Papp Vanda, Vadkerti Bence, Bányai István, Kéki Sándor, Kéri Mónika
Department of Physical Chemistry, University of Debrecen, H-4032 Debrecen, Hungary.
Department of Applied Chemistry, University of Debrecen, H-4032 Debrecen, Hungary.
J Phys Chem B. 2025 Jun 5;129(22):5607-5620. doi: 10.1021/acs.jpcb.5c01046. Epub 2025 May 25.
In this study, the swelling properties and structural changes during the interaction with liquid media of biodegradable cross-linked polyurethanes promising from medical and environmental points of view are reported. To characterize the polyurethane samples, containing sucrose as cross-linking agent in different concentrations, in the dry state, and swollen in water and dimethyl sulfoxide (DMSO), low- and high-field liquid-phase NMR spectroscopic methods, such as relaxometry, diffusometry, and cryoporometry, were applied. Based on the NMR relaxation features of the swelling liquids and the swollen cross-linked polymers, the difference in the interaction with the two liquids was evaluated; furthermore, the rigid and mobile domains in the amorphous part of the polymer were successfully identified. The change of their ratio with the sucrose content and the restricted diffusion of DMSO in the swollen polymer network reflected the cross-link density and highlighted the role of dangling chains. The swelling process in DMSO was followed by the change of the relaxation of the infiltrating liquid in time and was described by the second-order kinetic model with a suggested, detailed swelling mechanism. Cryoporometry measurements enlightened the effect of swelling on the size change of the liquid domains in the cross-linked structure.
本研究报道了从医学和环境角度来看具有前景的可生物降解交联聚氨酯在与液体介质相互作用过程中的溶胀特性和结构变化。为了表征不同浓度下含有蔗糖作为交联剂的聚氨酯样品，这些样品处于干燥状态，以及在水和二甲基亚砜（DMSO）中溶胀后的状态，应用了低场和高场液相核磁共振光谱方法，如弛豫测量法、扩散测量法和低温孔率测定法。基于溶胀液体和溶胀交联聚合物的核磁共振弛豫特征，评估了与两种液体相互作用的差异；此外，成功识别了聚合物无定形部分中的刚性和可移动区域。它们的比例随蔗糖含量的变化以及DMSO在溶胀聚合物网络中的受限扩散反映了交联密度，并突出了悬垂链的作用。DMSO中的溶胀过程伴随着渗透液体弛豫随时间的变化，并由具有建议的详细溶胀机制的二级动力学模型进行描述。低温孔率测定测量揭示了溶胀对交联结构中液体域尺寸变化的影响。
