Effect of non‐rubber substances on vulcanization kinetics of natural rubber

Wang, Ping‐Yue; Wang, Yongzhou; Zhang, Bei-Long; Huang, Honghai

doi:10.1002/app.36851

Cited by 17 publications

(4 citation statements)

References 21 publications

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“…According to vulcanization curves at different temperatures, the plots of ln( M H – M t ) versus t – t 0 are obtained ( M H is the maximum torque, M t is the torque at the vulcanization time t and t 0 is the time for minimum torque), as shown in Figures S6–S9. In Figures S10–S13, such ln( M H – M t ) versus t – t 0 plots exhibits a good fitting effect at different temperatures by the following equation − where A is a constant, k is a reaction rate constant, and α is a modified coefficient. From the fitting procedure, the k of induction period at different temperatures are abstracted and then E a of vulcanization period is calculated by the Arrhenius equation (Figure S14).…”

Section: Resultsmentioning

confidence: 77%

Design of Vulcanization Intermediates with Low Steric Hindrance Contributing to Vulcanization Network Formation

Hou

Xie

Liu

et al. 2023

ACS Appl. Polym. Mater.

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Sulfur cross-linking, known as vulcanization, is an extraordinarily important process to endow rubbers with practical performances in the rubber industry. However, the steric hindrance of vulcanization intermediates hinders the formation of vulcanization networks, limiting the property enhancement of vulcanized rubbers. To promote the formation of vulcanization networks, our group lowers the steric hindrance of vulcanization intermediates through decreasing the length of alkyl chain. Temperature-dependent Fourier transform infrared spectroscopy suggests the formation of bridging bidentate zinc/fatty acid salt complex (vulcanization intermediates) with different steric hindrances. The reduction in steric hindrance of vulcanization intermediates increases the coordination interactions between sulfur and vulcanization intermediates, promoting the ring-opening of sulfur and formation of vulcanization networks. As a result, with the reduction in steric hindrance of vulcanization intermediates, the properties of vulcanized rubbers improve greatly. This work promotes the formation of vulcanization network through lowering the steric hindrance of vulcanization intermediates, which provides a simple generic strategy for the development of high-performance rubbers.

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Section: Resultsmentioning

confidence: 77%

Design of Vulcanization Intermediates with Low Steric Hindrance Contributing to Vulcanization Network Formation

Hou

Xie

Liu

et al. 2023

ACS Appl. Polym. Mater.

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“…Therefore, the highest viscosity of the 14 kGy‐irradiated blend might be achieved by increased crosslinking structures between NR and SIS owing to smaller particle size brought by the irradiation. In another work, it was assumed the non‐rubber components have promoted the formation of vulcanized intermediates 19 . Furthermore, the storage modulus, G ′ was increased when strain increased (Figure 1c).…”

Section: Resultsmentioning

confidence: 92%

“…In another work, it was assumed the non-rubber components have promoted the formation of vulcanized intermediates. 19 Furthermore, the storage modulus, G 0 was increased when strain increased (Figure 1c). The linear viscoelastic range of NR below 0.01% strain indicates that the NR/SIS chains were stable when a small deformation was applied.…”

Section: Strategy To Control Particle Size and Rheology Properties Of...mentioning

confidence: 92%

Optimizing natural rubber blends for examination gloves: Vacuum radiation for mechanical strength and solvent barrier

Lazim,

Shamsudin,

Hidzir

et al. 2023

J of Applied Polymer Sci

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Natural rubber (NR) is emblematic of sustainability compared to synthetic rubber. However, the tradition of adding sulfur as a vulcanization ingredient results in the release of toxic substances and the potential for health issues. In this study, a feasible strategy was proposed to replace sulfur and discover a safe bulk modification process for NR films. The results have shown that the NR particle size was disintegrated to below 10 nm by gamma irradiation. High tension strength up to 24.45 MPa was observed in the vulcanized NR blend film, which could be elongated up to 800% strain after exposure to an optimum dose of 14 kGy. In comparison to commercial NR latex and nitrile gloves, the vulcanized NR/ SIS films exhibited better chemical resistance ability against hexane, methanol, toluene, and acetone, as revealed by the permeation test. The appearance of amorphous regions and highly oriented NR crystallites was observed through transmission electron microscopy. Findings from this study propose the vacuum radiation strategy that can replace conventional vulcanization methods, resulting in NR films with high mechanical and barrier performance. Furthermore, the emission of toxic substances is reduced by this green process, making it practically useful for potential chemical‐resistant examination glove applications.

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“…For vulcanized NR, there will be three types of networks in vulcanized NR, i.e., vulcanized cross-linked network, naturally occurring network and entanglements, where naturally occurring network and entanglements contribute to higher effective crosslink densities and stronger strain-induced crystallization, respectively [ 13 ]. At the same time, the nonisoprene components in NR not only directly participate in the construction of the naturally occurring network, but also can promote the vulcanization reaction of NR; this facilitates the formation of a more complete vulcanized cross-linked network [ 14 ]. Wei et al demonstrated by differential scanning calorimetry that the introduction of nonisoprene components can effectively reduce the activation energy of the vulcanization reaction and increase the mechanical property of the vulcanizate [ 15 ].…”

Section: Introductionmentioning

confidence: 99%

Effect of Nonisoprene Degradation and Naturally Occurring Network during Maturation on the Properties of Natural Rubber

et al. 2022

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It well-known that the superior performance of natural rubber (NR) compared to its synthetic counterpart mainly derives from nonisoprene components and naturally occurring network, which varies during the progress of the maturation and thereby results in technically graded rubber with different properties. However, identifying the roles of these two factors in the forming of excellent performance of NR is still a challenge as they change simultaneously during the maturation process. Here, influences of naturally occurring networking and nonisoprene degradation on the components, structures and properties of NR were systematically investigated by tailored treatments of maturation. It was found that the maturation-induced formation of natural network structure contributes to the increase in initial plastic value, Mooney viscosity and gel content for un-crosslinked NR, while the decomposition of nonisoprene components plays a dominant role in improving the mechanical properties of vulcanized NR. Stress-strain curve and Mooney-Rivlin analysis demonstrate that the biodegradation of the nonisoprene components significantly boost the vulcanization process, which significantly increases the number of chemical cross-link networks and effective cross-link density of the material, greatly improving the mechanical properties of NR vulcanizates. This resulted in the tensile strength of TSR 10CV being able to reach 22.6 MPa, which is significantly improved compared to 15.8 MPa of TSR 3CV. Evidenced by tubular model fitting, the increase in chemical cross-linking points effectively reduces the movable radius of the molecular chain under dynamic loading, making the molecular chain more difficult to move, which suppresses the entropy change under dynamic loading and consequently endows NR excellent dynamic mechanical properties. This resulted in a significant decrease in the temperature rising of TSR 10CV to 3.3 °C, while the temperature rising of TSR 3CV was still as high as 14.5 °C. As a minor factor, the naturally occurring network improves the mechanical properties of vulcanizates in the form of sacrificial bonds.

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Effect of non‐rubber substances on vulcanization kinetics of natural rubber

Cited by 17 publications

References 21 publications

Design of Vulcanization Intermediates with Low Steric Hindrance Contributing to Vulcanization Network Formation

Design of Vulcanization Intermediates with Low Steric Hindrance Contributing to Vulcanization Network Formation

Optimizing natural rubber blends for examination gloves: Vacuum radiation for mechanical strength and solvent barrier

Effect of Nonisoprene Degradation and Naturally Occurring Network during Maturation on the Properties of Natural Rubber

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