Research On The Elastic Properties Of PTT/PET Bicomponent Filament And Fabic

PTT(Polytrimethylene terephthalate)/PET(Polyethylene terephthalate) bicomponent fiber is self-crimping fiber composed of PTT and PET polyester fibers, and is a new composite fiber based on PTT industrialized manufacture. This fiber combines PTT and PET property, and exists helical crimp. Moreover, its helical crimp configuration provides this fiber high bulk and elastic recovery which become special elastic fiber. In recent three or five years, the production of PTT/PET increases up to tens of thousands of tons.Currently, the researches of PTT/PET composite fiber mainly have focused on spinning process, but there wasn't result about its excellent elongation and elasticity with different crystal structure. Based on existing research, internal structure,crimp configuration fiber and fabric properties of different PTT/PET filament were tested, which provided reference for PTT / PET filament flexible design. The following were four main results:1. PTT / PET fiber component and crystalline were analyzed by useing FT-IR and DSC, except immature process GXD, the crystalline of PTT and PET of three kinds of PTT/PET fibers after 100 temperatures wet-heated. Through optical microscope, the PTT/PET bicomponet filament had spiral-shaped crimp, and after heat treatment, crimp frequency was significantly increased, and the regularity of some crimps yarn became better. The crimp property of PTT/ PET filament was excellent, which was impacted slightly by linear density.2. Based on existed test standard, pretension of 0.01 cN/dtex was appropriate for PTT/PET mechanical test. The testing results showed that there were typical two steps and two yield points in the force-elongation curve of PTT/PET filaments. Breaking strength decreased, and both the crimp and original elongations of the treated filaments rose significantly, which contributed to the increasing of breaking elongations after wet-heat treatment. Moreover, modulus of elasticity and stiffness of PTT/PET filaments decreased and its flexibility increased for wet-heat treated filament. Relative to original filaments, the wet-heat treated filaments owned much excellent elastic recovery based on the helical crimp configuration, but wet-heat treatment influence slightly elastic recovery of different filament.3. Fabric elastic recovery were tested, through monothetic analysis, material,twist and yarn density were main impact factors. The relationship equation of between elastic recovery rate and the fabric structure parameters through multiple linear regression were established, PTT / PET weft elastic fabric decreased with weft tight and twist and increased with the weft density and the PTT / PET component in weft. There were a good fit between measured and predicted elastic elongation through the regression equation which illustrated regression equation that reflected relatively the real relationship between the fabric elasticity and other parameters, so it can be used to predict fabric flexibility.4. Through analysis of elongation curve, PTT / PET fabric had a high elongation,maintained high elongation at low tensile modulus and had long low tensile modulus area; PTT / PET fabric with excellent elastic recovery properties indicated its fabric with excellent elongation and abrasion resistance. The ratio of four kinds of PTT / PET fabric and filament elastic elongation was about 5.5 percent, and both have a high correlation, so fabric elasticity can be predicted by the elasticity of PTT/PET filaments.