Crystallization and Transformation of Polybutene‐1

Abstract

The isothermal crystallization and phase II ! I transformation of bulk polybutene-1 at various temperatures have been characterized by x-ray diffraction. The crystallization rate can be increased or decreased by the addition of various solids, with sodium salicylate and talc, e.g., increasing the rate by .100% and, unexpectedly, decreasing the rate by .300%, respectively. The nucleating agents have no effect on the transformation rate, which, however, is increased slightly in the presence of water and ethanol and significantly in the presence of liquids that are solvents at elevated temperatures or by temperature cycling. As shown previously, the transformation rate of nontreated polymer is greatest near 258C, decreasing at higher and lower temperatures and is increased by tension or uniaxial compression.

Crystal structures and polymorphism of polymers: Influence of defects and disorder

“…The physical properties of iPB are greatly affected by the spontaneous form II‐form I transformation because of the increase of density, melting temperature, and mechanical strength . The transformation is rather slow and is complete only after days or weeks at room temperature . The kinetics of this solid state transition depends on the aging temperature and on the molecular structure, in particular, the molecular mass, the stereoregularity, and the presence of comonomer units .…”

The effect of a synthetic double layer hydroxide on the rate of II→I phase transformation of poly(1-butene)

“…The structure of LDH derives from brucite, i.e. Mg(OH) 2 , with layers obtained by isomorphous substitution of divalent cations. The replacement of Mg 2+ by M 3+ ions generates a net positive charge that is balanced by incorporation of anions in interlayer space.…”

Control of Chain Orientation in Blends of Polypropylene and Polybutene‐1

“…A PP sheet containing the nucleating agent and a pure PP/PB sheet without the nucleating agent were also prepared as reference samples. Before the measurements, the obtained sample sheets were stored at room temperature for one week to allow the PB crystals to transform into the stable form‐I …”

“…Before the measurements, the obtained sample sheets were stored at room temperature for one week to allow the PB crystals to transform into the stable form-I. [20][21][22][23] For thermal property characterization, 1000 ppm of the nucleating agent was added to PB using a 30 cc batch-type internal mixer (Labo-Plastmill, Toyoseiki, Japan) at 280 °C for 5 min to fully dissolve the nucleating agent in PB. The blades were rotated at 30 rpm.…”