Effect of Deformation on the Crystallization of Supercooled Cured and Uncured Rubbers

Bukhina, M.F.

doi:10.5254/1.3540332

Cited by 5 publications

(1 citation statement)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, the volumes of the crystallite of NR and PVNR at −50 °C were 100 times smaller as compared to the volumes at 50 °C. The rate of crystallization increases sharply with the degree of supercooling . At −50 °C, the rate of crystallization is significantly reduced because it is very close to the T g of NR of −70 °C.…”

Section: Resultsmentioning

confidence: 89%

Crystal and Crystallites Structure of Natural Rubber and Peroxide-Vulcanized Natural Rubber by a Two-Dimensional Wide-Angle X-ray Diffraction Simulation Method. II. Strain-Induced Crystallization versus Temperature-Induced Crystallization

et al. 2013

View full text Add to dashboard Cite

New insights into the strain-induced crystallization (SIC) and temperature-induced crystallization (TIC) of unvulcanized natural rubber (NR) and peroxide-vulcanized natural rubber (PVNR) have been obtained by wideangle X-ray diffraction (WAXD) and small-angle X-ray scattering (SAXS). The SIC samples were deformed at various temperatures (from −50 to 50 °C) to determine the effect of temperature on the crystallite structure. In the WAXD patterns, highly oriented sharp crystal reflections were observed for the SIC samples, whereas sharp rings without preferred orientation were observed for the TIC samples. A novel 2D method to calculate WAXD patterns was used to obtain information on the crystallite structure. For the SIC samples, the crystallite sizes, volume, number of chains per crystallite, crystallite orientation, and crystal displacement disorder increased with increasing temperature but with a decrease in the number of crystals. The crystallite sizes and volume were much larger for the TIC samples as compared to the SIC samples. In the SAXS patterns, the presence of a lamellar peak was observed only for the SIC samples at low temperatures, whereas diffuse scattering was observed for the SIC samples at high temperatures and for the TIC samples. A two-phase stacking model was applied to the 1D integrated intensities of the TIC samples to determine the thicknesses of the crystalline and amorphous phases and the long-period spacing. The long period increased with increasing temperature, which was attributed to the reduction in the number of crystallites and the translation of chains from the crystalline regions to an amorphous state.

show abstract

Section: Resultsmentioning

confidence: 89%

Crystal and Crystallites Structure of Natural Rubber and Peroxide-Vulcanized Natural Rubber by a Two-Dimensional Wide-Angle X-ray Diffraction Simulation Method. II. Strain-Induced Crystallization versus Temperature-Induced Crystallization

et al. 2013

View full text Add to dashboard Cite

show abstract

Crystallization in stretched polymer networks. I. trans‐polychloroprene

Gent

1965

J. Polym. Sci. A Gen. Pap.

View full text Add to dashboard Cite

Measurements are described of the rates of crystallization of uncrosslinked trans‐polychloroprene over a range of temperature and of three crosslinked samples over a wide range of extension and temperature. The large increases in rate with extension are attributed to corresponding increases in the equilibrium melting temperature and hence degree of supercooling. The rise in melting temperature has been measured and is found (1) to account satisfactorily for the observed changes in rate, and (2) to be in good agreement with Flory's treatment of oriented crystallization in stretched networks. The form and magnitude of the changes in tensile stress are also in accord with the formation of oriented crystallites, and seem incompatible with folded‐chain crystallization. When reduced to a condition of constant segmental mobility, the rates of crystallization are shown to follow a common dependence upon the degree of supercooling. This relation is compared with the predictions of nucleation theory.

show abstract

Crystallization in stretched polymer networks. II. Trans‐polyisoprene

Gent

1966

J. Polym. Sci. A‐2 Polym. Phys.

View full text Add to dashboard Cite

Measurements are described of the rates of crystallization and crystal melting temperatures in stretched test pieces of trans‐polyisoprene, crosslinked to various degrees. The increase in rate with extension are attributed to the corresponding increases in melting temperature and hence degree of supercooling. The rise in the melting temperature of both the α‐ and β‐crystal forms is found to be in satisfactory agreement with Flory's treatment of oriented crystallization. The changes in tensile stress are also generally in accord with the formation of oriented crystallites. For the more lightly crosslinked materials, a pronounced rise in tensile stress occurred during the later stages of crystallization, at extensions below about 100%. Reasons are given for attributing this phenomenon primarily to the relatively large contraction in volume on crystallization, rather than to the formation of folded‐chain crystallites.

show abstract

Effect of Deformation on the Crystallization of Supercooled Cured and Uncured Rubbers

Cited by 5 publications

References 0 publications

Crystal and Crystallites Structure of Natural Rubber and Peroxide-Vulcanized Natural Rubber by a Two-Dimensional Wide-Angle X-ray Diffraction Simulation Method. II. Strain-Induced Crystallization versus Temperature-Induced Crystallization

Crystal and Crystallites Structure of Natural Rubber and Peroxide-Vulcanized Natural Rubber by a Two-Dimensional Wide-Angle X-ray Diffraction Simulation Method. II. Strain-Induced Crystallization versus Temperature-Induced Crystallization

Crystallization in stretched polymer networks. I. trans‐polychloroprene

Crystallization in stretched polymer networks. II. Trans‐polyisoprene

Contact Info

Product

Resources

About