Abstract
A comparative study has been made of the molecular weight characteristics of poly(4′,4″-diphenylenephthalide) pyromellitimide (PI) prepared by polycyclization of the appropriate polyamidoester (PAE) by different methods. Viscosity measurements along with fractionation results and sedimentation analysis show that transition from PAE to PI by solid phase thermal cyclization is accompanied by a reduction in the intrinsic viscosity [η] and in the weight average degree of polymerization X w , and the MWD broadens to become the most probable. No rise in polydispersity occurs in the case of thermal cyclization of PAE to PI in nitrobenzene, but increases in [η] and X w are observed. In the conversion of PAE to PI in solution in presence of acetic anhydride and pyridine, no changes in [η], X w or in the polydispersity were detectable.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.