The kinetics of crystallization of polychloroprene rubber

Grmela, V.; Megarskaya, L.

doi:10.1016/0032-3950(68)90327-4

Cited by 8 publications

(4 citation statements)

References 9 publications

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“…During the stretching process, molecular chains can slide relatively, and the ability of molecular chains to combine into microcrystals is controlled by the stretching process. 17 Compared with U-CR, A192-CR is crosslinked by double bonds and dechlorinated, which leads to the decrease of its structural regularity and the decrease of the number of orientable free crystallizable chains. The relative molecular weight between crosslinking points decreases with the increase of crosslinking density.…”

Section: Crystallinity Indexmentioning

confidence: 99%

“…The unit cell of polychloroprene is orthogonal, with four polymer chains passing through and parallel to the c‐axis, 5 which is oriented in the direction of stretching, and belongs to the class of strained crystalline elastomers. During the stretching process, the rubber molecular chains stretched and transition from folded to stretched conformation, resulting in strain‐induced crystallization (SIC) 15–17 . SIC is closely related to the fracture strength and fatigue fracture resistance of rubber 10,18,19 .…”

Section: Introductionmentioning

confidence: 99%

“…During the stretching process, the rubber molecular chains stretched and transition from folded to stretched conformation, resulting in strain-induced crystallization (SIC). [15][16][17] SIC is closely related to the fracture strength and fatigue fracture resistance of rubber. 10,18,19 Elongated crystallites are most likely to form during stretching, and the grains are oriented along the chain axis parallel to the stretching direction, which results in significant changes in the degree of crystallinity and molecular chains orientation of the rubber.…”

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confidence: 99%

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Changes in crosslinking structure of thermo‐oxidative aging chloroprene rubber and its effect on strain‐induced crystallization

Jiang,

Qin,

Han

et al. 2023

J of Applied Polymer Sci

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Chloroprene rubber (CR) is frequently quoted as an example of strain‐induced crystallizing elastomer. Many researchers have focused on studying the aging mechanism and mechanical properties of aged CR, little has been done on the effect of crosslinking structure on strain‐induced crystallization (SIC). The present paper related systematic investigations combining the changes of crosslinking structure and its influence on SIC. It was firstly investigated based on FTIR, crosslinking density test and GPC. The results showed that the molecular chains were oxidized in the early stage of aging, but the crosslinking reaction still dominated. At the same time, sol content and polydispersity decreased. In the later stage of aging, CR was oxidized, resulted in severe molecular chains fracture and an increase in the free sol content and polydispersity. The impact of aging on SIC under tensile condition was further investigated by the tensile tests. An obvious stress‐hardening was found for unaged CR, but not in aged CR. The crystallinity and microcrystalline region orientation tests showed that oxidation, crosslinking by double bonds and dechlorination during aging were not conducive to the orientation of molecular chains during stretching. It is the aging process that has an adverse effect on the SIC of CR.

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Section: Crystallinity Indexmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Changes in crosslinking structure of thermo‐oxidative aging chloroprene rubber and its effect on strain‐induced crystallization

Jiang,

Qin,

Han

et al. 2023

J of Applied Polymer Sci

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“…A first important point is that crystal structures are in general similar for QC and SIC [8][9]. QC in elastomers that readily strain-crystallize is quite often a slow process even at optimal degrees of super-cooling, and crystallization half-times are counted in hours or days [10][11]; folded conformation is most probable and spherulitic or lamellar growth is observed under some conditions [6][7][8]. The crystallization kinetics progressively accelerate with increasing applied elongation and crystallites become oriented with the chain-axis on average parallel to the stretching direction [11,[15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Strain-induced crystallization in an unfilled polychloroprene rubber: Kinetics and mechanical cycling

Gac

Albouy

Petermann

2018

Polymer

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Polychloroprene rubber is often quoted as an example of strain-crystallizing elastomer; however, this fundamental property, known to impart good mechanical properties and fatigue resistance, has received much less attention in this class of compounds than natural rubber. The present paper relates systematic investigations combining mechanical and X-ray diffraction measurements. Crystallization kinetics are first investigated based on tensile impact tests. An approximately logarithmic timedependence is found for the crystalline content and the time-constants are estimated at various temperatures. The impact of strain-induced crystallization on stress-strain curves under mechanical cycling conditions is further assessed. It is demonstrated that one main effect of strain-induced crystallization is a partial relaxation of the strain experienced by the amorphous fraction, although stress-hardening is simultaneously observed. Based on the stress-optical law, the contribution of the amorphous phase to the stress is shown to level off after crystallization onset, and stress-hardening is attributed to crystallite networking. The crystallite network rapidly disintegrates at the beginning of recovery, and the stress-optical law shows that the amorphous fraction becomes the only contributor to the stress at still non-negligible crystalline contents. Please note that this is an author-produced PDF of an article accepted for publication following peer review. The definitive publisher-authenticated version is available on the publisher Web site.

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Some structure-property relationships in oriented polychloroprene

Andrews

Reeve

1971

J Mater Sci

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The kinetics of crystallization of polychloroprene rubber

Cited by 8 publications

References 9 publications

Changes in crosslinking structure of thermo‐oxidative aging chloroprene rubber and its effect on strain‐induced crystallization

Changes in crosslinking structure of thermo‐oxidative aging chloroprene rubber and its effect on strain‐induced crystallization

Strain-induced crystallization in an unfilled polychloroprene rubber: Kinetics and mechanical cycling

Some structure-property relationships in oriented polychloroprene

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