Ultrathin Polypropylene Fibres from Polymer Blend Melts

The physicochemical characteristics of production of ultrathin polypropylene fibres from polymer blend melts by use of specific fibre-formation are examined. The determining role of thermodynamic compatibility in fibre formation of one polymer in another is demonstrated and a method is proposed for improving it by adding special substances — compatibilizers — to the binary mixture. The copolymer of ethylene and vinyl acetate and sodium oleate are recommended as compatibilizers for PP/CPA blends. The types of specific reaction between the copolyamide macromolecules and the additives were established by IR spectroscopy. These include dipole-dipole and ion-dipole bonds that alter the rheological properties and improve the spinnability of the blend melts. Specific fibre formation for a PP/CPA ratio corresponding to the phase shift region appeared for the first time due to compatibilization. Complex fibres are obtained from polypropylene microfibres in spinning through one opening.     

Nylon 6/66/11 Copolymer Used for Hot-Melt Adhesives: Synthesis and Properties

A new copolyamide, nylon 6/66/11, used for hot-melt adhesives, was prepared by hydrolytic polymerization and melt polycondensation. Intrinsic viscosity, melting point, glass transition temperature, cold crystallization, thermogravimetry (TG) and adhesion strength of the resultant hot-melt adhesives were investigated. DSC thermograms of the copolyamide showed that both the melting point and glass transition (T _g) temperatures decreased as the molar fraction of aminoundecanoic acid increased. The T _g practically did not change as the mole fraction of aminoundecanoic acid increased from 60% to 80%, but cold crystallinity of the copolyamide decreased. The thermal gravimetric analysis indicated that the resultant copolyamide had a high thermal stability. The copolyamide had the best combination of properties when the molar fraction of aminoundecanoic acid was about 65%.     

Combustion of Titanium with Nonmetal Nitrides

The specific features of the combustion of mixtures of titanium with powders of nonmetal nitrides BN and Si₃N₄ are investigated for the first time. Upon combustion, these nitrides serve as a solid source of reactive nitrogen. It is shown that the mechanism of combustion includes both gasless stages and a reaction of gaseous nitrogen with solid or liquid titanium. Here the gasless interaction prevails in the Ti—BN system, and the combustion of the Ti—Si₃N₄ system occurs according to a complex mechanism including gasless and gas–phase processes.     

Production of refractory blocks in induction-heated fusion-crystallization devices

Conclusions The feasibility was demonstrated experimentally with compositions of the system ZrO₂ — Al₂O₃ — SiO₂ as examples that fused blocks of refractory materials can be produced without the casting operation in an induction-heated fusion-crystallization device.The fusion process is characterized by the almost complete absence of melt contamination and by an adequate agreement of the chemical compositions of the blocks and the starting mix.The porosity of baddeleyite — corundum blocks produced by this method was low. The structure of the blocks varies with the composition of the starting material and is characterized by the presence of baddeleyite and corundum crystals and a vitreous phase.The blocks are fissured as a result of the high rate of cooling. Fissuring can be reduced or prevented by heat-treating the blocks in an annealing device immediately after crystallizing.Translated from Ogneupory, No. 5, pp. 41–44, May, 1976.     

A fragment of the phase diagram of polysulfone in dimethyl acetamide

Conclusions -- The temperature—concentration limits of the solubility of PS in DMAc have been determined, and it has been shown that the solubility increases with rise in temperature.-- The phase breakdown of solutions of PS in DMAc has been identified as amorphous without the intervention of crystallization.-- A fragment of the phase diagram for the ternary system PS-DMAc-H₂O shows that the region of solutions is strongly narrowed on increasing the concentration of the polymer.Translated from Khimicheskie Volokna, No. 4, pp. 20–21, July–August, 1990.     

