Elastic properties of refractory aluminosilicate concrete based on high-alumina cement

Conclusions The authors have determined the dynamic modulus of elasticity of aluminosilicate concrete in relation to the heating and cooling temperature of the latter, the amount of high-alumina cement, and the Al₂O₃ content of the filler.The change in the modulus of elasticity at different temperatures permits an assessment of the character of the structural changes in the concrete due to dehydration, the content and composition of the vitreous phase, and thermal stresses.Hysteresis between the curves of the modulus of elasticity during heating and cooling has been established. The extent of the hysteresis is determined by the heating temperature and the corresponding amount of the vitreous phase.An increase in the high-alumina cement content from 15 to 25% increases the modulus of elasticity of the concrete at 20–400°C, and an increase in the Al₂O₃ content of the filler increases it at 20–400 and 1250–1400°C.Translated from Ogneupory, No. 6, pp. 22–26, June, 1979.     

Quantitative correlation of creep and stress relaxation in synthetic fibres

The quantitative correlation of creep and stress relaxation was determined. The reliability of the indicial equation and calculated deformation characteristics for describing the different conditions with a given law of deformation was confirmed.All-Russian Scientific-Research Institute of Technical Fabrics, Yaroslavl'. Institute of Textile and Light Industry, St. Petersburg. Translated from Khimicheskie Volokna, No. 6, pp. 41–42, November–December, 1992.     

Flexural properties of surface reinforced wood/plastic deck board

Decking and railing is the largest and fastest growing market for wood–plastic composites (WPCs). Despite WPC's advantages in comparison to lumber, its modulus and creep resistance need to be further improved for demanding structural applications. In this study, WPC deck boards were reinforced by the composite sheets made of commingled glass and polypropylene fiber. Various reinforcement arrangements were carried out to identify the optimal one. Scanning electron microscopy revealed good bonding at the reinforcement/WPC interface. All reinforced samples exhibited considerably increased modulus of rupture, modulus of elasticity, and strain at break. The creep resistance of the reinforced WPC boards was also greatly improved. Creep strain was simulated with Findley's model. Master curves of creep compliance were generated by time–temperature–stress superposition principle. The Prony series was found to be the analytical expression of the master curves with acceptable accuracy. With improved mechanical properties, the reinforced WPC board can be used in more demanding applications. POLYM. ENG. SCI., 47:281–288, 2007. © 2007 Society of Plastics Engineers.     

High-temperature creep of refractory ceramics. Kinetics and the effect of experimental conditions

High-temperature creep curves of samples of refractory ceramics are considered. It is shown that in the vast majority of cases strain in samples accumulates linearly. Regularities of creep flow rate change under the effect of temperature and loads are established. The sample structure is shown to affect the creep kinetics.Translated from Ogneupory, No. 6, pp. 2–8, June, 1994.     

Mechanical Properties of Hot-Pressed Zirconium Carbide Tested to 2600°C

Tensile, creep, and modulus of elasticity data were determined for hot-pressed zirconium carbide. The material was relatively impure, containing 1 to 2% nitrogen and 1 to 2% free carbon. Tension and creep properties, which were measured to 2600° C, indicated that above 2100°C the strength was 2000 psi or lower and the elongation was 40% or more, thus signifying little structural usefulness. It is proposed that the results were influenced by impurities at the grain boundaries. Room-temperature modulus of elasticity values averaging 51.6 × 10⁶ psi were obtained by dynamic methods.     

The fatigue properties of viscose rayon cord yarn containing structure-forming and thermo-oxidation inhibiting additives

Conclusions 1. It has been shown that it is desirable to combine a limited intensity of stretch-draw with a fairly prolonged exposure of the fibrous filament or thread in the hot-draw zone if increased modulus of elasticity is to be obtained.2. It has been made clear that the ratio of the intensities of plasticised to hot stretch-draw has little effect on the properties of polyvinyl alcohol fibre.3. It has been shown that the mechanical properties and the water resistance of stretch-drawn polyvinyl alcohol fibre is determined, in the first instance, by the intensity of hot draw, i.e., the orientation processes. The effect of the duration of the hot draw on these properties is manifested only over a limited interval of time, which may enable the orientation processes either to proceed or may worsen them.Leningrad Branch of the All-Union Scientific-Research Institute for Man-Made Fibre (VNIIV). Translated from Khimicheskie Volokna, No. 6, pp. 45–47, November–December, 1969.     

Effect of diameter nonuniformity in unoriented monofilament on stretch ratio and strength of the final fibre

Conclusions Dependences have been obtained which make it possible, for the stretching scheme examined, to carry out a comparison with a monofilament which is uniform in diameter, with respect to limiting stretch ratio and strength after stretching, at any character of change in diameter of an undrawn filament.It has been shown that the stretch ratio and the strength of a drawn monofilament are determined by the ratio of the maximum diameter to the minimum diameter (D/d), and also by the character of the change in diameter over the length of the undrawn monofilament.Translated from Khimicheskie Volokna, No. 6, pp. 11–12, November–December, 1987.     

