Advantages And Disadvantages Of Starch

Over past many decades the polymers and their composite materials have become integral components of human life. One cannot imagine a life without these materials. They have received so much attention and acceptance among public and industry alike because of their high aspect ratio. They can offer good mechanical, thermal, flame retardant, insulating, conducting and corrosion resistant properties with appreciable reduction in weight compared to metals and alloys. More over these properties can be engineered into these materials as per the requirement. Their utility includes agriculture, aerospace, automobile, construction, sports, domestic and many more. Increase in population and industrial growth have resulted in the increased production

Starch, a naturally renewable carbohydrate polymer, is the majorly used raw material to produce biodegradable plastics due to its low-cost and ready availability [Babu et al., 2013; Kalambur and Rivzi, 2006]. Investigation, to find its potential utility in aqua-soluble pouches to store detergents and insecticides, have been carried out along with other studies, to use them in flushable liners, bags and medical delivery systems and devices [Fishman et al., 2000]. Amylose (linear molecule with few branches) and amylopectin (branched chain molecule) are the constituents of starch. The presence of amylose in major quantity in starch gives strength to films when it is processed. The tensile stress of films is found to decrease when the amylopectin content is predominant in starch [Tharanathan,

Across the world rice is the most commonly used food commodity. Many countries grow paddy from which rice is harvested and each year its production estimates nearly 500 million tons [http://www.fao.org/worldfoodsituation/csdb/en/]. Based on the paddy varieties, rice starches have different characteristics [Ali Abas Wani et al., 2012], which results in biodegradable films of different properties. They have been used to produce biodegradable films instead of synthetic films, because of their low cost, renewability and good mechanical properties [Xu et al., 2005; Rindlav-Westling et al., 1998; Pagella et al., 2002]. But these rice starch films do not possess efficient barrier against low polarity compounds, hence applications are limited [Kester and Fennema, 1986]. This led to the modification of rice based starch films to provide better properties. The starch blends with various proteins have resulted in films having resistance to water vapour permeability and improved tensile strength [Jagannath et al. 2003; Chambi and Grosso, 2011]. Zhang et al. [2007] have pointed at drawbacks of lower mechanical properties, low resistance against moisture and release of low molecular weight plasticizer from the starch matrix. Other than starch, polysaccharides such as cellulose and chitin have been found to be potential sources of nanosized reinforcements. These molecules have