FRICTIONAL SURFACE-TEMPERATURE DETERMINATION OF HIGH-TEMPERATURE-RESISTANT SEMICRYSTALLINE POLYMERS BY USING THEIR DOUBLE MELTING FEATURES

Most semicrystalline polymers exhibit multiple melting peaks in the co urse of normal differential scanning calorimetry (DSC) measurements. W hen their amorphous versions are annealed above the glass transition t emperatures, the lower endothermic temperatures (T-m1) appearing on th e subsequent DSC heating traces are highly dependent on the annealing temperature (T-a). In consideration of the fact that temperature is th e critical environmental factor controlling polymer crystallization, t hermal history experienced by the material during annealing in the DSC cell is basically equivalent to that under frictional heating, and th e surface temperature prevailing under sliding wear can be estimated f rom DSC scans taken on the worn surface. In this case, the lower melti ng peak temperature observed (which can be correlated with the anneali ng temperature) serves as an indicator for the flash temperature. In a ddition, this thermoanalytical method can also provide information abo ut microstructural changes due to wearing. (C) 1997 John Wiley & Sons, Inc.