The morphology of PPTA pulp is investigated by means of optical microscope and scanningelectron microscope (SEM). It shows that PPTA pulp has feather-like branch, needle point-likeend, and irregular cross-section, whi...The morphology of PPTA pulp is investigated by means of optical microscope and scanningelectron microscope (SEM). It shows that PPTA pulp has feather-like branch, needle point-likeend, and irregular cross-section, which are very important for PPTA pulp as a reinforcer. Theseparation limitation of PPTA pulp is also investigated from both torn and brittle break cross-sec-tion. A packing mechanism is proposed to illustrate the microfibril packing in the gel system.展开更多
High viscous PPTA copolymer is prepared by low temperature solution copolycondensation of terephth-aloylchloride, p-phenylenediamine and p, p'-diamino-phenylpiperazine in the NMP-CaCl2 solvent system. The inherent...High viscous PPTA copolymer is prepared by low temperature solution copolycondensation of terephth-aloylchloride, p-phenylenediamine and p, p'-diamino-phenylpiperazine in the NMP-CaCl2 solvent system. The inherent viscosity of all copolymers is more than 5. If more quantity of 3rd monomer is introduced into the macromolecular chain, the inherent viscosity becomes higher. The copolymer's ash content is less than 1000 μg/g. The heat durability of copolymer is close to that of PPTA, and its dissolubility is superior to that of PPTA.展开更多
文摘The morphology of PPTA pulp is investigated by means of optical microscope and scanningelectron microscope (SEM). It shows that PPTA pulp has feather-like branch, needle point-likeend, and irregular cross-section, which are very important for PPTA pulp as a reinforcer. Theseparation limitation of PPTA pulp is also investigated from both torn and brittle break cross-sec-tion. A packing mechanism is proposed to illustrate the microfibril packing in the gel system.
文摘High viscous PPTA copolymer is prepared by low temperature solution copolycondensation of terephth-aloylchloride, p-phenylenediamine and p, p'-diamino-phenylpiperazine in the NMP-CaCl2 solvent system. The inherent viscosity of all copolymers is more than 5. If more quantity of 3rd monomer is introduced into the macromolecular chain, the inherent viscosity becomes higher. The copolymer's ash content is less than 1000 μg/g. The heat durability of copolymer is close to that of PPTA, and its dissolubility is superior to that of PPTA.
