SPATIAL INHOMOGENEITIES IN EMULSION POLYMERIZATIONS - REPULSIVE WALL CALCULATIONS

被引:20
作者
CROXTON, CA
MILLS, MF
GILBERT, RG
NAPPER, DH
机构
[1] UNIV SYDNEY,SCH CHEM,SYDNEY,NSW 2006,AUSTRALIA
[2] UNIV NEWCASTLE,DEPT MATH,NEWCASTLE,NSW 2308,AUSTRALIA
关键词
D O I
10.1021/ma00066a014
中图分类号
O63 [高分子化学(高聚物)];
学科分类号
070305 ; 080501 ; 081704 ;
摘要
The extent of the spatially inhomogeneous distribution of polymer particles in a latex formed by emulsion polymerization, dictated by thermodynamic considerations, is investigated computationally. Polymer chains suffer a loss of freedom near the particle surface, causing an entropic repulsion away from the surface and so favoring enhanced monomer concentration near the surface and thus polymerization by encapsulation. Thermodynamic calculations of the equilibrium polymer segment density distribution within a swollen latex particle show that while substantial entropic repulsions do occur, these are countered at higher polymer concentrations by polymer crowding effects. These calculations are performed using the iterative convolution technique to evaluate the segment-segment and segment-boundary correlations, corroborated where practicable with Monte Carlo calculations. This technique represents an advance over previous work which neglected polymer excluded-volume effects. Although the calculations were for low polymer fraction, trends from the results show that repulsive wall effects are highly unlikely to give rise to any significant inhomogeneities in latex particles formed from emulsion homopolymerization in conventional systems.
引用
收藏
页码:3563 / 3571
页数:9
相关论文
共 22 条
[1]  
CHEN SA, 1990, MAKROMOL CHEM-RAPID, V11, P443
[2]   POLYMERIZATION IN NONUNIFORM LATEX-PARTICLES - DISTRIBUTION OF FREE-RADICALS [J].
CHERN, CS ;
POEHLEIN, GW .
JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY, 1987, 25 (02) :617-635
[3]   THE DEVELOPMENT OF LOOPS, TRAINS, AND TAILS IN A SELF-AVOIDING POLYMER SEQUENCE AT A RIGID BOUNDARY AS A FUNCTION OF SOLVENT COMPOSITION [J].
CROXTON, CA .
MACROMOLECULES, 1988, 21 (01) :244-249
[4]   ITERATIVE CONVOLUTION CALCULATIONS OF PARTICLE SCATTERING FUNCTIONS FOR SELF-AVOIDING POLYMER SYSTEMS [J].
CROXTON, CA .
MACROMOLECULES, 1988, 21 (10) :3023-3030
[6]   AN ITERATIVE CONVOLUTION APPROACH TO THE STATISTICS OF POLYMER CONFORMATION [J].
CROXTON, CA .
JOURNAL OF PHYSICS A-MATHEMATICAL AND GENERAL, 1984, 17 (10) :2129-2135
[8]   HIGH-MOLECULAR-WEIGHT POLYMER SEGMENT DISTRIBUTION IN SMALL LATEX-PARTICLES [J].
DABDUB, D ;
KLEIN, A ;
SPERLING, LH .
JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS, 1992, 30 (07) :787-789
[9]   POLYMER-SOLUTIONS NEAR AN INTERFACE .1. ADSORPTION AND DEPLETION LAYERS [J].
DEGENNES, PG .
MACROMOLECULES, 1981, 14 (06) :1637-1644
[10]  
DELACAL JC, 1990, J POLYM SCI POL CHEM, V8, P1011