Activation Energy and Thermodynamic Parameters of Cyclization in Purified Natural Rubber Latex Using a Trimethyl Silyl Triflate

Riyajan, Sa‐Ad

doi:10.1177/0095244308092437

Cited by 7 publications

(4 citation statements)

References 18 publications

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“…This might be due to the exposure of thermal effect that would induce the release of the free radicals from ZnO. 7 In fact, ZnO has been used as the curing activator for effective cross-linking. The traces of ZnO in the samples would be activated when subjected to thermal treatment to generate free radicals for further inducing the cross-linking process.…”

Section: Analysis Of Factors Affects Tensile Strengthmentioning

confidence: 99%

Factorial design investigation on two-way quaternary factors of thermal aging of chlorinated nitrile latex tensile properties

Sin

Bee

et al. 2013

Journal of Elastomers & Plastics

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This study aims at investigating the quaternary factors, namely zinc di-N-butyl dithiocarbonmate (ZDBC), sulfur, zinc oxide (ZnO), and potassium hydroxide (KOH) on the tensile strength and elongation of chlorinated nitrile latex film. Full factorial design analysis was employed to examine the factors and their combination two-way interactions with the tensile properties. The factors' effect on the variability or the stability of the resulting latex films were analyzed as well. The results showed that KOH, which was used to adjust the pH of the latex system greatly affected the tensile strength of the latex film, whereas sulfur has minor influence on tensile strength. Meanwhile, KOH also interacted in combination with ZnO and sulfur to affect the elongation of the latex films. Addition of KOH changed the pH by affecting the electronic repulsion and gelling stability of the latex matrix. Consequently, the variability in tensile strength and elongation of latex film were according to the amount of KOH. Finally, the simple mathematical models with a regression range 0.73-0.86 were developed to relate the factors and the tensile properties of the latex.

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Section: Analysis Of Factors Affects Tensile Strengthmentioning

confidence: 99%

Factorial design investigation on two-way quaternary factors of thermal aging of chlorinated nitrile latex tensile properties

Sin

Bee

et al. 2013

Journal of Elastomers & Plastics

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“…Cyclized rubber is a modified NR where the molecular structure contains cyclic rings. The cyclized NR was used as material for formulating adhesives and printing inks, 6 and for blending with other types of polymers. 7 Cyclized NR can be produced by treating the NR with a proton donor, such as sulfuric acid, 8,9 stannic chloride, 10 or hydrochloric acid, 11 in either solid, 12 solution, 13 or latex form.…”

Section: Introductionmentioning

confidence: 99%

“…A higher degree of cyclization corresponds to a higher gel content, improved thermal stability, and increased glass transition temperature. 6,9,[15][16][17] Although various information is available from prior reports, the effects of cyclization on properties of NR remain not entirely understood, since many studies have focused on the preparation parameters and on cyclizing deproteinized natural rubber (DPNR) latex. Only few prior studies have focused on the influence of cyclization on the properties of NR but these studies mostly paid attention to the mechanical, dynamic mechanical, and thermal properties.…”

Section: Introductionmentioning

confidence: 99%

Influence of acid concentration on thermomechanical, tensile and thermal properties of cyclized natural rubber

Jaratrotkamjorn

Hayeemasae

Zakaria

et al. 2023

Journal of Elastomers & Plastics

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Properties of cyclized natural rubbers (NR) with various degrees of cyclization (∼4-22%) were investigated in this study. Prior to compounding with rubber additives, the cyclized rubbers were initially prepared by dropping various concentrations of acid (5-30 wt%) to the NR latex, followed by coagulation and drying. The results revealed that the degree of cyclization increased with acid concentration. Increased ring structure formation in the modified NR tended to increase the torque difference during crosslinking, as the cyclic ring structures acted as steric hindrances. The crosslink density was found to decrease with increasing cyclization level due to the loss of active sites for crosslink formation, increasing swelling capability of the cyclized rubbers. The 100% and 300% moduli, tensile strength and extensibility of the NR reduced with increasing degree of cyclization due to a reduction of crosslink density. As a result of cyclic structure formation and a reduction of unsaturated double bonds in the NR, the stability of cyclized NR at elevated temperatures was improved over the pure NR, in a manner dependent on the level of cyclization. Single glass transition temperature was seen in the NR while two glass transition temperatures were noticed in the cyclized NR. The thermal stability of 22% cyclized NR was 50°C higher than that of the pure NR and the aging properties of the cyclized NRs were also greater mainly due to a reduction of unsaturated double bonds. This suggests that cyclized NR may find applications in products requiring thermal resistance.

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“…Chemical modifications are usually employed to improve the properties of natural rubber (NR). For example, epoxidation, 1, 2 cyclisation, 3–4 hydrogenation 5 and grafting 6–7 have been carried out to modify the properties of NR. Among the chemical modification techniques, grafting is a technique for improving some of the weak properties of NR.…”

Section: Introductionmentioning

confidence: 99%

Preparation and properties of natural rubber latex-g-modified cationic polyacrylamide copolymers and its palm oil absorbent

Riyajan

Maneechay

2014

Plastics, Rubber and Composites

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The grafting of a modified cationic polyacrylamide (MCPAM) onto natural rubber (NR) latex to form a copolymer using potassium persulphate (K2S2O8) to generate active radicals on both the NR particle surface as well as on the MCPAM molecules was confirmed by ATR-FTIR. The copolymers showed a marked ability to absorbe palm oil up to 10 g g−1. First, the high molecular weight cationic polyacrylamide (CPAM) was reduced by using a combination of K2S2O8 and hydrogen peroxide (H2O2) through thermal degradation. The molecular weight of the CPAM as determined by viscosity was about 4000 g mol−1. It was then added to the NR latex in the presence of Terric16A16 at 60°C for 3 h and cast as a film on a glass plate to obtain the NR-g-PAM. In a water medium, the swelling ratio of the modified NR decreased as a function of the CPAM concentration. Also the thermal stability of the modified NR-g-PAM was higher than of the NR/PAM blend as confirmed by TGA. Finally, the ability of NR-g-MCPAM to absorb palm oil was investigated.

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Activation Energy and Thermodynamic Parameters of Cyclization in Purified Natural Rubber Latex Using a Trimethyl Silyl Triflate

Cited by 7 publications

References 18 publications

Factorial design investigation on two-way quaternary factors of thermal aging of chlorinated nitrile latex tensile properties

Factorial design investigation on two-way quaternary factors of thermal aging of chlorinated nitrile latex tensile properties

Influence of acid concentration on thermomechanical, tensile and thermal properties of cyclized natural rubber

Preparation and properties of natural rubber latex-g-modified cationic polyacrylamide copolymers and its palm oil absorbent

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