NMR study of ring opening reaction of epoxidized natural rubber in presence of potassium hydroxide/isopropanol solution

Dahham, Omar S.; Hamzah, R.; Bakar, Mohamad Abu; Noriman, N. Z.; Dahham, Saad Sabbar; Ting, Sam Sung

doi:10.1016/j.polymertesting.2017.01.006

Cited by 46 publications

(10 citation statements)

References 26 publications

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“…C 11 was assigned to methyl carbon and was evidence of ring‐opened epoxide . C 13 was methine carbon in the ether group (H C OC) . Based on the proposed structure in Figure , further evidence of epoxide ring‐opening should be provided by a new signal.…”

Section: Resultsmentioning

confidence: 97%

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The effect of epoxide content on compatibility of poly(lactic acid)/epoxidized natural rubber blends

Klinkajorn

Tanrattanakul

2020

J of Applied Polymer Sci

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The objective of this work was to determine the effect of the epoxide content in epoxidized natural rubber (ENR) on the miscibility and compatibility with poly(lactic acid) (PLA) in prepared PLA/ENR blends. PLA was blended with 10 wt% of ENRs (epoxidized at 10, 15, 20, and 25 mol%). The presented study showed that the in situ graft copolymer, PLA‐g‐ENR, was formed during melt blending in the blends containing 10 and 15 mol% ENR. This work is the initial study showing the presence of PLA‐g‐ENR in the blends by 1H‐NMR and 13C‐NMR. PLA‐g‐ENR acted as a compatibilizer, producing a partially miscible blend, indicated by an inward shift of the α‐transition temperatures of PLA and ENR in the blends. PLA‐g‐ENR also greatly reduced the particle size of ENR and increased the impact strength, tensile strength, and elongation at break of the blends. The epoxide content of ENR changed deformation mechanisms of the blends.

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Section: Resultsmentioning

confidence: 97%

“…[26] C 13 was methine carbon in the ether group ( HC O C ). [27] Based on the proposed structure in Figure 7, further evidence of epoxide ring-opening should be provided by a new signal. C 12 assigned to the carbon attached to the hydroxyl group.…”

Section: Characterization Of Enrmentioning

confidence: 97%

The effect of epoxide content on compatibility of poly(lactic acid)/epoxidized natural rubber blends

Klinkajorn

Tanrattanakul

2020

J of Applied Polymer Sci

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“…Figure a presents the 1 H NMR spectrum of LIR, EIR, and FEIR, respectively. Compared with LIR, new signals at 2.71 ppm (e) and 1.29 (d) ppm attributed to the protons of epoxy groups [ 37 ] appeared in EIR, which demonstrated the successful epoxidation of LIR and the content of epoxy group of EIR was 48.0%. The two new peaks at 2.85–2.93 ppm (f) and 2.45–2.60 ppm (g) were assigned to the protons of methylenes (CH 2 CH 2 ) from the moiety of fluorinating reagent PFDT and the reduced epoxy group signals at 2.71 (e) and 1.29 (d) exhibiting in the spectrum of FEIR demonstrate that the click reaction between epoxy groups and mercapto groups happens and the content of fluoroalkyl side chain of FEIR was 25.7%.…”

Section: Resultsmentioning

confidence: 99%

Strong Hydrophobic and Ultraviolet Reflective Film from Fluorinated Polyisoprene with Microphase Separation via Thiol–Epoxy Click Chemistry

Liu

Cheng

Yang

et al. 2022

Macro Chemistry & Physics

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Polyisoprene is widely used in the industrial production of tires, thermoplastic elastomers, pressure sensitive adhesives, coatings, plasticizers, lubricants, and other functional materials. However, due to the inherent molecular defect of containing many unsaturated double bonds, polyisoprene exhibits relatively weak environmental endurance, especially under extreme environmental conditions. To incorporate the excellent features of fluorinated polymer such as tough environmental endurance, a new type of fluorinated polyisoprene is tailored and a facile procedure of introducing fluoroalkyl side chains onto polyisoprene backbone is carried out via epoxidation and thiol–epoxy click chemistry under mild conditions. The results demonstrate that fluorinated alkyl side chains are successfully clicked onto backbone chains of polyisoprene and the corresponding film exhibits a microphase separation structure. As for the fluorinated polyisoprene film after the introduction of fluoroalkyl groups, the water contact angle enhances significantly from 79.4° to 114.8° and the UV reflectivity improves markedly. In addition, the surface chemical constituents confirm that the incorporated fluoroalkyl groups have a tendency to migrate and enrich spontaneously onto the film surface.

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“…Furthermore, HENR exhibited new characteristic signals at 1250 and 875 cm −1 ; these were assigned to epoxide symmetric and asymmetric stretching, and the signals at 3436 and 1064 cm −1 corresponded to OH stretching and CO(H) stretching, respectively. These signals represent the presence of the epoxide and hydroxyl functional groups on the isoprene units of NR …”

Section: Resultsmentioning

confidence: 99%

Effect of modified rubber powder on the morphology and thermal and mechanical properties of blown poly(lactic acid)–hydroxyl epoxidized natural rubber films for flexible film packaging

Phetphaisit

Wapanyakul

Phinyocheep

2019

J of Applied Polymer Sci

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In this study, we prepared and used modified natural rubber powder to increase the toughness of poly(lactic acid) (PLA) films. We blended PLA and hydroxyl epoxidized natural rubber (HENR) via a melt‐mixing process with twin‐screw extruder and a blowing machine. We investigated the influence of the HENR content in the blend films on the microstructure, thermal, mechanical, and optical properties. The morphology of the blend showed a coarse surface and elongated fibrils of HENR in the PLA matrix. After blowing, the dispersion of small particles of HENR in the substrate was seen. The size of the remaining HENR particles was smaller than that of the starting powder. The compatibility of HENR and the remaining rubber particles may have synergistically contributed to improvements in the elongation at break, impact strength, and ultraviolet–visible transition protection of the PLA films. The elongation at break drastically increased from 3 to 228% after PLA was blended with 20 wt % HENR. On the other hand, all of the blends exhibited lower glass‐transition temperatures and cold crystallization temperatures than the pure PLA films. We concluded that the blend was partially compatible and may have increased the flexibility of the PLA films. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47503.

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NMR study of ring opening reaction of epoxidized natural rubber in presence of potassium hydroxide/isopropanol solution

Cited by 46 publications

References 26 publications

The effect of epoxide content on compatibility of poly(lactic acid)/epoxidized natural rubber blends

The effect of epoxide content on compatibility of poly(lactic acid)/epoxidized natural rubber blends

Strong Hydrophobic and Ultraviolet Reflective Film from Fluorinated Polyisoprene with Microphase Separation via Thiol–Epoxy Click Chemistry

Effect of modified rubber powder on the morphology and thermal and mechanical properties of blown poly(lactic acid)–hydroxyl epoxidized natural rubber films for flexible film packaging

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