THEORY OF ELASTIC MECHANISMS IN FIBROUS PROTEINS
THEORY OF ELASTIC MECHANISMS IN FIBROUS PROTEINS
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DOI：
10.1021/ja01601a025
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发表时间：
1956-01-01
影响因子：
15
通讯作者：
FLORY, PJ
中科院分区：
文献类型：
--
作者：
FLORY, PJ
本文讨论的是由长链分子组成的系统在适当条件下以天然纤维蛋白的高阶特征状态发生尺寸变化的问题。特别注意的是分子链的无序过程，这被视为晶体和非晶态之间的可逆相变。力/、温度T和长度L之间的热力学关系适用于结构均匀的纤维、性质轴向变化的纤维和含有第二组分（稀释剂）的系统。迄今为止尚未解释的典型纤维蛋白的热弹性特性，很容易用“长度的减少意味着结晶区域的融化”这一假设来解释。从聚合物体系弹性的统计力学理论的角度考虑了定向（结晶）状态下交联聚合物链形成的网络结构。与以通常方式交联无序链形成的网络相比，值得注意的显著差异是：预计在没有力的情况下，交联纤维在熔化时收缩的长度约为交联度的平方根；当拉伸量大大大于松弛长度时，回缩力应与交联程度无关。通过将弹性统计理论的这些结果与热力学关系b (f/T)/d (l/T)= AH/AL（其中AH和AL是伴随熔化的热量和长度的潜在变化）相结合，力、长度和温度可以在包括相变在内的范围内联系起来。对有序态交联引起的熔点升高进行了理论处理。
This paper is concerned with problems relating to dimensional changes in systems comprising long chain molecules so constituted as to occur, under suitable conditions, in the state of high order characteristic of native fibrous proteins. Particular attention is given to the process of disordering of the molecular chains, which is treated as a reversible phase change be-tween crystalline and amorphous states. Thermodynamic relations between the force/, the temperature T and the length L are developed for fibers of uniform constitution, for fibers whose properties vary axially, and for systems containing a second component (diluent). The hitherto unexplained thermoelastic characteristics of typical fibrous proteins are readily ac-counted for by the hypothesis that decrease in length signifies melting of crystalline regions. Network structures formed by cross-linking polymeric chains in the oriented (crystalline) state are considered from thepoint of view of thestatistical me-chanical theory of elasticity of polymeric systems. Significant differences as compared to networks formed by cross-linking disordered chains in the usual manner are noted: the length to which the cross-linked fiber will shrink on melting in the ab-sence of a force is predicted to increase approximately as the square root of the degree of cross-linking; at extensions sub-stantially greater than this relaxed length, the force of retraction shouldbe independent of the degree ofcross-linking. By combining these results ofthe statistical theory of elasticity with the thermodynamic relationship b (f/T)/d (l/T)= AH/AL, where AH and AL are the latent changes in heat and length accompanying melting, the force, length and tempera-ture may be related over ranges which include the phase change. The elevation of the melting point which should result from cross-linking in the orderedstate is treated theoretically.