Structure Of Polyvinyl Alcohol Research Articles

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Articles published on Structure Of Polyvinyl Alcohol

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Crosslinked PVA-PS thin-film composite membrane for reverse osmosis

With bicarboxylic acids as crosslinking agents and H 2SO 4 as catalyst, polyvinyl alcohol (PVA) was crosslinked in the temperature range of 90–120°C, resulting in thin-film composite membranes with polysulphone as substrate. IR analysis showed that crosslinking changes the chemical structure of PVA, involving H 2SO 4 in the reaction. Besides oxalic acid, other bicarboxylic acids, such as malonic acid, succinic acid and citric acid can also crosslink PVA in the temperature range given above. RO tests showed that the salt rejection of membranes using oxalic acid as crosslinking agent was higher than that of membranes using other bicarboxylic acids.

Desalination

Jan 1, 1987
She Jian + 1

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Effect of sodium acetate on the structure of polyvinyl alcohol

The effect of sodium acetate on the degree of crystallinity of PVA has been studied by IR spectroscopy and wide and low angle X-ray structural analysis. It is shown that the introduction of sodium acetate into the PVA samples raises the degree of crystallinity with practically no change in the size of the crystalline regions over a wide filling range. From the results of X-ray structural analysis an assumption is made on the character of the distribution of sodium acetate in the PVA samples as a function of the concentration of filler.

Polymer Science U.S.S.R.

Jan 1, 1984
G.D Korodenko + 5

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Study of the role of intermolecular interactions (hydrogen bonds) in the initial stage of orientation of polyvinyl alcohol and vinyl alcohol copolymers

The effect of hydrogen bond rupture on the process of destruction of the starting crystallite structure of polyvinyl alcohol and copolymers of vinyl alcohol and N-vinylpyrrolidone and e-vinylcaprolactam has been investigated. The differential spectrum method is used to establish the frequency (3200 cm−1) of the band corresponding to the vibrations of the bound hydroxyl groups; the temperature dependence of the optical density of the 3200 cm−1 band has been recorded. The strength of the starting structure is calculated from the stress-strain diagram and its temperature dependence is plotted. It is concluded that the strength of the starting structure is chiefly determined by the presence of hydrogen bonds between the polymer macromolecules.

Polymer Mechanics

Jan 1, 1973
A N Savitskaya + 3

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The effect of reactive dyes on the supermolecular structure of polyvinyl alcohol (PVALC)

Polymer Science U.S.S.R.

Jan 1, 1973
B.N Narzullayev + 3

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Investigation of polyvinyl alcohol solutions

Investigation of the properties and structure of solutions of polyvinyl alcohol (PVA) in dimethylformamide, dimethylsulphoxide and water in the temperature range 25–150°C by polarized-light microscopy, X-ray analysis, IR spectroscopy and the Rayleigh scattering of light has shown that “crystalline” separation is observed in the case of PVA solutions in dimethylformamide, just as in glycerine and ethylene glycol. The crystalline structure of PVA separated from solutions in these solvents is confirmed by direct structural methods of investigation of these systems. The results obtained give evidence that the sharp rise in light-scattering with its subsequent decrease is found both in the case of systems having macro-separation and also when gels are formed, and consequently, it is a consequence of micro-separation of the system.

Polymer Science U.S.S.R.

Jan 1, 1973
V.M Andreyeva + 3

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POLYVINYL ALCOHOL FIBERS PREPARED FROM POLYVINYL ACETATE POLYMERIZED AT LOW TEMPERATURE

Photo-polymerization of vinyl acetate was carried at 0°C and -30°C using uranyl acetate as sensitizer.Polyvinyl acetate thus obtained was saponified to polyvinyl alcohol (PVA), and the properties of this PVA and fibers prepared from it were compared with those of commercial PVA.The contents of 1, 2 glycol structure of PVA decreased and the gelation of aqueous solution was accelerated with lowering polymerization temperature of polyvinyl acetate from which the PVA was produced.Heat treated and not formalized fibers prepared from this PVA had good resistance to hot water up to 110°C, and its tenacity, elongation and elastic recovery were not inferior to the fibers from commercial PVA.

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