General applications Glass transition temperature

Because of the angled structure of poly(arylene ether sulfone)s, they generally do not crystallize. They are thus amorphous and optically transparent with glass transition temperatures between 150-200 °C. They are soluble in some polar solvents, hydrolysis resistant, and inherently flame resistant. Fields of application for these materials are found particularly in the area of electronics and membrane technology. 

For binders in particular - but also for plasticizers - it is important to know the glass transition temperature. The value of the glass transition temperature should be as low as possible but at least -50 °C. If the temperature of a polymer drops below Tg, it behaves in an increasingly brittle manner. As the temperature rises above Tg, the polymer becomes more rubber-like. Therefore, knowledge of Tg is essential in the selection of materials for various applications. In general, values of Tg well below room temperature correspond to elastomers and values above room temperature to rigid, structural polymers. 

For many applications, the toughness of sPS is insufficient, which has thus led to many attempts in the past to increase its toughness significantly compared with HIPS by blending with rubbers. In the stress field of softer or harder particles than the sPS matrix, typical deformation processes inherent to the matrix are initiated. For rubber modification it is important that the application or test temperature is above the glass transition temperature of the rubber, otherwise the stiffnesses of the two components hardly differ from each other and local stress fields around the rubber particles are not formed. The formation of numerous deformation zones round the rubber particles is generally the basis of impact modification [10]. 

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