Acetalization of polyvinyl alcohol fibres with glutaraldehyde

Conclusions Essentially shrink-free polyvinyl alcohol fibres have been obtained by acetalizing them with glutaraldehyde.The free aldehyde group content of fibres of this type, and their degree of acetalization, are determined by the catalyst concentration, the glutaraldehyde concentration, and the duration and temperature of the treatment.By graft copolymerization of acrylic acid to polyvinyl alcohol which has been acetalized with glutaraldehyde, cation exchange fibres have been obtained which have a static exchange capacity of 4.4 mmoles/g.Translated from Khimicheskie Volokna, No. 6, pp. 39–40, November–December, 1984.     

Oxidation of polyvinyl alcohol fibres in the presence of phosphorus-containing compounds

The oxidation temperature-time regime that results in carbon fibre materials (CFM) with a yield of approximately 30% and a 94–95% concentration of carbon was established based on a study of the fundamental characteristics of thermal transformations of polyvinyl alcohol (PVA) fibres in the presence of phosphorus-containing compounds. It was shown that the effective active energy of decomposition of oxidized PVA fibres and their capacity for coke formation increase in the presence of [NH ₄]₂HPO₄. The effect of the increase in the elasticity of CF caused by the action of the phosphorus-containing compound on cross-linking of the carbon during high-temperature treatment was determined. Translated from Khimicheskie Volokna, No. 2, pp. 14–18, March–April, 1997.     

Preparation of fibres from graft copolymers of acrylonitrile and polyvinyl alcohol

Conclusions The possibility of spinning fibres from graft copolymers of polyvinyl alcohol and acryonitrile by the scheme for spinning polyacrylonitrile fibre has been established.It has been shown that spinning solutions can be prepared directly from latexes of the graft copolymers.The suggestion has been made that long side chains in the copolymers participate in formation of supermolecular structural elements and aid in obtaining fibres with adequately high mechanical strength and an increased thermal stability.Translated from Khimicheskie Volokna, No. 1, pp. 13–15, January–February, 1988.     

Manufacture of graft copolymers of polyvinyl alcohol fibres with vinyl polymers

Conclusions 1. Methods have been developed, and the conditions studied, for obtaining graft copolymers of PVA fibres with polyacrylic acid, poly-2-methyl-5-vinylpyridine and polyacrylonitrile, using for formation of macroradicals carboxyl, aldehyde, and titanium groups, introduced into the fibres when they are rendered hydrophobic.2. Certain properties of the graft copolymers thus obtained have been studied. It is shown that fibres with ionogenic graft copolymers have high exchange capacities, reaching 5.8 meq/g when poly-2-methyl-5-vinylpyridine is used.S. M. Kirov Leningrad Institute of Textile and Light Industries (LITLP). Translated from Khimicheskie Volokna, No. 5, pp. 14–16, September–October, 1969.     

聚乙烯醇结构与性能的研究

采用红外光谱(FT-IR)法、核磁共振氢谱(1H-NMR)法、核磁共振碳谱(13C-NMR)法、凝胶色谱(GPC)法、反相HPLC(高效液相色谱)法和广角X射线衍射(XRD)法等对PVA(聚乙烯醇)的分子结构、聚合度大小与分布、醇解度大小与分布、嵌段分布与特征系数、立体结构、聚集态结构与结晶度以及PVA的改性进行了研究。研究结果表明:PVA的分子结构、立体结构和结晶结构等对其性能影响很大,通过控制PVA的结构和改性,可获得满足客户需求的预期性能。     

Thermal properties of polyvinyl alcohol fibres in the presence of a phosphorus-containing catalyst

The thermal properties of polyvinyl alcohol in the presence of phosphorous-containing and other inorganic compounds were investigated. The catalytic role of a phosphorus-containing fireproofing compound — diammonium phosphate — in thermooxidative decomposition of PVA was revealed. It was found that dehydration of PVA is intensified, the activation energy of decomposition of PVA increases, and its coke-forming power also increases in the presence of (NH ₄)₂HPO₄. Translated from Khimicheskie Volokna, No. 1, pp. 23–27, January–February, 1997.     

Fabrication of chemisorption fibres from graft copolymers of polyvinyl alcohol and polyglycidyl methacrylate

Mathematical modeling and optimization of fabrication of PVA-PGMA graft copolymers were conducted. The optimum parameters of graft polymerization which allow obtaining a graft copolymer with a high concentration of graft polymer were established. It was found that fluctuation of the temperature in the range of ±2‡C did not significantly affect graft polymerization. A chemisorption fibre with SEC for HCl of 3.5 mmole/g was fabricated from PVA-PGMA graft copolymers; it exhibits sorption activity with respect to copper ions, and the degree of extraction from dilute solutions is 90–97%. Translated from Khimicheskie Volokna, No. 3, pp. 13–16, May–June, 1998.     

Effect of high-temperature treatment on thermochemical transformations of oxidized polyvinyl alcohol fibres

The thermochemical transformations of PVA fibres containing diammonium phosphate were investigated in high-temperature treatment in nonoxidizing medium in the 500–900°C region. It was shown that deep thermochemical transformations that make it possible to conduct subsequent carbonization at a lower temperature (approximately 800°C) take place in the selected conditions of thermooxidation of PVA fibre (temperature of 200°C, duration of 16 h, presence of diammonium phosphate). Moscow State Textile Academy. Translated fromKhimicheskie Volokna, No. 2, pp. 5–7, March–April, 1999.     

