NMR carbon-13 high resolution study of poly(ethylene-co-vinyl acetate)

Stael, Giovanni Chaves; Tavares, Maria Inês B.

doi:10.1016/s0142-9418(96)00047-5

Cited by 11 publications

(13 citation statements)

References 9 publications

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“…13 CC P-MAS NMR spectra (which were performed at two different spinningr ates to differentiate between peaks ands ide bands) revealed an ew peak after catalysis at 169.8 ppm, which corresponds to (C=O) of an acetate group (Supporting Information Figures S11a nd S12). [84][85][86][87] In contrast, the peaks related to terminal and internal carbons of vinyl linkersa ta round 113a nd 138 ppm, respectively observed for the fresh catalyst are absent after catalysis (Supporting Information Figure S12). For comparison the biphenyl acetoxylation reactionw as carried out in the presence of poly(divinylbenzene) under the described reaction conditions.…”

Section: Activityinc àHa Ctivationmentioning

confidence: 99%

Polymer‐Supported Palladium(II) Carbene Complexes: Catalytic Activity, Recyclability, and Selectivity in C−H Acetoxylation of Arenes

Majeed

Shayesteh

Wallenberg

et al. 2017

Chemistry A European J

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Heterogeneous catalysts for selective oxidation of C-H bonds were synthesized by co-polymerization of new N-heterocyclic carbene-palladium(II) (NHC-Pd ) monomers with divinylbenzene. The polymer-supported NHC-Pd -catalysed undirected C-H acetoxylation of simple and methylated arenes as well as polyarenes, with similar or superior efficiency compared to their homogeneous analogues. In particular, the regioselectivity has been improved in the acetoxylation of biphenyl and naphthalene compared to the best homogeneous catalysts. The new polymer-supported catalysts maintain the original oxidation state of Pd after repeated catalytic reactions, and exhibit no significant leaching of palladium. In addition, the new catalysts have been successfully recovered and reused without loss of activity over several cycles of reactions.

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Section: Activityinc àHa Ctivationmentioning

confidence: 99%

Polymer‐Supported Palladium(II) Carbene Complexes: Catalytic Activity, Recyclability, and Selectivity in C−H Acetoxylation of Arenes

Majeed

Shayesteh

Wallenberg

et al. 2017

Chemistry A European J

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“…The combination of ethylene-vinyl acetate copolymer (EVA) with nanoclay or other base matrix polyethylene (PE) has wide commercial applications (such as packaging films and cables), which depend on the vinyl acetate (VA) contained in the main chain. As the VA content increases, the copolymer presents less crystallinity and different behavior [2]. With production cost in mind, nanocomposites provide an extremely attractive scenario because they achieve comparatively higher improvements with only a fractional weight of the filler as compared to conventional microcomposites.…”

Section: Introductionmentioning

confidence: 99%

Morphological influence on mechanical characterization of ethylene-vinyl acetate copolymer-clay nanocomposites

Chaudhary¹,

Prasad²,

Gupta³

et al. 2005

Polym. Eng. Sci.

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Ethylene-vinyl acetate copolymer (EVA)/montmorillonite (MMT) clay nanocomposites with varying degree of intercalation and exfoliation have been prepared using direct melt blending techniques with various degrees of polarity (9, 18, and 28 wt% vinyl acetate [VA]) and two different types of clay modification. Morphological characterization using wide-angle X-ray scattering (WAXS) and transmission electron microscopy (TEM) have indicated/confirmed the presence of intercalation and/or a combination of intercalation and exfoliation existing in the nanocomposites. The effects of these (simple intercalation or mixed intercalation/exfoliation) states and the effect of changing matrix polarity (by changing VA wt% content) on the nanocomposite mechanical behavior were studied. There is sufficient evidence from the mechanical studies that 1) the presence of nanoclay can simultaneously improve modulus and strength of the nanocomposites, and 2) the mechanical properties are a combined function of the clay concentration and the nanocomposite morphology (due to the VA wt% and presence of clay). It is shown here that interrelation between the VA wt% content and the clay exfoliation affects the mechanical properties in a way that has a positive and increasing slope with increasing loading of clay. It is shown that a clear understanding of the nanocomposite mechanical properties can be obtained from its morphological analysis. POLYM. ENG. SCI., 45:889 -897, 2005.

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“…As the vinyl acetate (VA) content increases, the copolymer presents increasing polarity but lower crystallinity, and therefore different mechanical behavior. [20] The increasing polarity with increasing VA content is apparently useful in imparting a high degree of polymer-clay surface interaction and then enhancing the dispersion of clay. [21][22][23] In this study, EVA/OMMT nanocomposites were prepared through melt mixing with EVA and two types of OMMT.…”

Section: Introductionmentioning

confidence: 99%

Effects of Modified MMT on Mechanical Properties of EVA/MMT Nanocomposites and Their Foams

Park

Kim

et al. 2008

Macromolecular Symposia

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Summary: In this study, nanocomposites of poly(ethylene-co-vinyl acetate) with two kinds of organically modified montmorillonite (OMMT) were prepared by melt intercalation. Their structures and mechanical properties were characterized by X-ray diffraction (XRD) and tensile test respectively. Especially, foaming of these nanocomposites mixed with chemical blowing agent was carried out through compression molding. Influences of OMMT on foaming ratio and mechanical properties were investigated by density test, tensile test and tear test. Results revealed that both kinds of OMMT with proper content increased tensile strength and Young's modulus of nanocomposites without a compromise of elongation at break. For foaming, OMMTs apparently improved foaming ratio and in particular, one of them can improve tear strength, tensile strength, Young's modulus and elongation although the density was decreased.

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NMR carbon-13 high resolution study of poly(ethylene-co-vinyl acetate)

Cited by 11 publications

References 9 publications

Polymer‐Supported Palladium(II) Carbene Complexes: Catalytic Activity, Recyclability, and Selectivity in C−H Acetoxylation of Arenes

Polymer‐Supported Palladium(II) Carbene Complexes: Catalytic Activity, Recyclability, and Selectivity in C−H Acetoxylation of Arenes

Morphological influence on mechanical characterization of ethylene-vinyl acetate copolymer-clay nanocomposites

Effects of Modified MMT on Mechanical Properties of EVA/MMT Nanocomposites and Their Foams

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