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Morphology and mechanical properties of biaxially oriented films of polypropylene and HDPE blends
Author(s) -
Kim Woo Nyon,
Hong SukIn,
Choi JinSung,
Lee KwangHo
Publication year - 1994
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1994.070541116
Subject(s) - high density polyethylene , materials science , spherulite (polymer physics) , polypropylene , polyethylene , differential scanning calorimetry , copolymer , composite material , polymer blend , ultimate tensile strength , scanning electron microscope , phase (matter) , crystallization , izod impact strength test , polymer chemistry , polymer , chemical engineering , chemistry , physics , organic chemistry , engineering , thermodynamics
Abstract Biaxially oriented films of blends of high‐density polyethylene (HDPE) with polypropylene (PP) homopolymer and PP copolymers prepared by twin‐screw extrusion and lab‐stretcher have been investigated by scanning electron microscopy (SEM), polarized microscopy, differential‐scanning calorimeter, and universal testing machine. Three different kinds of PP copolymers were used: (i) ethylene–propylene (EP) random copolymer; (ii) ethylene–propylene (EP) block copolymer; (iii) ethylene–propylene–buttylene (EPB) terpolymer. In the SEM study of the morphology of films of HDPE with various PP blends, phase separation is observed between the PP phase and the HDPE phase for all blends and compositions. In all blends, HDPE serves to reduce the average spherulites size, probably acting as a nucleating agent for PP. The reduction of spherulite size appeared most significantly in the blend of EPB terpolymer and HDPE. A large increase of crystallization temperature was found in the blend of EPB terpolymer and HDPE compared with the unblended EPB terpolymer. For the blend of EPB terpolymer and HDPE, the improvement of tensile strength and modulus is observed with an increase of HDPE content, and this can be considered as a result of the role of HDPE in reducing average spherulite size. © 1994 John Wiley & Sons, Inc.