The Chemistry of Bio-based Polymers

Johannes Karl Fink

• Publisher: Wiley-Scrivener
• Year: 2019
• Print ISBN: 9781119681311
• eBook ISBN: 9781119681267
• Edition: 2
• Topic: Technology & Engineering
• Subtopic: Chemical & Biochemical Engineering
• Index: Technology & Engineering

The recent explosion of interdisciplinary research has fragmented the knowledge base surrounding renewable polymers. The Chemistry of Bio-based Polymers, 2nd edition brings together, in one volume, the research and work of Professor Johannes Fink, focusing on biopolymers that can be synthesized from renewable polymers. After introducing general aspects of the field, the book's subsequent chapters examine the chemistry of biodegradable polymeric types sorted by their chemical compounds, including the synthesis of low molecular compounds. Various categories of biopolymers are detailed including vinyl-based polymers, acid and lactone polymers, ester and amide polymers, carbohydrate-related polymers and others. Procedures for the preparation of biopolymers and biodegradable nanocomposites are arranged by chemical methods and in vitro biological methods, with discussion of the issue of "plastics from bacteria."

The factors influencing the degradation and biodegradation of polymers used in food packaging, exposed to various environments, are detailed at length. The book covers the medical applications of bio-based polymers, concentrating on controlled drug delivery, temporary prostheses, and scaffolds for tissue engineering. Professor Fink also addresses renewable resources for fabricating biofuels and argues for localized biorefineries, as biomass feedstocks are more efficiently handled locally.

1
An Overview of Methods and Standards

Biocomposites are considered the next-generation materials as they can be made using natural/green ingredients to offer sustainability, eco-efficiency, and green chemistry (1–3). Nowadays, biocomposites are being utilized by numerous sectors, which include automobile, biomedical, energy, toys, sports, and others.

An effort has been made to provide a comprehensive assessment of the available green composites and their commonly used in order to make materials capable of meeting present and future demands. Various types of natural fibers have been investigated with polymer matrixes for the production of composite materials that are on par with the synthetic fiber composite. Also, the requirements for green composites in various applications from the viewpoint of variability of fibers available and their processing techniques have been detailed (4).

1.1 History of Biodegradable Plastics

In the late 1980s, biodegradable plastics came into use. However, these came to be misapplied in a number of situations. The misapplication of inappropriate or incompletely developed technology led to products which often did not meet performance claims and expectations. The so-called first generation technologies often lacked one or more of the following issues (5):

• Rate or extent of biodegradation, primarily due to limitations of starch incorporation,
• Necessary physical properties and related characteristics
• An economical means to effectively and efficiently manufacture starch-based blends,
• Intermediate product compatibility with conventional plastics product conversion processes, and
• Lower limits on film thickness caused by the use of non-gelatinized starch materials.

The synthesis, processing, and technology of renewable polymers has been reviewed (6–27). Furthermore, the state-of-the-art for food packaging applications has been reviewed (28–32). Using biomass for the production of new polymers can have both economic and environmental benefits (33).

Biomass-derived monomers can be classified into four major categories according to their natural resource origins (34):

1. Oxygen-rich monomers including carboxylic acids, e.g., lactic acid succinic acid, itaconic acid, and levulinic acid, but also ethers, such as furan,
2. Hydrocarbon-rich monomers including vegetable oils, fatty acids, terpenes, terpenoids and resin acids,
3. Hydrocarbon monomers, i.e., bio-olefins, and
4. Non-hydrocarbon monomers such as carbon dioxide.

Carbon dioxide is an interesting synthetic feedstock, which can be copolymerized with heterocycles such as epoxides, aziridines, and episulfides. In 1969, Inoue reported the zinc catalyzed sequential copolymerization of carbon dioxide and epoxides as a new route to poly(carbonate)s (9, 35). The reaction is shown in Figure 1.1.

Figure 1.1 Reaction of carbon dioxide with epoxides (35).

Plants produce a wide range of biopolymers for purposes such as maintenance of structural integrity, carbon storage, and defense against pathogens as well as desiccation. Several of these natural polymers can be used by humans as food and materials, and increasingly as an energy carrier. Plant biopolymers can also be used as materials in certain bulk applications such as plastics and elastomers (36).

Lignin, suberin, vegetable oils, tannins, natural monomers like terpenes, and monomers derived from sugars are typically natural precursors for bio-based industrial polymers. Glycerol and ethanol also play a potential role as future precursors to monomers (37).

1.2 Green Chemistry

The principles and concepts of green chemistry are the subjects of several monographs (38–47). Recent progress in enzyme-driven green syntheses of industrially important molecules has been summarized (48). Studies in biotechnological production of pharmaceuticals, flavors, fragrance and cosmetics, fine chemicals, as well as polymeric materials (49) have been documented. Biocatalysis is a transformational technology uniquely suited to delivering green chemistry solutions for safer, efficient, and more cost-effective chemical synthesis.

The different catalytic processes for the conver...

Table of contents

• Cover
• Table of Contents
• Preface
• 1 An Overview of Methods and Standards
• PART I: BIO-BASED POLYMERS DEGRADATION AND CHEMISTRY
• PART II: APPLICATIONS
• Index
• Also of Interest
• End User License Agreement