Study On Preparation And Structure Properties Of CMSs/MWNTs Flame Retardant Pet Firber

As fire incidents caused by polymer materials occurs frequently, the harmto people tends to be more serious. As we are all known, PET ranks the firstamong the synthetic fibers, but the limiting oxygen index is only about21%,which belongs to the combustible fiber and forms easily a large numberof droplets during combustion.These droplets can lead to the secondarydisaster.Therefore, the study on the flame retardant PET is an urgent need.Among the inorganic flame retardants, carbon microspheres (CMSs) andcarbon nanotubes (MWNTs) have thermal stability, chemical stability and soon. The recent studies are mostly about the carbon nanotubes as flameretardant,but the studies on carbon microspheres have been reported slightlyand the complex of CMSs and MWNTs has never been reported so far.This paper firstly chose CMSs and MWNTs as additive flameretardant,prepared the different amounts of CMSs/PET, MWNTs/PETcomposites by melt blending and studied systematically the flame retardance, thermal stability and mechanical performance of the two kinds ofcomposites.Because CMSs and MWNTs all flawed in the fire-retardantproperty, combined with the complex technology,the different contents indifferent mass ratios of CMSs/MWNTs/PET composites were obtained.Thebest mass ratio of CMSs to MWNTs in flammability were focused on moreresearch,and the other properties were also studied.But the results showed thecompatibility of CMSs/MWNTs in PET matrix was poor. To improve thepoor compatibility, the CMSs and MWNTs were respectively modifiedthrough microencapsulation technology, and a layer of oligomer PET wererespectively coated on the surface of CMSs and MWNTs by situpolymerization to prepare the encapsulated carbon microspheres (PCMSs) andencapsulated carbon nanotubes (PMWNTs).The microstructure and molecularstructure were characterized.The PCMSs/PMWNTs/PET composites weremanufactured, and the flame retardance,thermal stability and other propertieswere analyzed.Finally, the different amounts of PCMSs/PMWNTs/PETfibers in the best ratio were prepared by melt spinning method.Researches onthe microstructure, orientation degree, hygroscopicity, thermal stability andflame retardant property of the fibers were discussed.Through experimental studies, the conclusions of this paper were drew asfollows:(1) Adding a small amounts of nano-carbon material in PET matrix had apreferable flame retardant effect. Wherein the mass fraction of1%CMSs made the LOI values of PET reach as high as28.9%than that of pure PETimproving by7.2,and the vertical flammability rating reached the V-0standard, but the anti-droplet performance slightly improved. And the1%mass fraction of MWNTs made the LOI values of PET rise only to22.3%andthe vertical flammability rating was V-0standard, but the anti-dropletperformance significantly improved, with the droplet number decreasing to6droplets per minute from24droplets per minute.(2) The CMSs/MWNTs was a highly functional flame retardant, when themass fraction was1%and the ratio of CMSs to MWNTs was1to2, the flameretardant effect was best, and the LOI values can be as high as27.3%, and theanti-droplet performance significantly improved with only4droplets perminute, and the vertical flammability rating reached the V-0standard.(3) After encapsulation,the compatibility between PCMSs/PMWNTs andPET matrix has improved and turned out to be better dispersibility. Comparedwith CMSs/MWNTs/PET composites， the mechanical property ofPCMSs/PMWNTs/PET has significantly increased, when the1%massfraction of PCMSs/PMWNTs was in the mass ratio of1to2, the tensilestrength has increased by26.1%, and the tensile strength have all risen inother mass ratios.(4) After encapsulation, the thermal stability performance of PET hasimproved significantly.When the1%mass fraction of PCMSs/PMWNTs wasin the mass ratio of1to2, the quality loss has reduced with the remaining quality rising from12.65%to15.70%.And the LOI values of PET hasincreased from21.7%to28.1%with only3droplets per minute, and thevertical flammability rating reached the V-0standard.(5) Compared with pure PET fiber, adding the0.4%of PCMSs/PMWNTsin PET fiber, the dispersibility, mechanical properties and orientation degreeof PCMSs/PMWNTs/PET fiber were preferable.The optimum moistureabsorption and flame retardance of PET composites fiber were ideal in1%ofPCMSs/PMWNTs, with the LOI value of27.4%, the droplet number of11droplets per minute and vertical flammability rating of V-0standard.