Factors affecting diluent toughening of PS

Experiments on toughening of PS with PB diluents of different isomer compositions showed that the achievable tensile toughness depends importantly on the isomer composition of the diluent and reaches a maximum at around 35 °C at 7.0MJ/m with the PB composition of the highest fluidity, as shown in Fig. 13.18. 

Tg of the PS matrix, resulting in an overall decrease of the plastic resistance of the homo-PS, this becomes the dominant effect and the additional decrease in the flow stress of the matrix due to the PB-induced plasticization is of lesser importance. This behavior suggests that the plasticization effect of the blends can be viewed as being based on changes of free volume coming either from sorption of PB diluent 

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