Vázquez B, Gurruchaga M, Goñi I, San Román J
Instituto de Ciencia y Tecnología de Polímeros, CSIC, Madrid, Spain.
Biomaterials. 1997 Apr;18(7):521-6. doi: 10.1016/s0142-9612(96)00091-9.
Hydrogels based on ethoxytriethyleneglycol monomethacrylate/methyl methacrylate copolymers were prepared by free radical polymerization at 70 degrees C in bulk with 2,2'-azobisisobutyronitrile as initiator. The swelling behaviour of the hydrogels was studied by immersion of the films in water and in buffered solutions at various pHs. The hydration process was followed gravimetrically measuring the water uptake of the films with the time of treatment. The kinetics fit adequately a Fickian law for reduced sorption coefficients, Mt/M infinity, lower than 0.6. The values of the diffusion coefficient were lower at neutral pH than at acidic or alkaline pHs, and they seemed to be independent of the copolymer composition. The results obtained were consistent with the stress relaxation model of polymer chains predicted for a relatively fast hydration process. The swelling process is reversible and the polymeric films are stable after repeating cycles of hydration and desorption promoted by the change of pH in appropriate buffered solutions.
以乙氧基三甘醇单甲基丙烯酸酯/甲基丙烯酸甲酯共聚物为基础的水凝胶，通过在70℃下以2,2'-偶氮二异丁腈为引发剂进行本体自由基聚合制备。通过将薄膜浸泡在水和不同pH值的缓冲溶液中来研究水凝胶的溶胀行为。采用重量法跟踪水合过程，测量薄膜在处理时间内的吸水量。对于降低的吸附系数Mt/M∞低于0.6的情况，动力学充分符合菲克定律。在中性pH值下扩散系数的值低于酸性或碱性pH值下的值，并且它们似乎与共聚物组成无关。所获得的结果与预测的相对快速水合过程的聚合物链应力松弛模型一致。溶胀过程是可逆的，并且在适当缓冲溶液中通过pH值变化促进的水合和解吸重复循环后，聚合物薄膜是稳定的。
