Study On Modified Poly(vinyl Alcohol)Fibers Prepared By A New Kind Of Spinning

Poly(vinyl alcohol)is a multi-hydroxyl polymer with excellent mechanical properties,thermal properties,moisture absorption,corrosion resistance,weather resistance and interfacial bonding properties,which is the raw material of vinylon.However,the multi-hydroxyls of PVA make its melting point close to its decomposition temperature.As a result the thermal processing of PVA is difficult.So PVA fibers are usually prepared by wet spinning.However,the complicated processing,heavy pollution and poor mechanical properties of wet spinning limit PVA fibers applications.Therefore,it has great theoretical and socio-economic values to explore a new green spinning process and preparing high-performance PVA fibers.In this paper,a metal ion complexing agent M,environmentally friendly plasticizer A and polyether plasticizer B formed a compound modifier.I added it to raw PVA to prepare modified PVA.By FTIR,DTA-TG and XRD,this paper studied the effects of different contents of modifier on hydrogen bonding,thermal properties and crystallization of modified PVA.By capillary rheometer,this paper studied the effects of different contents of each modifier,processing temperature and shear rate on the rheological behavior of modified PVA.1 spun below the melting point of the modified PVA,which is called quasi-melt-spinning process.By polarizing fiberscope,FTIR,XRD,DTA-TG,I studied the surface morphology of as-quasi-melt-spun fibers of modified PVA,changes of hydrogen bonds,crystallization and thermal properties.By a drafting equipment,I studied the effects of drawing temperature,drawing speed and the content of metal ion complexing agent M on breaking elongation of modified PVA fibers,and thus got the best parameters of drawing process.The results show that:adding a metal ion complexing agents can improve the thermal stability of the M-modified PVA,lower the melting point.It is not contribute to the spinning process,but it's advantageous in suppressing thermal degradation in drawing process,and thus improving the final mechanical properties of fibers;Adding environmentally friendly plasticizer A and a little polyether plasticizer B can improve the fluidity and spinnability of the modified PVA.The cross-section of as-quasi-melt-spun fibers prepared at 130? is circular.Because the increasing of the draw temperature and the decreasing of draw speed are beneficial to increase breaking elongation of modified PVA fibers,draw temperature is set to 190? drawing speed is set to 0.24mm/s.The quasi-melt-spun PVA fibers were drawn 11 times and the breaking tenacity reached 7.92cN/dtex,the modulus achieved 288.6 cN/dtex.