Transitions of morphological patterns of crystallizing polycarbonate in thin films

Abstract

This article reports the transitions of morphological patterns of polycarbonate crystals in thin films by solvent-induced crystallization (SINC). As a substrate (silica glass) deposited with an amorphous and micronthick bisphenol A polycarbonate polymer film is partially dipped into a liquid acetone bath, acetone penetrated rapidly through the polymer film. The rate of acetone penetration is significantly higher than the predicted by Fickian diffusion or anomalous diffusion model, indicating that the capillary force through stress-induced cracks may have played a major role in the upward transport of acetone through the polymer films. The morphologies of polycarbonate at different vertical positions on a substrate surface were analyzed by scanning electron microscopy and atomic force microscopy. It was observed that depending on the local acetone concentration the polymer morphologies showed quite diverse patterns ranging from stressinduced cracks to fully developed three-dimensional spherulites. The diverse morphologies developed during the thin film SINC may serve as a useful platform for further detailed mechanistic analysis of structures and crystallization kinetics.

UltraHigh Molecular Weight Nonlinear Polycarbonates Synthesized in Microlayers

“…The resulting partially crystallized polycarbonate microlayers exhibited three-dimensional spherulitic morphology as reported in the literature. 26,27 The residual acetone was removed by air and vacuum drying at room temperature for 48 h. The degree of crystallization of the partially crystallized BPAPC microlayers was measured by differential scanning calorimetry (DSC), and it was about 32% for most of the crystallized samples. The polymerization experiments were carried out in a reaction chamber at 230 °C and 10 mmHg.…”

Analysis of polymer parts: buried problems

“…There have also been studies on the solvent crystallization behaviour of PC at surfaces . These studies have focused on changes to the surface of the PC that affect the wettability of the surfaces.…”

Peanut-Like Crystals in Polycarbonate/Plasticizer Blends

“…Bulk bisphenol-A polycarbonate (BAPC) is usually categorized as an amorphous polymer for its extremely slow crystallization rate, i.e., a crystallization half-time of 12 d by only thermal treatment at the most optimal temperature of 190 °C. [1] However, some solvents including acetone, [2,3] diphenylpropane, [4] and supercritical carbon In our recent work, the BAPC/poly(diallyl phthalate) blends with high optical transparency, good flowability, and high mechanical properties were obtained through the plasticization and polymerization of the reactive plasticizer diallyl phthalate (DAP). [10] During the preparation of the BAPC/DAP blend films with the help of dichloromethane, BAPC crystals were achieved in the blends with a DAP content more than 5 wt% after the evaporation of solvent.…”

“…Bulk bisphenol‐A polycarbonate (BAPC) is usually categorized as an amorphous polymer for its extremely slow crystallization rate, i.e., a crystallization half‐time of 12 d by only thermal treatment at the most optimal temperature of 190 °C . However, some solvents including acetone, diphenylpropane, and supercritical carbon dioxide (ScCO 2 ) have been demonstrated to greatly accelerate the growth of BAPC crystals. Ye and Choi immersed BAPC films in an acetone bath for 30 s at room temperature and obtained discrete micrometer‐sized spherulitic particles with large specific surface area, high crystallinity, and melting temperature .…”