Abstract: The present invention relates to a preparation method of para-aramid nanofibers, and belongs to the technical field of novel polymer materials. The para-aramid nanofibers prepared in the present invention have a diameter of 10-100 nm, and a length of hundreds of microns. The preparation method includes: adding a certain amount of surfactant in a PPTA low-temperature polymerization process, and controlling aggregation of PPTA molecules along with growth of a PPTA molecule chain, thereby preparing the para-aramid fibers with a uniform size and an adjustable nano-scale diameter under assistance of other means (e.g., a coagulator and high-speed shearing dispersion). The present invention is short in production process and simple in equipment, can realize stable batch production to meet needs of large-scale production of the para-aramid nanofibers, has wide application prospects and can be applied to preparing a lithium-ion battery separator, a high-performance composite material and the like.

Abstract: A method for analyzing molecular weight of the poly-p-phenylene terephthalamide (PPTA) utilizing near infrared spectrum is provided for reducing the time required to analyze the molecular weight of PPTA. The method uses PPTA samples to build a spectrum-viscosity fitting curve. The molecular weight of an unknown PPTA is analyzed via a near infrared analysis software and the spectrum-viscosity fitting curve. The method is beneficial in that it has a short process time and high reliability.

Abstract: The present invention relates to a preparation method of para-aramid nanofibers, and belongs to the technical field of novel polymer materials. The para-aramid nanofibers prepared in the present invention have a diameter of 10-100 nm, and a length of hundreds of microns. The preparation method includes: adding a certain amount of surfactant in a PPTA low-temperature polymerization process, and controlling aggregation of PPTA molecules along with growth of a PPTA molecule chain, thereby preparing the para-aramid fibers with a uniform size and an adjustable nano-scale diameter under assistance of other means (e.g., a coagulator and high-speed shearing dispersion). The present invention is short in production process and simple in equipment, can realize stable batch production to meet needs of large-scale production of the para-aramid nanofibers, has wide application prospects and can be applied to preparing a lithium-ion battery separator, a high-performance composite material and the like.

Abstract: A method for analyzing molecular weight of the poly-p-phenylene terephthalamide (PPTA) utilizing near infrared spectrum is provided for reducing the time required to analyze the molecular weight of PPTA. The method uses PPTA samples to build a spectrum-viscosity fitting curve. The molecular weight of an unknown PPTA is analyzed via a near infrared analysis software and the spectrum-viscosity fitting curve. The method is beneficial in that it has a short process time and high reliability.