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Effects of calcium stearate addition of ultrahigh molecular weight polyethylene in direct compression molding
Author(s) -
Utsumi Masahiro,
Nagata Kazuya,
Suzuki Masahiko,
Mori Akiko,
Sakuramoto Itsuo,
Torigoe Yuuichi,
Kaneeda Toshiaki,
Moriya Hideshige
Publication year - 2002
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.11584
Subject(s) - calcium stearate , stearate , materials science , polyethylene , scanning electron microscope , ultimate tensile strength , microstructure , composite material , calcium , molding (decorative) , fourier transform infrared spectroscopy , compression molding , accelerated aging , chemical engineering , chemistry , metallurgy , organic chemistry , raw material , mold , engineering
The effects of calcium stearate addition in molding of ultrahigh molecular weight polyethylene (UHMWPE) were investigated by tensile testing, scanning electron microscope (SEM), Fourier transform infrared (FT‐IR) spectroscopy, and elemental analysis. Four types of UHMWPE specimens with varying contents of calcium stearate (<5, 50, 100, and 1000 ppm) were used in this study. SEM observation revealed that calcium stearate added specimens have smoother and more homogeneous microstructures. After accelerated aging, subsurface oxidative degeneration was observed in all specimens; however, calcium stearate added specimens had less oxidative degeneration in comparison with specimens without additives. Specimens showed better mechanical properties with increasing content of calcium stearate. Though all specimens aggravated their mechanical properties due to oxidation after accelerated aging, the specimens of 100 ppm of calcium stearate showed better properties at 3.7 MPa larger yield strength and four times larger value of elongation at fracture than the specimens without additives. These results indicate that calcium stearate addition produces dense packing of UHMWPE particles, which brings about stronger fusion among the particles and fewer structural defects, and results in better mechanical properties and better resistance to oxidative degeneration. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1602–1609, 2003