The invention provides a direct
spinning technique for preparing polyphenylene terephthalamide by using end capping
oligomer. The method includes steps as follows: firstly, polyesterification of phthaloyl
chloride and
phenylene diamine for obtaining PPTA
oligomer with low molecular weight, passivating two ends of molecule using end-capping
reagent for forming end capping PPTA resin; secondly, adding polar
solvent and latent
solvent into the resin for confecting a composite solution; finally,
processing solution polyesterification in the composite solution for obtaining PPTA
polymer with high molecular weight, and
processing stock solution spinning preparing PPTA fibre. The method makes PPTA
polymer giant molecule dissolving into the composite solution associated with polar
solvent and latent solvent by using reaction
inertia and solvent effect of end capping PPTA resin that is convenient for
spinning. The method breaches technique difficult problem that the prior
liquid crystal spinning technique for preparing
aramid fiber with high quality must need concentrated
sulfuric acid as solvent, avoid usage of concentrated
sulfuric acid with causticity and is hoping to become an universality direct spinning technique with high effect and low cost, green and environmental protective.