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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 22, Number 11
BKCSDE 22(11)
November 20, 2001 

Analysis of Excluded Volume Effect in Theta Solvent Systems of Polymethyl Methacrylate and Polystyrene by Means of a Modified Scaled Temperature Parameter
Myung Ju Kim, Il Hyun Park
Polymethyl methacrylate, Hydrodynamic size, Expansion factor, Universality, Scaled reduced temperature parameter.
The expansion of two different kinds of hydrodynamic size of polymethyl methacrylate (PMMA Mw: 1.56- 2.04 × 106 g/mol) has been measured by dynamic light scattering and viscometry above the Flory θ temperature of the various solvents such as n-butyl chloride, 3-heptanone, and 4-heptanone. The expansion of PMMA chains was analyzed in terms of universal temperature parameters and also compared with previous results of polystyrene (PS) system. First it was found that simple τ/ τc parameter no longer had its universality for the expansion behavior of hydrodynamic size in the chemically different linear polymer chains. However after modifying τ/ τc parameter into (Mw/Ro2)3/2 (τ/τc), we observed a much better universality for both PMMA and PS systems. Here Mw, Ro, τ[=(T-Θ)/Θ], and τc[=(Θ-Tc)/Tc] are defined as the weight average molecular weight, the unperturbed end-to-end distance, the reduced temperature and the reduced critical temperature, respectively.
1255 - 1260
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