Modification of a polyimide film by blending with nylon 6. Its characterization and thermal property evaluation

A polyimide blend system has been prepared from a base polyimide of PMDA-4, 4 ' oxydianiline by adding epsilon -caprolactam at the poly(amic acid) stag e where F-caprolactam is also undergoing polymerization during the curing c ycle of the polyimide. The blend has been characterized by elemental analys is, IR, C-13 CPMAS NMR, XRD and simple chemical methods. The thermal analys is study (TGA, DTA & DSC) shows that the stability of the blend system is m ore in comparison to the control polyimide system. The isothermal study at 400 degreesC in inert atmosphere shows that the blend system is equally sta ble but the isothermal study in air at 400 degreesC shows that the blend fi lms are more stable up to a certain extent of time compared to that of the control film. Also isothermal study in air at 500 degreesC shows rapid loss of weight (more than 90%) for all the films but in inert atmosphere the fi lms show higher thermal stability. XRD pattern of the blend films shows a h igher crystallinity. It has been also observed that the density of the blen ded film is higher than that of the control film. (C) 2001 Elsevier Science Ltd. All rights reserved.