Linear diepoxide-terminated poly(ethylene glycol) (PEG) of molar mass 600, 1000 and 2000 g mol −1 was end-linked with dendrimer-star polymer (PAMAM) of generations 1.0 in water to prepare architecturally well-defined copolymer hydrogels. The structures and properties of the products were characterized using infrared, 1 H NMR, DSC measurements, scanning electron microscopy (SEM) and swelling behavior tests. The swelling behavior of these hydrogels was tested in distilled water at constant temperature and the equilibrium swelling ratio (ESR) was determined for structurally different hydrogels and various environmental conditions, which showed that ESR was influenced by the molecular weight of PEG, the molar ratio of H amine groups/epoxy groups, temperature and pH. Higher ESR was obtained for either longer-chain PEG, non-stoichiometric H amine/epoxy groups ratio, acidic pH or lower temperatures. When the hydrogel was switched from 10 °C to 65 °C and pH 3.5 to 11.5, the swelling behavior of the hydrogels showed good reversibility for swelling–deswelling. When the molecular weight of PEG was changed in the range of 600–2000, the lower critical solution temperature (LCST) of hydrogel increased from 30 to 40 °C. When the molar ratio of H amine/epoxy groups was changed, the LCST was not significantly changed.

中文翻译：

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由线性聚乙二醇和树枝状星型聚合物制备的末端连接的水凝胶的制备和溶胀行为

在水中将摩尔质量分别为600、1000和2000 g mol -1的线性双环氧化合物封端的聚乙二醇（PEG）与1.0的树枝状大分子星形聚合物（PAMAM）进行末端连接，以制备结构明确的共聚物水凝胶。使用红外，1 H NMR，DSC测量，扫描电子显微镜（SEM）和溶胀行为测试对产物的结构和性质进行表征。在恒温蒸馏水中测试了这些水凝胶的溶胀行为，并确定了结构上不同的水凝胶和各种环境条件下的平衡溶胀比（ESR），这表明ESR受PEG分子量，PEG摩尔比的影响。 H胺基/环氧基，温度和pH。较长链的PEG的ESR较高，非化学计量的H胺/环氧基比率，酸性pH或较低温度。当水凝胶从10°C切换到65°C，pH从3.5切换到11.5时，水凝胶的溶胀行为显示出良好的溶胀-溶胀可逆性。当PEG的分子量在600–2000范围内变化时，水凝胶的较低临界溶液温度（LCST）从30°C增加到40°C。当H胺/环氧基的摩尔比改变时，LCST没有显着改变。水凝胶的最低临界溶液温度（LCST）从30°C升高到40°C。当H胺/环氧基的摩尔比改变时，LCST没有显着改变。水凝胶的最低临界溶液温度（LCST）从30°C升高到40°C。当H胺/环氧基的摩尔比改变时，LCST没有显着改变。