American Journal of Engineering Research (AJER) 2014 www.ajer.org Page 96 American Journal of Engineering Research (AJER) e-ISSN : 2320-0847 p-ISSN : 2320-0936 Volume-03, Issue-02, pp-96-104 www.ajer.org Research Paper Open Access Effects of Native Cassava Starch and Compatibilizer on Biodegradable and Tensile Properties of Polypropylene *Obasi, H. C., and Igwe, I. O. Department of Polymer and Textile Engineering, Federal University of Technology, P.M.B. 1526, Owerri. Abstract: - The effects of starch content and polypropylene-graft-maleic anhydride (PP-g-MA) as a compatibilizer on the properties of indigenous cassava starch filled polypropylene blends have been investigated. The blends were prepared by the addition of cassava starch of particle size 0.075 mm to polypropylene matrix using an injection machine with a screw speed of 50 rpm and at a temperature range of 160 - 190°C. Starch contents ranged between 0 and 50 wt. % and PP-g-MA was 10 wt. % based on starch content. Tensile, water absorption, weight loss and morphological properties were studied. Tensile strength and elongation at break decreased, while Young's modulus, water absorption and weight loss percent increased with increasing starch content. However, on addition of PP-g-MA, these properties were improved due to enhanced interfacial adhesion between the starch and the matrix though tensile strength and elongation at break were still lower than the neat PP. The morphological studies of fractured surfaces using SEM corroborated the deterioration in the properties. Keywords: - Cassava starch, polypropylene, PP-g-MA, tensile properties, water absorption, weight loss, SEM. I. INTRODUCTION The advent of biodegradable polymers can be considered a best approach to solving the menace of municipal solid wastes in our environment. As a result, a great number of biodegradable polymers have been synthesized and microorganisms and enzymes capable of degrading them have also been identified [1]. In Nigeria and other developing countries, environmental degradation and pollution by synthetic polymers have assumed alarming proportions. Attempts therefore have been made to solve these problems through structural modifications of the synthetic polymers to enhance their biodegradability. The combination of synthetic polymers such as polyethylene, polystyrene, polypropylene and natural additives like cellulose, starch, and chitin is an important way to improve biodegradability of polymers [2-5]. The bioplastics obtained offer great benefits over conventional materials - socially, economically and much more environmentally friendly. The fast pace of these bioplastics have endeared the chemical and plastics industries to invest heavily in this sector, and have high expectations of the new generations of bioplastics which are now competing favourably with the traditional petroleum-based plastics. These bioplastics can be degraded into natural ecosystems such as active sludge, natural soil, lake and marine [6]. Accordingly, the biodegradability of polymers corresponds to the ability to be chemically transferred by the action o biological enzymes or microorganisms [7, 8]. Biodegradation for limited periods is a reasonable approach for the complete assimilation and disappearance of an article leaving no toxic or environmental harmful residue [1]. Biodegradable polymers have been found very useful in medical, agriculture, drug release and packaging applications. Polypropylene is one of the most widely used plastics for packaging and production of bags and other consumer products. It has high melting point (160°C) with combination of properties such as strength, lightness, stability, flexibility, moisture and chemical resistance and ease of processability [9]. Polypropylene is also employed in the production of automotive interiors, fibres and non-absorbable sutures and in composites with other materials [10]. Starch is a natural polymer obtained from crops which include corn, rice, potatoes, cassava and wheat. Starch has been extensively used as a raw material in bioplastics production due to increasing prices and declining availability of conventional polymer resins.