Preparation Of Biaxially Oriented Polylactide(BOPLA) Film

Biodegradable PLA has obvious adventages in the field of film materials.The film reforming ability and static stretching process of imported PLA and domestic PLA were studied by cast film lab machine and biaxially oriented lab machine in this paper.PBC,chain extender ADR and anti-blocking agent M150 were used as additive in PLA to study PLA film property.On this basis,imported PLA and domestic PLA was industrial pilot plant tested by Multifunctional test machine.Drying condition of PLA,the change of PLA property before and after stretching were studied.And optimum processing condition of BOPLA film was successfully found out.The major results are summarized as following:(1)Adding chain extender ADR to BOPLA film can improve thickness uniformity,tensile strength and elasticity modulus of PLA film.When ADR's content was 0.2%,the property of PLA film was optimum.After adding 0.2% ADR to imported PLA,MD(machine direction)tensile strength increase 5.9%,TD(transverse direction)tensile strength increase8%,few increase.For domestic PLA,MD tensile strength and TD tensile strength increase33.8% and 32.6%,wide increase.(2)PBC can obvious improve film reforming ability,thickness uniformity and brittleness of imported PLA.But when PBC content was over 10%,transparency and thickness uniformity of PLA film become worse.When ADR's content was 0.2%,the property of PLA film was optimum.After adding 0.2% ADR to imported PLA,MD tensile strength reduces 17.5%,TD tensile strength reduces 21.6%,MD elongation increases 33.7%,TD elongation increases 28.3%.(3)Optimum drying condition was 5hours at 80?.On this condition,PLA's water content was under 200 ppm.(4)Optimum processing parameters were found out.Cast temperature: 25?;MD oriented:Pre-heating 55~70?;Stretching 70?;Annealing 60??MD oriented:Pre-heating60~90?;Stretching 90~110?;Annealing 120~140??Stretching ratio:MD×TD=3×3.