Small-Angle X-ray Scattering Analysis on the Estimation of Interaction Parameter of Poly( n -butyl acrylate)- b -poly(methyl methacrylate).

The temperature dependence of the Flory-Huggins interaction parameter χ for poly( n -butyl acrylate)- b -poly(methyl methacrylate) (PBA- b -PMMA) was quantified from small-angle X-ray scattering (SAXS) analysis using random phase approximation (RPA) theory. It was found from the χ estimation (χ=0.0103+14.76/T) that the enthalpic contribution, χH, a measure for temperature susceptibility of χ, is 1.7-4.5 folds smaller for PBA- b -PMMA than for the conventional styrene-diene-based block copolymers, which have been widely used for thermoplastic elastomers. This finding suggests that these fully acrylic components can be a desirable chemical pair for constituting terpolymers applied for thermally stable and mechanically resilient elastomers.