Study On Synthesis Of PBO New Monomer And Exploration Of Polymerizing Method

PBO has high-performance of excellent chemical and thermal stability and mechanical performance, which can be spun into fibers with exceptionally high tensile modulus and strengths. Much more attentions are attached to the studies of the preparation and application of PBO monomer and fiber. This paper talks about the studies on the preparation of PBO and its monomer DAR. In this thesis, stability and polymeric performance of different DAR salts and synthesis of a AB new monomer is studied. Also the polymerization of different monomers is explored.Results from exploring experiments of different DAR salts shows that the stability of DAR2H3PO4 is the best, DAR/TPA takes the second place, DAR '2HC1 is the worst.A new monomer AB is contrived based on the results upwards in order to increase the stability and polymeric performance. A series of synthetic exploring experiments are carried out to gain the AB monomer. The chemical structure of all the intermediate are identified and confirmed by IR. NHABE is also identified by N.M.R. and elementary organic analysis. The results is shown as follows:DNR is prepared from resorcinol by tri-sulfonation di-nitration hydrolysis. Refined by solvent A-H2O, the total, yield is 62.36% with the HPLC purity of over 99%.In ethanol, ANR HC1 is formed from DNR through the reduction by hydrazine hydrate under the catalysis of Fe2+/C. Farther experiments find the better technologic conditions, which has the yield of 90.73% and the HPLC purity of 94.05%.By condensation, cyclization starting from ANR HC1 and methyl p-chlorocarbonyl benzoate, NHABE is prepared of with the yield of 70.60% and the HPLC purity of 90.02%.Hydrolysis in KOH glycol solution of NHABE gives NHAB of the HPLC purity of 99.70% with the yield of 80.33%. Then AB monomer is gained with the yield of 73.04% and the HPLC purity of 92.57%, prepared from NHAB by catalytic hydrogenization. Thus, the total yield of AB monomer from resorcinol is 14.44%.At the same time, AHABE is prepared from NHABE by catalytic hydrogenization with the yield of 84.01% and the HPLC purity of 94.64%. The total yield from resorcinol is 20.67%.Farther exploring polymeric experiments is carried out and PBO polymer is prepared from different monomers such as DAR 2H3PO4 DAR/TPA, AHABE, AB new monomer, which has respective intrinsic viscosity of 0.49, 0.99, 1.24, 1.89dl/g(in methanesulfonic acid at 25 ). This result shows that perhaps the AB monomer and AHABE have better polymeric capacity.