a biodegradable plastic composition prepared by mixing : dry unmodified starch , e . g . pearl starch , a copolymer of an olefin and a comonomer selected from the group of c 1 - 6 alkylacrylates , c 1 - 6 alkylmethacrylates , and vinyl acetate , and optionally also including , a polyolefin or a polyolefin , and articles manufactured by injection molding or blowing films of this composition .