Multifunctional Materials E-Book

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 1106

Veröffentlichungsjahr: 2025

Beschreibung

This comprehensive book is essential for anyone looking to deepen their understanding of advanced materials and their transformative impact across multiple disciplines, from cutting-edge technologies to innovative solutions in engineering and biology.

Multifunctional Materials: Engineering and Biological Applications is a comprehensive guide on advanced materials, a class of materials that exhibit novel properties, high performance, and unique functionalities that make them suitable for a wide range of applications. These materials are typically engineered at the molecular or atomic level, allowing precise control over their structure and properties. The field of advanced materials is vast, covering a range of material types and applications.

This volume covers topics on the chemistry, properties, and applications of advanced materials. The study of advanced materials involves multiple disciplines, including materials science, chemistry, physics, and engineering. Advances in this field have led to the development of new and improved technologies, such as high-efficiency solar cells, lightweight and strong materials for aerospace applications, and new drug delivery systems for disease treatment.

The volume:

• Demonstrates materials synthesis and characterization of multifunctional materials;
• Examines properties and functionalities of multifunctional materials, such as mechanical, electrical, and thermal properties, as well as other functional properties;
• Outlines multifunctional materials applications, including their use in biomedical devices, aerospace and defense systems, and consumer electronics;
• Provides a comprehensive overview of this rapidly evolving field, covering topics related to materials science, engineering, and technology.

Audience

Researchers, industry scientists and engineers, academics, and postgraduate students working in the fields of materials chemistry, applied chemistry, nanotechnology, chemical technology, polymer science and engineering, and industrial chemistry.

Leseprobe

Scrivener Publishing100 Cummings Center, Suite 541JBeverly, MA 01915-6106

Publishers at ScrivenerMartin Scrivener ([email protected])Phillip Carmical ([email protected])

Multifunctional Materials

Engineering and Biological Applications

Edited by

Divya Bajpai Tripathy

Dept. of Chemistry, School of Basic Sciences, Galgotias University, Greater Noida, India

Anjali Gupta

Dept. of Chemistry, School of Basic Sciences, Galgotias University, Greater Noida, India

and

Arvind Kumar Jain

Professor of Basic and Applied Sciences, Dean of Student Welfare IILM University, Greater Noida, India

This edition first published 2025 by John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, USA and ScrivenerPublishing LLC, 100 Cummings Center, Suite 541J, Beverly, MA 01915, USA© 2025 Scrivener Publishing LLCFor more information about Scrivener publications please visit www.scrivenerpublishing.com.

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, except as permitted by law. Advice on how to obtain permission to reuse material from this title is available at http://www.wiley.com/go/permissions.

Wiley Global Headquarters111 River Street, Hoboken, NJ 07030, USA

For details of our global editorial offices, customer services, and more information about Wiley products visit us at www.wiley.com.

Limit of Liability/Disclaimer of WarrantyWhile the publisher and authors have used their best efforts in preparing this work, they make no representations or warranties with respect to the accuracy or completeness of the contents of this work and specifically disclaim all warranties, including without limitation any implied warranties of merchant-ability or fitness for a particular purpose. No warranty may be created or extended by sales representatives, written sales materials, or promotional statements for this work. The fact that an organization, website, or product is referred to in this work as a citation and/or potential source of further information does not mean that the publisher and authors endorse the information or services the organization, website, or product may provide or recommendations it may make. This work is sold with the understanding that the publisher is not engaged in rendering professional services. The advice and strategies contained herein may not be suitable for your situation. You should consult with a specialist where appropriate. Neither the publisher nor authors shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages. Further, readers should be aware that websites listed in this work may have changed or disappeared between when this work was written and when it is read.

Library of Congress Cataloging-in-Publication Data

ISBN 978-1-394-23412-7

Cover images courtesy of Adobe Firefly and Wikimedia CommonsCover design by Russell Richardson

Preface

Multifunctional materials have gained significant attention due to their ability to perform diverse applications and functionalities. Combining multiple functions into a single material offers numerous advantages, such as increased effectiveness, enhanced performance, and the potential for innovative applications. These materials can occur naturally or be engineered at the molecular or nanoscale level by modifying their mechanical, electrical, thermal, optical, and other properties to render them multifunctional. They may also be hybrids combining natural and synthetic components. The integration of various functionalities aims to create materials with unique features or improved performance not achievable with single-function materials. Additionally, this approach enhances system efficiency by reducing the volume and weight of individual components. Multifunctional materials should also be highly application-specific, leveraging their wide range of combinations and resulting characteristics. Multifunctional polymeric materials, with their adaptability and specific properties, find applications across industries, advancing materials science, health-care, electronics, and drug delivery systems.

Chapters 1-3 discuss sustainable approaches to synthesizing multifunctional polymeric materials, such as biopolymers, using enzymatic methods and renewable feedstock, while summarizing their properties, characterization, and applications in biomedical, energy, structural, and environmental fields.

