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首页> 外文期刊>European Polymer Journal >Cryostructuring of polymeric systems. 48. Influence of organic chaotropes and kosmotropes on the cryotropic gel-formation of aqueous poly(vinyl alcohol) solutions
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Cryostructuring of polymeric systems. 48. Influence of organic chaotropes and kosmotropes on the cryotropic gel-formation of aqueous poly(vinyl alcohol) solutions

机译：聚合物系统的冷冻水平。 48.有机络杂波和kosmotropes对水性聚（乙烯醇）溶液的冷颤凝胶形成的影响

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Physical (non-covalent) macroporous cryogels of poly(vinyl alcohol) (PVACGs) are formed as a result of the consecutive freezing of concentrated PVA solutions, their incubation in a frozen state and then thawing. If some additional low-molecular-weight solutes are present in the feed system to be gelled cryogenically, such additives can affect more or less the physicochemical properties and the microstructure (porous morphology) of the resultant PVACGs. In this study the influence of the additives of organic non-ionic and ionic chaotropes (urea and guanidine hydrochloride) or kosmotropes (trehalose and hydroxyproline) on the PVA cryotropic gel-formation, as well as on the properties and structural features of the respective PVACGs was explored. It was shown that both the strength and the heat endurance of cryogels formed in the presence of chaotropes progressively decreased with increasing the additive concentration. In turn, in the case of cryogels prepared in the presence of kosmotropes the dependences of the physicomechanical characteristics on the additive concentration were of a bell-like (concave) type, while the heat endurance of the samples grew monotonically. The microstructure of the PVAGCs containing various amounts of the chaotropes and the kosmotropes was studied using the optical microscopy of thin sections followed by the mathematical analysis of the images. The average size of the pore crosssection and the "conditional porosity" of the respective specimens were characterized quantitatively.
机译：作为连续冷冻浓缩的PVA溶液连续冷冻的结果，形成物理（非共价）多孔冷冻凝胶，其在冷冻状态下孵育，然后解冻。如果在进料系统中存在一些额外的低分子量溶质待冷冻地凝胶化，则这些添加剂可以影响或多或少地影响所得pVACG的物理化学性质和微观结构（多孔形态）。在该研究中，有机非离子和离子椎间型椎间椎间型（盐酸脲）或kosmotropes（海藻糖和羟脯氨酸）对PVA冷颤凝胶形成的影响，以及各自PVACG的性质和结构特征的影响探索了。结果表明，随着添加剂浓度的增加，在络合物的存在下形成的细菌的强度和耐热性逐渐降低。反过来，在kosmotropes存在下制备的冷冻胶质的情况下，物理机械特性对添加剂浓度的依赖性是喇叭（凹的）类型，而样品的热耐久性单调均匀地生长。使用薄部分的光学显微镜进行含有各种量的椎弓孔和kosmotropes的PVAGC的微观结构，然后进行图像的数学分析。定量表征孔隙横截面的平均尺寸和各个样本的“条件孔隙率”。

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