Kinetics and parameters affecting degradation of purified natural rubber

Phetphaisit, Chor. Wayakron; Phinyocheep, Pranee

doi:10.1002/app.12982

Cited by 21 publications

(17 citation statements)

References 18 publications

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“…(2). 19 The degree of epoxidized NR units contained in the synthesized ENR was found equal to 17.8 % (ENR-17.8). C during 6 h. At the end of the reaction, the mixture was precipitated in methanol.…”

Section: Synthesis Of Epoxidized Natural Rubber (Enr)mentioning

confidence: 99%

“…The NR transformation was done using two-step modification (Scheme 4) in which the first step involved the epoxidation of NR carried out in latex stage using performic acid generated in situ from hydrogen peroxide and formic acid. 19 This is considered as the most economical process for preparation of epoxidized NR (ENR) as the reaction was carried out in water at the original state of NR obtained from Hevea tree. The formation of oxirane rings along NR chains was confirmed by both FTIR and 1 H NMR spectroscopies as shown in Figures 9 and 10, respectively.…”

Section: Two-step Modification Of Nr For Preparation Of Bromoalkyl-fumentioning

confidence: 99%

“…19 NR latex (30% dry rubber content) was stabilized using Teric 16A16 (3 phr) at room temperature for 12 h in a reactor. Then, 20 mol % formic acid and 40 mol % of H 2 O 2 were slowly added to the stabilized latex.…”

Section: Synthesis Of Epoxidized Natural Rubber (Enr)mentioning

confidence: 99%

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Synthesis of NR‐g‐PMMA by “grafting from” method using ATRP process

Vayachuta¹,

Phinyocheep²,

Derouet³

et al. 2011

J of Applied Polymer Sci

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Grafting poly(methyl methacrylate) or PMMA from natural rubber (NR) using ATRP process, NR has to be transformed into bromoalkyl-functionalized NR (NRBr) acting as ATRP macroinitiator. The NRBr was prepared by two-step chemical modification i.e., epoxidation and epoxide ring opening reaction using a nucleophile containing bromine atom such as 2-bromopropionic acid (A1) and 2-bromo-2-methylpropionic acid (A2). The fixation of A1 and A2 on 4-methyl-4-octene, a model representing one repeat unit of NR, modified by epoxidation was prior studied and it was found that the resulting addition products from A2 using as ATRP initiator for MMA gave a better control of M n,exp and low PDI of PMMA than that from A1. Then, the NR was transformed into ATRP rubber macroinitiator via epoxidation, followed by epoxide ring addition with only A2.1 H NMR was employed to determine the amount of A2 addition units on NR, which is considered to be the same amount of grafting sites for ATRP of MMA. The grafting of PMMA was then successfully carried out from the NR backbone by ATRP process. The PMMA grafts of the NR-g-PMMA were indeed linked to the NR backbone via ester linkage of the A2 unit. The PMMA grafts could be cleaved from the NR backbone by acid hydrolysis, while PMMA grafting by other conventional radical reaction could not be done. Then, the average MW of PMMA grafts after separation using acetone extraction was evaluated. V C 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121: 508-520, 2011

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Section: Synthesis Of Epoxidized Natural Rubber (Enr)mentioning

confidence: 99%

Section: Two-step Modification Of Nr For Preparation Of Bromoalkyl-fumentioning

confidence: 99%

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Synthesis of NR‐g‐PMMA by “grafting from” method using ATRP process

Vayachuta¹,

Phinyocheep²,

Derouet³

et al. 2011

J of Applied Polymer Sci

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“…Temperature has an influence on the reaction when it determines the efficiency of the initiation and degradation reaction. [5,6] The reactions that were carried out at room temperature did not show any significant degradation even though the reagent was added into the NR latex solution and it was placed under the UV light. When the temperature increased to 40 C, the number average molecular weight (Mn) was decreased from 549.3 Â 10 À3 to 489.6 Â 10 À3 g/mol.…”

Section: Effect Of Reaction Temperaturementioning

confidence: 99%

Preliminary Study on Photochemical Degradation of Natural Rubber Latex

Ibrahim

Othman

Nor

et al. 2017

Macromolecular Symposia

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Summary Liquid natural rubber (LNR) is considered as a new material which can be obtained from degradation of natural rubber (NR). In this work, the degradation of NR latex using photochemical degradation under UV light has been studied. In this preliminary result, the degradation degree was found to depend on parameters such as dry rubber content (DRC) of latex and reaction temperature. At the optimized parameters, the molecular weight (Mn) of NR was able to reduce from about 500 kg/mol to as low as 13 kg/mol. The molecular structure of LNR obtained was similar to that the NR, however, the presence carbonyl and hydroxyl groups were observed on the LNR chain as a result of the chain cleavage.

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“…Various degradation reagents such as phenylhydrazine-ferrous chloride [21], periodic acid [10], potassium persulfate and propanal [22,23] as well as ozone [24] had been used in the preparation of LNR and epoxidized LNR in latex state. Gazeley and Mante [25] patented a method of producing LNR latex using peroxides and metal nitrite.…”

Section: Introductionmentioning

confidence: 99%

Functionalization of Liquid Natural Rubber via Oxidative Degradation of Natural Rubber

2014

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Natural rubber (NR) is a high molecular weight natural polymer and can be degraded to liquid natural rubber (LNR) leaving certain functional groups at the end of chains. In this study, LNR samples prepared via oxidative degradation using H2O2 and NaNO2 as reagents were found to have different end groups depending on the pH of the reaction medium. In an acidic medium, LNR with hydroxyl terminal groups was formed as the degradation reaction was initiated by hydroxyl radicals produced from decomposition of peroxynitrite acid. In contrast, a redox reaction took place in an alkaline medium to yield LNR with carbonyl terminal groups. The mechanisms of reaction are discussed and proposed to explain the formation of different end groups when reaction carried out in acidic and alkaline media. Chain degradation in an acidic medium seems to be more effective than in an alkaline medium, and thus yields LNR with lower Mn.

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Kinetics and parameters affecting degradation of purified natural rubber

Cited by 21 publications

References 18 publications

Synthesis of NR‐g‐PMMA by “grafting from” method using ATRP process

Synthesis of NR‐g‐PMMA by “grafting from” method using ATRP process

Preliminary Study on Photochemical Degradation of Natural Rubber Latex

Functionalization of Liquid Natural Rubber via Oxidative Degradation of Natural Rubber

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