以TiO₂/SiO₂[n（TiO₂）：n（SiO₂）=90：10]为催化剂，催化合成了低分子质量聚四氢呋喃二苯甲酸酯（PTMGDB）。采用单因素法进行条件筛选，借助响应面分析法建立连续变量曲面模型，优化反应工艺并预测最佳反应工艺条件为：反应时间为4 h、反应温度为202℃、催化剂质量分数为0.319%（占酸醇总质量）、n（苯甲酸）：n（聚四氢呋喃）=2.077：1。预测的转化率为99.96%，实验重复3次，酯化率高达99.91%，相对误差为0.05%，并通过FT-IR、GPC对产品结构进行表征。结果表明，该模型能成功预测酯化反应结果。加入10% PTMGDB增塑后，PVA水凝膜熔点从183.5℃降低至116.9℃，热稳定性提高；拉伸强度由77.9 MPa降至38.4 MPa；熔体流动速率由0.005 g/min升至4.28 g/min。因此，低分子质量PTMGDB可提高PVA热稳定性、力学性能及熔体流动性，可解决PVA难以热塑性加工的难题。

Low molecular weight polytetrahydrofuran dibenzoate (PTMGDB) is synthesized by using TiO₂/SiO₂[n(TiO₂):n(SiO₂)=90:10] as catalyst.The esterification process is optimized by adopting single factor method for condition screening and establishing a continuous variable surface model through response surface methodology.The predicted optimum reaction process conditions are determined as follows:reaction spends 4 h,reaction temperature is set at 202℃,catalyst dosage is 0.319% of total mass of acid and alcohol,and n(benzoic acid):n(polytetrahydrofuran)=2.077:1.Conversion rate is predicted to be 99.96%.The esterification rate is as high as 99.91% with a relative error of 0.05% in three repeated experiments.It is indicated that the established model can successfully predict the results of this esterification reaction.What's more,the structure of PTMGDB product is characterized by FT-IR and GPC.After being plasticized by adding 10% PTMGDB,the melting point of PVA hydrogel membrane is lowered from 183.5℃ to 116.9℃,its tensile strength declines from 77.9 MPa to 38.4 MPa,and its melt flow rate increases from 0.005 g·min^-1 to 4.28 g·min^-1.Therefore,it is verified that low molecular weight PTMGDB can help PVA improve thermal stability,mechanical properties and melt fluidity,thus overcoming the difficult in the thermoplastic processing of PVA.

李纲(1984-),男,工学学士,工程师,研究方向为BDO与PTMEG的生产及应用,ligang.nxnh@sinopec.com