Dynamic Viscoelasticity in Sol and Gel States for 1,3:2,4-bis-O-(p-methylbenzylidene)-D-sorbitol/molten Polystyrene Systems

PDTS (1,3:2,4-bis-O-(p-methylbenzylidene)-D-sorbitol) is one of physical gelators and PDTS/Polystyrene (PS) system causes sol-gel transition. The viscoelasticity of the PDTS/PS system in the sol and gel states was investigated. In the sol state, the master curves of G' and G'' are identical with those of the matrix of PS melt, indicating that dissolved PDTS molecules in molten PS do not affect the viscoelasticity of the system. In the gel state, plateau region of G' due to the formation of PDTS network structures is observed. The values of G' in the gel state are well superposed in higher frequency region independent of the molecular weight of PS, indicating that the viscoelasticity of the gel network structures made of PDTS molecules predominates over that of matrices of PS melt in PDTS/PS systems. In lower frequency region, G' of the gel with the highest molecular weight of PS shows higher value than other gels. However, G' becomes close to that of other gels at the lowest frequencies where G' of the matrix PS is in the flow region.