The expressions of polymer-solvent interaction parameter χ and the mutual interaction parameter g for the quasibinary system consisting with multicomponent poly(α-methylstyrene) and cyclohexane were formulated as a function of concentration and temperature employing critical point data obtained from the measurements of phase volume ratio. The Flory's theta solution temperature was also evaluated. An effort has been made to observe how the average molar mass and molar mass distribution of the original polymer sample effect to the variation of critical point of the solution system studied. The polymer, synthesized by anionic bulk polymerization, was fractionated by fractional precipitation method to give a series of fractions having values of M_w/M_n from 1.14 to 1.73 and mass-average molar mass range of 1.13 x 10⁵ to 6.04 x 10⁵ to 6.04 x 10⁵ g/mol. Cloud points are determined by turbidity titrations. Concentration determinations for the phases separated lead to the construction of coexistence curves. Temperature range observed was 8.2∼27.4℃ and polymer concentration detected was in the range of 0.5∼21% by weight. The critical point data obtained both from the volume ratio of two phases separated and cloud point curve yielded g(T, φ) and χ(T, ψ)function as, g(T, ψ)=0.508 + 66.00/T + 0.223 ψ + 0.072 ψ², χ(T, ψ)=0.290 + 64.56/T + 0.302 ψ + 0.216 ψ². In case where both the coefficients χ₁ and χ₂(eq. 6) are assumed to be dependent on the temperature, the χ(T, ψ) is modified as, χ(T, ψ)=0.377 + 37.79/T + (-0.567 + 270.13/T)ψ. The θ-temperature found from these relationships was in the range of 34.00∼34.31℃, which was well agreed with the value so far published for the same system.

다분산성 poly(α-methylstyrene)과 cyclohexane으로 되는 quasibinary system에 대하여 중합체의 분자량분포에 따른 critical point의 변화를 조사하므로서 온도와 농도에 따른 interaction parameter χ 및 mutual interaction parameter g를 산출할 수 있는 실험식을 확립하였으며 Flory의 θ-온도도 결정하였다. 음이온 중합으로 얻어진 poly(α-methylstyrene)을 재침전법으로 분별하였다. 분별시료들의 중량평균분자량은 1.31 x 10⁵에서 6.04 x 10⁵g/mol의 범위였으며 M_w/M_n 값의 범위는 1.14에서 1.73이었다. 이들 분별시료들의 cloud point는 turbidimeter로 측정하였고 coexistence curve는 분리된 상의농도를 측정하여 구하였다. 이때 측정된 온도와 농도의 범위는 각각 8.2∼27.4℃와 0.5∼21wt%이었다. 분리된 두상의 체적비와 cloud point를 결정하고 이들 critical point data를 이용하여 다음과 같은 g(T, φ) 및 χ(T, φ)에 관한 실험식을 산출하였다. g(T, φ)=0.508 + 66.00/T + o.223 φ + 0.072φ², χ(T, φ)=0.290 + 64.56/T + 0.302 φ + 0.216φ². 계수 χ₁(식6)도 온도 의존성이라고 가정하면 χ(T, φ)는 다음과 같이 변형되었다. χ(T, φ)=0.377 + 37.79/T + (-0.567 + 270.13/T)φ. 이들 실험식들로부터 산출된 θ-온도범위는 34.00∼34.31℃이었고, 이값은 이미 발표된 값과 잘 일치하였다.