Alam Md Nur, Islam Md Shahidul, Christopher Lew P
Biorefining Research Institute, Lakehead University, 1294 Balmoral Street, Thunder Bay, Ontario P7B5Z5, Canada.
Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada.
ACS Omega. 2019 May 29;4(5):9419-9426. doi: 10.1021/acsomega.9b00651. eCollection 2019 May 31.
Nowadays, most of the commonly used superabsorbent polymers (SAPs) are derived from synthetic polymers, particularly acrylic acid and its copolymers made with acrylamide. Here, we describe a novel and environmentally friendly aqueous-based process for fabrication of a new, natural, cellulose-based SAP (hydrogel). In this two-step process, cellulose was first reacted with sodium monochloroacetate (MCA) to obtain carboxymethyl cellulose (CMC) and then cross-linked with epichlorohydrin (ECH). In distilled water (d-water), the water retention value (WRV) of the newly fabricated hydrogels reached 725 g d-water/g gel, which is significantly greater than any other commercially available superabsorbent cellulose-based material (WRV of 10-100 g/g) and comparable to the commercial synthetic (polyacrylate) SAP gels (WRV of up to 1000 g/g). In saline water (s-water; 0.9% NaCl), the maximum WRV attained was 118 g s-water/g gel, which exceeds more than 2-fold the WRV of commercial gels (40-50 g/g). Compositional analysis was carried out to determine the amount of carboxyl groups and average molecular mass, and the parameters for hydrogel preparation were optimized. The natural SAP was characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The hydrogels showed good re-swelling properties losing only 5-10% of their capabilities to reabsorb d-water when reused in four consecutive cycles. Because of their superior swelling properties in physiological saline, the new hydrogels can compete with their synthetic counterparts in applications such as high-value hygiene and biomedical products.
如今，大多数常用的高吸水性聚合物（SAPs）都来源于合成聚合物，尤其是丙烯酸及其与丙烯酰胺制成的共聚物。在此，我们描述了一种新颖且环保的水基工艺，用于制备一种新型的、天然的、基于纤维素的SAP（水凝胶）。在这个两步法工艺中，纤维素首先与一氯乙酸钠（MCA）反应以获得羧甲基纤维素（CMC），然后与环氧氯丙烷（ECH）交联。在蒸馏水中，新制备的水凝胶的保水值（WRV）达到725 g蒸馏水/g凝胶，这显著高于任何其他市售的基于纤维素的高吸水性材料（WRV为10 - 100 g/g），并且与商业合成（聚丙烯酸酯）SAP凝胶相当（WRV高达1000 g/g）。在盐水中（0.9% NaCl），达到的最大WRV为118 g盐水/g凝胶，超过商业凝胶WRV（40 - 50 g/g）的2倍多。进行了成分分析以确定羧基的含量和平均分子量，并优化了水凝胶制备的参数。使用扫描电子显微镜（SEM）、傅里叶变换红外光谱（FTIR）和X射线衍射（XRD）对天然SAP进行了表征。当在四个连续循环中重复使用时，水凝胶显示出良好的再溶胀性能，仅损失其重新吸收蒸馏水能力的5 - 10%。由于它们在生理盐水中具有优异的溶胀性能，这种新型水凝胶在高价值卫生和生物医学产品等应用中可以与其合成同类产品竞争。