Chapters 4 and 7 explore graphene oxide-based and other nanocomposites in medical domains like drug delivery, tissue engineering, biosensing, and bioimaging, as well as their use in electronics, aerospace, defense, and energy sectors. Chapter 5 highlights multifunctional supramolecular polymers for energy storage, pollution sensors, diagnostics, medicine delivery, hygiene products, and self-repairing materials. Chapter 6 analyzes microbial-based biolubricants, including their industrial feasibility.

Chapters 8-9 provide an overview of polymeric emulsions, their classification, synthesis, and applications in energy and environmental science. Chapter 10 examines nanotechnology-based smart drug delivery systems using carbon nanotubes, quantum dots, silver nanoparticles, and more. Chapter 11 reviews multifunctional materials in engineering and processing applications. Chapter 12 details optical and electronic properties and advancements in multifunctional materials for optoelectronic devices like LEDs, solar cells, and photodetectors.

Chapter 13 describes analytical tools such as XRD, SEM, TEM, FTIR, XPS, DSC, TGA, and AFM for understanding material morphology and structure. Chapter 14 focuses on polysaccharides and their application in solar cells. Chapter 15 highlights the industrial applications of multifunctional biopolymers. Chapters 16-17 cover nanotechnology in agriculture and industrial sectors, including synthesis, properties, and potential applications. Finally, Chapter 18 examines magnetization dynamics of ferromagnetic nanostructures for spintronics and biomedical applications.

The editors are grateful to all of the contributors to this book, and special thanks go to Martin Scrivener and Scrivener Publishing for their support and publication.

The EditorsJanuary 2025

1Multifunctional Polymer Chemistry: Sustainable Synthetic Procedures

Prem Shankar Mishra1*, Rakhi Mishra2, Kabikant Chaurasiya1 and Tanya Gupta1

1Department of Pharmacy, School of Medical and Allied Sciences, Galgotias University, Greater Noida, Uttar Pradesh, India

2Noida Institute of Engineering and Technology (Pharmacy Institute), Greater Noida, Uttar Pradesh, India

Abstract

Naturally occurring polymers such as DNA strands and polypropylene, which are widely used as plastic worldwide, are examples of polymers that surround us. Due to the required performance and poor recycling rates of polymers, there is a continuing demand for virgin polymers; nonetheless, this exacerbates serious challenges associated with the plastics sector, such as waste creation and greenhouse emissions. It is necessary to assess the sustainability effects of bio-based polymers to retain their biodegradation potential while maximizing their utilization in the functional use stage. The several green chemistry-based synthetic techniques used to produce multifunctional polymers are the main subject of this study. This chapter also includes information on the applications, challenges, and future possibilities of multifunctional polymers.

Keywords: Chemoenzymatic, polypropylene, controlled radical polymerization, microbial synthesis

1.1 Introduction

Sustainability is the responsible use of natural resources, preservation of the environment, waste minimization, and avoidance of dangerous materials so that future human generations can continue to live a decent standard of living on Earth (Figure 1.1) [1]. These days, sustainability and green chemistry are the primary strategies due to growing public knowledge of environmental deterioration, climate change, and the earth’s diminishing resources. In order to be achieved by 2030, the United Nations adopted 17 sustainable development goals (SDGs) in 2015. Since polymers are ubiquitous, they are essential to achieving these objectives [2].

Another way to think of sustainability as a business strategy is to maximize the positive effects of an organization on the environment, communities, economy, and society [3].

Figure 1.1 Impact of sustainability on different aspects.

Businesses are starting to see the benefits of sustainability, including increased exposure and lower manufacturing costs, energy use, risks, and dangers [4]. Sustainability can take on a variety of shapes depending on the enterprises involved, such as the following:

The environmentally benign and non-hazardous production of commercial items using resources derived from agriculture.

The use of “natural” components in commercial goods, particularly in applications related to food, cosmetics, and personal hygiene.

The enhancement of existing industrial processes by reduction of non-recyclable plastic usage, reduction of needless byproducts, development of a greener supply chain, and/or reduction of carbon footprint.

Enhancing the environmental, health, and safety aspects of existing product lines through prudent management [

5

,

6

].

Today, disposing of plastic garbage is a major environmental issue since plastics are being produced in large quantities and are being used in more areas of our daily lives [7]. As a result, these problems contribute to the rising threat of the warming planet brought on by carbon dioxide emissions caused by burning conventional, non-biodegradable polymers, such as polyethylene, polypropylene, and polyvinyl chloride [8].

Polymers can be divided into two categories: natural polymers and synthetic polymers.

Biocatalysts, often enzymes, are invariably engaged in in vivo processes that produce natural polymers in the natural world. All living things, including humans, animals, and plants, include natural polymers. Among the natural polymers are lignocellulose, starch, protein, DNA, RNA, and polyhydroxyalkanoates (PHAs). Natural polymers often have clearly defined structures, while some, like lignocellulose, are an exception [9].

