BULK TO INTERPHASE TRANSITION IN POLYAMIDE-6 COMPOUNDS WITH HIGH FILLER CONTENT

The influence of aluminum berate whiskers upon the morphology of polya mide 6 was studied by wide-angle X-ray scattering and by differential scanning calorimetry. The whiskers did not promote the formation of ei ther the hexagonal gamma or the monoclinic beta crystalline phase. A n ew experimental procedure has been devised for the production of very thin polymer layers on the whiskers. In the procedure, styrene coacryl onitrile polymer is used as a processing aid and is later extracted. T he procedure allows for the generation of polyamide layers less than 3 0 nm thick. Crystallinity in these thin layers was suppressed. An expr ession has been developed to characterize the crystallinity gradient i n the interphase of the whisker surface. The equation shows that the i nitial 1.4 nm of polymer is fully amorphous and produces excellent eva luations of the crystallinity gradient to layer thicknesses of 70 nm. (C) 1997 John Wiley & Sons, Inc.