The viscosity-temperature relationship of acrylic oligomers diluted with four solvents which had different solubility parameters was studied.
An easy method to determine the constant C
2 in WLF equation through the modification of WLF equation was proposed. WLF equation was applicable for all solutions investigated.
Fractional free volume was calculated from Doolittle equation. The additivity of fractional free volume at various concentrations was observed in all oligomer-solvent systmes.
Tg obtained from the extrapolation of fractional free volume (
fT) in
fT-
T plot almost agreed with that obtained from WLF equation. The greater the difference of solubility parameter between oligomer and solvent was, the smaller the fractional free volume of mixture became.
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