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
A theory for the shear degradation of high polymers is presented. It assumes the molecules to exist in the rubbery or liquid state and does not include the effects of chemical reactions which might occur subsequent to chain rupture. The computation shows that the entanglements along the chains play a major part in the rupture process. Expressions for the rate of chain rupture are obtained in terms of the melt viscosity, shear rate, and molecular weight. Other factors enter also, but the sensitive variables are those listed. The variation of molecular weight distribution with shear degradation is considered. It is pointed out why oxidative scission during shear is not a random process. In general, the theoretical result agrees with the limited experimental data available.
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