Swollen characteristic ratio

Neutron-scattering studies on polystyrene solutions have shown that while short-length scale correlations are perturbed, in the same manner as single chains in cood solvent, the large-length scale properties are indeed Gaussian. Daoud predicted that the mean squared end-to-end distance of the chains is swollen relative to a pure. melt but can be described simply by a swollen characteristic ratio Coo(( )... 

Another possible choice for the reference state is the equilibrium swelling degree of the network. In that case the thermodynamic characteristics of the actual polymer-swelling solvent system would be taken into account. However this choice does not consider the conditions of network formation. Moreover when the gel is swollen to equilibrium, the elastic chains are extended with respect to the corresponding free chains, and the extension ratio is not easy to evaluate13. ... 

Nomura et al. [74,75] proposed an experimental method to study the competitive particle nucleation mechanisms (micellar nucleation versus homogeneous nucleation) in a given emulsion polymerization system. This approach involves the emulsion copolymerization of relatively hydrophobic styrene with relatively hydrophilic monomers such as methyl methacrylate or methyl acrylate. The composition of copolymer produced during the very early stage of polymerization (far lower than 1% monomer conversion), which reflects the characteristic of copolymer at the locus of particle nucleation, is then determined. Emulsion copolymerization of styrene with methyl methacrylate (or methyl acrylate) was carried out, where sodium dodecyl sulfate was used to stabilize the emulsion polymerization system and where the weight ratio of styrene to methyl methacrylate (or methyl acrylate) was kept constant at 1 1. The experimental results show that the compositions of copolymers obtained from emulsion polymerizations in the presence and absence of monomer-swollen micelles are quite different. This provides supporting evidence of the generally accepted Smith-Ewart theory that micellar nucleation controls the particle nucleation process in the emulsion copolymerization of styrene with... 

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