Neighbouring group effect on the kinetics of acetalisation of poly(vinyl alcohol)

Raghavendrachar, P.; Chanda, Manas

doi:10.1016/0014-3057(83)90112-x

Cited by 8 publications

References 7 publications

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Vinyl Acetal Polymers

Knapczyk

2000

Kirk-Othmer Encyclopedia of Chemical Technology

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Poly(vinyl acetal) resins are made by the acid‐catalyzed acetalization of poly(vinyl alcohol) with aldehydes. The reaction favors formation of the 1,3‐dioxane ring, which is a characteristic feature of this class of resins. As of this writing (ca 1997), only poly(vinyl butyral) and poly(vinyl formal) are made in sizable commercial quantities. Most poly(vinyl butyral) is plasticized and made into interlayer for vehicle and architectural safety glazing. The primary use for poly(vinyl formal) is as an important component in coatings for electrical wire and cable insulation. Applications for poly(vinyl butyral) and poly(vinyl formal) resins make use of their toughness, resilience, optical clarity, high pigment/filler binding capacity, and the high adhesion the resins may provide when appropriately formulated. The history and general characteristics of poly(vinyl acetal) resins are briefly reviewed. Chemical and physical characteristics, manufacture, and principal applications are discussed. Special attention is given to poly(vinyl butyral) and its use for safety glazing interlayer, because glazing interlayer is by far the largest single application for the poly(vinyl acetal) class of resins.

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Vinyl Acetal Polymers

Knapczyk

2000

Kirk-Othmer Encyclopedia of Chemical Technology

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Substantial modifications of ethylene/vinyl acetate copolymers: Saponification and graft copolymerization

Liaw¹,

Su²

1993

Angew. Makromol. Chem.

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Modifications of ethylenehinyl acetate copolymers (EVA) by saponification and graft polymerization with various acids were studied. The greater the degree of saponification, the higher is the melting temperature, the crystallinity and the melt viscosity of poly(ethy1ene-co-vinyl alcohol-co-vinylacetate). Tensile tests display that the flexibility of EVA decreases gradually as the degree of saponification increases. This effect may be caused by the interaction of hydrogen bridges after saponification. Graft copolymers of EVA with various acids were studied. The greater the portion of vinyl acetate of EVA, the greater is the graft ratio with fumaric acid because of the reactive acetoxy ester groups. The graft ratio with various acids decreases in the order acrylic acid > fumaric acid > itaconic acid > maleic anhydride; this order may reflect a steric effect.Relationships between peel strength and the degree of saponification of EVA show that the adhesive strength increases initially and reaches a maximum value at a degree of saponification in the range of 20 -30%. The adhesive strength of EVA grafted with acid increases remarkably at low acid contents (less than 0.5 wt.-Yo) and then remains constant even at greater acid content in the graft copolymer.ZUSAMMENFASSUNG: Die Modifikation von Poly(ethy1en-co-vinylacetat) (EVA) durch Verseifung und Pfropfpolymerisation mit verschiedenen Sauren wurde untersucht. Schmelzpunkt, Kristallinitat und Schmelzviskositat des Poly(ethy1en-co-vinylalkohol-co-viny1acetat)s steigen rnit dem Verseifungsgrad an. Zugversuche zeigen, daD die Flexibilitat des modifizierten EVA mit steigendem Verseifungsgrad allmahlich abnimmt, was moglicherweise durch Wasserstoffbriickenbindungen im verseiften Material verursacht wird. Pfropfcopolymere von EVA rnit verschiedenen Sauren wurden charakterisiert. Das Pfropfverhaltnis rnit Fumarsiiure nimmt wegen der reaktiven Acetoxygruppen rnit wachsendem Vinylacetatanteil im EVA zu. Das Pfropfverhaltnis nimmt beim Vergleich der verschiedenen Sauren in der Reihenfolge Acrylsaure > Fumarsaure > Itaconsaure > Maleinsaureanhydrid ab, miiglicherweise durch sterische Effekte bedingt. Die Beziehung zwischen der Schalfestigkeit und dem Verseifungsgrad des EVA zeigen, darj die Adhasionskraft anfanglich ansteigt und bei Verseifungsgraden zwischen 20 und 30% ein Maximum erreicht. Die Adhasionskraft des gepfropften EVA steigt bei kleinen Sauregehalten (< 0,s Gew.-%) deutlich an und bleibt dann auch bei grorjeren Saureanteilen im Pfropfcopolymeren konstant.

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Blends of poly(vinyl butyral‐co‐vinyl alcohol) and poly(ethylene terephthalate‐co‐ethylene naphthalate): thermal, mechanical, and morphological properties

Chang

Park

Kang

et al. 2001

J of Applied Polymer Sci

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ABSTRACT:The miscibility behavior and morphology of a series of poly(vinyl butyralco-vinyl alcohol) (PVBA) copolymers containing 29, 52, 76, and 88 mol % of vinyl alcohol units with poly(ethylene terephthalate-co-ethylene naphthalate) (PETN) was investigated by DSC and SEM. Blends of the PETN with PVBA were prepared by coprecipitation from a chloroform/o-chlorophenol (20/80 wt %) mixture solvent. It was found that PVBAs with different vinyl alcohol content will form an immiscible phase with the amorphous PETN in the solution-cast films. Also, PETN and PVBA with 29 mol % vinyl alcohol (PVBA-29) are not miscible within the whole composition range. The glasstransition temperatures of the blends were higher than those of the two-component polymers. The values of the tensile properties of the blend films were also better than those of the original copolymer films.

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Neighbouring group effect on the kinetics of acetalisation of poly(vinyl alcohol)

Cited by 8 publications

References 7 publications

Vinyl Acetal Polymers

Vinyl Acetal Polymers

Substantial modifications of ethylene/vinyl acetate copolymers: Saponification and graft copolymerization

Blends of poly(vinyl butyral‐co‐vinyl alcohol) and poly(ethylene terephthalate‐co‐ethylene naphthalate): thermal, mechanical, and morphological properties

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