Light Scattering Studies on Separation and Dissolution Process in GPC

在过去的两年里，我们建立了以下两个主题，并成功地解决了问题。(1)光散射流动池和光浴的设计和构造，以及聚合物溶液循环泵送系统的设计和构造我们构造了一个新的动态光散射仪器，通过消除杂散光，可以在每5个散射角（从10到150）进行测量。通过初步测量，我们确认泵送系统可以将聚合物溶液循环通过流动池，流速低至10<@D1-2@>D2 ml/min至1.0 ml/min，这是GPC测量中常用的速率。(2)本研究相关实验数据的积累我们广泛研究了聚合物在稀、半稀和浓态下的扩散。我们提出了一些可能与这项研究密切相关的新信息。聚合物在纠缠网络中的自扩散和示踪扩散可以用半稀态和浓态的相同函数来描述，用段摩擦系数和纠缠之间的分子量作为约化变量。发现嵌段共聚物溶液中由于微相分离而形成规则晶格的聚合物取决于扩散链大小与晶格常数的比值R。对于r1，聚合物以Rouse型自由扩散机制进行扩散，对于r1，扩散运动比重复理论预测的扩散运动受到更严格的限制。

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.