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用超速离心法分离高抗冲聚苯乙烯预聚体来研究相平衡及单体在橡胶(R)相和聚苯乙烯(PS)相中的分配。发现所生成的接枝物溶于橡胶相,使橡胶总含量和R相体积增加。因此对以前由模拟体系求得的三元相图作了改进。并建立了以下数学模型: 1.相分离点的转化率 x_c=[(1-Φ_1)_c-C_(RO)]/(1-C_(RO)) (1-Φ_1)=(1/(m_2~(1/2))+1/(m_3~(1/2)))~2/(2x_(23)) 2.相分离后两相的平衡浓度 C_(ps)=0.01537+1.263C_R 1.263C_R~2+{0.01537-1.263(1+E)C_(RO)-(1-C_(RO))X+C_(RO)E}C_R-0.01537(1+E)C_(RO)=0 3.两相体积比 Φ_R/Φ_(PS)=C_(PS)(1+E)C_(RO)/[(1-C_(RO))x-C_(RO)E]式中C_(PS)和C_R分别为PS相和R相的聚合物浓度;C_(RO)为初始橡胶浓度;E为橡胶接枝率;m_2,m_3分别为PS和R的聚合度;X为转化率;X_(23)为PS和R的相互作用参数。以上模型在计算上计算的结果表明,C_(RO)<3％的体系不需搅拌就可得到转相了的产品;C_(RO)>11％的体系预聚结束时还不会转相。
The high impact polystyrene prepolymer was isolated by ultracentrifugation to study phase equilibria and monomer partitioning in the rubbery (R) and polystyrene (PS) phases. The resulting graft was found to dissolve in the rubber phase, resulting in an increase in the total rubber content and the R phase volume. Therefore, the ternary phase diagram obtained by the simulation system has been improved. And the following mathematical models are established: 1. Conversion rate of phase separation point x_c = [(1-Φ_1) _c-C_ (RO)] / (1-C_ (RO)) (1 -Φ_1) = (1 / (m_2 ~ (1/2)) + 1 / (m_3 ~ (1/2))) ~2 / (2x_ (23)) 2. The equilibrium concentration of the two phases after the phase separation C_ (ps) = 0.01537 + 1.263C_R 1.263C_R ~ 2 + {0.01537-1.263 (1 + E) C_ (RO) - (1-C_ (RO)) X + C_ (RO) E} C_R- 0.01537 (1 + E) C_ (RO) The phase volume ratio Φ_R / Φ_ (PS) = C_ (PS) (1 + E) C_ (RO) / [(1-C_ (RO)) x_C_ (RO) E where C_ (PS) and C_R Is the polymer concentration of PS phase and R phase; C_ (RO) is the initial rubber concentration; E is the rubber grafting rate; m_2 and m_3 are the degree of polymerization of PS and R respectively; X is the conversion; X 23 is PS And R’s interaction parameters. The calculated results from the above models show that the system with C_ (RO) <3% can get the phase-reversed product without agitation; the phase-prepolymer with C_ (RO)> 11% does not change phase at the end of prepolymerization.