类离子液体增塑改性聚乙烯醇的制备及性能

Preparation and Properties of Polyvinyl Alcohol Plasticized by Pseudo Ionic Liquids

为了实现聚乙烯醇(PVA)的熔融纺丝,采用氯化胆碱(ChCl)与木糖醇(Xyl)合成类离子液体(PILs),将其作为增塑剂,辅以润滑剂硬脂酸钙和抗氧剂B225,对PVA进行增塑改性。通过差示扫描量热仪、热重分析仪、熔体流动速率仪研究了PILs对PVA热性能和流动性的影响;通过红外光谱仪、X射线衍射仪和扫描电镜对PILs增塑改性PVA的分子间氢键作用、结晶度和相容性进行了表征和分析;并研究了纺丝温度对改性PVA可纺性及力学性能的影响。结果表明,PILs能与PVA的羟基之间形成新的氢键,减弱PVA自身的氢键作用,从而降低PVA的熔点和结晶度,提高其热稳定性和流动性;当PILs的配比为1:2,质量占比为12.5时,改性PVA的热分解温度、熔点和熔体流动速率分别为291.2℃,169.4℃和6.20 g/10 min;改性PVA在230~250℃的温度时均能熔融纺丝,随着纺丝温度升高,纤维断裂强度逐渐降低,断裂伸长率先升高后降低。

In order to realize the melt spinning of polyvinyl alcohol(PVA),pseudo ionic liquids(PILs)were synthesized from choline chloride(ChCl)and xylitol(Xyl),which were used as plasticizer,supplemented by calcium stearate and irganox B225,to plasticize polyvinyl alcohol(PVA).The effects of PILs on the thermal properties and fluidity of PVA were obtained by differential scanning calorimeter,thermogravimetric analyzer and melt flow rate measurer;the intermolecular hydrogen bonds,crystallinity and compatibility of PVA plasticized by PILs were characterized and analyzed by FT-IR,XRD and SEM.The effects of spinning temperature on the spinnability and mechanical properties of modified PVA were investigated.The results show that PILs can form strong hydrogen bond with PVA,which weaken the hydrogen bonds of PVA,thereby reducing the melting point and crystallinity of PVA,and improving its thermal stability and fluidity.The thermal decomposition temperature,melting point and melt flow rate of the modified PVA are 291.2℃,169.4℃and 6.20 g/10 min,respectively,when the mole ratio of PILs is 1:2 and the mass ratio is 12.5.The modified PVA can be melt spun at 230~250℃.The breaking strength of the fiber gradually decreases,and the elongation at break first increases and then decreases with the rising of spinning temperature.