The most popular way to create synthetic polymers is to polymerize compounds with simple structures derived from petroleum. Synthetic polymer preparation often involves the use of chemical catalysts, particularly metal catalysts. The growth of the petrochemical industry, the simultaneous availability of cheap petroleum oils, the development of well-established and sophisticated polymerization techniques, and the availability of cheap petroleum oils have led to the development of many synthetic polymers, including phenol-formaldehyde resins, polyolefins, polyesters, polyvinyl chloride, polystyrene, and polyamides. Plastics, a broad category of synthetic polymers, gained popularity early in the 20th century and are today widely found in many different items, including textile fibers, films, bags, bottles, and cartons [10].

Biodegradable polymers are materials that, after a short time of use and under controlled circumstances, disintegrate into components that can be readily disposed of [11]. They can be made from a variety of wastes or bioresources, such as food, animal, and agro-waste waste, as well as cellulose and starch, Businesses are concentrating on generating bioplastics produced from renewable resources since they are often more cost-effective than those obtained from microbiological resources [12].

Using biodegradable polymers helps the environment by lowering the emissions of carbon dioxide, which contribute to global warming, promoting biodegradation, and regenerating raw resources [13]. Microorganisms such as bacteria and fungi can ingest bio-degradable polymers, which subsequently undergo degradation into H2O, CO2, and methane. The substance’s composition has an impact on the biodegradation process. Polymer shape, structure, molecular weight, and exposure to radiation and chemicals are some of the elements that affect how quickly a polymer degrades [14].

The market for biodegradable plastics is quite promising. However, as selective bio-waste collection grows, they must be created simultaneously with a comprehensive analysis and worldwide integration with organic waste management and end-of-life treatment techniques. One advantage of biodegradable plastics is that they may be naturally decomposed at the end of their lives through processes like anaerobic digestion or composting. Biodegradable plastic composting is widely acknowledged and well-documented worldwide [14]. This chapter describes multifunctional polymers and the many environmentally friendly synthetic processes that are employed to create them using green chemistry. Details on the uses of multifunctional polymers, as well as their prospects and difficulties, are also included in this chapter.

1.1.1 Multifunctional Polymers

Materials known as polymer composites are created by adding fibers or other appropriate reinforcement to the polymer matrix [15, 16]. These are often described in various ways. The kind of matrix might be either natural or synthetic, depending on the intended use. Synthetic polymers are utilized to provide the matrix for most applications; biopolymers have only recently been employed in this capacity [17]. Fibers, either natural (like coir, bagasse, pine needles, hemp, flax, and sisal) or synthetic (such as carbon and glass), are the most common types of reinforcing materials. Both the polymer matrix and the reinforcement have been found to have a substantial impact on the overall physicochemical properties of the composites [18].

Due to the growing potential for polymer multifunctional application, researchers from many domains have recently focused a great deal of emphasis on two related essential topics: biopolymers and biomaterials (Figure 1.2) [19]. These days, biopolymers are a hot issue because of their prospective uses in the food, pharmaceutical, textile, medical, and other industries as well as in addressing the problems associated with rising environmental contamination [20].

The ecosystem has already suffered greatly from the careless use of easily accessible and reasonably priced synthetic plastic, and these materials are now posing a major danger to all life on Earth [21, 22]. Because synthetic plastic is used so extensively in everyday products, it is becoming a severe hazard to human health. In this regard, bio-based, sustainable, and biodegradable polymers hold great promise as a quick replacement for synthetic polymers generated from petrochemicals. To create bioplastics, a variety of biopolymers, including polysaccharides, proteins, and their mixtures, are frequently employed. The characteristics of biopolymer-based polymers are similar to those of synthetic ones [23, 24].

The addition of functional components such as nanomaterials, essential oils, phytochemicals, and bioactive components further enhances the physical and functional properties of the biopolymer-based materials. It has been demonstrated that one practical way to alter the mechanical characteristics of the polymer matrix is by adding fillers, as well as imparting thermal and electrical conductivity and increasing thermal resistance concerning glass transition and degradation temperatures. While the potential of biomaterials and biopolymers to create sustainable materials is great, there are still several issues that need to be resolved before further development can begin. These materials are more expensive than the ones that are typically used, which limits their application in many industries. To create future materials, a deeper understanding of biopolymers and biomaterials is needed [25–28].

Figure 1.2 Examples of products formed by biodegradable polymers.

However, there has been a significant shift in the production of novel materials made from renewable resources in biorenewables in recent years as a result of increased environmental consciousness, health concerns, and the depletion of petroleum resources [19]. Well-known instances of ecologically friendly polymeric materials derived from biorenewable resources are among the biopolymers are polysaccharides, such as animal protein-based biopolymers, cellulose, alginate, starch, chitin/chitosan, and carbohydrate polymers, like collagen, silk, wool, and gelatin [29, 30]. Numerous industries, most notably the biomedical and automotive sectors, are currently using bio-based materials made from different natural resources. The product has several notable qualities, including biodegradability, low density, recyclability, easy separation, high toughness, superior thermal characteristics, reduced tool wear, non-skin irritation, and enhanced energy recovery are just a few of the many qualities that have made bio-renewable materials a material of choice [31–33].

