Amine-terminated Polyimide Research Articles

Nylon-6 and single-walled carbon nanotubes polyamide composites

Two methods for the functionalization of single-walled nanotubes were proposed, namely grafting of acyllactam groups or amine-terminated polyimides. Such modification allows for the preparation of stable nonsagging nanotubes dispersions in the melted ∊-caprolactam. These dispersions were further utilized for in situ ring-opening anionic polymerization of ∊-caprolactam with ∊-caprolactam magnesium bromide as a catalyst and N-acetyl-∊-caprolactam as an activator. Some unique features of the obtained novel nylon-6/nanotubes composites are significantly increased thermal stability ( T5% up to 400°C), enhanced compression modulus and Izod impact strength of polymer blocks (by 25% and 150%, respectively) and advanced tensile strength and elongation of polymer films. Such an improvement in the properties of the composites in comparison with neat nylon-6 was gained by the addition of as little as 0.1–0.01 wt% of modified nanotubes.

Synthesis and properties of hyperbranched polyimides from A2+ B′B2 monomers and A2+ B′B2 + B2 monomers with various comonomer ratios

A series of hyperbranched polyimides were successfully synthesized by A2 + B′B2 approach based on 2,4,6-triaminopyrimidine(TAP) and biphenyl dianhydride(BPDA) . The resulting polyimides were characterized by FTIR, SEC/MALLS, NMP, DSC, TGA. The results showed that BPDA-TAP hyperbranched polyimides had poor thermal stability. In accord with this fact, difunctional B2 comonoer (4,4′-oxydianiline(ODA))was added into the polymer structure to improve heat resisting property of HBPIs by incorporation. This approach could be described as A2+ B′B2 + B2 or more simply A2 + B3 + B2 copolymerization. Both for the BPDA-TAP-ODA and BPDA-TAP hyperbranched polyimides, the amine-terminated polyimides showed higher glass transition temperature and 10 % weight loss compared with the corresponding anhydride-terminated ones, which can be attributed to the different terminal functional groups and the anhydride residues.