Poly PVAc/siloxane

Figure 5.1. Molecular structures of the chemical repeat units for common polymers. Shown are (a) polyethylene (PE), (b) poly(vinyl chloride) (PVC), (c) polytetrafluoroethylene (PTFE), (d) polypropylene (PP), (e) polyisobutylene (PIB), (f) polybutadiene (PBD), (g) c/5-polyisoprene (natural rubber), (h) traw5-polychloroprene (Neoprene rubber), (i) polystyrene (PS), (j) poly(vinyl acetate) (PVAc), (k) poly(methyl methacrylate) (PMMA), ( ) polycaprolactam (polyamide - nylon 6), (m) nylon 6,6, (n) poly(ethylene teraphthalate), (o) poly(dimethyl siloxane) (PDMS).

Figure 7.9. Dependence of the melt viscosity rj of polymers on the parameter Zw (see text) at 021 0. For easier comparison, the 17 values of the different types of polymer have all been multiplied by a constant factor of C. PDMS, Poly(dimethyl siloxane) PIB, poly(isobutylene) PB, poly(butadiene) PMMA, poly(methyl methacrylate) PVAC, poly(vinyl acetate) PS, poly(styrene) (after T. G. Fox).

Recently, renormalization group calculations have been used to derive new scaling laws for the molecular weight dependence of the interaction parameter, Xab between unlike polymers (A and B) in a good solvent and the critical demixing concentration. The purpose of this paper is to present some experimental results which verify this theory for several mixtures of two polymers polystyrene (PS) - poly(dimethyl-siloxane) (PDMS), poly(methyl-methacrylate) (PMMA)-PDMS, PS-PMMA and PS-poly (vinylacetate) (PVAc). 

---