There is a strong link between the rising number of interdisciplinary studies and the expanding utilization of innovative materials in current technologies [34]. Finding structurally well-defined polymers that surpass the state of the art is an ongoing objective in the case of polymers. To produce multifunctional polymers having two or more orthogonally accessible functions for use in several potential uses, such as gene therapy, tissue engineering, and medication delivery, application-driven research has been focused on these materials [35–37].

1.1.2 Importance of Sustainable Synthetic Procedures in Polymer Chemistry

Natural polymers like starch, cellulose, or chitin can be chemically modified to produce sustainable polymers from renewable resources. Comparing sustainable synthetic techniques to conventional synthetic procedures would result in lower pollution emissions, less water and non-renewable energy use, and a reduction in the synthesis of polymer chemistry. The following is a list of additional advantages provided by using sustainable synthetic processes using polymers:

Environmentally friendly

Lower energy and cost

Toxicity reduction

Efficiency of reactions and economy of atoms [

38

]

Create and learn about new manufacturing techniques, chemicals, and product stewardship procedures

Protection and enhancement of human health [

39

]

1.2 Sustainable Synthetic Procedures for Multifunctional Polymer Synthesis

High levels of environmental sustainability and energy efficiency are promoted by the design, preparation, and use of polymers made using sustainable resources for a variety of cutting-edge applications [40].

Because of this, the need for polymers will only increase along with the number of people on Earth, modernity, and advancements in technology. However, our understanding of the usage of polymers has changed because of the depletion of fossil fuels, the rise in plastic waste production, ocean pollution, and the corresponding increase in greenhouse gas emissions. A linear polymer economy is unsustainable, even if polymers were never intended to be recycled. The design for life-cycle assessments, recycling, and reuse will become more and more crucial components, and this may be accomplished by using a variety of techniques and approaches [41].

1.2.1 Green Chemistry Principles and Their Application to Polymer Synthesis

In polymer synthesis, the green chemistry method (Figure 1.3) aims for sustainability [42]. Herein, usually, (1) utilizing renewable resources as raw ingredients to produce polymers and (2) applying green methodologies for the synthesis of polymers are essential components of green polymer chemistry [43].

Three components are needed to produce polymers using green chemistry: (1) catalysts, solvents, and raw ingredients; (2) environmentally congenial synthesis procedures; and (3) low-carbon, sustainable polymers that can be recycled or disposed of with little harm to the environment include (bio) degradable polymers and others [44]. Below is a discussion of various techniques for creating sustainable biodegradable polymers using the green chemistry concept [45].

The application of ecologically friendly materials and sustainable procedures has been emphasized in the application of green chemistry concepts to polymer synthesis in a variety of ways. Utilizing renewable feedstock, atom economy, and waste reduction are a few of the fundamental tenets of green chemistry. These ideas have been incorporated into the creation of multifunctional polymers, as demonstrated by the production of polymer Nanocomposite materials using environmentally benign thiol-ene chemistry [46].

Figure 1.3 Green chemistry and its principles.

Figure 1.4 Different methods of synthesis under green chemistry.

Furthermore, the 12 green chemistry principles have been particularly examined and applied to the manufacture of polymers, emphasizing their applicability to present procedures and the possibility of sustainable progress in this area [47, 48].

Several of the techniques comprise (Figure 1.4)

Ring-opening polymerization (ROP);

Enzymatic ROP;

Anionic ROP;

Photo-initiated radical polymerization;

Chemo enzymatic method;

Enzymatic polymerization;

ROP; and

Coordinative ring opening polymerization.

1.2.1.1 Ring-Opening Polymerization (ROP)

The word “ROP” refers to the process by which cyclic monomers are polymerized into acyclic monomeric units (Figure 1.1). Here, the cyclic monomer ring system is opened to create a long polymer chain, with the final portion of the polymeric chain functioning as a center of reactivity. There are three recognized propagation centers: cationic, radical, and anionic. This procedure is thought to be among the most adaptable ways to synthesize large amounts of biopolymers [49].

1.2.1.2 Radical Ring-Opening Polymerization

Free radical ROP (FROP) is the progressive incorporation of free radicals as structural elements created by different methods that use distinct initiator chemicals to make polymers. Chain growth is caused by the newly created starting free radicals extending the polymer chain’s monomer units. One of the most flexible types of polymerizations is free radical polymeric chain ends’ (FROP) easy interactions with different substrates or chemicals [50]. Materials based on ε-Caprolactone are synthesized by this approach.

