Flory状态方程理论与聚合物混合物的热力学

由Flory状态方程理论的化学位公式推导了二元混合物的亚稳单相极限线,同时导出了状态方程参数的温度、压力依赖性,计算表明Flory理论是可以像McMaster修正理论一样描述聚合物的相溶性行为的。 指出前人的工作由于假定相互作用能和熵参数均为0,分子量和状态方程参数对相界的影响被誇大了,相分离也只发生在很窄的浓度范围内。如果考虑了实际体系中相互作用能和熵参数均不为0,上述因素对相界的影响以及相界的形状将趋于合理。     

STATISTICAL THERMODYNAMICS OF POLYMER MIXTURES

Based on a hole model the equation of state of polymeric liquids, the chemical poten-tial and the spinodal of polymer mixtures are derived. In the model the volume changesof liquids are realized through changing the distance between molecules (size of the cell)and number of holes in liquids. If these two factors are considered one by one, two setsof equations of the above equilibrium properties are obtained but one common chemicalpotential equation. With further simplification all the formulas are reduced to that of theFlory or the Sanchez theory respectively.     

焙烧法制备凝胶渗透色谱用硅胶

多孔硅胶是凝胶渗透色谱用的一种填料。它具有化学惰性好,可用于除碱性外各种溶剂;机械强度高,能承受高压不破碎;热稳定性好,在高温溶剂下经久耐用等优点。并且它装柱简单,可直接使用干胶装柱。不溶胀,可在柱中直接更换溶剂。使用寿命长,可反复装柱且数据重复,在色谱中对液流的阻力小。有良好的分离效率。在制备各种孔径的多孔硅胶时,一般都以小孔径的硅胶作为原料,通过适当的方法来“扩孔”使孔径扩大1—2个数量级,以得到所需要孔径范围的硅胶。扩孔方法通常采用焙烧法在炉中焙烧。它操作简单,容     

CLOUD POINT CURVES OF POLY(ETHYLENE GLYCOL)/POLY(PROPYLENE GLYCOL) MIXTURES AND THEIR THERMODYNAMIC EXPLANATION

In the study of poly(ethylene glycol) (PEG) and poly(propylene glycol) (PPG) mixtures not only a bimodal shape but also a reverse trend of the dependence on molecular weight of the cloud point curves were observed.This trend indicates that the miscibility of the studied mixtures decreases as the molecular weight of one component decreases. The excess volumes of the mixtures show that the interaction parameter between two components decreases at first and increases after passing a minimum as the concentration of one component increases. This supports the explanation of Koningsveld on the bimodal shape of cloud point curves. Based on a binary interaction model a formula was derived revealing that the interaction between PPG and the end group of PEG and the hydrogen bonding interaction between ether and hydroxy end group inner or inter PEG molecules are not favorable for mixing. The latter interaction is an "attractive" force in PEG molecules. The two interactions are responsible for the observed abnormal dependence.     

应用反气相色谱法研究高分子-溶剂相互作用

应用反气相色谱法研究了聚乙二醇和若干溶剂的相互作用。实验表明以表面处理多孔硅胶为担体,为获得准确的保留体积,需考虑作固定相在担体上涂布量外推。据此计算出相互作用参数X和 ,可和静态蒸汽吸附法或混合体积测定等所得数据相比,并反映了聚乙二醇和溶剂相互作用的某些特点。     

低渗透极限交联聚苯乙烯型凝胶色谱填料

本文通过低交联度聚苯乙烯凝胶的合成,讨论了它的成孔机理以及致孔剂(稀释剂)的作用;并就若干低分子化合物作标样时,相对于聚苯乙烯标样的换算关系作简略介绍;测定填料的结构参数,并与色谱性能结合,指出即使是低交联度的凝胶也存在非均匀的分子链网孔结构。     

ASPECTS OF THERMODYNAMICS OF POLYMER MIXTURES

In this brief review article some aspects of the thermodynamics of polymer mixtures are discussed, mainly based on the author's research. The studies of poly (methyl methacrylate)/chlorinated polyethylene (CPE), poly (butyl acrylate)/CPE and CPE/CPE (different chlorine content) mixture verify the "dissimilarity" and "similarity" principles for predicting miscibility of polymer mixtures. The sign of heat of mixing of oligomeric analogues is not sufficient in predicting the miscibility. The Flory equation of state theory has been applied to simulate the phase boundaries of polymer mixtures. The empirical entropy parameter Q_(12) plays an important role in the calculation, this reduces the usefulness of the theory. With energy parameter X_(12)≠0 and Q_(12)≠0 the spinodals so calculated are reasonable compared to experiments. A hole model was suggested for the statistics of polymer mixtures. The new hole theory combines the features of both the Flory equation of state theory and the Sanchez lattice fluid theory and can be reduced to them under some conditions.     

高分子溶液及混合物的统计热力学

本文以空胞模型为基础讨论了高分子液体的状态方程式、它们的溶液和混合物的化学位公式以及相分离条件。这时液体的体积变化可以以分子间距离的改变(即囚胞尺寸的变化)和液体中孔洞数的增减来实现。若分别讨论其中某一个因素的贡献,我们得到了有关上述问题的两组方程式,但化学位公式是共同的。若作进一步简化,则分别地得到了Flory状态方程理论和Sanchez格子流体理论所给出的公式。     

对Maron理论处理高分子稀溶液的一点修改

近年来应用Maron溶液理论处理高分子溶液的一系列关于溶剂的热力学性貭,得到满意的結果。現有的例子都属高分子-良溶剂溶液。对稀溶液渗透压数据的处理,作者等巳指出可用π/c(1+qc)对c(1+qc)的作图法,得到直线关系,其中(符号均按Maron的写法,参阅文献[4])