Takahiro Fukuoka

Novel photosensitive polymer based on polycarbodiimide and photoamine generator

A novel photosensitive polymer based on end-capped polycarbodiimide (E-PCD) and the photoamine generator N-{((4,5-dimethoxy-2-nitrobenzyl)oxy)car- bonyl}-2,6-dimethylpiperidine (1) was developed. The E-PCD was prepared by polycon- densation of tolylene-2,4-diisocyanate in the presence of 3-methy-1-phenyl-2-phos- pholene-1-oxide as a catalyst. The reaction of carbodiimide and secondary amine was studied. The nucleophilic addition of amine to the carbodiimide moiety proceeded smoothly and provided a guanidine base that acted as a crosslinking agent. A litho- graphic evaluation of the system of E-PCD and 1 revealed that the dissolution rate of the exposed area after the postexposure bake decreased drastically, although no obvi- ous change of the dissolution rate in the unexposed area was observed. The E-PCD containing 10 wt % 1 functioned as a negative working photosensitive polymer when it was exposed to 365-nm UV light, postbaked at 120 °C for 5 min, and developed with toluene at 25 °C.

One-Pot Synthesis of Aromatic Polycarbodiimide by in Situ Activation of Diamine:

A one-pot synthesis of aromatic polycarbodiimide from aromatic diamine has been developed. This method involves the preparation of carbamate by the reaction of 4, 4′-hexafluoroisopropylidenebis(p-phenyleneoxy)dianiline (6FPA) with phenylchloroformate, followed by the transformation of the carbamate with trimethylsilylchloride-triethylamine to diisocyanate, and then the polycondensation of the resulting diisocyanate in the presence of 3-methyl-1-phenyl-2-phosopholene-1-oxide. The polycarbodiimide (6FPCD) from 6FPA was obtained in quantitative yield having a number average molecular weight up to 5000. The thermal treatment of 6FPCD gave a crosslinkined polymer having a high glass transition temperature up to 200 °C.