Crystal Structures of Isotactic Polystyrene Ultrafine Particles

Abstract

Abstract: Ultrafine particles, with average equivalent diameters in the range of 60～330 nm, prepared by freeze-drying very dilute(about 2×10^-5 g/mL) solutions of isotactic polystyrene in benzene at 0 ℃ were studied by TEMand DSC, respectively. It was found that two different structures of widely different thermal stabilities can form at identicaltemperatures. One melt(mode A) at 220 ℃ just as the recognized structure of isotactic polystyrene(3₁ helix). The other(mode B) melt at 65 ℃ and produced distinct electron diffraction patterns which, however, differ decisively from those provided by crystals A. The melting point of crystals Bis also significantly lower than those of iPSdried gel crystals, which give an endotherm at 120 ℃ in calorimetric measurements. According to ¹³ C NMR measurement, the material used in this study should be practically fullyisotactic.

Key words: Isotactic polystyrene, Ultrafine particles, Crystallization

CLC Number:

O631

TrendMD:

WANG Song, DAI Qing-Ping, HONG Jian-Min, YAN Xiao-Hu, CHENG Rong-Shi . Crystal Structures of Isotactic Polystyrene Ultrafine Particles[J]. Chem. J. Chinese Universities, 1998, 19(9): 1526.

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Crystal Structures of Isotactic Polystyrene Ultrafine Particles

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