Abstract
Experimental studies have been made for the retentivity of polycarbonate in processing the material under uniaxial compression in the temperature range from cold to warm.
The“Solvent Method”polycarbonate“Iuplion”was used as test specimen. The strain recovery of the test specimen compressed at various processing temperatures was measured by free annealing at the temperatures higher than the processing temperatures. It has been revealed that the strain recovery is complete when the annealing temperature is higher than the glass transition temperature of the polymer, though the polymer has excellent cold processing ability of freezing the strain when the temperature is lower than the glass transition temperature.
A new“Modified Erichsen”testing apparatus was proposed for measuring the temperature dependence of the processing ability of sheet plastics in relation to the cold and warm processing of the polymer. Sheet specimen was penetrated by a solid punch at constant rate of stroke at various temperatures and the penetration depth at fracture was measured. The processing ability of polycarbonate sheet (1mm thick) was gradually improved as the increase of the temperature up to the glass transition temperature.
The strain recoverey in the Erichsen test was examined in the same way as the uniaxial compression test, and a well parallelism between the results obtained under a combined stress such as the Erichsen bulging and those under an uniaxial compression as the above was found.
Test specimen worked by the“Modified Hot Erichsen”testing apparatus is being intended to be available for the environmental stress cracking test of the polymer.
