HOW FAR IS FAR FROM CRITICAL-POINT IN POLYMER BLENDS - LATTICE CLUSTER THEORY COMPUTATIONS FOR STRUCTURED MONOMER, COMPRESSIBLE SYSTEMS

被引:50
作者
DUDOWICZ, J
LIFSCHITZ, M
FREED, KF
DOUGLAS, JF
机构
[1] UNIV CHICAGO,DEPT CHEM,CHICAGO,IL 60637
[2] NATL INST STAND & TECHNOL,DIV POLYMER,MAT SCI & ENGN LAB,GAITHERSBURG,MD 20899
关键词
D O I
10.1063/1.466028
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Although the lattice cluster theory (LCT) incorporates many features which are essential in describing real polymer blends, such as compressibility, monomer structures, local correlations, chain connectivity, and polymer-polymer interactions, it still remains a mean field theory and is therefore not applicable in the vicinity of the critical point where critical fluctuations become large. The LCT, however, permits formulating the Ginzburg criterion, which roughly specifies the temperature range in which mean field applies. The present treatment abandons the conventional assumptions of incompressibility and of composition and the molecular weight independent effective interaction parameter chi(eff) upon which all prior analyses of the Ginzburg criterion are based. Blend compressibility, monomer structure, and local correlations are found to exert profound influences on the blend phase diagram and other critical properties and, thus, exhibit a significant impact on the estimate of the size of the nonclassical region. The LCT is also used to test various methods which employ available experimental data in computations of the Ginzburg number Gi. The reduced temperature tau = \T-T(c)\/ defining the range of the validity of mean field theory (tau > tau(MF)) and the onset of the Ising-type scaling regime (tau > tau(crit) are quite different, and renormalization group estimates of tau(MF) and tau(crit) are presented as a function of Gi to more precisely specify these scaling regimes.
引用
收藏
页码:4804 / 4820
页数:17
相关论文
共 56 条
[41]   CRITICAL-POINTS OF MIXTURES - ANALOGY WITH PURE FLUIDS [J].
MOLDOVER, MR ;
GALLAGHER, JS .
AICHE JOURNAL, 1978, 24 (02) :267-278
[42]   TEMPERATURE-DEPENDENCE OF THE INTERACTION PARAMETER OF POLYSTYRENE AND POLY(METHYL METHACRYLATE) [J].
RUSSELL, TP ;
HJELM, RP ;
SEEGER, PA .
MACROMOLECULES, 1990, 23 (03) :890-893
[43]   STATISTICAL THERMODYNAMICS OF POLYMER-SOLUTIONS [J].
SANCHEZ, IC ;
LACOMBE, RH .
MACROMOLECULES, 1978, 11 (06) :1145-1156
[44]   VOLUME FLUCTUATION THERMODYNAMICS OF POLYMER-SOLUTIONS [J].
SANCHEZ, IC .
MACROMOLECULES, 1991, 24 (04) :908-916
[45]   A UNIVERSAL COEXISTENCE CURVE FOR POLYMER-SOLUTIONS [J].
SANCHEZ, IC .
JOURNAL OF APPLIED PHYSICS, 1985, 58 (08) :2871-2874
[46]   CRITICAL PROPERTIES OF THE FLORY-HUGGINS LATTICE MODEL OF POLYMER MIXTURES [J].
SARIBAN, A ;
BINDER, K .
JOURNAL OF CHEMICAL PHYSICS, 1987, 86 (10) :5859-5873
[47]   EARLY STATE OF SPINODAL DECOMPOSITION STUDIED WITH SMALL-ANGLE NEUTRON-SCATTERING IN THE BLEND DEUTEROPOLYSTYRENE AND POLYVINYLMETHYLETHER - A COMPARISON WITH THE CAHN-HILLIARD-COOK THEORY [J].
SCHWAHN, D ;
JANSSEN, S ;
SPRINGER, T .
JOURNAL OF CHEMICAL PHYSICS, 1992, 97 (11) :8775-8788
[48]  
SENGERS JV, 1978, PROG LIQUID PHYSICS, pCH7
[49]  
SENGERS JV, COMMUNICATION
[50]   STUDY OF MISCIBILITY AND CRITICAL PHENOMENA OF DEUTERATED POLYSTYRENE AND HYDROGENATED POLYVINYL METHYL-ETHER) BY SMALL-ANGLE NEUTRON-SCATTERING [J].
SHIBAYAMA, M ;
YANG, HJ ;
STEIN, RS ;
HAN, CC .
MACROMOLECULES, 1985, 18 (11) :2179-2187