In the material science and engineering world, most researchers often refer to pivotal eras in human history by the materials that dominated them—most notably, starting from the Stone Age, then Bronze Age, and the Iron Age. All these periods lasted for a long period of time. Since two centuries ago, the development of cement (1824), carbon fiber (1879), fiber glass (1938), Polyester (1941), and the discovery of nanostructural materials, like the fullerence molecule (1985) and carbon nanotubes (1991), has revolutionized new research focuses on designing new structural materials with better properties and qualities, for different kinds of engineering applications. However, due to the shortage of natural resources, such as fossil fuels, many countries have been striving for better alternatives to use renewable resources for new material development and energy harvesting.
Over the past decade, many studies have been done to look at the possibilities of using natural materials, such as plant-based or animal-based fibers to mix with different types of soft materials to form a new class of biocomposites. The term of “biocomposite” refers to a material which is formed by a matrix and a reinforcement of natural fiber. The matrix can be a polymeric or cementitious material depending on applications. The fiber normally plays a role in taking load while the matrix protects the fiber by holding them together, avoiding environmental degradation, and maintaining the shape of resultant structures. The major purpose of biocomposites is to ensure that the new materials are either recyclable or biodegradable after disposal. The resin is also made of renewable resources, to allow a new composite to be degraded naturally, without the need for extra chemicals or energy to decompose it.
Common types of plant-based fibers are crop fibers which are extracted from cotton, flax, hemp, sisal, or regenerated cellulose materials. Biocomposites made by plant-based fiber are commonly seen in automobile, construction, and some interior components inside aircraft or railway coaches. In fact, plant-based fiber has been commonly used since ancient times; e.g., straw was added into mud to make a wall for a house. Animal-based fibers, commonly extracted from spiders, silkworm cocoons, chicken feathers, and even human hair, have also demonstrated their effectiveness of reinforcing biocompatible and bioresorbable polymers for implant applications. As the major content of these fibers is protein, it is suitable to be mixed with bioresorbable polymers for temporary reinforcing elements used inside the human body.
In view of the importance of this field, this book collects comprehensive information about the development of natural fiber-reinforced biodegradable polymer composites. It contains a total of 9 chapters, which cover a wide range of studies and applications of natural fiber-reinforced biodegradable or bioresorbable polymer composites.
Chapter 1, Natural fiber-reinforced polymer-based composites, gives an overview of recent development of natural fiber-reinforced polymer materials. Different types of fiber and their potential applications are introduced. The effectiveness of using silk-based bioresorble polymer composite for stem cell growth is also discussed.
Chapter 2, Particleboards from agricultural lignocellulosics and biodegradable polymers prepared with raw materials from natural resources, introduces the use of agriculture wastes, mainly extracted particles from wood to mix with polymer to form a new class of composites. The recent development of wood/polymer composites is discussed in the chapter. Production processes with the consideration of cost factors and consumption rate are also analyzed.
Chapter 3, Green composites made from cellulose nanofibers and bio-based epoxy: processing, performance, and applications, provides an overview of cellulose nanofibers (CNFs)-reinforced polymer composites. CNFs are bio-based nanostructures with remarkably high mechanical properties as compared with other natural fibers. Their manufacturing process and the properties of composites are also introduced.
Chapter 4, Biodegradable fiber-reinforced polymer composites for construction applications, discusses the importance of fiber surface treatment, which can enhance the bonding strength and, thus, the overall mechanical properties of natural fiber-reinforced polymer composites. The Pine bleached fiber (PBF) content for its optimal mechanical properties in Polylactic acid (PLA) matrix environment is discussed.
Chapter 5, Bleached kraft softwood fibers reinforced polylactic acid composites, tensile and flexural strengths, presents the use of natural polymer in the construction industry to make bricks, blocks, and panels. Biodegradable polymers were used to stabilize a natural fiber-reinforced soil material. Several experimental tests showed that the mechanical properties of soil material were improved substantially. Microscopic images also showed that a good bonding between the natural fiber and matrix was achieved, which governed the success of stress transfer in the material.
Chapter 6, Silk for sustainable composites, describes the potentiality of using silk fiber for bio-based composite materials. This fiber can be used for making biodegradable polymer composites for different engineering applications. The structure of cocoon silk fibers and their properties are discussed. The mechanical properties of a new type of silk-reinforced biofoam is also introduced.
Chapter 7, Effects of cellulose nanowhiskers preparation methods on the properties of hybrid montmorillonite/cellulose nanowhiskers reinforced polylactic acid nanocomposites, investigates the manufacturing process and mechanical properties of montmorillonite/cellulose nanowhisker-reinforced biodegradable polymer composites. Both nanowhisker and montmorillonite are nanostructural fillers that can be used to enhance the properties of polymers. This chapter provides a comprehensive view on how to produce the composites and their potential applications.
Chapter 8, Bio-based resins for fiber-reinforced polymer composites, gives a comprehensive view on different types of bioresins that can be used to make biocomposites. These resins are extracted from renewable natural resources. The structures of different biomass are described and analyzed on their usefulness and applications.
Chapter 9, Processing of lignocellulosic fiber-reinforced biodegradable composites, discusses the properties and production processes of lignocellulose fiber- reinforced biopolymers. The comparison of different types of lignocellulosic fiber with synthetic fibers, such as carbon and glass fibers, is given. These fibers are very sensitive to processing temperature and their applications are highly restricted by the production process.
The editor would like to express his sincere appreciation and thanks to all the authors and coauthors for their scientific contribution to this book. I also applaud Elsevier for their support and encouragement for arranging and editing this book, and their staff for their special attention and timely response.
Alan Kin-tak Lau
Swinburne University of Technology, Melbourne, VIC, Australia
This page intentionally left blank