Peanut-Like Crystals in Polycarbonate/Plasticizer Blends

Abstract

Bisphenol‐A polycarbonate (BAPC) crystal with unusual morphology is obtained in the solution‐cast films of BAPC/plasticizer blends. It seems like Siamese twin spherulites, and owns a peanut‐like morphology with more than one nucleating sites. Furthermore, concentric black dotted rings, which should be the aggregation regions of plasticizers, are also observed within the peanut‐like crystals. The peanut‐like morphology has no selectivity to the kinds of plasticizer and the casting temperature. The development of these peanut‐like crystals is mainly ascribed to the local orientations of BAPC chains, which are induced by the concentration fluctuation during solvent evaporation and further fixed by the quick drying process. The concentric black dotted rings within the peanut‐like crystals shall be attributed to the driving effect of BAPC crystalline lamellae and phase separation between plasticizers and BAPC. This work opens a new window for the regular arrangement of small molecules.

Dielectric, Thermal and Mechanical Properties of l,d-Poly(Lactic Acid) Modified by 4′-Pentyl-4-Biphenylcarbonitrile and Single Walled Carbon Nanotube

“…According to the literature [57] the peak registered on heating at ca. 150 °C is related to melting of l , d -PLA, while around 55 °C to glass-transition [58].…”

Making a Rapid Completion of Crystallization for Bisphenol A Polycarbonate by a Double-Layer Film Method

“…The presence of two aromatic rings bridged by methylene unit in PC leads to low chain flexibility. , Although bulk PC is hard to crystallize, dense fibrillar lamellar crystals were observed by AFM in the 30 nm thick spin coated PC films after annealing at 200 °C for 24 h by Ata et al Von Falkai et al reported that the first crystallites of PC appeared after one full day and it took longer than a week to obtain a complete PC spherulite at 190 °C . Along these years, various methods have been tried to obtain high crystallinity for PC samples, such as by blending, − adding plasticizers, surfactants, solvent vapor exposure, − or ultrasound-assisted crystallization (sonocrystallization), and so on. In order to lower the temperature of crystallization, Sundararajan studied the crystallization of PC in the presence of a surfactant, which required a temperature of 80 °C for 24 h, far less than the others as reported to date, whereas the report of the crystallization of polycarbonate in the presence of a surfactant is limited.…”