Polymer and Materials Science
Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
The effect of peroxide and coagent, alone and together, on the crosslinking of HDPE during melt extrusion was studied. The melt flow index decreased rapidly with peroxide (1,3-bis (t-butylperoxy-isopropyl) benzene), and smoothly with trimethylolpropanetriacrylate (TMPTA), but showed a small increase with parabenzoquinone (PBQ).Melt viscosity of 0.3 phr peroxide-treated PE responded elastically, whereas that of 0.3 phr TMPTA showed yield behavior. Tm (crystalline melting temperature) and Tc (crystallization temperature) increased with peroxide, Tm decreased, and Tc increased with TMPTA. ΔHf (heat of fusion) increased at 0.05 phr followed by a sharp drop, more with peroxide and less with TMPTA. Hardness and preyield properties increased with TMPTA, and peroxide (except hardness) with the loss of elongation at break. The most significant improvement was obtained with impact strength, over 5 times with peroxide and 7 times with TMPTA.When the TMPTA was used in combination with peroxide, more redution in MI, followed by a further increase of hardness, modulus, and strength, was obtained, but impact strength was decreased below that of TMPTA alone. © 1993 John Wiley & Sons, Inc.
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