Relationship between the structure and the swelling of polyvinyl alcohol fibres

Conclusions 1. The kinetics of the swelling of PVA fibres in aqueous sodium sulphate solution can be characterised fairly accurately by a first-order kinetic equation.2. The anisotropy of swelling and the initial rate of swelling of PVA fibres depend on the orientation and the supermolecular structure of the fibres. These magnitudes can be used as characteristics of the structural changes in the fibres caused by their drawing.3. The coefficients of the rate of swelling of transverse sections of PVA fibres not subjected to heat treatment are in direct relationship with the strength of the fibres.S.M. Kirov Leningrad Institute for the Textile and Light Industries. Translated from Khimicheskie Volokna, No. 2, pp. 23–25, March–April, 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.     

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.     

纺丝原料对高强高模聚乙烯醇纤维结构性能的影响

研究了纺丝原料聚合度、转化率对聚乙烯醇(PVA)纤维高强高模化的影响。结果表明:高聚合度有利于减少端基缺陷,提高纤维性能;低转化率PVA相对高转化率PVA具有高的聚合度和线性程度,所得纤维力学性能更高。同时发现,低转化率原料纺得纤维在高倍拉伸后有强度模量较高的横纹丝产生,因此适合制备高强高模纤维。     

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.     

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.     

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.     

Effect of nano silicon dioxide on the structure and properties of FeCl3-doped polyvinyl alcohol photopolymer film

The polyvinyl alcohol (PVA) photopolymer films (PFs) were prepared based on iron(III) trichloride as the photosensitizer and PVA as the polymer matrix (Fe(III)-PVA). The nano silicon dioxide (nano-SiO₂) was mixed with the resin in proportions of 0.5, 1.0, 2.0, and 5.0 wt %, respectively. The iodine gallium lamp (350–450 nm) was used as a UV curing light source. The effects of nano-SiO₂ on the structures and properties of Fe(III)-PVA PFs were studied by scanning electron microscopy(SEM) analysis, ultraviolet–visible absorption spectroscopy(UV/Vis), X-ray diffraction (XRD), dynamic thermomechanical analysis(DMA), gel content test, tensile strength test, and Shore hardness test. The Fe(III)-PVA PFs with the content of 1.0 wt %-nano-SiO₂ exhibits the highest gel content and tensile strength. The Fe(III)-PVA PFs with the content of 2.0 wt % nano-SiO₂ exhibits the highest Shore hardness. Photolithographic patterning of the Fe(III)-PVA PFs using a UV source has been carried out, which leads to a good contrast behavior after development in an aqueous media when the content of nano-SiO₂ was lower than 2.0 wt %. After evaluating the structure, performance, and development results, the Fe(III)-PVA PFs with the content of 1.0 wt % nano-SiO₂ exhibits the best overall properties. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47702.     

聚乙烯醇对氧化铝支撑体性能的影响

以α-Al2O3粉末为骨料，以聚乙烯醇（PVA）作粘接剂和成孔剂，采用塑性挤压成型技术和固态粒子烧结法制备氧化铝多孔陶瓷支撑体。研究了有机物作粘接剂的同时也作成孔剂使用时对多孔氧化铝支撑体性能的影响。研究结果表明：以有机物PVA作开孔剂以及泥料的预处理工艺可以极大地提高氧化铝支撑体的纯水通量；有机物PVA作开孔剂时其加入种类、方式和加入量对氧化铝支撑体的平均孔径及孔径分布、孔隙率、抗弯强度等性能都有影响。通过选用合适的成孔剂种类、加入方式以及加入量，可制得平均孔径1．9μLm、孔隙率45．6％、抗弯强度22．31MPa的高通量氧化铝支撑体。     

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.     

Structure and properties of polyvinyl alcohol amidoxime chelate fiber

Polyvinyl alcohol amidoxime (PVAAO) chelate fiber prepared in our laboratory is a good adsorbent. Comparing with other adsorbents, it has many advantages, such as higher hydrophilicity, better adsorbability and easier synthesis. In this work, the synthesis course, structure and properties of PVAAO fiber have been studied by the means of FT-IR, SEM, ESR, and TG. The structural changes of the fiber associated with adsorbed copper ions have also been investigated using ESR, FT-IR, and XPS. In addition, chelating mechanisms of the fiber-adsorbing copper ions have been discussed. © 1994 John Wiley & Sons, Inc.     

Thermal and mechanical properties of nano-titanium dioxide-doped polyvinyl alcohol

Organic polymers exhibit poor thermal stability and inferior mechanical properties. Significant improvement in mechanical and thermal properties of polymers can be achieved by homogeneous distribution of inorganic materials preferably in nano size. In this study, these properties of polyvinyl alcohol were found to improve by addition of nano-titanium dioxide. Microwave irradiation method was used to prepare nano-titanium dioxide and doped in polyvinyl alcohol matrix to formulate the composite film. The spectral and morphological characterizations of the composites were carried out by the conventional techniques. Various mechanical properties were determined by Tinus Oisen universal testing machine. Thermal gravimetric analysis and differential scanning calorimetry were used for studying the thermal properties of the composites. Shift in decomposition temperature of polyvinyl alcohol indicated the enhanced thermal stability of polyvinyl alcohol. The composite also exhibited significant improvement in all the mechanical properties.     

聚乙烯醇改性的热塑性淀粉的结构与性能

采用双螺杆挤出法,以甘油为增塑剂,研究了低质量分数的聚乙烯醇对玉米淀粉的改性作用。用扫描电镜观察了淀粉和聚乙烯醇共混物的微观结构,借助差热分析考察了共混物的热性能,拉伸试验测得各种比例共混物的力学性能。研究结果表明,在聚乙烯醇质量分数低于15%时,聚乙烯醇在淀粉中呈均匀分散状态,力学性能接近淀粉的力学行为;在聚乙烯醇质量分数介于15%~25%时,聚乙烯醇与淀粉共混物呈现两相连续状态,淀粉力学性能逐步改善;在聚乙烯醇质量分数大于30%时,聚乙烯醇相趋于呈现连续相分布,力学性能得到明显提高。