Study On Biodegradable Polymers Based On Cellulose Acetate Propionate

"Biomass polymer", prepared from renewable sources using modem theory and technology, had been paid much attention to us, to find the substitution of normal plastics has already been the important field of the world because world energy sources crisis and serious white pollution destroy the sustainable environment for human being. As one of the most abundant renewable biopolymers, cellulose is an almost inexhaustible polymeric material bearing fascinating properties.Acetate propionate cellulose (CAP) synthesized from natural cellulose was provided with good optical clarity, high tensile and dissolvability.CAP prepared in heterogeneous reaction, improved its properties blending with environment-friendly plasticizers and biodegradable synthetic polymers, and it could be made by co-rotating twin screw extruder and blowing-model to gain biodegradable film. It provide reliable path, which solve worldly pollution of plastics, having a boundless prospective and bright future.Firstly, cellulose was activated by acid at first, and then added with anhydride as the ester agent, sulfuric acid as the catalyst and acid as a dispersion medium. The optimized condition was obtained as follows: activation temperature was 60℃, activation time was 1h, reaction temperature was 50℃, reaction time was 1h. The structure and properties of CAP were investigated by IR, DSC, XRD, and ¹³C NMR the crystallinity and Tg of CAP declines as the degree of substitution increased.Secondly, environment-friendly plasticizers and biodegradable synthetic polymers were added to improve the properties of CAP, this article used solution blending to develop CAP-based membrane which made use of advantage of its components and avoided its disadvantage.The mechanical, water-tolarance and thermal properties of the blends were characterized by tensile strength-elongation, water absorption, TGA, DMA, TMA, X-Ray, TEM. The results show that CAP/PCL blends was partialy miscible.Thirdly, CAP with the extruder operating conditions were discussed by the influence of current, water absorption and melt flow speed. The compatible condition as follows: screw rotating speed was 500r/h, screw temperature was 140℃,170℃,170℃,170℃,160℃, CAP-based biodegradable film was prepared by extrusion and blowing method from blends of CAP and PCL, plasticized with TEC, and the film showed good properties.Fourthly, The biodegradability of CAP/PCL film were determined by means of degradable trials of soil test, the molecular weight of film decreased after three months, it showed that CAP/PCL film had some biodegradability.