writer：Haiying Tan, Jun Zheng, Donghua Xu, Dong Wan, Jian Qiu, and Tao Tang*.
keywords：///
source：期刊
specific source：J. Phys. Chem. B 2014, 118, 5229?5239.
Issue time：2014年

Rheological behavior of three-arm and six-arm star polystyrene (SPS) with

a small amount of polyhedral oligosilsesquioxane (POSS) was studied. Both linear

oscillatory frequency sweep and steady state shear results of SPS/POSS composites

showed the reduction of melt viscosity in the unentangled SPS matrix and the increase of

viscosity in the entangled SPS matrix. In particular, when molecular weight of the arm

(Ma) of SPS was smaller than the critical molecular weight for entanglement (Mc) of PS,

the melt viscosity of SPS/POSS composites with low content of POSS was lower than that

of pure SPS. The abnormal phenomenon of reduced melt viscosity in SPS/POSS

composites was in coincidence with the melt viscosity behavior of SPS/C60 composites

reported in our previous work (Soft Matter 2013, 9, 6282?6290), although the diameters

of two nanoparticles and their interaction with SPS matrix were different. A possible

mechanism behind the melt viscosity behavior was discussed. Furthermore, the time?

temperature superposition principle (TTS) was applied in SPS and SPS/POSS

composites. The Cox?Merz empirical relationship was verified to be valid for SPS/POSS composites when the content of

POSS was low (1 wt %).