Thermooxidative decomposition and combustion of halogen—Tin-containing synthetic fibres

The possibility of decreasing the combustibility of PCA and PETP fibres by treatment with acetone solutions of PVC containing tin oxides or salts was investigated. It was found that the PVC—ZnSn(OH)₆ system is the most efficient fire-retardant system for PETP. The oxygen index of PETP after treatment with this system was 27.1%. It was shown that in contrast to other types of halogen—metal-containing fire retardants whose effect is basically manifested in the gas phase, the synergistic system containing PVC and tin-containing compounds changes the direction of the reactions in the condensed phase of combustion. The capacity of the polymer (PCA, PETP) for carbonization increases in the presence of PVC and tin-containing compounds as a result of the formation of thermostable structures characterized by a high concentration of halogen, and the temperature of the onset of oxidation decreases.Moscow State Textile Academy. Translated from Khimicheskie Volokna, No. 6, pp. 34–36, November–December, 1993.     

Structural features of aromatic copolyamides

Conclusions The extreme dependence of texture parameters on copolyamide composition indicates a limited isomorphism of the PI and PA units.The limits is isomorphism are caused both by microdeformation of the copolymer units, and also by a breakdown in their statistical sequence.Translated from Khimicheskie Volokna, No. 1, pp. 30–32, January–February, 1986.     

Effect of SiO2, Fe2O3, and TiO2 on stabilization of cubic ZrO2 in the presence of Al2O3

Several compositions are investigated in order to determine the essence of the phase transformations occurring at temperatures up to 1600°C in the ZrO₂ — Ln₂O₃ (Ln is Nd, Y, Yb) — Al₂O₃ — SiO₂ (Fe₂O₃, TiO₂) systems. The efficiency of using Y₂O₃ and Yb₂O₃ to stabilize cubic ZrO₂ in the presence of a mixture of Al₂O₃ and SiO₂ (Fe₂O₃, TiO₂) is shown. Data show the possibility of fabricating high-quality zirconium-corundum articles with any proportion of Al₂O₃ and ZrO₂.Translated from Ogneupory i Tekhnicheskaya Keramika, No. 6, pp. 17 – 20, June 1996.     

Rearrangement of conodes of the phase diagram of the MgO-Al2O3-SiO2 system and its technological prospects

The subsolidus structure of the phase diagram of the MgO - Al₂O₃ -SiO₂ system is studied and the boundaries of the domains of existence and the probability of the existence of all stable phases in the entire temperature region are determined. The temperature of the pseudobinary spinel — mullite eutectic is refined. The results are taken into consideration in constructing the corresponding nonisothermal section of the phase diagram, which opens new technological possibilities due to the rearrangement of the conodes of the MgO -Al₂O₃ - SiO₂ system.Translated from Ogneupory i Tekhnicheskaya Keramika, No. 11, pp. 4 – 8, November, 1996.     

尼龙6/尼龙共聚物共混体系的热行为研究

探讨了两种尼龙共聚物对尼龙６共混改性物的热行为的影响，表明：含酰胺和酯两种基团的共聚尼龙，因其含酯基而减弱了尼龙６分子链间相互作用的结果，促进了尼龙６的结晶作用，致使冰骤冷试样观察不到冷结晶峰，仅含酰胺基团的共聚尼龙，基本上没改变尼龙６分子间的氢键相互作用，但共聚尼龙的非结晶性和无序的链结构，导致它对尼龙６结晶过程的干扰，表现为熔体结晶峰温降低和冷结晶峰温提高及峰强度（峰高）增大。     

Estimation of the Combustion and Detonation Parameters for Hydrocarbon Gas Hydrates

Calculated combustion and detonation parameters for methane—oxygen (air)—H₂O and acetylene—oxygen (air)—H₂O mixtures are presented. The values of the critical detonation–initiation energy are estimated as applied to methane and acetylene hydrates.     

A heat-bonded fibrous material from polyethylene

Conclusions The fundamental possibility of preparing a heat-bonded fibrous material from polyethylene has been established.It has been found that a heat-bonded fibrous material from polyethylene is inferior in basic consumer properties to material from copolyamide.It is recommended to use heat-bonded material from polyethylene for joining fabrics in the sewing industry.Translated from Khimicheskie Volokna, No. 1, pp. 32–33, January–February, 1990.     