Interaction of mass exchange and jet tension in spinning of nitron fibres

The reciprocal effect of mass exchange and tension of spun Nitron fibre in the spinning bath was demonstrated. The concentration region of the concentration of solvent in the spinning bath which guarantees attaining high elasticity and a strength of 100 cN/tex and the more finished fibre with a linear density of 0.01 tex was established.Nitron Plant, Novoiazot Industrial Association, Uzbekistan; Mogilev Institute of Technology, Belarus'. Translated from Khimicheskie Volokna, No. 6, pp. 41–43, November–December, 1993.     

Mechanisms of breakdown of the structure of glass cloth during impregnation with polymer binders

The basic sources of worsening of the quality indexes of insulating glass cloth and the requirements for the properties of the cloth and binder during impregnation were determined: short pile, gas inclusions, thermodynamic characteristics of binder and monofilament on the binder—monofilament, binder—air, and air—monofilament interface, internal stresses in the structure of the cloth, weave geometry, and position of monofilaments in the complex fibre.Stekloplastik—Sertifikat Co., Moscow. Translated from Khimicheskie Volokna, No. 3, pp. 43–46, May–June, 1994.     

Realization of the strength of carbon fibres in microplastics

Based on the model of fracture of carbon-filled plastics by breakage of fibres in stretching, the strength of CF realized in a microplastic was examined as part of the strength of fibres at their critical length. Based on an analysis of the experimental and calculated data for ENFB epoxy—phenol binders, the empirical dependence of the coefficient of realization of the strength of CF in a microplastic on the modulus of elasticity of the fibres and parameter B of the scale effect of the strength of CF was established. It was shown that the parameters of the strength scale effect and modulus of elasticity of CF have the determining effect on the strength of the microplastic.Translated from Khimicheskie Volokna, No. 1, pp. 42–45, January–February, 1995.     

PET／PTT双组分纤维的卷曲形貌和卷曲弹性参数分析

分析了不同张力和温度条件下,PET／PTT单丝和复丝的卷曲形貌和卷曲弹性参数。结果表明：随着热处理张力的增加,单丝的卷曲数和卷曲半径减小,单丝和复丝的卷曲伸长率减小,卷曲弹性回复率增加,卷曲模量增加;随着热处理温度的增加,单丝的卷曲数增加,卷曲半径减小,单丝和复丝的卷曲伸长率减小,卷曲弹性回复率增加,卷曲模量增加;在温度100-120℃且张力较小的条件下进行热处理时,PET／PTT纤维的单丝和复丝的卷曲弹性较好。     

Structural features and properties of fibres based on mixtures of an ethylene-vinylacetate copolymer with a copolyamide

Conclusions By x-ray analysis, we have confirmed the previously expressed hypothesis of a forced deformation of SÉVA on flow of an SÉVA—SPA mixture as a result of specific interaction of the components at the interface: the degree of orientation of the SÉVA macromolecules in the microfibres is higher than in a monofilament from the starting polymer.It has been shown that ultrathin SÉVA fibres are characterized by a porosity, caused by micro- and macro-hollows, which causes a decrease in their strength as compared with the strength of ordinary SÉVA fibres.Kiev Technological Institute for Light Industry. Translated from Khimicheskie Volokna, No. 2, pp. 39–41, March–April, 1992.     

Description of creep of complex fibres made from rigid-chain polymers

The possibility of applying the temperature—time analogy principle for quantitatively describing creep of SVM fibre was demonstrated. An increase in the modulus of elasticity of SVM fibre was found in the region of nondestructive stress.     

Ultrastrong fibres fabricated by orientational crystallization from gel. A review

The methods of fabrication of ultrastrong chemical fibres from flexible-chain polymers examined in the review require use of a starting polymer with an ultrahigh-molecular-weight. Attaining ultrahigh draw ratios is a common technological condition. This is almost exclusively determined by the ratio between the deformation rate, temperature, and initial state of the polymer. Gel technology is a priority method of fabrication of ultrastrong fibres. The polyester fibres fabricated by this method attain strengths of 6–7 GPa and Young's modulus of 220–250 GPa. All ultrastrong fibres have the structure of a fibrillar crystallite with a significant fraction of KVTs. All ultrastrong fibres have a melting point 5–10°C higher than for oriented fibres and elevated technical stability with high temperatures and moderate loads.Ukrainian Scientific-Research Institute of Fibres, Kiev. Translated from Khimicheskie Volokna, No. 6, pp. 8–17, November–December, 1992.     

