Journal of Polymer Science Polymer Physics Edition · 1973 · 26 citations · 9 references
Natural SciencesChemistryMaterials ScienceMaterials ChemistryMaterials PhysicsPhysical ChemistryPolymer CharacterizationPolymer Physical ChemistryPolymer PhysicsDecay ExperimentsGlass TransitionLow-temperature MaterialsPeroxy IntermediatesPeroxy Radical ChemistryPolyethylenePolymer Amorphous Phase BehaviorPolymer Glasses
Abstract The rate of peroxy radical accumulation as a function of strain at various temperatures in AC1220 high molecular weight polyethylene has been determined by EPR spectroscopy. The results of isothermal radical decay experiments are used, where appropriate, to correct the apparent accumulation rate to the actual rate. An exponential dependence of radical concentration [R], on true strain is observed at all temperatures investigated in the range from 160 to 294°K. For constant effective strain, measured from the approximate strain at which radical accumulation initiates, it is found that d [R]/ d e exhibits two sharp transitions as a function of temperature. One of these, at low temperature, is believed to be associated with the glass transition of the amorphous phase of the material; the other, at higher temperature, is believed to occur as a result of a change in the rate‐controlling mechanism of deformation.
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