Preparation And Properties Of Biodegradable Poly(butylene Terephthalate-co-butylene Adipate) Films

Poly(butylene adipate-co-terephthalate)(PBAT) copolyester, which have good processing properties, is a new biodegradable synthetic polymer materials in recent years, but it is not saticified with the market requirements, because of its cost is very high. If its application in the field of life, according to its structure and characteristics of the processing modification. This paper studies the PBAT blends system: PBAT and thermoplastic starch(TPS) blend can be degradable films, PBAT and poly(propylene carbonate)(PPC) blend degradable films. The main contents and conclusions of this paper are as follows:Maleated thermoplastic starch(MTPS) was prepared through reactive modification of thermoplastic starch(TPS) with maleic anhydride(MA) as compatibilizer agent. Melt-blends of poly(butylene adipate-co-terephthalate)(PBAT) with TPS or MTPS were then prepared by reactive extrusion to produce PBAT/TPS and PBAT/MTPS films, respectively. Fourier transform infrared spectroscopy revealed that the interesterification reaction was happened between PBAT and MTPS. Differential scanning calorimetry measurements indicated that the glass transition temperature(Tg) of PBAT increased with increasing MTPS content. However, degree of crystallinity was decreased, which was coincident with wide angle X-ray diffraction analysis. Furthermore, the melt elasticity and viscosity of the PBAT/MTPS blends increased. It was benefit to extrude blend and blow film. The better dispersion of MTPS in PBAT matrix was observed in SEM images, leading to a higher tensile strength and elongation at break of PBAT/MTPS films. Compared with the PBAT/TPS films, the tensile strength and elongation at break of the 50/50 PBAT/MTPS films increased by 6.2 MPa and 281 % at the mechanical direction, respectively. Finally, the contact angle measurement showed that hydrophobic was decreased.Biodegradable PBAT/PPC blend films were prepared through an extrusion and blown films processing. The thermal behavior, phase morphology, crystallite dimension, mechanical properties, barrier properties, and biodegradability of PBAT/PPC films were investigated. Differential scanning calorimetry results confirmed that the glass transition temperature(Tg) of PPC was increased about 13 oC compared with that of the virgin PPC. With increasing PPC content, the thermal stability decreased of the PBAT/PPC films. Wide angle X-ray diffraction confirmed that the crystallite dimension of PBAT decreased. From the morphological observation, the PPC domains were evenly dispersed in the PBAT matrix while the PPC content was increased from 10 to 30%. Increasing PPC content up to50 wt%, it indicated the formation of the co-continuous phase of PBAT and PPC. From the mechanical properties testing, the tensile strength were increased from 28 MPa and 25 MPa to 41 MPa and 40 MPa of PBAT/PPC sample in the machine direction and the transverse direction, respectively; however, the elongations at break were decreased significantly. The oxygen, nitrogen, and carbon dioxide permeability coefficient of the PBAT/PPC films were decreased continuously. From SEM images and weight loss, it demonstrated that the films were remarkably biodegraded.