The rheology of ultra-high molecular weight poly(ethylene oxide) dispersed in a low molecular weight carrier.
The rheology of ultra-high molecular weight poly(ethylene oxide) dispersed in a low molecular weight carrier.
复制标题
DOI：
10.1063/5.0077122
复制
发表时间：
2022-02
影响因子：
4.6
通讯作者：
Craig D. Mansfied;Tianran Chen;Mubashir Q. Ansari;D. Baird
中科院分区：
文献类型：
--
作者：
Craig D. Mansfied;Tianran Chen;Mubashir Q. Ansari;D. Baird
凝胶纺丝是将亲水性超高分子量 (UHMW) 聚合物树脂与疏水性支撑聚合物相结合以生产用于细胞分离的复合丝的工业方法。细胞分离术是一种从血液中去除白细胞的医疗技术。凝胶纺丝用于避免超高分子量树脂的高熔体粘度和热敏感性以及基材树脂的高熔体温度，但需要回收有毒溶剂。使用UHMW树脂是因为它在水存在下形成稳定的凝胶相；较低分子量树脂 (LMW) 会简单溶解。 UHMW 和 LMW 树脂均为聚环氧乙烷 (PEO)，基材为聚芳基砜 (PAS)。文献表明，PEO 在 200 °C 以上会发生非氧化热降解，而 PAS 的加工温度可达 350 °C。动态振荡剪切流变测定法用于研究 0、25、40、50、60 和 75 wt. LMW PEO 中的 % UHMW PEO 利用粘度对分子量和材料构型变化的敏感性，指示降解。将样品暴露在 220 °C、230 °C、240 °C、250 °C、275 °C 和 300 °C 温度下 5 分钟，以探索可能导致样品降解的条件。对于暴露在相同温度下的样品，随着 UHMW PEO 含量的增加，粘度降低得较少；而对于具有相同 UHMW PEO 含量的样品，随着暴露温度的增加，粘度降低得更多。根据观察到的数据对参数进行回归，通过将粘度与分子量、剪切速率、温度和时间相关的经验主义来预测分子量的变化。
Gel spinning is the industrial method of choice for combining hydrophilic ultra-high molecular weight (UHMW) polymer resins with a hydrophobic support polymer to produce composite filaments for cytapheresis. Cytapheresis is a medical technique for removal of leukocytes from blood. Gel spinning is used to avoid high melt viscosity and thermal sensitivity of UHMW resins and the high melt temperature of the substrate resin but requires the recovery of toxic solvents. The UHMW resin is used because it forms a stable gel phase in the presence of water; a lower molecular weight resin (LMW) simply dissolves. UHMW and LMW resins were both poly(ethylene oxide) (PEO) and the substrate was polyarylsulfone (PAS). The literature indicated PEO undergoes non-oxidative thermal degradation above 200 °C and PAS is processed up to 350 °C. Dynamic oscillatory shear rheometry was used to study 0, 25, 40, 50, 60, and 75 wt. % UHMW PEO in LMW PEO to take advantage of the sensitivity of viscosity to changes in molecular weight and material configuration, indicating degradation. Samples were exposed to 220 °C, 230 °C, 240 °C, 250 °C, 275 °C, and 300 °C temperatures for 5 min to explore conditions that could result in sample degradation. The viscosity decreased less with increasing UHMW PEO content for samples exposed to the same temperature and the viscosity decreased more with increasing exposure temperature for samples with the same UHMW PEO content. Parameters were regressed from observed data to predict the change in molecular weight via empiricisms relating the viscosity to molecular weight, shear rate, temperature, and time.