1.2.1.3 Chemo Enzymatic Method of Polymerization

It is widely acknowledged that chemoenzymatic synthesis yields active pharmacological ingredients (AAPIs) (Figure 1.5). Using this technique, researchers have produced a few prodrugs made of polymers that have optical activity. High molecular weight substrates of nonsteroidal anti-inflammatory drugs make up these prodrugs. This process combines traditional polymerization with a very effective enzymatic approach. Chemoenzymatic synthesis is believed to be highly beneficial in producing substantial molecular weight Biodegradable polymeric materials (BPMS). For instance, a chemoenzymatic procedure could be used to create poly lactic acid (PLA) monomer [51].

1.2.1.4 Photo-Initiated Radical Polymerization

The approach known as photo-initiated ROP (Figure 1.6) is intriguing due to its ability to achieve spatiotemporal control over fast polymerization rates under physiological settings. It gets rid of the need to add a hazardous cross-linker to the reaction medium. This more environmentally friendly method is frequently utilized to synthesize the majority of polymers that are frequently employed in biomedical applications [52].

Figure 1.5 Chemo enzymatic polymerization.

Figure 1.6 Photo-initiated ring-opening polymerization.

1.2.1.5 Enzymatic Polymerization

One innovative and environmentally friendly way of producing polymers is the enzymatic synthesis of biodegradable polymers. Biocatalysts with high catalytic activity that are renewable and non-toxic are called enzymes. Compared to traditional synthesis methods, less activation energy is needed when using enzymes to synthesize biodegradable polymers [53]. Even under milder circumstances, biodegradable polymers may be synthesized enzymatically without the usage of metal or hazardous organic pollutants. This broadens the range of domains in which it is applied, particularly in the biomedical sector [54]. For example, using methyl 12HS (12HS-Me), lipase is a catalyst used in the production of novel biodegradable polymers, such as polyester. It is a bio-based thermoplastic elastomer [55].

1.2.1.6 Anionic Ring-Opening Polymerization

Among the sophisticated techniques for creating telechelic polymers with a variety of topologies, including anionic ROP produces hyper branched, linear, star, and core-shell polymers. Because it offers an increased level of conversion of monomers, has no adverse effects, and has adjustable polymerization kinetics, anionic ROP is regarded as among the most beneficial techniques [56].

1.2.1.7 Coordinative Ring-Opening Polymerization

The ester cyclic molecule will be arranged by the metal atom in coordinative ROP. In this instance, the electrophilic catalytic center is the metal atom. For cyclic esters, this coordination insertion process activates the carbonyl group, while for cyclic phosphates, it activates the phosphorus atoms. The initiator, which might be amino, alkoxy, alkyl, etc., forms a direct link with the metal or a weak coordination with it. A reaction complex is formed by the coordination of the two monomers and initiators [57]. Pseudo-anionic ROP is another name for “coordination-insertion” ROP. Via live polymerization, this kind of polymerization will produce polyesters with distinct structures [58].

1.2.1.8 Enzymatic Ring-Opening Polymerization

Lipase is a more often used enzyme in this kind of polymerization. Porcine pancreatic lipase (PPL), pseudomonas cepacia lipase, and Burkholderia cepacia lipase PS are few of the lipase enzymes [59]. Temperature, solvent concentration, and water content are three major influences on the factors of the enzymatic ring opening polymerization synthesis process [60]. For instance, the process of ROP by enzymes is utilized to synthesize high molecular polylactic acid employing Antarctic lipase enzyme from Candida albicans and free enzyme (CALB).

1.2.2 Bio-Based Monomers and Renewable Feedstocks for Polymer Synthesis

Recent efforts have centered on the production of sustainable monomers and polymers, either to replace petroleum-based resources or to build multifunctional polymers, by using the structural variety of various biomass resources [61].

The bio-based monomers are renewable resources that are produced from biomass feed-stock in a clean, energy-efficient method that leaves no harmful residues to contaminate the finished goods. As a result, the creation of green polymers and the prospects for a sustainable polymer sector are made possible by the polymerization of bio-based monomers into renewable polymers. These developments will ultimately be crucial to the realization and upkeep of a sustainable and bio-based society [62, 63].

Biotechnology and processes used in biorefineries are used to provide monomers that are replenishable and polymerized in very efficient traditional gas-or melt-phase polymerization techniques, rather than creating new pathways in biotechnology to produce biopolymers with somewhat laborious purification of polymers and challenging processing property tweaking. Monomers are significantly simpler to purify than polymers. Furthermore, the resultant bio-based polymers combine the benefits of gas-phase and solvent-free melt polymerization methods’ high resource and energy efficiency with a minimal carbon footprint—a characteristic of feedstocks that are renewable. To prevent problems with food production, feedstocks, such as trash from forestry and agriculture, are employed preferentially. Numerous other bio-based monomers may be made through the fermentation of glucose, which is made from lignocelluloses and starch [64].

