Structure and reversible deformability of oriented crystallizing polymers

A. I. Slutsker; T. P. Sanphirova; A. A. Yastrebinskii; V. S. Kuksenko

doi:10.1002/polc.5070160749

A Simulation Approach to Crystallinity Gradients Developed in the Injection Molding Process of Slowly Crystallizing Polymers

Journal of Reinforced Plastics and Composites ◽

10.1106/lr6t-3r0q-ll28-wgb2 ◽

2000 ◽

Vol 19 (5) ◽

pp. 377-395

Author(s):

QIN SHENG ◽

SHANGYU DUAN ◽

CHANG-MENG HSIUNG

Keyword(s):

Injection Molding ◽

Injection Molding Process ◽

Simulation Approach ◽

Molding Process ◽

Crystallizing Polymers

Download Full-text

The effect of aliphatic chain length on thermal properties of poly(alkylene dicarboxylate)s

e-Polymers ◽

10.1515/epoly.2007.7.1.658 ◽

2007 ◽

Vol 7 (1) ◽

Cited By ~ 6

Author(s):

Corrado Berti ◽

Annamaria Celli ◽

Paola Marchese ◽

Elisabetta Marianucci ◽

Giancarlo Barbiroli ◽

...

Keyword(s):

Thermal Properties ◽

Three Dimensional ◽

The Other ◽

Aliphatic Chain ◽

Melting Temperatures ◽

Avrami Analysis ◽

Isothermal Analysis ◽

Dimensional Growth ◽

Crystallizing Polymers ◽

Crystalline Forms

AbstractSome poly(alkylene dicarboxylate)s, derived from ethanediol or 1,4- butanediol and different diacids, have been synthesized and analyzed by DSC to determine the correlations existing between the thermal properties and the length of the aliphatic chain. The polymers show crystallization and melting temperatures and enthalpies which increase as the polymethylene segments lengthen, due to the formation of more stable crystals. The samples derived from ethanediol are peculiar; they show reorganization processes during the melting and the melting temperatures are notably higher with respect to those of the other polyesters. This behavior is discussed. Isothermal analysis highlights that poly(alkylene dicarboxylate)s are fast crystallizing polymers. The Avrami analysis suggests a crystallization mechanism characterized by heterogeneous nucleation and three dimensional growth; secondary crystallizations is present only in the samples characterized by short -(CH2)- sequences, due to the reorganization of less perfect crystalline forms. A comparative study between the crystallization rates as a function of the undercooling is reported.

Download Full-text

Polymer Crystallization History and Resultant Properties

Rubber Chemistry and Technology ◽

10.5254/1.3539256 ◽

1969 ◽

Vol 42 (3) ◽

pp. 769-779 ◽

Cited By ~ 4

Author(s):

John R. Collier

Keyword(s):

Mechanical Properties ◽

Glassy State ◽

Polymeric Materials ◽

Neck Formation ◽

Rapid Crystallization ◽

Platelet Morphology ◽

Treatment Conditions ◽

Crystallizing Polymers ◽

Small Platelet ◽

Crystallization From The Melt

Abstract Mechanical properties of semicrystalline polymeric materials are strongly influenced by the morphology into which these materials crystallize. In addition the morphology can be altered by changes in crystallization temperature and regime, crystallization pressure, melt treatment conditions, shear history, and probably other processing conditions. The mechanical properties reflect the changes in morphology not only in the initial moduli values but also the overall stress-strain relationships, including the fracture mechanism. A strong influence is noted, at least in the polymers cited, even when slight changes occur in average spherulite size, spherulitic fine structure, and in the nature of interlamellar ties. Smaller, finer textured spherulites with higher interconnections arc apparently more susceptible to yielding by neck formation and elongation to high values than are the larger, coarser textured spherulites than tend to fail by random brittle failure mechanisms at low elongations. In addition, if the chlorinated polyether (Penton) is typical of slowly crystallizing polymers, the change from spherulitic morphology obtained during crystallization from the melt to the small platelet morphology obtained during slow crystallization from quenched glassy state has a complex effect on mechanical properties. The specimens slowly crystallized from the glass exhibit initial shear and tensile moduli values higher than those exhibited for rapid crystallization from the melt and rapid crystallization from the glass, but lower than the corresponding values for slow crystallization from the melt. In addition, the only specimens of this chlorinated polyether that exhibited the ability to draw to high degrees of elongation (as a result of yielding by a necking phenomenon) were those crystallized slowly from the quenched glassy state.

Download Full-text