and contained then to the resulting product is added 25 g of polylactic acid at 190 u00b0 c in a nitrogen atmosphere followed by stirring for 0 5 hour the above block copolymer containing vinyl acetate and propylene has compatibility with both polyvinyl acetate and polypropylene and admixes with them polylactic acid can be admixed with polypropylene through polyvinyl acetate and the above block copolymer thus there is obtained 146 g of an admixture of polylactic acid polyvinyl acetate polypropylene and a block copolymer of vinyl acetate and propylene in which vinyl acetate content is 42 5 g ethylene content is 33 5 g propylene content is 45 g and polylactic acid content is 25 g when the content of polypropylene is to be increased polypropylene is further added in the above state followed by stirring for 0 5 hour another example of a method of synthesis of a mixture comprising polyvinyl acetate polypropylene a block copolymer of vinyl acetate and propylene and polylactic acid which uses polyisoprene in place of the above polystyrene and polyethylene first explanation is made of a block copolymer of polyvinyl acetate and polypropylene a cation polymerization initiator is added to 250 ml of anhydrous heptane in a nitrogen atmosphere of room temperature and further 6 mmols of triethyl aluminum diluted to 10 wt with heptane is added followed by stirring as the polymerization initiator there are metal chlorides such as titanium chloride iii and.