Occurrence of Volatile Nitrogen-containing Compounds in Nitrogen-fixing Cyanobacterium Aphanizomenon flos-aquae

The occurrence of volatile nitrogen-containing compounds in the cyanobacterium Aphanizomenon flos-aquae has been studied. Twenty compounds belonging to four groups—amides of carboxylic and fatty acids, heterocyclic compounds and their derivatives, aromatics, and alkoxyamines and amides were identified by gas chromatography–mass spectrometry that used serially coupled capillary columns with different polarity of stationary phases. Distribution of bioactive non-toxic and toxic nitrogen-containing metabolites in cyanobacteria are discussed.     

Study of Solutions of Heterocyclic Para-Copolyamide

Polycondensation copolyamide solutions are homogeneous systems according to spectroturbidimetric evaluation. Solutions of reprecipitated copolyamide are heterogeneous. The heterogeneity could be caused by relatively strong supramolecular formations that are not decomposed by the solvent. The use of turbidimetric titration curves for assessing the molecular-weight distribution of copolyamide is problematic, since irregular distribution of the units, the acidity of the medium, and primary structure formation, together with the molecular weight, can affect separation of copolyamide from a solution of the copolymer by the precipitant. The extreme character of the dependence of the intrinsic viscosity of copolyamide on the acidity of the solution suggests that in certain conditions, the copolyamide can exhibit polyelectrolytic properties.     

SO2 Oxidation Catalyst Model Systems Characterized by Thermal Methods

The molten salts M₂S₂O₇ and MHSO₄, the binary molten salt systems M₂S₂O₇—MHSO₄ and the molten salt-gas systems M₂S₂O₇—V₂O₅ and M₂S₂O₇—M₂SO₄—V₂O₅ (M = Na, K, Rb, Cs) in O₂, SO₂ and Ar atmospheres have been investigated by thermal methods like calorimetry, Differential Enthalpic Analysis (DEA) and Differential Scanning Calorimetry (DSC). Fundamental thermodynamic data like temperatures and molar heats of solid--solid transition and fusion, phase diagrams, heat capacities of solids and liquids, heat of mixing and heats of complex formation have been obtained and the results are discussed in relation to the mechanism of SO₂ oxidation by V₂O₅ based industrial catalysts.     

Evaporation of polymer-solvent mixtures

Summary The Stefan-Winkelmann diffusion technique has been used to determine vapor pressures of high boiling point compound-solvents mixtures. Data are reported at a temperature of 67°C for the mixtures polyphenyl ether (6 rings) — benzene and carbowax 1500 — benzene and at a temperature of 100°C for the mixtures polyphenyl ether (6 rings) — toluene and tricresylphosphate-toluene. The range of concentration is only limited by the appearance of a solid phase, and results are in good agreement with those determined by vapor pressure osmometry.Nomenclature A Vapour source - B Flowing gas phase - c Concentration, g-mol/cm³ - D_AB Molecular diffusion coefficient, cm₂/s - h_i Total interface depth, cm - K Parameter defined by equation (6), dimensionless - I Polymer or high boiling point compound - M_A Molecular weight - N_AZ Molar flux, g-mol/(cm₂) (s) - P_A Partial pressure at the interface, atm - P Total pressure, atm - R Gas constant, (atm) (cm₃) / (°K) (g-mol) - T Temperature, °K - t Time, s - Y_A Molar fraction at the interface, dimensionless - z_o Initial interface depth, cm - z_i Drop of the interface depth, cm - z Interface position Greek Letters _A Density of the liquid phase, g/cm³     

Specific Features of the Formation of Crystalline Phases of the W—C—N System in a Cumulative Process

Results of x–ray diffractometric studies of coatings and powders of the W—C, W—N, and W—C—N systems that were obtained under conditions of a shaped–charge explosion are reported. The dependence of the phase composition on the experimental conditions is investigated. Diffusion of nitrogen to the initial polycrystalline tungsten is shown.     