超高分子量聚乙烯纤维蠕变性能改性研究

通过紫外线照射对超高分子量聚乙烯(UHMWPE)纤维进行交联改性。运用密度梯度法、声速取向测试及广角X射线衍射(WAXD)等手段测试分析了蠕变过程中纤维结晶度的变化和相变情况,并通过计算机编程对蠕变数学模型进行拟合,该方法可以快速、精确地拟合出材料的相关性能参数。拟合结果表明紫外照射处理的UHMWPE纤维普弹模量E_1略有降低,而高弹模量E_2、推迟时间τ和本体粘度η_3有一定的提高。说明紫外照射交联能改善纤维蠕变性能。     

Structure and physicomechanical properties of polycaproamide monofilaments

Conclusions The molecular weight of the polymer, filament diameter, and cooling conditions during spinning exert a considerable effect on the size of the skin and the structural nonuniformity over the cross section of polycaproamide monofilaments.A monofilament with minimum skin dimensions is the most transparent and elastic.At low spinning temperatures and with the use of organic liquids for cooling, it is possible to obtain a monofilament with no skin.Translated from Khimicheskie Volokna, No. 4, pp. 41–43, July–August, 1983.     

A Statistical Formulation for Master Modulus Curves of a Vinyl Ester Polymer

Master modulus curves are developed for a vinyl ester polymer with variability in its material properties. Tensile creep strains were obtained at three temperatures below the T_g through digital image correlation. A spectrum function was used to represent the viscoelastic strain response and modulus. A two-parameter Weibull distribution was used to characterize the probability distribution of the longitudinal modulus. The Weibull probability density functions of the viscoelastic modulus were obtained for each test configuration and found to be time and temperature dependent. Longitudinal modulus curves at constant probabilities were used to develop the master curves using the time–temperature superposition principle.     

Use of chemically dyed low-molecular polycaproamide to prepare dyed polypropylene yarn

Conclusions Chemically dyed LMPCA have been synthesized by the direct reaction of three types of active dyes with LMPCA at temperatures below 100°C for 3–6 h; they contain up to 20–40% (of the weight of the dyed product) of chemically bonded dye.The chemically colored LMPCA are soluble in solvents for LMPCA; they form a finely crystalline structure, have a melting point close to that of the starting LMPCA, and have significantly improved thermal properties.Upon addition of chemically dyed LMPCA to PP flake, colored undrawn monofilaments were formed, whose strength at an additive content of 10% on the weight of PP did not differ from the strength of monofilament spun under analogous conditions, and the specific bulk electrica resistance was 2–10 times smaller.Translated from Khimicheskie Volokna, No. 6, pp. 22–24, November–December, 1986.     

Filler fraction effect on creep response of crosslinked polyester matrix with mineral filler

The effect of a particle marble filler on the creep response of a crosslinked polyester matrix before and after physical aging is described. Composites with various filler–polyester matrix percentages are prepared by applying mixing technology, curing at room temperature, and postcuring above the glass‐transition temperature. Two groups of specimens of identical composition are studied. The first group is tested 1 month after preparation (relatively nonaged), whereas the second group is tested after 13 years of storage at stable room temperature and humidity, at current atmospheric pressure, and in the absence of direct light (aged). The two groups of specimens (aged and nonaged) are subjected to creep measurements. The modulus of elasticity and the creep compliance are determined, plotted against the filler volume fraction, and fit by empirical equations. A simple mechanical model is proposed to fit the compliance curves, and good agreement between the measured and predicted values is shown. The mechanical behavior of the composites is also described, using empirical equations that fit the relation between the composite/matrix ratio of the deformation characteristics and the filler volume fraction. A crucial matrix influence is proposed to fit the compliance curves, and good agreement between the measured and predicted values is shown. Experimentally established natural regularities can be used to predict the creep compliances of composites from a less demanding experimental program. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3329–3335, 2003     

Investigation of rheology and morphology to follow physical fibrillar network evolution through fiber spinning of PP/PA6 blend fiber

This work is aimed at investigating the influence of fibrillar morphology of deformed Polyamide 6 (PA6) droplets dispersed in Polypropylene (PP) matrix on the melt viscoelastic behavior of their blends. The blends of PP with various amounts of PA6 (1%, 6%, 10%, and 20%) were prepared by melt mixing in a co‐rotating twin screw extruder and fibrillated by fiber spinning process. Scanning Electron Microscopy revealed that the PA6 spherical droplets form fibrillar inclusions after fiber spinning. The steady and transient shear rheological responses of samples were evaluated in both linear and nonlinear ranges of deformation. Non‐terminal behavior of storage modulus at low frequency appeared as a typical characteristic of fibrillar morphology whose width and value depend on fibril growth. Storage modulus and complex viscosity of the blends containing PA6 fibrillated structure were remarkably enhanced compared to as‐extruded samples. The fibrillar‐induced elasticity of the fibers is a distinguishable behavior which was revealed by conducting transient stress and creep‐recovery measurements and upon appearing mature fibrils, elasticity of the polymer blend fibers increased significantly. POLYM. ENG. SCI., 58:1251–1260, 2018. © 2017 Society of Plastics Engineers