Morphology investigation on high‐pressure crystallized bisphenol‐A polycarbonate/dioctyl phthalate blends

Abstract

The high-pressure crystallized bisphenol-A polycarbonate/dioctyl phthalate (BAPC/DOP) blend samples were investigated using wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The specimens were prepared in a piston-cylinder high-pressure apparatus by varying the temperature, the pressure and the crystallization time for a BAPC/DOP (90/ 10, wt/wt) blend. The other four specimens were also prepared with different weight ratios of BAPC/DOP. The DSC results showed that the amorphous BAPC could be crystallized in 45 min by the blending with DOP and the subsequent high-pressure treatment. A wide variety of morphologies of BAPC crystals were disclosed by SEM, including spherulites, spatial dendrites, crystalbars, platelets and regular polygonal crystals of different characteristics. The folded-chain lamellar crystals were found to be the substructures of these observed BAPC microstructures. The SEM revealed a granular substructure of the lamellae in a low-crystallinity sample as well, which indicated that the crystallization of BAPC in the multiphase system might possibly agree with the model developed by Strobl.

Spherulitic Growth of Poly (Ether Ether Ketone) Crystallized at High Pressure

“…[42,[44][45][46] We recently observed such granular substructure in a multiphase polymer system of BAPC incorporated with dioctyl phthalate (DOP) by using SEM. [26] So, the above SEM measurements may possibly indicate that the growth of the PEEK spherulitic crystals, in this single-phase polymer system with rigid chains, is also compatible with the model by Strobl.…”

Unique pressure‐crystallized structures in ternary bisphenol‐a polycarbonate/dioctyl phthalate/fullerene C60 composites

“…Figure 4 gives out the WAXD pattern of a PC/DOP/C60 (89/10/1, wt/wt/wt) composite sample, crystallized at 300 MPa, 300°C for 24 h, which is typical of the obtained profiles for such characterization. All main diffraction lines should be assigned to monoclinic form, just as those of PC or PC/DOP samples crystallized at high pressure 30,34. The relative intensity of the corresponding peaks was somewhat different for various prepared samples.…”

“…The melting behavior of the crystals was investigated through a heating scan with a heating rate of 10°C/min at N 2 atmosphere. The crystallinity X c was calculated from the melting enthalpy Δ H m by means of the following equation:30 …”

“…In this work, pressure‐controlled fast growth of unique crystalline structures of PC was achieved for the first time by the simultaneous introduction of dioctyl phthalate (DOP), a viscous plasticizer, and fullerene C60. This strategy is based on the followings: it has been reported that the crystallization rate of polymers was increased by appropriate pressure treatment,25,26 and the chain mobility of such aromatic polymer was hastened significantly simply through the incorporation of a viscous plasticizer 27–30. In addition to serving as a nucleating agent to decrease the crystallization active energy in the ternary system, C60 was found recently to be a promising material in promoting the formation of new polymeric structures at high pressure 31.…”

On crystallization of bisphenol-A polycarbonate thin films upon annealing

“…The surfaces of the samples annealed for less than 17 hours are smooth, and cloudy-like surface is seen for that annealed for 30 hours due to the beginning of transformation from amorphous phase to crystalline phase in BAPC film. Branchtype structures are observed for the film annealed for 48 hours, showing that good spherulites [27][28][29][30][31] are formed in BAPC film merely upon a long time annealing. The results also indicate that some structural relaxation must have happened before spherulites formation.…”