The use of renewable feedstocks and bio-based monomers in polymer synthesis is growing to lessen the environmental effect of polymer manufacturing and disposal. Among the important ideas and sources are as follows:

1.2.2.1 Renewable Energy Sources

Basic monomers that rely on coal, natural gas, and petroleum as starting materials are now included in the utilization of renewable energy sources in polymer research [65].

1.2.2.2 Feedstocks from Agriculture and Forestry

Feedstocks from agriculture and forestry, such as maize fiber, wheat, and other renewable resources, are the primary raw materials utilized to manufacture bio-based polymers [66, 67].

1.2.2.3 Microbial Synthesis

Using renewable resources, microbial synthesis has been employed to create bio-based monomers and polymers [68].

1.2.2.4 Polymerization of Bio-Based Monomers

Bio-based monomers, specifically 1,3-propanediol, have been used to polymerize bio-based polymers (PDO) [69, 70].

1.2.3 Catalysts and Reaction Conditions for Sustainable Polymerization Processes

Research and development on catalysts and reaction conditions for sustainable polymerization processes has been substantial. One technology that can help in the production of sustainable polymers is catalysis [71].

Many catalytic techniques have been included in green and sustainable chemistry during the past 20 years [72, 73]. The activity, content, and possible environmental effects of catalysts were assessed. The most useful catalysts frequently do away with the need for purification or synthesis stages and can withstand a broad variety of functional groups. In addition to being low in toxicity, desirable catalysts also reduce chemical waste and enable the replacement of dangerous chemicals with safe ones. Catalysts should ideally have long lives and only need small amounts of catalytic loadings [74].

Three major types of enzymes—oxidoreductases, transferases, and hydrolases—among the six primary classes have been used as catalysts in the production of multifunctional polymers. Similar to in vivo enzymatic processes, the proper design of a reaction involving an enzyme catalyst combined with a monomer produces macromolecules with precisely controlled structures. For the ability to select certain substances, including chemo-, regio-, stereo-, and choro-selectives, the reaction regulates the product structure [75].

Vinyl polymerizations and other oxidation polymerizations of aromatic compounds are catalyzed by oxidoreductases. Transferases are useful catalysts that may be used to create polyesters and polysaccharides with different architectures. The cleaving of macromolecules’ bonds in vivo and the in vitro creation of new bonds, resulting in the formation of different polysaccharides and functionalized polyesters, is catalyzed by hydrolases [76]. The initial in vitro synthesis of complex natural polysaccharides such as chondroitin, cellulose, hyaluronan, amylose, xylan, and chitin, was made possible by enzymatic polymerizations. These polymerizations are considered “green” in several ways, including low byproduct production, excellent catalyst efficiency, somewhat selective reactions with renewable starting materials and environmentally friendly solutions, and nontoxicity of the enzymes. To maintain a sustainable civilization, for environmental reasons and “green polymer chemistry,” enzymatic polymerization is therefore beneficial [44].

1.3 Functionalization of Multifunctional Polymers

Many upcoming uses of polymeric materials need the design and production of multifunctionalized, structurally controlled polymers [77]. Multifunctional polymers may be made more unique by adding particular chemical groups to their structure, a process known as functionalization. Because of this modification, the polymers can acquire new characteristics or improve their current ones, which makes them beneficial for a variety of uses [78, 79]. As an illustration, atom transfer radical polymerization (ATRP) was applied to produce low molecular weight star, hyperbranched, and linear polymers (methyl acrylate). Radical addition processes were then used to end-functionalize the polymers. By adding allyl tri-n-butyl stannane at the end of the polymerization process, allyl groups were added to the polymer (methyl acrylate). Allyl alcohol or monomers of 1,2-epoxy-5-hexene that cannot be polymerized by ATRP, were introduced with high acrylate monomer conversion rates, and at the polymer chain terminus, the functionalities of epoxy and alcohol were present., respectively [80].

Different approaches for functionalization of multifunctional polymers are as follows:

Post-polymerization functionalization: This method entails modifying polymers to add particular functional groups after they are synthesized. In a group of uniform dispersity and molecular weight, it permits the adjustment of both physical and optoelectronic characteristics [81].

Polymerization-Induced Self-Assembly (PISA): Multifunctional polymersomes have been prepared using PISA, making it simple to create functionalized polymers with certain features [82].

Click Chemistry: A ubiquitous and simple method for creating multifunctional polymers that enable the controlled insertion of several functional groups is click chemistry [83].

Reactive handles may be easily introduced by using the Ugi reaction as a multifaceted click response to effectively create several multipurpose polymers by cross-synthesizing them or further functionalizing existing ones [84].

1.3.1 Sustainable Functionalization Reactions for Multifunctional Polymers

To create multifunctional polymers, several sustainable functionalization processes have been created. These processes emphasize the application of ecologically friendly materials as well as green chemistry concepts. For instance, a green approach method utilizing environmentally friendly thiol-ene chemistry has been developed for the production of multi-functional polymer nanocomposite material [85].

