The Synthesis And Application Of New Monomers For Benzobis(Z)Azole-Modified Kevlar And Hydroxy-or Peptide-Modifid PBZ

poly(p-phenylene terephthalamide)(Kevlar)and PBZ fiber,with high strength,excellent heat resistance and mechanics performance,become widely used as super organic fiber.but they have defects respectively,such as poor of compression performance and composite bonding.In this paper,aiming to further improve the mechanics and resistance to the pressure performance of fibers,new polymers of benzobis(Z)azole-modified Kevlar and hydroxy-or peptide-modified PBZ were designed and new monomers of the polymers were synthetized and explorated.At the same time the synthetic process of new monomer was also optimizedFirstly,(1)the monomer of benzobisthiazole-modified Kevlar,trans-benzobisthiazole-2,6-dianiline(TBTDA)and cis-benzobisthiazole-2,6-dianiline(CBTDA),was received from condensation and cyclization reaction of ammonium thiocyanate with p-phenylenediamine and m-phenylenediamine as raw materials,then we systematicly investigated its synthesis condition and the purity of the product reached the monomer of polymer-grade after refining.At the same time,we successfully explorated the new process of cis-benzobisoxazole-2,6-dianiline(CBODA)with m-phenylenediamine and sodium cyanate as starting material,and optimized them of which applied to benzobisoxazole-modified Kevlar.(2)The synthetic process of poly(6-hydroxy-2,5-benzoxazole)(H-PBO°)with high performance to price ratio was creatively proposed and the synthesis of the new AB-type monomer 2,4-dihydroxy-5-aminobenzoic acid(DHABA)was studied The synthetic process of DHABA was researched,which was respectively prepared by nitrification and reduction of ?-resorcylic acid(DHBA)or hydrolysis and reduction of 2,4-dichloro-5-nitrobenzoic acid(DCNBA).The result shows that the hydrolysis and reduction of DCNBA is the best way to get DHABA,and the best reducing method is Iron reduction,which lays a new monomer foundation for the study of H-PBO and hydroxy-modified PBO.Secondly,for peptide-modified PBZ,the preparation of 5-mercapto benzothiazole-2,6-dianiline(MBTDA)and 6-hydroxybenzoxazole-2,5-dianiline(HBODA)was explored respectively,the synthetic route of 4-methoxy-5-nitrobenzene-1,2-dianiline(MNPD)and the intermediate of(HBODA)was studied by ammonia,alcoholysis and selectively reduction reaction from 1,5-dichloro-2,4-dinitrobenzene.However,the synthesis of the new monomer HBODA and MBTDA of peptide-modified PBZ is more difficult,which still needs further study.Finally,the use of benzobisoxazole-modified Kevlar fiber and hydroxyl-modifid PBO fiber was explored.We abtained poly(benzobis thiazole terephthalamide)(PBTTA),poly(benzobisthiazole dihydroxy terephthalamide)(PBTDHTA),H-PBO°,the co-polymer of PBO and H-PBO°(chain ratio 1:0.59 and 1:2.27).Their intrinsic viscosity were 0.64 dL/g,0.60 dL/g,9.6 dL/g,14.6 dL/g and 16.1 dL/g,and the decomposition temperature was 348.0?,358.1?,561.9?,641.6? and 669.8?.All of the chemical compound studies is confirmed by the qualitative analysis of IR,NMR,MS and so on in this paper.