Results 261 to 270 of about 89,235 (304)
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Poly(Vinyl Alcohol) for Adhesives
1990Poly(vinyl alcohol) (PVOH) is a water-soluble synthetic resin. It is produced by the hydrolysis of poly(vinyl acetate); the theoretical monomer, CH2=CHOH, does not exist. Discovery of PVOH was credited to German scientists W.O. Herrmann and W.
Harold L. Jaffe, Franklin M. Rosenblum
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Polymer, 1994
Poly(vinyl alcohol) (PVA) Sloviol R was modified to different degrees by acetalization reactions with aldehyde (formaldehyde, acetaldehyde, propionaldehyde and n-butyraldehyde) for 6 h at 60°C in the presence of HCl as catalyst. Samples of the modified PVA were tested as dispersants in vinyl chloride suspension polymerization.
V. Macho +4 more
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Poly(vinyl alcohol) (PVA) Sloviol R was modified to different degrees by acetalization reactions with aldehyde (formaldehyde, acetaldehyde, propionaldehyde and n-butyraldehyde) for 6 h at 60°C in the presence of HCl as catalyst. Samples of the modified PVA were tested as dispersants in vinyl chloride suspension polymerization.
V. Macho +4 more
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Poly-Sugar: Modification of Poly(vinyl Alcohol)
Journal of Macromolecular Science: Part A - Chemistry, 1979Abstract This paper describes the attachment of sugar (sucrose) onto low molecular weight poly(vinyl alcohols) (etherification) to produce a new class of synthetic sweetener. Because of its regulated molecular weight, the new sweetener would pass through the digestive tract and be excreted in its original molecular form. We have termed the new class of
A. M. Usmani, I. O. Salyer
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Thermal analysis of poly(vinyl alcohol) and poly(vinyl acetate) fractions
Die Angewandte Makromolekulare Chemie, 1975AbstractThe commercially available poly(vinyl alcohol) (PVA) and poly(vinyl acetate) (PVAc) were fractionated by precipitation to give nine and six fractions respectively. The dependence of the thermal stability of the polymer on the molecular weight of the samples was investigated by dynamic thermogravimetry in air.
I. K. Varma, R. K. Sadhir
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Photochemical reactions in poly(vinyl chloride)/poly(vinyl alcohol) blends
Journal of Photochemistry and Photobiology A: Chemistry, 2005Abstract Poly(vinyl chloride) and poly(vinyl alcohol) (PVAL) blends with various molar ratios were UV-irradiated ( λ = 254 nm) at room temperature and in air atmosphere. Photochemical reactions were monitored by FTIR and UV–vis absorption spectroscopy.
Halina Kaczmarek +2 more
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Journal of Polymer Science Part A: Polymer Chemistry, 1996
During the emulsion polymerization of vinyl acetate (VAc) using poly(vinyl alcohol) (PVA) as stabilizer and potassium persulfate as initiator, the VAc reacts with PVA forming PVA-graft-PVAc. When the grafted polymer reaches a critical size it becomes water-insoluble and precipitates from the aqueous phase contributing to the formation of polymer ...
G. S. Magallanes Gonz�lez +5 more
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During the emulsion polymerization of vinyl acetate (VAc) using poly(vinyl alcohol) (PVA) as stabilizer and potassium persulfate as initiator, the VAc reacts with PVA forming PVA-graft-PVAc. When the grafted polymer reaches a critical size it becomes water-insoluble and precipitates from the aqueous phase contributing to the formation of polymer ...
G. S. Magallanes Gonz�lez +5 more
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Characterization of associating hydrogels of poly(vinyl alcohol) and poly(vinyl pyrrolidone)
Journal of Applied Polymer Science, 2009AbstractIn this study, hydrogels were prepared from blends of poly(vinyl alcohol) (PVA) and poly(vinyl pyrrolidone) (PVP). The miscibility of the polymers was confirmed with differential scanning calorimetry with the appearance of a single glass‐transition temperature.
X. Liu +3 more
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Study of the compatibility in the poly (vinyl-chloride) -poly (vinyl-alcohol) system
Polymer Bulletin, 1985Although poly (vinyl-chloride) — PVC — and poly (vinyl-alcohol) — PVA —mixtures are used in practice for coatings, containers, fibers, few studies are encounterd concerning their compatibility (7, 8). This paper establishes both the optimum compatibility ratio and the thermal behaviour of the mixtures.
Silvia Patachia +2 more
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Polymer Degradation and Stability, 1987
Abstract Systematic studies of the degradation of vinyl polymers may contribute to a better understanding of the ‘zipping’ mechanism of polymer degradation. Based on experimental results on the kinetic zip length of polyene formation and on polyene distribution in PVC, PVA and PVAc, it is deduced that the formation of conjugated double bonds depends ...
H. Anders, H. Zimmermann
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Abstract Systematic studies of the degradation of vinyl polymers may contribute to a better understanding of the ‘zipping’ mechanism of polymer degradation. Based on experimental results on the kinetic zip length of polyene formation and on polyene distribution in PVC, PVA and PVAc, it is deduced that the formation of conjugated double bonds depends ...
H. Anders, H. Zimmermann
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Polymer Bulletin, 1993
The compatibility of nylon 6 with poly(vinyl acetate)(PVAc) and poly(vinyl alcohol)(PVA) was investigated in terms of the melting-temperature depression. In order to vary the compatibility systematically, a hydroxylated poly(vinyl actate)(m-PVAc) was prepared by hydrolyzing PVAc with KOH in CH3OH.
Chang-Sik Ha +3 more
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The compatibility of nylon 6 with poly(vinyl acetate)(PVAc) and poly(vinyl alcohol)(PVA) was investigated in terms of the melting-temperature depression. In order to vary the compatibility systematically, a hydroxylated poly(vinyl actate)(m-PVAc) was prepared by hydrolyzing PVAc with KOH in CH3OH.
Chang-Sik Ha +3 more
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