Physical Constants of Poly(vinyl acetate)

Lindemann, Martin

doi:10.1002/0471532053.bra029

Cited by 4 publications

(3 citation statements)

References 117 publications

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“…5 displays the DSC traces and the glass transition temperatures (T g ) of the pure homopolymers and the copolymers synthesized in the presence of various amounts of thiocol. The T g s determined for both thiocol (T g = À56.1°C) and PVAc (T g = 30.4°C) were in good agreement with the values reported in literature for these polymers [1,30], while in the case of the copolymers, the DSC analysis revealed only one glass transition in each case, placed in-between those of pure homopolymers. The T g of the copolymers diminished as F VAc decreased, as encountered in the case of statistical copolymers.…”

Section: Ss ð%þ ¼supporting

confidence: 88%

Free radical polymerization of vinyl acetate in the presence of liquid polysulfides

Teodorescu

Stănescu

Iovu

et al. 2010

Reactive and Functional Polymers

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Section: Ss ð%þ ¼supporting

confidence: 88%

Free radical polymerization of vinyl acetate in the presence of liquid polysulfides

Teodorescu

Stănescu

Iovu

et al. 2010

Reactive and Functional Polymers

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“…The conversion between vol% and wt% was carried out by using the values of 1.19 and 1.50 g/cm 3 for PVAc (Lindemann 1989) and sisal whisker (Gindl and Keckes 2004), respectively.…”

Section: Resultsmentioning

confidence: 99%

Sisal cellulose whiskers reinforced polyvinyl acetate nanocomposites

2006

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Sisal nanowhiskers were used as novel reinforcement to obtain nanocomposites with polyvinyl acetate (PVAc) as matrix phase. They are seen as attractive materials due to the widespread availability and low cost of the sisal source material. Statistical analysis of the sisal whisker length and diameter resulted in average values of 250 nm and 4 nm, respectively, resulting in an average aspect ratio in the upper range of reported cellulose nanowhisker values. The high aspect ratio ensures percolation, with resulting mechanical improvements and thermal stability, at lower fiber loads. Water uptake and thermal behaviour of the sisal whisker -PAVc composites were studied. Whisker addition was found to stabilize the nanocomposites with no benefit seen when increasing the whisker content beyond the percolation threshold: For all whisker contents studied above percolation, the water uptake stays constant, and the Tg does not vary with whisker content at a given relative humidity. The water diffusion rate however increases due to water accumulation at the whisker -PVAc interface. Below whisker percolation, stabilization is only noticed at low relative humidity, whereas high humidity results in disruption of whisker -PVAc interactions. This work shows the potential of cellulose nanowhiskers to stabilize polar polymers even at high humidity conditions with minimal reinforcement addition.

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“…The value of k −C O has not been measured in PVAc or in ethyl acetate. Because the relative permittivities (Riddick et al 1986, Lindemann 1999 of isooctane (ε = 1.94), ethyl acetate (ε = 6.02), and PVAc films (ε = 3.5 at 50 • C) are similar, we use k −C O in isooctane for the values in ethyl acetate and PVAc. As mentioned above, radicals in both of the radical pairs can diffuse from their initial solvent cages and undergo out-of-cage reactions that result in fragmentation products (3-5), radical pair B-like combination products (2, 2BN, and 4BN but from different original partners), and a crossed combination product, 2,3-diphenylbutane (6) (Scheme 2).…”

Section: Combinations Of Radical Pairs a And B From (R)-1 General Comentioning

confidence: 99%

Photo-Fries rearrangements of 1-naphthyl (R)-2-phenylpropanoate in poly(vinyl acetate) and ethyl acetate: influence of medium polarity and polymer relaxation on motions of singlet radical pairs

George

Weiss

2006

An. Acad. Bras. Ciênc.

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Both the regio-and stereo-chemistries of the photoreactions of 1-naphthyl (R)-2-phenylpropanoate have been investigated in poly(vinyl acetate) films in their glassy (at 5 • C) and melted (at 50 • C) states and in ethyl acetate. These results are compared with those from irradiations in polyethylene films and in n-hexane. The regioselectivity of the intermediate 1-naphthoxy/(R)-2-phenylpropanoyl radical pair combinations is much higher in both the melt and glassy states of poly(vinyl acetate) films than that in the melt state of completely amorphous polyethylene films, but the stereoselectivity of intermediate prochiral 1-naphthoxy/1-phenylethyl radical pair combinations is much lower in poly(vinyl acetate). The results emphasize the need to control the ratio between the rates of radical tumbling and translation, as well as the ratio between the rates of in-cage motions and cage-escape, if high stereo-and regio-selectivities of combination products are to be achieved. A mechanistic picture of how the radicals of the intermediate pairs are affected by and interact with the various media is advanced.

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Physical Constants of Poly(vinyl acetate)

Cited by 4 publications

References 117 publications

Free radical polymerization of vinyl acetate in the presence of liquid polysulfides

Free radical polymerization of vinyl acetate in the presence of liquid polysulfides

Sisal cellulose whiskers reinforced polyvinyl acetate nanocomposites

Photo-Fries rearrangements of 1-naphthyl (R)-2-phenylpropanoate in poly(vinyl acetate) and ethyl acetate: influence of medium polarity and polymer relaxation on motions of singlet radical pairs

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