Research Of Polylactide/Poly(Butylene Carbonate) Blends And Blown Films

In order to solve the problem of white pollution and make it possible for people living a green healthy and harmony life.It has become focus of research of biodegradable materials like polylactide. Unfortunately, the application of PLA as commodity plastics is restricted by its brittle behavior. In this article, a series of experiments was done to modify the biodegradable material PLA.(1)In this experiment, PLA was melt blended with PPA to prepare the blends for investigation. Thermal and dynamic mechanical analysis revealed that PPA is partially miscible with PLA. SEM micrographs of PLA/PPA blends also show good compatible.The 90/10 PLA/ PPA blend presents an elongation-at-break value of 157% and tension strength value of 49.6MPa. It can cause plastic deformation and obtain excellent mechanical properties. The impact strength was improved significantly from 4.7kJ/m2 for neat PLA to 106.5kJ/m2 for the 75/25 PLA/PPA blend. Because of the plasticization effect of PPA, in the molten state, the PLA/PPA blends exhibits plastic deformation and lower complex viscosity. These results indicate that PPA could act as a good plasticizer of PLA.(2)We utilize poly(1,2-propylene glycol adipate) as plasticizer to improve PLA’s performance without compromising the biomass origin and compostable properties of the material. Due to the plasticization effect of PPA, melt rheology of PLA and adhesion of the result paper plastic laminates were greatly improved. Through the extrusion casting process, the molten PLA with paper were rolled forming PLA/paper laminates. The laminates have a higher tensile strength and tear strength, good water resistance comparing with paper, which can be further prepared using as medical products, such as operation sheet, medical scarf.(3)The biodegradable PPA and poly(butylene carbonate)(PBC) are used as the plasticizer and tear resistance modifier of PLA to prepare the biodegradable films. The blends exhibited immiscible two-phase system with PBC uniformly dispersed within the PLA/PPA matrix. From the mechanical test, the 85.5/9.5/5 PLA/PPA/PBC film had elongation at break of 148.3% and 131.1%, while the tensile strength remained as high as40.8 and 38.6 MPa in the machine direction and the transverse direction, respectively. At the same time, the tear resistance of the films kept high level of 143.6 and 138.5 KN m-1.As a result, a kind of novelty polylatide-based biodegradable films with high tensile and tear strength was achieved and the softness was also improved significantly along withincreasing PBC content. The shear yielding induced by cavitation of PBC particles was the major tearing mechanism of films.