Hot-Pressed ceramics of ultradisperse composite powders

The regularities of variation of the microstructure, phase composition, degree of crystallinity, and properties of hot-pressed ceramics prepared from ultradisperse composite powders of the Si₃N₄ - Y₂O₃ system depending on the / phase ratio in Si₃N₄ and the concentration of Y₂O₃ are discussed. An increase in the concentration of Y₂O₃ in composite powders up to 15 – 18% and a decrease in the / ratio of Si₃N₄ lead to a change of the composition of the secondary crystalline phases with an increase in their refractoriness (from silicon oxynitride and yttrium silicates to complex yttrium — silicon oxynitrides), a lower concentration of the vitreous phase, a higher degree of crystallinity, and a higher content of stretched grains in the structure of the ceramics. The presence of the high-melting phase of yttrium — silicon oxynitrides improves the phase and granular homogeneity of the structure that forms by the type of solid solutions, with an essentially similar composition of the grains and the intergranular phase. The formation of a high-melting fine-grained self-toughening structure with a coefficient of grain elongation up to 8 – 9 ensures a high and practically stable level of the mechanical properties of the synthesized materials at temperatures up to 1400 – 1500°C.Translated from Ogneupory, No. 2, pp. 13 – 20, February, 1994.     

Polyether-segmented nylon hemodialysis membranes. IV. Membrane morphologies and permeability characteristics of dialysis membrane composed of poly(ethylene oxide)-segmented Ny69/M10

Dialysis membrane was prepared by a phase inversion method using a new polyether-segmented nylon which dissolves in common organic solvents such as dimethylsulfoxide. The polyether-segmented nylon contained poly(ethylene oxide) block and nylon block (random copolyamide: Ny69/M10) prepared by sebacic acid, azelaic acid, m-xylenediamine, and hexamethylenediamine. The morphologies and permeability characteristics of the membranes were investigated. It was shown by scanning electron microscope observation that the membrane had a fingerlike structure when dimethylsulfoxide was used as a polymer solvent, and a spongelike structure when an additive such as calcium chloride was added to the polymer solution. The high permeability for the solutes such as urea and vitamin B₁₂ were observed in comparison with the polyether-segmented Ny610 membranes prepared by a phase inversion method. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1731–1737, 1997     

Fabrication of polypropylene blends with excellent low‐temperature toughness and balanced toughness‐rigidity by a combination of EPR and SEEPS

To overcome serious rigidity depression of rubber‐toughened plastics and fabricate a rigidity‐toughness balanced thermoplastic, a combination of styrene‐[ethylene‐(ethylene‐propylene)]‐styrene block copolymer (SEEPS) and ethylene‐propylene rubber (EPR) was used to toughen polypropylene. The dynamic mechanical properties, crystallization and melting behavior, and mechanical properties of polypropylene (PP)/EPR/SEEPS blends were studied in detail. The results show that the combination of SEEPS and EPR can achieve the tremendous improvement of low‐temperature toughness without significant strength and rigidity loss. Dynamic mechanical properties and phase morphology results demonstrate that there is a good interfacial strength and increased loss of compound rubber phase comprised of EPR component and EP domain of SEEPS. Compared with PP/EPR binary blends, although neither glass transition temperature (T_g) of the rubber phase nor T_g of PP matrix in PP/EPR/SEEPS blends decreases, the brittle‐tough transition temperature (T_bd) of PP/EPR/SEEPS blends decreases, indicating that the increased interfacial interaction between PP matrix and compound rubber phase is also an effective approach to decrease T_bd of the blends so as to improve low‐temperature toughness. The balance between rigidity and toughness of PP/EPR/SEEPS blends is ascribed to the synergistic effect of EPR and SEEPS on toughening PP. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45714.