Effect of moisture content on relaxation transitions in viscose and polyvinyl alcohol fibres

Conclusions The deformation of viscose and polyvinyl alcohol fibres in a moist medium has been examined in conformity with the principles of sorption-time analogy.It has been shown that the method described permits one to predict the deformation of man-made fibres in sorptively-active media. Moreover, the sorption-time shear function, generalized curve, and deformation rate parameter and closely connected with the vapor sorption isotherm, the sorption mechanism, and the nature of the polymer, and permit one to analyze and interpret them.Translated from Khimicheskie Volokna, No. 3, pp. 49–51, May–June, 1985.     

Radiation crosslinked polyvinyl alcohol/polyvinyl pyrrolidone/acrylic acid hydrogels: swelling,crosslinking and dye adsorption study

Iranian Polymer Journal - Hydrogels were produced from mixtures of polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), and acrylic acid (AAc) using γ-radiation at doses of 3, 7, and...     

Mechanical property and swelling behavior of semi-interpenetrating polymer networks based on polyvinyl alcohol and polyurethane

We have studied the mechanical property and swelling behavior of semi-interpenetrating polymer networks (semi-IPNs) of poly(vinyl alcohol) (PVA) and polyurethane (PU) with reactive groups under different experimental conditions. Tensile strength and elongation of these semi-IPNs are strongly dependent on the composition of IPNs and degree of PU crosslinking. It is clear that the composition of PVA and PU forms different IPNs morphology, which would determine the final mechanical property. The experimental results also demonstrate that the degree of crosslinking, which is controlled by heat treating temperature time, and amount of reactive groups, affects the swelling behavior of IPNs. With a change in the degree of crosslinking, the degree of swelling of IPNs is also different. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67: 473–479, 1998     

氧化淀粉与聚乙烯醇混溶性研究

对氧化淀粉与聚乙烯醇(PVA)水溶液的混溶性进行了研究,探讨了氧化淀粉/PVA体系的某些因素(如含量、黏度、pH、电导率、羧基含量和乙酰化等)对混溶性的影响。研究结果表明:混溶稳定性随体系含量、黏度的增大而提高;羧基含量越高,混溶性越好;pH越高,混溶性越好,在碱性条件下稳定性大幅提高;体系电导率对混溶性有一定影响,尤其在较高电导率下,混溶性迅速变差;乙酰化对混溶性影响较小,提高乙酰基含量不能明显提高相容性;提高氧化淀粉本身热力学稳定性能够提高体系的稳定性。     

Control of swelling properties of polyvinyl alcohol/hyaluronic acid hydrogels for the encapsulation of chondrocyte cells

Hydrogel scaffolds for tissue engineering are important biomaterials. The target in this study was to prepare polyvinyl alcohol/hyaluronic acid hydrogels for the encapsulation of chondrocyte cells by a simple cross‐linking reaction. Control of the swelling properties and morphology of the hydrogels for cultivation of chondrocytes was studied. The hydrogels were prepared from polyvinyl alcohol and hyaluronic acid derivatives bearing primary amine and aldehyde functionalities, respectively. The formation of the hydrogel upon mixing the aqueous solutions of the polymer derivatives took place at room temperature in a few seconds. The swelling properties of the hydrogels were found to depend on the polymer concentration and degree of substitution of the modified polymers. Scanning electron microscopy studies showed that the hydrogels had a suitable porous morphology for cell encapsulation. Furthermore, in vitro cell viability tests with the hydrogels showed no cytotoxicity for chondrocytes and that the cells grew well in the hydrogel scaffolds. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42272.     

Thermal transformations of polyvinyl alcohol and hydrated cellulose fibres in the presence of phosphates of nitrogen-containing organic compounds

Effective new pyrolytic additives 5-methyl-2-ethyl-3-hydroxypyridine and polyhexamethyleneguanidine phosphates, which ensure a high yield of carbon fibre (31–34%) from hydroxyl-containing polymeric precursors, are proposed as a result of the studies. The high activity of these activated carbon-fibre materials in sorption of acetone was demonstrated. __________ Translated from Khimicheskie Volokna, No. 3, pp. 3–6, May–June, 2007.     

Use of polyvinyl alcohol in the manufacture of polyvinyl chloride

The stabiliser used in the suspension polymerisation of vinylchloride influences greatly the quality of the resulting polyvinyl chloride, in particle size and distribution, and the absorption rate of plasticiser, etc. The relationship between the manufacturing conditions of polyvinylalcohol (PV-OH) and its dispersing power was studied using vinyl acetate and trichloro-ethylene in place of vinyl chloride monomer. It was found that the dispersing power increased with greater the blocklike distribution of the intramolecular residual acetyl group and uneven distribution of the intermolecular residual acetyl groups of PV-OH. When such PV-OH was used in suspension polymerisation of vinyl-chloride monomer, good quality polyvinylchloride was obtained. PV-OH with such characteristics is preferable as stabiliser for the suspension polymerisation of vinyl chloride monomer.