Abstract

PEG-based smart hydrogels have excellent properties and are widely used in the drug delivery, tissue engineering and other fields. In this article, a temperature responsive and pH sensitive dual responsive hydrogel which is suitable for water plugging and profile control in the Daqing oil field was prepared via graft copolymerization using polyethylene glycol (M_n = 600, 1000, and 2000) and polyamidoamine (PAMAM) as raw materials. The structure and properties of the products were characterized using infrared, ¹H NMR and UV–Vis spectroscopy, end group titration, scanning electron microscopy (SEM) and swelling behavior tests. The influence of the molecular weight of the PEG precursor on the critical phase transition temperature (LCST) and pH sensitivity of the hydrogel were systematically studied. The experimental results showed that when the molecular weight of the PEG precursor was varied in the range of 600–2000, the hydrogel showed obvious temperature sensitivity and the LCST increased from 40 to 50°C. When the pH was in the range of 8–11, the hydrogel exhibited obvious pH sensitivity, swelling under alkaline conditions under acid shrinkage conditions, and the swelling ratio of the hydrogel increased upon increasing the molecular weight of the PEG precursor. The hydrogel was switched at temperatures between 10 and 60°C, pH values between 3 and 11, and the swelling behavior of the hydrogel showed good reversibility for swelling–deswelling, which provides the possibility for water plugging and profile control in an oil field. SEM showed that the hydrogels in their dry state had a spherical structure and as the molecular weight of the PEG precursor increased, the size of the spherical particles decreased and the porosity increased.

中文翻译：

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聚乙二醇接枝聚酰胺型胺树枝状聚合物水凝胶的合成及其对温度和pH的敏感性

摘要

基于PEG的智能水凝胶具有出色的性能，并广泛用于药物输送，组织工程和其他领域。在本文中，温度响应和pH敏感的双响应性水凝胶，其是适用于水堵塞和在大庆油田轮廓控制使用聚乙二醇通过接枝共聚制备（中号_Ñ = 600，1000和2000）和聚酰胺胺（PAMAM ）作为原料。产品的结构和性能用红外光谱仪表征，¹H NMR和UV-Vis光谱，端基滴定，扫描电子显微镜（SEM）和溶胀行为测试。系统地研究了PEG前体的分子量对水凝胶的临界相变温度（LCST）和pH敏感性的影响。实验结果表明，当PEG前体的分子量在600-2000范围内变化时，水凝胶显示出明显的温度敏感性，LCST从40°C增加到50°C。当pH值在8-11范围内时，水凝胶表现出明显的pH敏感性，在碱性条件下在酸收缩条件下溶胀，并且水凝胶的溶胀率随PEG前体分子量的增加而增加。在10至60°C的温度，3至11的pH值之间切换水凝胶 水凝胶的溶胀行为表现出良好的溶胀-溶胀可逆性，这为油田堵水和控制剖面提供了可能性。SEM表明，干燥状态的水凝胶具有球形结构，并且随着PEG前体分子量的增加，球形颗粒的尺寸减小，孔隙率增大。