Relations between microscopic crosslinking structure and heterogeneity of physical gels and macroscopic properties.

我们设计了一种红外光谱仪，在10 μ m尺度下测量凝胶或薄膜样品在拉伸过程中的二色性，以观察分子在拉伸变形刺激下的运动。研究了两种微晶交联区类型不同的聚乙烯凝胶的红外二色性随延伸率的变化。一种是用四氢化萘作为溶剂使薄膜膨胀而制成的膨胀凝胶。另一种是通过逐渐冷却通过加热膨胀凝胶得到的溶液而制备的溶液凝胶。膨胀凝胶分两步变形；在第一步中，凝胶通过由片层组成的交联区域的旋转而变形，在第二步中，晶体和非晶体区域通过伸长定向。另一方面，溶液凝胶通过一步变形，其中晶体和非晶体区域同时被伸长取向。研究了含有微晶区包围的巨球晶的聚丙烯薄膜的变形行为。随着延伸的进行，微晶区取向很大，而巨球晶几乎没有取向，这意味着与微晶区相比，球晶是相当刚性的。在微晶区，在完成屈服现象之前几乎保持无取向状态，在屈服点之后迅速取向。然后取向逐渐进行，进一步伸长。在大球晶区，α_晶体中各晶束的片层发生分离和缠结。α_<混合>晶体不易变形，因为子片层阻止了母片层的变形。β晶体易碎，扭曲片层的纠缠在小应力作用下容易解除。α晶体相对孤立于微晶区，而β晶体则与微晶区纠缠在一起，球晶的变形对体系的变形影响较大。少

We designed an infrared spectrometer for dichroism measurement under microscopic scope of 10 μ m size during elongation of samples of gels or films in order to observe molecular motions responding to stimulus of elongational deformation.We measured infrared dichroism change with elongation for two types of polyethyelene gels with different type of crosslink regions of microcrystallite. One is a swelling gel prepared by swelling the film in tetralin as solvent. The other is a solution gel prepared by gradually cooling a solution obtained by heating the swelling gel. The swelling gel deformed by two steps ; In first step, gel deformed by the rotation of crosslink region consisting of lamellae, and in second step crystalline and non-crystalline regions were oriented by elongation. On the other hand, the solution gels deformed by One step, in which crystalline and non-crystalline regions were simultaneously oriented by elongation.We investigated the deformation behavior of polypropylene fi … More lm including giant spherulites surrounded by microcrystallite region. When elongation proceeded, microcrystallie region was oriented largely while the giant spherulites were scarcely oriented, which means that the spherulite is fairly rigid in comparison with the microcrystalline region. In the microcrystalline region, it almost keeps unoriented state before finishing yield phenomenon and rapidly oriented just after the yield point. And then the orientation gradually proceeded with further elongation. As for the giant spherulite region, in α_ crystals, separation and entanglement of lamellae occurred for each bundles of crystals. α_<mix> crystals did not easily deform because child lamellae prevent from deformation of parent lamellae. β crystal was fragile and entanglement of twisted lamella was easily disentangled by small stress. α crystals were fairly isolated from the microcrystalline region, while β crystals entangled with microcrystalline region and deformation of spherulite in largely influence to the deformation of the system. Less