Unlike many biopolymer products being developed and marketed, very few biode­gradable composites have been developed, with most of their technologies still in the research and development stages. This is despite the fact that the environmen­tally friendly composites, where biodegradability is important, provide designers new alternatives to meet challenging requirements. These include aquatic and ter­restrial environments, municipal solid waste management and compostable packag­ing, while those for automobiles include parcel shelves, door panels, instrument panels, armrests, headrests and seat shells. Accordingly, a wide range of biodegrad­able products have been produced using LC fibers and biopolymers for different applications, ranging from automotive vehicles including trucks, construction (hur­ricane resistant housing and structures, especially in the USA) and insulation pan­els, to special textiles (geotextiles and nonwoven textiles).122 The hurricane resistant housing, structures and a variety of products developed using soy oil with LC fi­bers could be the predecessor for diverse range of applications for the biodegrad­able composites. Other identified uses for these materials include bathtubs, archery bows, golf clubs and boat hulls. This is further underlined with the estimated global market of about 900,000 metric tons of wood plastics and natural fiber composites as per Steven Van Kourteren, Consultant, Principia Partners.123 Hence the market for biodegradable composites can be expected to grow in the future. This is based on continued technical innovations, identification of new applications, persistent political and environmental pressures, and investments mostly by governments in new methods for fiber harvesting and processing of natural fibers.124125

17.2 CONCLUDING REMARKS

Renewable resources based products finding privilege particularly because of envi­ronmental friendliness and dwindling petroleum resources. Biopolymers reinforced

with natural fibers have developed significantly over the past two decades because of their significant processing advantages, biodegradability, low cost, low relative density, high specific strength and renewable nature. These composites are preor­dained to find more and more application in the near future. Interfacial adhesion between natural fibers and matrix will remain the key issue in terms of overall per­formance, since it dictates the final properties of the biocomposites. Research on biodegradable polymer and its composites has been very impressive due to their environmental friendliness, carbon dioxide sequestration, sustainability, nontoxicity and varieties of other reasons. The potential areas of applications for these compos­ites are packaging, structural, transportation and automotive, agriculture and various consumer products. The market scenario has been changing continuously due to the development of newer biodegradable polymers, processing techniques and imposi­tion of stringent environmental laws. Raw materials, processing techniques and ap­plication of biocomposites have been studied and well documented in recent years. Still there are lot of issues need to be addressed for further improvement pertaining to those above areas.

One of such issue is the nonavailability of quality fiber used as reinforcing agent in the composites. The production of quality fiber may be obtained through better cultivation, which includes the use of generic engineering. Exploration of nontra­ditional fiber as a source of reinforcing agent is another important area. In order to achieve proper reinforcement, the introduction of hybrid nanocomposite may be at­tempted. The processibility and development of new biodegradable polymers with much improved properties in terms of moisture resistance, mechanical strength, thermal stability and biodegradability are some of the areas which require much attention. The variation of properties along with the high cost of the bio-composites prevents their uses in various application sectors. The possibility of using high per­centage of reinforcing fiber may be tried in order to achieve a reduction in cost. Therefore, the requirement of improving interfacial interaction between reinforcing agent, filler and matrix is another critical area to be looked upon. The develop­ment of newer processing tools at lower temperature is another important aspect that needs to address.

The introduction of nanomaterials in the biocomposites is one of the effective ways to enhance the properties. Research effort should be directed towards develop­ment of nanowhiskers and nanofibers from different lignocellulosic materials and their inclusion in biocomposites for improving various properties. Efforts may also be required to derive resin, reinforcing agent and coupling agent from renewable resources. Efforts may be directed towards searching for new and improved bio­resin, fiber with better properties or new composite manufacturing technology to meet with the future environmental goals. The concept of biodegradability should be directed to ‘triggered’ biodegradability.

The price of biodegradable polymers for making composites is expected to re­duce further in the coming years due to development of raw material, manufacturing techniques and hence it may be considered as a valid alternative to conventional composites. It is also envisaged that further research and development on biode­gradable composite may lead to open up new avenues to meet the local as well as global challenges and thus may expand the horizon of applications.

[1]1 Coefficient of thermal expansion (CTE) between (Tg — 35)°C and (Tg -10)°C. *2 Coefficient of thermal expansion (CTE) between (Tg + 10)°C and (Tg + 35)°C.