Calculation of glass transition temperature

Figure 1.1. Calculation of glass transition temperature Tg and density p at room temperature of polystyrene as an example of the application of group contribution techniques, (a) The structure of a polystyrene repeat unit, (b) Fonnal breakdown of this structure into two "groups", (c) Each group makes a contribution to the molecular weight M of the repeat unit, to the "molar glass transition function" Yg, and to the amorphous molar volume V [3a], M, Yg and V arc sums of these contributions ...

Acrylic ester polymers and their copolymers with styrene or methyl methacrylate can be readily prepared with a wide range of Tg s, but vinylidine chloride presents problems. Its Tg is normally given as 255°K, which is the glass transition temperature of the amorphous polymer. Polyvinylidine chloride behaves as a crystalline polymer for which the glass transition occurs at about 370 - 410°K and calculations of glass transition temperatures are pointless for this monomer. 

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