Bio-Based Polymers and Composites

Richard Wool, Xiuzhi Susan Sun

• Verlag: Academic Press
• Jahr: 2011
• ISBN:
  9780080454344
• Thema: Technology & Engineering
• Thema: Materials Science

Bio-Based Polymers and Composites is the first book systematically describing the green engineering, chemistry and manufacture of biobased polymers and composites derived from plants. This book gives a thorough introduction to bio-based material resources, availability, sustainability, biobased polymer formation, extraction and refining technologies, and the need for integrated research and multi-disciplinary working teams. It provides an in-depth description of adhesives, resins, plastics, and composites derived from plant oils, proteins, starches, and natural fibers in terms of structures, properties, manufacturing, and product performance. This is an excellent book for scientists, engineers, graduate students and industrial researchers in the field of bio-based materials.* First book describing the utilization of crops to make high performance plastics, adhesives, and composites
* Interdisciplinary approach to the subject, integrating genetic engineering, plant science, food science, chemistry, physics, nano-technology, and composite manufacturing.
* Explains how to make green materials at low cost from soyoil, proteins, starch, natural fibers, recycled newspapers, chicken feathers and waste agricultural by-products.

1

OVERVIEW OF PLANT POLYMERS: RESOURCES, DEMANDS, AND SUSTAINABILITY

Xiuzhi Susan Sun

Publisher Summary

Renewable biomaterials that can be used for both bioenergy and bioproducts are a possible alternative to petroleum-based and synthetic products, which are unsustainable and contribute to pollution. This chapter provides an overview of biomass resources and the basics of plant-derived polymers and sustainability issues. It provides an introduction to biomass feedstock processing along with the development of plant materials synthesis and formation, especially with protein, starch polymers, and oils. Plant protein, oil, starch, and cellulosic materials are all important platforms for bioproduct applications. Lignin from cellulosic-based biomass should also be utilized for biofuels and bioproducts. Agricultural commodities typically cannot be used as they appear in nature. They need to be converted into functional polymers and materials by various technologies, including chemical reactions, fermentation, and modifications. The chapter describes the methods used for the modifications of agricultural fibers and cellulose, plant starches, plant oils, and plant proteins for different industrial uses. Durability, compatibility, affordability, and sustainability are the challenges of converting renewable resources into industrial materials. The design of bio-based materials should favor increased materials supplements, optimized land use, improved plant biodiversity, minimized environmental pollution, and improved energy efficiency while at the same time meeting consumer demands.

Advances in petroleum-based fuels and polymers have benefited mankind in numerous ways. Petroleum-based plastics can be disposable and highly durable, depending on their composition and specific application. However, petroleum resources are finite, and prices are likely to continue to rise in the future. In addition, global warming, caused in part by carbon dioxide released by the process of fossil fuel combustion, has become an increasingly important problem, and the disposal of items made of petroleum-based plastics, such as fast-food utensils, packaging containers, and trash bags, also creates an environmental problem. Petroleum-based or synthetic solvents and chemicals are also contributing to poor air quality. It is necessary to find new ways to secure sustainable world development. Renewable biomaterials that can be used for both bioenergy and bioproducts are a possible alternative to petroleum-based and synthetic products.

Agriculture offers a broad range of commodities, including forest, plant/crop, farm, and marine animals, that have many uses. Plant-based materials have been used traditionally for food and feed and are increasingly being used in pharmaceuticals and nutraceuticals. Industrial use of agricultural commodities for fuels and consumer products began in the 1920s, but they were soon replaced by petroleum-based chemicals after World War II because of petrochemicals’ low cost and durability. This chapter focuses on bio-based polymers derived from plant-based renewable resources, their market potential, and the sustainability of the agriculture industry of the future.

The three major plant-based polymers are protein, oil, and carbohydrates. Starch and cellulose, also called polysaccharides, are the main naturally occurring polymers in the large carbohydrate family. Agricultural fiber is also a member of the carbohydrate family. Natural fiber such as flax, hemp, straw, kenaf, jute, and cellulose consists mainly of cellulose, hemicellulose, and lignin, but is usually listed as a material when used as a fiber in composites, as discussed in Chapters 5 and 13.

Corn, soybean, wheat, and sorghum are the four major crops grown in the United States (Table 1.1), with total annual production of about 400 million metric tons (800 billion pounds) in the year 2000. Annually, 10–15% of these grains are used for food, 40–50% for feeds, and the rest could be for various industrial uses. Based on U.S. Department of Agriculture statistics, the total land used for crops is about 455 million acres, which is about 20% of the total usable land (Figure 1.1) [1]. Including other crops, such as rice, barley, peanuts, and canola, the United States has the potential to produce about 550 million metric tons of grains and legumes. At least 150 million metric tons of grains and legumes are available for nonfood industrial uses. In general, seeds make up about 45–52% of the dry mass of a plant. This means that there is the potential to produce about 400 million metric dry tons of cellulosic sugar-based biomass (agriculture fiber residues) annually in the United States alone based on the total production of corn, soybean, wheat, and sorghum. Including other crops, plants, and forest products, the total annual U.S. production of cellulosic sugar...