long lasting, and can be spun into fabric.
➢ The fabric can withstand heat and steam and is strong, glossy, moisture-resistant, simple to dye, and retains color.
1.3.4 Polyesters
Polyester is a class of polymer in which an ester functional group is present in every repeating unit of the polymer chain. Some polyesters are naturally occurring compounds found in plants and insects, some are synthetic compounds like polybutyrate. But it most frequently refers to a type of substance known as polyethylene terephthalate as a specific material (PET
