Bio‐based diblock copolymers prepared from poly(lactic acid) and natural rubber

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The objective of this work was to determine the compatibilization effect of different concentrations of maleic anhydride (MA) in poly(lactic acid) blended with epoxidized natural rubber (PLA/ENR). ENR-grafted MA [ENR-g-MA] was synthesized using four concentrations of MA: 0.15, 0.30, 0.45, and 0.60 phr. Using an internal mixer, binary (PLA/ENR, PLA/ENR-g-MA) and ternary (PLA/ENR/ENR-g-MA) polymer blends were prepared with a constant rubber content of 10 wt %. ENR impaired the mechanical properties of PLA, perhaps due to the relatively large size of the rubber particles. The compatibilization effect of MA was evaluated from the results of impact strength testing. ENR-g-MA was a toughening agent for PLA when the concentration of MA was in the range of 0.30-0.60 phr. MA increased miscibility between PLA and ENR. This effect was indicated in the blends by reductions in rubber particle size, the glass transition temperature of PLA, and the α-transition temperatures of PLA and ENR. In the binary polymer blends, the MA concentration in ENR-g-MA that produced the optimal mechanical properties of PLA was 0.60 phr. In the ternary blends, mechanical properties of PLA did not improve at any concentration of MA in ENR-g-MA.

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Compatibilization of poly(lactic acid)/epoxidized natural rubber blend with maleic anhydride

Klinkajorn

Tanrattanakul

2019

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“…NR has been modified by graft copolymerized with PLA (NR‐g‐PLA), poly(methyl methacrylate) (NR‐g‐PMMA), poly(vinyl acetate) (NR‐g‐PVAc), glycedyl methacrylate (NR‐g‐GMA), and maleic anhydride (NR‐g‐MA) . PLA‐NR‐PLA triblock copolymer, PLA‐NR diblock copolymer, and epoxidized natural rubber (ENR) have been used as a toughening agent of PLA. These modified NRs have been used to toughen or compatibilize PLA/NR blends, and 10 wt% of NR has been reported as the rubber content that provided the highest impact strength …”

Section: Introductionmentioning

confidence: 99%

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

Klinkajorn

Tanrattanakul

2020

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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.

“…Our group developed a specific methodology for producing oligo‐isoprenes (NR oligomers) containing carbonyl chain ends . The reduction of the carbonyl chain end leads to hydroxyl telechelic oligomers, which have been used as a source of diols for the production of PUs as films or foams . Several studies of biobased PHUs have been reported in which tannin, cashew nut shell liquid, isosorbide, and vegetable oil have been used as starting materials .…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of elastomeric, biobased, nonisocyanate polyurethane from natural rubber

Jaratrotkamjorn

Nourry

Pasetto

et al. 2017

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Linear and crosslinked polyhydroxyurethanes (PHUs) based on natural rubber (NR) were synthesized by a polyaddition reaction without a solvent or catalyst to exploit the reactivity of diamines or triamines with dicyclic carbonate groups. Oligoisoprenes were obtained from the controlled oxidative degradation of NR and successive modifications of the chain ends. The syntheses of linear PHU were carried out with two approaches. The first one consisted of a reaction between amino telechelic oligoisoprenes and aromatic or aliphatic dicyclic carbonates. The second approach proceeded through a reaction between oligo-isoprenes bearing cyclic carbonate chain ends and difunctional or trifunctional amines. The evolution of these reactions was studied by Fourier transform infrared spectrometry. The influence of the carbonate-to-amine molar ratio, the chain length of the oligo-isoprenes, and the reaction temperatures were investigated. The thermal properties of the PHUs were studied by differential scanning calorimetry and thermogravimetric analysis.