Guibin Wang

Crystallization and melting behavior of poly(p-phenylene sulfide) in blends with poly(ether sulfone)

Crystallization and melting behaviors of poly(p-phenylene sulfide) (PPS) in blends with poly(ether sulfone) (PES) prepared by melt-mixing were investigated by differential scanning calorimetry (DSC). The blends showed two glass transition temperatures corresponding to PPS- and PES-rich phases, which increased with increasing PES content, indicating that PPS and PES have some compatibility. The cold crystallization temperature of the blended PPS was a little higher than that of pure PPS. Also, the heats of crystallization and melting of the blended PPS decreased with increasing PES content, indicating that the degree of crystallinity decreased with an increase of PES content. The isothermal crystallization studies revealed that the crystallization of PPS is accelerated by blending PPS with 10 wt % PES and further addition results in the retardation. The Avrami exponent n was about 4 independent on blend composition. The activation energy of crystallization increased by blending with PES. The equilibrium melting point decreased linearly with increasing PES content.

Synthesis and Properties of Poly(aryl ether ketone) Copolymers Containing 2,7-Naphthalene Moieties

Poly(aryl ether ketone) copolymers containing 2, 7-naphthylene and hydroquinone (HQ) moieties with various compositions were prepared by the reaction of 4,4′-difluorobenzophenone (DFB) 2,7-naphthylene and hydroquinone in the presence of sodium carbonate and potassium carbonate (19: 1, mass ratio) in diphenyl sulfone (DPS). The thermal analysis results of the copolymers show that the glass transition temperatures (Tgs) increase, while the melting temperatures (Tm) and the 5.0% weight loss temperatures (Td) decrease with the increase of the 2,7-naphthalene moieties. For the copolymers synthesized at a molar fraction of 2,7-naphthalene in the difluoro monomers being over 0. 30, no peaks corresponding to the cold crystallization temperature and the melting temperature could be detected, indicating that these copolymers are almost amorphous. The crystal structures of the copolymers with a molar fraction of 2,7-naphthalene being less than 0. 30 are rhombic.

Crystallization Kinetics and Melting Behavior of PA1010/Ether-based TPU Blends

Polyamide 1010 (PA1010)/thermoplastic poly (ether urethane) elastomer (ether-based TPU) blends were prepared via melt extrusion. The crystallization kinetics and melting behavior of PA1010/ether-based TPU blends were systematically investigated using differential scanning calorimetry. The crystallization kinetics results show that the addition of ether-based TPU hinders the crystallization of PA1010, and the hindrance effect increases with the increase of the concentration of ether-based TPU. Both pure PA1010 and PA1010/ether-based TPU blends exhibit double melting peaks in the process of nonisothermal crystallization. The double melting peaks change differently with the variation of cooling rate and blend composition. The cooling rate only influences the lower melting peak; however, the blend composition influences not only the lower melting peak but also the higher melting peak. The reason for the phenomenon must be the interaction between the two compositions.