Sustainable Bio-Composites from Renewable Resources: Opportunities and Challenges in the Green Materials World A. K. Mohanty,1,2 M. Misra,1 and L. T. Drzal 1
Sustainability, industrial ecology, eco-efficiency, and green chemistry are guiding the development of the next generation of materials, products, and processes. Biodegradable plastics and bio-based polymer products based on annually renewable agricultural and biomass feedstock can form the basis for a portfolio of sustainable, eco-efficient products that can compete and capture markets currently dominated by products based exclusively on petroleum feedstock. Natural/Biofiber composites (Bio-Composites) are emerging as a viable alternative to glass fiber reinforced composites especially in automotive and building product applications. The combination of biofibers such as kenaf, hemp, flax, jute, henequen, pineapple leaf fiber, and sisal with polymer matrices from both nonrenewable and renewable resources to produce composite materials that are competitive with synthetic composites requires special attention, i.e., biofiber–matrix interface and novel processing. Natural fiber–reinforced polypropylene composites have attained commercial attraction in automotive industries. Natural fiber—polypropylene or natural fiber—polyester composites are not sufficiently eco-friendly because of the petroleum-based source and the nonbiodegradable nature of the polymer matrix. Using natural fibers with polymers based on renewable resources will allow many environmental issues to be solved. By embedding biofibers with renewable resource–based biopolymers such as cellulosic plastics; polylactides; starch plastics; polyhydroxyalkanoates (bacterial polyesters); and soy-based plastics, the so-called green bio-composites are continuously being developed. KEY WORDS: Sustainable bio-composites; natural fiber; bioplastic; cellulosic plastic; polylactides; polyhydroxyalkanoates; soybean-based plastic; fiber-matrix interface.
INTRODUCTION AND BACKGROUND There is a growing urgency to develop novel biobased products and other innovative technologies that can unhook widespread dependence on fossil fuel. Simply stated, bio-based materials include industrial products, but not food or feed, made from renewable agricultural and forestry feed stocks, including wood, wood wastes and residues, grasses, crops, and crops by-products. 1
Composite Materials and Structures Center, Michigan State University, 2100 Engineering Building, East Lansing, Michigan 48824. 2 To whom all correspondence should be addressed. Tel: 1-517-3535466; E-mail: firstname.lastname@example.org
Renewable, recyclable, sustainable, triggered biodegradable—all can make a difference in the environment today and tomorrow. The Technology Road Map for Plant/Cropbased Renewable Resources 2020, sponsored by the U.S. Department of Energy (DOE), has targeted to achieve 10% of basic chemical building blocks arising from plantderived renewable sources by 2020, with development concepts in place by then to achieve a further increase to 50% by 2050. The U.S. agricultural, forestry, life sciences, and chemical communities have developed a strategic vision  for using crops, trees, and agricultural residues to manufacture industrial products, and have identified major barriers  to its implementation.
1566-2543/02/0400-0019/0 2002 Plenum Publishing Corporation
Mohanty, Misra, and Drzal
Fig. 1. Concept of “sustainable” bio-based product.
Fig. 2. Carbon dioxide sequestration.
Eco-friendly bio-composites from plant-derived fiber (natural/biofiber) and crop-derived plastics (bioplastic) are novel materials of the twenty-first century and would be of great importance to the materials world, not only as a solution to growing environmental threat but also as a solution to the uncertainty of petroleum supply [3, 4]. Biopolymers are now moving...