Effect of the molecular weight of poly-para-aramids and structural changes in heat treatment on the mechanical indexes of the fibres

Abstract

The mechanical indexes of fibres based on tuv types of poly-para-aramids were investigated as a function ofC is the concentration of polymer in 96% sulfuric acid, equal to 0.5 g/dl. For PPTA, it was found that [11] = 1.3rllo ~ [3]. Using this expression, we can determine [11] and M w with one measurement of Tlrel. According to the equations reported above, the curve of Mw(qlog) is almost linear.Fibres with a linear density of 30 and 58.8 tex consisting of 100 and 300 filaments, respectively, were fabricated by spinning 20 wt. % liquid-crystalline (LC) sulfuric acid solutions of copolyamides through an air gap using spinnerets with an 0.08 mm opening diameter into an aqueous spinning bath with a temperature of 10~ at a take-up rate of 100 m/rain according to [4] with washing and drying of the 30 tex fibres on perforated bobbins at 20~ and continuous washing and Terlon Limited Partnership; All-Russian Scientific-Research Institute of Polymer Fibres, Mytishchi.