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Continuum theory of polymer crystallization

机译：聚合物结晶连续理论

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We present a kinetic model of crystal growth of polymers of finite molecular weight. Experiments help to classify polymer crystallization broadly into two kinetic regimes. One is observed in melts or in high molar mass polymer solutions and is dominated by nucleation control with G similar to exp(1/T Delta T), where G is the growth rate and Delta T is the supercooling. The other is observed in low molar mass solutions (as well as for small molecules) and is diffusion controlled with G similar to Delta T, for small Delta T. Our model unifies these two regimes in a single formalism. The model accounts for the accumulation of polymer chains near the growth front and invokes an entropic barrier theory to recover both limits of nucleation and diffusion control. The basic theory applies to both melts and solutions, and we numerically calculate the growth details of a single crystal in a dilute solution. The effects of molecular weight and concentration are also determined considering conventional polymer dynamics. Our theory shows that entropic considerations, in addition to the traditional energetic arguments, can capture general trends of a vast range of phenomenology. Unifying ideas on crystallization from small molecules and from flexible polymer chains emerge from our theory. (c) 2007 American Institute of Physics.
机译：我们提出了有限分子量聚合物晶体生长的动力学模型。实验有助于将聚合物结晶大致分为两个动力学机制。在熔体或高摩尔质量的聚合物溶液中观察到一种，并通过成核控制以类似于exp（1 / T Delta T）的G来控制，其中G是生长速率，而Delta T是过冷。另一个在低摩尔质量溶液（以及小分子）中观察到，并且对于小Delta T，其扩散控制类似于DeltaT。对于我们的模型，我们的模型将这两种体系统一为一个形式。该模型说明了在生长前沿附近聚合物链的积累，并调用了熵屏障理论来恢复成核和扩散控制的极限。基本理论适用于熔体和溶液，我们用数值计算了稀溶液中单晶的生长细节。还考虑常规聚合物动力学来确定分子量和浓度的影响。我们的理论表明，除了传统的精力充沛的论点之外，熵的考虑还可以捕获各种现象学的总体趋势。从小分子和柔性聚合物链中结晶的统一思想源于我们的理论。 （c）2007年美国物理研究所。

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