Crystallization of Syndiotactic Polystyrene in β-Form. 1. Positional Identification of Stacking Faults in the Solution-Grown Single Crystals

Abstract

The locations of the stacking faults in -form single crystals of syndiotactic polystyrene, which were grown isothermally from a dilute solution at temperatures ranging from 150 to 210°C, were identified in high-resolution and dark-field (DF) images taken by transmission electron microscopy. The shift or kink of the (210) lattice fringes, which shows the position of the fault, was directly detected in the high-resolution images. DF images taken using several reflections exhibited irregularly spaced striations parallel to the b-axis. Computer simulation of DF images based on the structural model of the stacking fault well supported the view that each striation corresponds to the position of the fault. The striations extended continuously and were very long, and accordingly, it was proposed that the stacking fault influences the attachment of a new polymer stem onto the lateral growth face which is not parallel to the bc-plane, resulting in irregular fold-surfaces of the single crystals.

Effects of polydispersity index and molecular weight on crystallization kinetics of syndiotactic polystyrene (sPS)

“…: +886 3 5712121x55306; fax: +886 3 5724727. the initial zig-zag planar structure of the chain into helical structure without destroying the orientation of fibers. The same solvent was also utilized to produce the crystallization in glassy sPS [5][6][7]. Greis et al [8] completed the structure characterization, reporting that three sPS macromolecules from clusters have two types of handedness.…”

Radiation effects and re-crystallization mechanism of syndiotactic polystyrene with β′-crystalline form

“…The irregular folding habit of the sPS chains is further supported by a recent finding that the fold surface energy of the b 0 -form sPS lamellae is only slightly larger than its lateral surface energy [37]. The lack of uniform folding directions plausibly resulted from the presence of stacking faults [41,43], which influence the new polymer stem to attach onto the growth face. Essentially, the polymer chains on the lamellar surface are not tightly folded but act like ''floating segments'' [42] which possess sufficient mobility for conformation change induced by appropriate thermal treatments.…”

“…Then another crucial question arises: where do the thickened lamellae associate with the re-crystallization process? Using a decoration method [40], Tosaka et al [41] and Ho et al [42] have shown that the polymer chains are irregularly folded even in the single lamellar crystals of sPS. The irregular folding habit of the sPS chains is further supported by a recent finding that the fold surface energy of the b 0 -form sPS lamellae is only slightly larger than its lateral surface energy [37].…”

Chain Conformation, Crystal Structures, and Structural Disorder in Stereoregular Polymers

“…54,55 Disorder in the stacking of ordered ac layers of chains along one direction is present, according to X-ray 54 and electron diffraction patterns. 188 The structure has been described in terms of two limit models; a limit-ordered β -form, described by the space group P 2 1 Figure 2.43. A regular succession of bilayers ABAB.…”