Structural Investigation of Poly(lactic acid) Cast Film by Using Synchrotron X-ray Scattering Technique

Abstract

Microstructure of polymer relates obviously to the materials’ properties. Understanding the orientation and arrangement of the structure guides how to obtain the desirable properties of the final product. This work investigated the preliminary structure of poly(lactic acid) (PLA) cast film by using synchrotron X-ray scattering technique. The PLA was compounded with an epoxidized soybean oil (ESO) and a microcrystalline cellulose (MCC) as a plasticizer and a nucleating agent, respectively. The film products were prepared by using a chillroll cast film extruder. Orientation and crystal structure of the PLA cast films without and with additives were characterized by two-dimensional small angle X-ray scattering (2D-SAXS) and wide angle X-ray diffraction (2D-WAXD) techniques. Moreover, investigation on post-processing, i.e. stretching at room temperature, was carried out by using a homemade stretcher. Varieties of chain arrangement due to the additives and stretching were exhibited.