Several techniques, like the chemistry of clicks, sequential post-polymerization modification, and controlled radical polymerization (CRP) processes, can be used to create multifunctional polymer synthesis reactions. The following are some essential processes and reactions for the production of multifunctional polymers [47, 86–89].

1.3.1.1 Controlled Radical Polymerization (CRP) Reactions

For the production of multifunctional polymers, CRP is an effective tool. There is a great deal of promise for the creation of multifunctional polymers when click chemistry and CRP reactions are combined.

1.3.1.2 Ugi Reaction

Several multifunctional PEGylation polymers have been effectively synthesized using the Ugi reaction as a multicomponent click reaction [69].

1.3.1.3 Sequential Post-Polymerization Modification

Using this method, polymers having monomer units that have hidden functions are modified sequentially and selectively after polymerization to create multifunctional homopolymers.

1.3.1.4 Polymerization-Induced Self-Assembly

Multifunctional polymersomes, which are vesicles with special qualities and uses, have been created using this technique.

1.3.1.5 Green Route Strategy

Using environmentally friendly thiol-ene chemistry, a green approach method for the production of multifunctional polymer nanocomposite material has been developed.

Succinic acid (SuA), for instance, is a significant bio-based aliphatic acid monomer. It is an odorless, white substance that dissolves in acetone, ethanol, and water. The US Food and Drug Administration (FDA) has approved the use of glycerol and SuA for medical purposes and recognizes them as safe materials. When combined, these two naturally occurring substances provide a cheap and plentiful source of starting materials for the production of dendrimers [90].

PGSuc dendrimers were synthesized, according to Carnahan et al., using the acetal of benzylidene as a protective group that, in some situations, can be removed selectively (Figure 1.7). It was discovered that these PGSuc oligomers were easily chemically degradable, quickly biodegradable, and non-ecotoxic [91].

PGSus dendritic formations have been used to repair corneal ulcers, as described by Luman et al. [92]. Other researchers have looked into their potential utility as transporters of tiny compounds, such as medications or dyes. An effective and high-yield divergent technique [93] was used to synthesize newly developed poly(glycerol succinate)-poly (ethylene glycol) composite dendritic-linear copolymers, which are made up of PEG dendritic blocks and polyethylene glycol (PEG) linear chains (Figure 1.8).

The possible methods for synthesizing bio-polypropylene from propylene were converted from methanol or ethanol with ZSM-5 catalysts. Engineered thermoplastics (ETP) and metaproterenol (MTP) conversions have the capacity to be sustainable bio-propylene sources given the abundance given the previously mentioned study on bio-EtOH generation and the studies currently available on bio-methanol (bio-MeOH) production [94–97].

Figure 1.7 General synthesis of glycerol polyesters.

Figure 1.8 Synthesis of poly(glycerol succinate)-poly(ethylene glycol) hybrid dendritic-linear copolymers.

Figure 1.9 Pyrolysis of biomass.

As a result of biomass pyrolysis producing a complicated mixture that contains propylene, catalytic pyrolysis of biomass (Figure 1.9) offers another viable pathway to produce bio-propylene [64, 65]. Quick pyrolysis and conversion of pyrolysis vapors are the two stages of the two-step process of pyrolyzing biomass, certain catalysts, such as calcium oxide and ZSM-5 have been researched [98]. The most studied method uses dimerization, metathesis, and dehydration of bioethanol to produce bio-propylene. As of right now, it seems possible to synthesize polypropylene using bio-propylene as the monomer input [99].

1.4 Applications of Multifunctional Polymers

Multifunctional polymers have a variety of uses because of their special qualities and the ability to tailor their functionalities. Some of the most promising applications of multifunctional polymers include:

1.4.1 Biomedical Applications

Multifunctional polymeric nanocarriers have been studied for their potential in nanomedicine, where they may improve the pharmacokinetics, bioavailability, and effectiveness of certain drugs or contrast agents. It is possible to make these nanocarriers biocompatible and safe for patients to use while administering a range of medications, such as chemotherapy and immunotherapy [100].

1.4.2 Sensors and Actuators

The ability of multifunctional polymers to respond to different stimuli, such as light, pH, and temperature, makes them valuable for the creation of sensors and actuators. These substances can be engineered to identify certain analytes or to respond upon detection of a given stimulus [101].

1.4.3 Energy Applications

Multifunctional polymers can be applied to energy-related devices like batteries and super-capacitors and solar cells. These materials’ design may improve the effectiveness of energy conversion and storage devices [102].

1.4.4 Environmental Applications

Environmental uses for multifunctional polymers include pollution removal and water treatment. These materials can be designed to boost the efficiency of wastewater treatment processes or to degrade or absorb contaminants [103].

1.4.5 Structural Applications

Multifunctional polymers can be used to create novel materials with enhanced electrical, thermal, and mechanical qualities. These materials can be applied to the construction, automotive, and aerospace sectors, among others, to increase the lifetime and performance of structures [104].

