Light Scattering Studies on Separation and Dissolution Process in GPC

在过去的两年里，我们成功地解决了以下两个主题。(1)光散射流动池和池的设计和建造以及聚合物溶液循环泵系统的设计和建造我们建造了一种新的动态光散射仪，该仪器通过消除杂散光，在10 °至150 °的每5个散射角处进行测量。从初步测量中，我们证实了泵送系统可以使聚合物溶液以低至10 D1 -2 D2 ml/min至1.0 ml/min的流速循环通过流动池，该流速是GPC测量中常规使用的速率。(2)与本研究有关的实验数据的积累我们广泛地研究了聚合物在稀、半稀和浓三种状态下的扩散。我们提出了一些可能与这项研究密切相关的新信息。缠结网络中聚合物的自扩散和示踪剂扩散可以用半稀态和浓态的相同函数来描述，用缠结之间的链段摩擦系数和分子量作为简化变量。嵌段共聚物溶液中的聚合物由于微相分离而形成规则的晶格，这取决于扩散链的尺寸与晶格常数的比值R。对于R1，聚合物扩散的Rouse型的自由扩散机制，并为R1，扩散运动受到更严格的限制比爬行理论预测的。

Following two theme were set up and we could successfully solve the problems during last two years.(1) Design and construction of flow cell and bath for light scattering and of a pumping system for circulation of polymer solutionsWe constructed a new dynamic light scattering instrument which permitts measurements at scattering angles of every 5 form 10 to 150 by eliminating stray light. From preliminary measurements, we confirmed that the pumping system could circulate polymer solutions through the flow cell with a flow rate of as low as 10<@D1-2@>D2 ml/min to 1.0 ml/min, a rate being routinely used in GPC measurements.(2) Accmulation of experimental data related to this researchWe extensively studied diffusion of polymers in the dilute, the semidilute and also the concentrated regime. We present a couple of new informations which may be closely related to this research. Self and tracer diffusion of polymers in entanglement networks can be described by a same function in the semidilute as well as the concentrated regime by using a segment friction coefficient and molecular weight between entanglements as reduced variables. Polymers in block copolymer solutions which form regular lattice due to microphase separation is found to depend on the ratio R of the size of the diffusing chain to the lattice constant. For R 1, polymers diffuse by the Rouse type of free diffusion mechanism, and for R 1, the diffusion motion is more severely restricted than that predicted by the reptation theory.