Caladium bicolor and Wild Dioscorea dumetorum Starches As Dual Purpose Polymer Additive

Increased elastic modulus and ultimate tensile strength of low density polyethylene has been achieved by incorporating Caladium bicolor (ornamental cocoyam) and wild Discorea dumetorum (sweet yam) starches into low density polyethylene using a standard hot-melt compounding technique. Some mechanical properties of compression moulded dumb bell shaped films of low density polyethylene containing up to a maximum of 20 wt % of each starch is reported. Increased density of the composite with time after being buried for a total of 12 weeks in composting environment is an evidence of the degradation of LDPE which may be linked to an initial breakdown of starch by microorganism in the soil which probably give rise to diffusion of unsaturated lipids into the porous polymer resulting in degradation by auto-oxidation.