National Research Council of Canada. NRC Industrial Materials Institute
The purpose of this study is to investigate the biaxial stretchability, the structure developed, molecular orientation and shrinkage of linear low‐density octene copolymers (LLDPEs) biaxially stretched using a laboratory biaxial stretcher. Seven resins having different molecular characteristics were used in this study. The effect of stretching temperature and rate on stretchability is assessed. Biaxial orientation factors for the crystalline axes as well as that of the amorphous phase were determined using FTIR spectroscopy and shrinkage of oriented films was measured. The results indicate that the high molecular weight tail (Mz) and comonomer content play important roles in orientation of the resins. Higher Mz, MWD and resin content eluting above 90°C (by TREF technique) tends to increase orientation, and finally, some correlation between orientation and Mz, MWD and resin content eluting above 90°C and between shrinkage and amorphous orientation were observed.
Polymer Engineering and Science44, no. 2: 252–260.