There are a multitude of potential applications for multifunctional polymers across several industries and enterprises. The advancement of environmentally friendly and sustainable synthesis techniques has further expanded the potential of multifunctional polymers for wider use [

105

].

Other examples of multifunctional polymers with their applications are shown in Table 1.1.

1.5 Future Perspectives and Challenges

Although there are many possible uses for multifunctional polymers, there are a few issues that must be resolved. Developing environmentally friendly and sustainable processes for the synthesis of multifunctional polymers is one of the primary problems [117]. Considering the rise in emphasis on the circular economy and the need to move away from single-use disposable items, this is especially crucial.

Enhancing the biodegradability or recyclable nature of multifunctional polymers presents another difficulty. Although high polymers are typically thought of as being inherently non-toxic, the desire to create polymers that are readily recycled or biodegraded is developing [118].

Multifunctional polymers have several potential prospects despite these obstacles. The creation of multifunctional biodegradable polymers, for example, that may be used for a range of biological applications is gaining attention [119].

Table 1.1 Examples of multifunctional polymers with their applications [39, 106–116].

S. no.

Multifunctional polymer

Example

Application

1.

Sodium carboxymethyl cellulose (CMC)

Used in tissue engineering and medication delivery systems

Biomedical field. Paper, personal care/cosmetic, food, pharmaceutical, and other sectors.

2.

Nanocomposites

Nanocomposites for mechanical, tribological, and fire-protection applications

Applications in tribology, mechanics, fire safety, and the aerospace and automotive industries.

3.

Polymer composites

Various applications in several fields include bioengineering, automobile production, space exploration, and the development of organic solar cells

Bioengineering, automobile production, organic solar cell development, and space exploration.

4.

Lipase-catalyzed polyester

Bio-based thermoplastic elastomers

Biomedical field. Successfully used for the synthesis of polyamides derived from renewable plant oils.

5.

PCL-PEG co-polymers

Biomedical applications

Biomedical field. Preparation of hydrogels for drug encapsulation and drug delivery.

6.

Fluorescent polymer nanomaterials

Water-soluble and biocompatible fluorescent polymer nanomaterials

Biomedical field. Bioimaging, biodetection, cancer therapy, and medical imaging modalities.

1.5.1 Current Limitations and Challenges in Sustainable Multifunctional Polymer Chemistry

Current limitations and challenges in sustainable multifunctional polymer chemistry include the following.

1.5.1.1 Lack of Standardized Methods

Standardized procedures are required for the synthesis and characterization of multifunctional, sustainable polymers to promote uniformity and repeatability in the scientific community [120].

1.5.1.2 Limited Availability of Renewable Feedstocks

A limiting issue in the synthesis of sustainable multifunctional polymers may be the cost and availability of renewable feedstocks. Because of this, increasing the production of these materials may be challenging [120].

1.5.1.3 Environmental Impact

Multifunctional polymer manufacture and disposal can have a substantial negative influence on the environment. It is necessary to create environmentally friendly and sustainable processes for the production of multipurpose polymers in addition to plans for the appropriate utilization and elimination of these materials [121].

1.5.1.4 Performance Limitations

Since sustainable multifunctional polymers cannot always operate to the same standards as conventional polymers, this could be a restriction. This may restrict their uses and make it more challenging for them to compete with well-established materials [122].

1.5.1.5 Cost

The price of creating multifunctional, sustainable polymers may be a major barrier. This may restrict these materials’ economic viability and make it challenging to scale up manufacturing [122].

1.6 Conclusion

Since their invention more than a century ago, polymers have significantly enhanced human well-being and are now essential to modern living and cutting-edge technology. They make advanced technology accessible to all people because of their intense energy-, economical and ecological, and resource-efficient manufacturing techniques, ease of processing, great adaptability regarding adjustable features, and an extensive range of uses. The world is currently moving away from an energy system reliant on fossil fuels and toward one that is powered by more sustainable and renewable resources.

An increasing number of people are interested in renewable polymer-based ecologically friendly products due to escalating environmental concerns and the exhaustion of petroleum-based materials. Throughout their life cycle, sustainable polymers also show a decreased influence on the environment. By decreasing the manufacture and using virgin plastics made from limited supplies, the creation of environmentally friendly polymers will hasten the age of eco-friendly polymers and bring about a fully circular plastics economy.

Many biopolymers made from transgenic plants or bacteria were not economically viable in the past due to their inadequate qualities and relatively low processability. Because biosynthesis requires such great accuracy, it might be challenging to modify their molecular structures to meet the requirements of polymer molding. Given the extremely quick cycle periods in injection molding, many biopolymers—like polyhydroxybutyrate, for example—crystallize too slowly. While commercial polymers require far more adaptable molar mass distributions with regulated branches on both short and long chains in addition to the ability for self-nucleation during the crystallization of polymers, all polymers in nature have equal chain lengths.

An additional issue with most synthetic polymers in biotechnology is the time-consuming task of extracting biopolymers that are produced as byproducts from cell proteins.