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采用去离子水溶胀聚乙烯醇(PVA),通过熔融纺丝法制备PVA纤维.研究了水质量分数35%和5%的PVA熔纺初生纤维在不同拉伸温度下的应力-应变曲线,以及其拉伸活化机制.结果表明:拉伸温度对水质量分数35%的PVA熔纺初生纤维表观拉伸黏度的影响分为3个区,即30~100 ℃,100~190 ℃,190~210 ℃,纤维在热拉伸时存在3个不同机制的活化过程,至少可采用三级拉伸;初生纤维拉伸受体系中水含量的影响,水含量减少,PVA分子链运动能力降低,表观拉伸黏度增大,水质量分数5%的PVA熔纺初生纤维的表观拉伸黏度随温度变化呈现两个区,活化机制改变,可采用两步拉伸.“,”Poly(vinyl alcohol)(PVA) was plasticized by deionized water and was melt-spun into PVA fiber.The stress-strain curves of the melt-spun PVA fibers with 35% and 5% water by mass fraction at different drawing temperatures were measured as well as the activation energy.The results showed that the effect of drawing temperature on the apparent extensional viscosity of melt-spun PVA fibers containing 35% water by mass fraction could be divided into three zones: 30-100 ℃,100-190 ℃ and 190-210 ℃,i.e.there were three different activation mechanisms and the fiber could be drawn at least through three steps;the stretching of the filaments was largely affected by the water content in the system;the motion ability of PVA molecular chains decreased and the apparent extensional viscosity of the melt-spun fibers increased with the reduction of the water content in system; the apparent extersional viscosity of the melt-spun PVA fiber with 5% water by mass fraction changed differently within two different temperature ranges,indicating two different activation mechanisms,so the as-spun fibers could be drawn through two steps.