Effect of orientation on the biodegradability of uniaxially stretched aliphatic copolyester films

The effects of uniaxial drawing conditions on the orientation of aliphatic copolyester films were investigated by using both Fourier transform infrared-attenuated total reflection (FTIR-ATR) dichroism and wide angle X-ray diffraction (WAXD) methods. The results showed that orientation in uniaxially drawn films was determined by the drawing rate and drawing temperature. At higher drawing rates and higher drawing temperatures, higher orientation was obtained due to a large deformation of spherulites. The WAXD patterns of drawn films exhibited the preferential orientation of lamellar crystallites. The results of microbial degradation indicated that development of crystalline orientation evidently depressed biodegradability of samples. Video microscopy observations revealed that the degree of orientation played a dominant role in determining the rate of surface erosion. (C) 1997 John Wiley & Sons, Inc.