Molecular aggregation structure and mechanical as well as thermal properties of novel well-defined multiblock copolymers consisting of crystalline syndiotactic polystyrene (sPS) and rubbery hydrogenated polyisoprene (hPIp) were investigated. The morphology and crystalline ordered structure of the multiblock copolymer films prepared by solvent casting from 1,2-dichlorobenzene solution depended on the volume fraction of sPS (VF sPS ) and number of blocks. The multiblock copolymer films exhibited ordered morphology with low crystallinity. The crystallinity of the sPS reduced with decreasing the VF sPS . The pentablock copolymer produced more ordered morphology and less crystallinity than the triblock copolymers. The anisotropic orientation and mechanical stability of the δ form sPS crystals in the spherical sPS domains during uniaxial stretching were demonstrated. Tensile testing and dynamic mechanical analysis indicated that these multiblock copolymer films with appropriate sPS fraction are strong, tough, and elastic and thus could be potential candidates for a new type of thermoplastic elastomer with discrete crystalline hard domains.
Polymers composed of polycyclic aromatic planar diimide (PCAD) units and flexible rubbery poly(propylene glycol) (PPG) chains were synthesized, and the morphology and viscoelasticity were investigated.
The effect of solvent on the polymerization of 3‐hexylthiophene with FeCl3 was evaluated using time‐dependent partial fluorescence yield X‐ray absorption fine structure measurements. FeCl3 acts as a catalyst when the reaction is performed in CHCl3, whereas it behaves as an oxidant in hexane.
The relationship between the scratch behavior and molecular aggregation states of polystyrene (PS), poly(2,6‐dimethyl‐1,4‐phenyleneoxide) (PPO), and their blends, is investigated based on differential scanning calorimetry (DSC), wide‐angle X‐ray diffraction (WAXD), polarized optical microscopy (POM), and indentation and scratch tests. DSC reveals that all the PS/PPO blends show the single glass transition temperature (Tg) and the Tg monotonically increase and Tg breadth exhibits a maximum, with an increase in PPO content. Furthermore, density and intermolecular chain distance obtained by WAXD exhibits maximum and minimum values at near 50 wt% of PPO, respectively. It is evident that densification occurs by blending PS and PPO. The scratch coefficient of friction (SCOF) value of PS is the largest and PS exhibits a fish‐scale pattern after scratch testing, while the SCOF value of PPO is much smaller than PS and PPO exhibits smooth groove formation. The PS50/PPO50 and PS20/PPO80 blends exhibit superior scratch and indentation resistance than PS and PPO. Damage morphology observation by POM and indentation tests reveals that molecular orientation is more restricted, and resistance against indentation increases for blends. This is due mainly to densification of the blend system.
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