Transition temperature shift microstructure

The Japanese model in JEAC 4201 (JEAC, 2007) involves an updated two-mechanism model using rate theory and measured microstructure characteristics (Soneda et ai, 2010). The new model provides mean predictions for CVN energy T41, transition temperature shift using a model with coefficients optimized using the most recent complete set of Japanese surveillance data. 

Another explanation for an abnormal increase in Tgl in polymer blends has been proposed by Manabe, Murakami, and Takayanagi 125). They used a three-layered shell model, which accounts for interaction between the dispsersed and continuous phases of the blend. Abnormal increases in the glass transition of polystyrene in blends with various rubbers were explained by thermal stresses which arise from the difference in thermal expansion coefficients of the component polymers. However shifts in the glass transition temperatures of the SIN s do not appear to arise from differences in the expansion coefficients of the components because samples with the same overall composition and almost identical microstructures have significantly different glass transition temperatures. 

An example of how polymer microstructure and polymer Tg impact performance is when vinyl-butadiene is increased from 10 to 50% in polybutadiene (Table 4.5) [8]. The glass transition temperature increases from —90 to —60 °C, with a corresponding shift in the tan-delta curve. Traction performance has improved significantly, but tread wear and rolling resistance rating drop. 

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