화학공학소재연구정보센터
홈 로그인 로그아웃 연락처 사이트맵
Polymer(Korea), Vol.22, No.1, 121-130, January, 1998
Export Citation
Poly(methyl methacrylate)/n-Butyl Chloride 계에서 척도화된 환산온도파라미터에 의한 사슬 팽창 거동 해석
Analysis of the Expansion Behavior of Poly(methyl methacrylate) Chains in n-Butyl Chloride by the Scaled Reduced Temperature Parameter
박일현, 김명주
초록
고분자량의 폴리메틸메타크릴레이트(PMMA)를 theta (Θ=41.8℃) 용매인 n-butylchloride (BC)레 녹인 뒤 용액의 온도를 높혀가면서 고분자 사슬의 팽창 거동을 레이저 광산란법 및 점성도법을 이용하여 조사하였다. 팽창계수 α, 고분자 사슬의 유체역학적 반경 RH에 대한 회전반경 RG의 비인 RG/R H,및 Kraemer계수 kK와 같은 사슬 팽창과 연관된 물리량들을 Flory의 팽창계수 α에 관한 식과 임계온도 TC에 관한 Schultz-Flory 식으로부터 유도하여 얻은 척도화된 환산온도파라미터 τ/τC로 해석하였다. 여기서 환산온도와 환산임계온도는 각각 τ=(T-Θ)/Θ, τC = (Θ-TC) /TC로 정의된다. 이 τ/τC 파라미터는 PMMA의 두 개의 서로 다른 분자량에 대하여 만능성을 보여주고 있으며, 또한 만능비 RG/R H도 theta 온도에서 1.26, 용액 온도가 높아지면서 (τ/τC=5.5 부근) 1.45 정도까지 관측되었는데 이러한 측정값은 renormalization group 이론으로부터의 예측과 좋은 일치를 보여주고 있다. PMMA의 BC 용매계에서의 고유점성도의 팽창계수 αη3은 완전히 αη3=αH3은 아니지만 αH3에 상당히 접근해 있는 것으로 보아 Weill의 예측(αη3=αS2αH)과는 다소 다르게 나타났다. 여기서 αS와 αH는 각각 회전반경과 유체역학적 반경의 팽창계수를 의미한다.
Expansion behavior of poly(methyl methacrylate) (PMMA) chains of high molecular weights dissolved in n-butyl chloride(BC) was investigated near the theta temperature (Theta=41.8 degrees C) by means of viscometry and laser light scattering. The expansion factor alpha, the universal ratio of the radius of gyration R-G to the effective hydrodynamic radius R-H, and Kraemer coefficient k(K) were analyzed in terms of the scaled reduced temperature parameter tau /tau(C), where tau=(T-Theta)/Theta, tau(C)=(Theta-T-C)/T-C, which was derived from the Flory equation for the expansion factor and the Schultz-Flory equation for the critical solution temperature T-C. The above-mentioned quantities for PMMA samples of two different molecular weights have shown the universality as the solvent power is increased, when plotted as a function of the tau/ tau(C) parameter. Especially, the R-G/R-H ratio was obtained as 1.26 at the Theta temperature, and 1.45 at tau/tau(C)=5.5. These agreed well with the values from the renormalization group theory. However the expansion factor of the intrinsic viscosity, alpha(eta)(3), was found to be rather close to alpha(H)(3), which was different from Weill's theoretical prediction of alpha(eta)(3)=alpha(S)(2) alpha(H), where alpha(S) and alpha(H) mean the expansion factors of R-G and R-H, respectively.
Keywords:Poly(methyl methacrylate);Laser Light Scattering Viscometry;Expansion Factor;Scaled Reduced Temperature Parameter
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