Study On Conductive Polypropylene Fibers And Its Properties

Conductive polypropylene masterbatches were obtained by using twin-screw ertruder mixed with low-molecular wax as dispersant and a little antioxidant and nano-sized SnO₂ as conductive particles treated by titanate coupling agent. A new kind of conductive polypropylene fiber was obtained by melt-spinning technic and fibers were treated by elongation and heating.Through some experiments in mathematics method,the effects of powder surface modification were analysized by the method of sedimentation volume.Various factors that influenced the results of powder surface modification were analysized. The results indicated that the amount of coupling agent was the most touching.The method of ultrasonic dispersion was better through the contrast and analysis of two kinds of surface modification methods.The researches showed that the use of coupling agent enhanced the consistentance between the inorganic powders and polymer and the dispersion of inorganic powders in polymer.The use of polyethylene wax was bad alone and it's use with coupling agent was better.The dispersion of dispersant with the molecular weight of 4000 was good and 3 wt% was better.2³ wt% of coupling agent was better in dry treatment and we could choose the temperature of 230℃ in the production of materbatches.The technic of second time production of masterbatches was proved bad.It was found that the crystal temperature of polypropylene was improved in the existence of nano-sized SnO₂ and the degree of crystal was increased too.The multiple and different crystal were formed and the crystal type didn't change before and after the adding of nano-sized SnO₂ and they were all standard a type.The results showed that 20 wt% of nano-sized SnO₂ was proper in conductive fibers,the voltage resistance of conductive fibers were 10⁶ Ω· cm and was far smaller with the contrast of pure polypropylene fibers' 10¹5 Ω· cm.The voltage resistance decreased after elongation and the rupture intensity rase with the increase of elongation multiples.Most fibers' rupture intensity reached around 3.0 CN/dtex and could meet the needs in textiles.The elongation temperature was good in 110℃.Moreover, the surface status of conductive powder and it's dispersion in masterbatches,the conductive and mechanic properties of the fibers were alsodiscussed using FTIR, SEM, TEM and DSC.The shrinkage ratio of conductive fibers in boiling water and their properties of acid-resistant and alkali-resistant were analysized.