Synthesis Of New Ab-pa Monomers And Preparation Of (Modified) PPTA And Exploration Of Its Properties

Poly(P-Phenylene terephthalamide)(PPTA)as the Super fiber,with excellent tensile strength,high temperature resistance and wide application,has become a research hotspot in 21 centry.In this paper,for the current existence of the compressive poor performance,inadequate and poor bonding properties of composite and synthesis deficiencies in PPTA,the modified PPTA and its modified new AB-type monomer was explorated.At the same time the synthesis of PPTA was also optimized.First,we started from performance optimization of polyamide,the introduction of methyl to the PPTA molecular structure was proposed,and four monomers of the new AB-type polyamide were successfully synthesized.With 4-amino-2',3-dimethyl-azobenzene(CI11160),methyl 4-(chlorocarbonyl)benzoate(MBC)and 2-methyl-1,4-phenylenediamine(MPPD)as raw materials,four monomers including methyl 4-((4-amino-2-methylphenylamino)carbonyl)benzoate(2-MACB),4-((4-amino-2-methylphenylamino)carbonyl)benzoic acid(2-AMCB),methyl 4-((4-amino-3-methylphenylamino)carbonyl)benzoate(3-MACB)and 4-((4-amino-3-methylphenylamino)carbonyl)benzoic acid(3-AMCB)had been synthesized after a simple process operation.The purity of products was more than 99%purity with the yields of 82.3%,95.7%,95.1%and 94.7%respectively,and all of them could achieve the levels of polymerization level.With the new type of four monomers,ordered polymer Poly(2-methyl-P-Phenylene terephthalamide)(2-M-PPTA),Poly(3-methyl-P-Phenylene terephthalamide)(3-M-PPTA)and the disordered polymer M-PPTA were synthesized.The results showed that the heat of these three polyamide material performance superiority from highest to lowest by the following:3-M-PPTA>disordered M-PPTA>2-M-PPPT,while disordered M-PPTA was closer to 2-M-PPTA,which means most of methyl was in second position.Based on the "M5" hydrogen bonds between molecules and composite bonding,as well as the excellent performance of PBO,we also explored and studied on the modified PPTA with the the structure of thiazole and hydroxyl.The yield of ordered H-PPTA,S-PPTA and SH-PPTA,of which prepared by polycondensation,is more than 86%,90%and 82%respectively,and the intrinsic viscosity is 1.12dL/g,1.64 dL/g and 1.01 dL/g respectively.The effects of solvent,monomer concentration,polymerization temperature etc on polymerization were systematically investigated.In this paper,the series of new monomers and intermediates molecular structure were confirmed by IR,1H-NMR,MS qualitative analysis.