Morphology and high modulus of laminated ultra-drawn polyethylene films with biaxial orientation prepared by microwave heating

To improve the poor mechanical properties of uniaxially ultra-drawn films along the transverse direction, lamination of two ultrahigh molecular weight polyethylene/ethylene dimethylaminoethyl methacrylate copolymer blend films was carried out in the rectangular elongation direction by a microwave heating method. The characteristics of the successful laminated films were analyzed theoretically and experimentally. The original orientation of the crystallites for the blend films was maintained perfectly after lamination, and the preferential directions intersected each other. The Young's modulus increased symmetrically with respect to the 45 °direction. This is the first report concerning a drastic improvement of the Young's modulus in the transverse direction for films ultra-drawn along one direction.