Calculation of temperature-time field characteristics in polymer fibre and yarn chemistry and technology

The temperature of the fibre surface in strong absorption is a nonlinear function of the time according to accurate and approximate expressions. Solving the problem of heating of a fibre by irradiation in weak and strong absorption will allow determining the optimum temperature regime in production of chemical fibres. __________ Translated from Khimichakie Volokna, No. 6, pp. 47–49, November–December, 2006.     

Effect of decreasing intermolecular interaction in the contact of synthetic fibres with water on fibre strength

Conclusions A quantitative estimate has been made of the change in intermolecular interaction energy in a series of synthetic fibres and yarns in the action of water on them.A quantitative correlation has been established between the relative decrease in intermolecular interaction energy and the relative strength decrease of synthetic fibres and yarns on contact with water.It has been confirmed that the activation energy of mechanical failure is an algebraic sum of the energies of thermooxidative degradation of the polymer and of intermolecular interaction in it.Translated from Khimicheskie Volokna, No. 3, pp. 44–46, May–June, 1985.     

Infrared spectroscopy method reveals hydrogen bonding and intermolecular interaction between components in polymer blends

An infrared spectroscopy method was devised to uncover evidence of hydrogen bonding and intermolecular interaction between components in solid poly(lactic acid) (PLA) and poly(hydroxyester ether) (PHEE) blends. The method compares Gaussian/Lorentzian deconvoluted infrared spectra of the polymer blends with deconvoluted spectra of weight ratio‐equivalent mixtures of the physically separated polymers. Infrared spectra of polymer blends, where hydrogen bonding exists, differ from spectra of physical mixtures of the polymers. Deconvoluting spectra of the blends into their underlying peaks revealed theoretically expected differences between hydrogen‐bonded and nonhydrogen bonded components. The findings are supported by differential scanning calorimetry, scanning electron microscopy, and mechanical rheometry studies. The new method, differential spectral deconvolution, afforded a quantitative estimate of the extent of hydrogen bonding between PLA and PHEE and could therefore be used to measure the degree of interaction between components in thermoplastic blends. This technique is superior to conventional spectral subtraction and it should be applicable to intimate mixtures or solid solutions in general. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 813–821, 2005     

Dynamic wetting of glass fibre and polymer fibre

To achieve high strength and chemical resistance in glass-reinforced plastics, it has been found essential to have a good bond between matrix and reinforcement. To obtain this bond it is necessary that good wetting of reinforcement by matrix must occur at some stage in the production cycle. Modern process developments have reduced the time during which wetting can occur to a few seconds in continuous sheeting manufacture. The wetting stage of this process has been investigated by the observation of dynamic contact angles. The rate of wetting has been found to be controlled by liquid flow and not surface tension at high processing speeds. Breakdown of this flow and intermittent wetting have been observed directly. When low energy surfaces are wetted by water, a different limiting factor is found. It is observed that a maximum dynamic contact angle is reached at relatively low wetting rates. It is suggested that these maximum angles offer a new means of assessing Zisman's ‘critical surface tension’ (γ_c) and by an extension of the technique may enable values of spreading pressure (π) to be measured.     

Enzymes in polymer chemistry

Summary In the present paper the synthesis of N-Methacryloyl-11-aminoundecanoyl-N-(1-amino-2-propanol) and the corresponding copolymer with styrene is described. The stereoselective enzyme-catalyzed acetylation of the monomers and copolymers in the presence of vinylacetate by two lipases was investigated.     

Carbon fibre in polymer reinforcement

The processing and the properties of carbon fibres are reviewed. Next the physical and mechanical properties of carbon and glass fibres are compared. Their use in polymeric composites is discussed.     

分子间相互作用理论研究现状及进展

简要介绍了近年来国内外分子间相互作用的理论状况与进展,主要是超分子方法(SM)、对称性匹配微扰理论(SAPT)、密度泛函理论(DFT)、定域相关方法及多种方法的结合对分子间相互作用的研究。在计算与模拟精确势能面(PES)时,超分子方法与微扰方法有效的结合,可以相互补充。SAPT与DFT的结合正在成为分子间作用理论的一种新近趋势。定域相关方法是一种选择性超分子方法,正在向更高水平的Mφller-P lesset微扰理论方向发展。当前对反映分子间主要电子相关效应的色散项的描述和计算仍有一定困难,并有相当挑战性。此外,阐述了分子间作用计算中所出现的基组问题,包括基组叠加误差及其均衡校正方案(counterpoise procedure,CP)存在的争议和基组饱和(basis set saturation)问题。     

Cooling of the polymer jet in fibre spinning

Conclusions The effect of various technological parameters (jet stretch ratio, temperature and flow rate of the polymer melt, temperature and velocity of the air which cools the melt, and rheological characteristics of the polymer) on the change in temperature and viscosity of the polymer jet along the length of the spinning zone has been investigated.It has been shown that the temperature of the cooling air, the Stanton number, and the velocity of the cooling air exert the greatest effect on the fibre temperature at the take-up device, but jet stretch ratio and rheological properties of the melt affect fibre temperature only slightly.Translated from Khimicheskie Volokna, No. 6, pp. 19–20, November–December, 1987.     

Curing behavior,mechanical properties,intermolecular interaction,and morphology of silicone/polypyrrole/polymer electrolyte composites

The curing behavior, mechanical properties, intermolecular interaction, and morphology of silicone, polypyrrole, and polymer electrolyte composites were studied. A rigid‐body pendulum rheometer was used to determine the curing behavior of silicone/PEL blends. The polymer structure was evaluated using FTIR and Differential Scanning Calorimetery. The mechanical properties, including stress, strain, and hardness, were measured using a material testing system. The morphology of the composites was measured using scanning electron micrographs. The intermolecular interaction of the composites was measurement using dynamic mechanical analysis. The results show that the curing reaction rate is fast upon addition of 10 wt % of polymer electrolyte for silicone. The linear molecular structure of the polymer electrolyte was wound around the silicone polymer network structure forming a semi‐interpenetrating network. The intermolecular interaction was influenced by the composites, and the Ppy film effect on the surface of SP10 blends is more uniform than that of silicone. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2754–2764, 2006     

Influence of molar mass on the thermal properties,conductivity and intermolecular interaction of poly(ethylene oxide) solid polymer electrolytes

The sample preparation pathway of solid polymer electrolytes (SPEs ) influences their thermal properties, which in turn governs the ionic conductivity of the materials especially for systems consisting of a crystallizable constituent. Majority of poly(ethylene oxide) (PEO)‐based SPEs with molar masses of PEO well above 10⁴ g mol^?1 (where PEO is crystallizable and should reach an asymptote in thermal behaviour) display molar mass dependence of the thermal properties and ionic conductivities in non‐equilibrium conditions, as reported in the literature. In this study, PEO of different viscosity‐molar masses (M _η = 3 × 10⁵, 6 × 10⁵, 1 × 10⁶, 4 × 10⁶ g mol^?1) and LiClO₄ salt (0 to 16.7 wt%) were used. The SPEs were thermally treated under inert atmosphere above the melting temperature of PEO and then cooled down for subsequent isothermal crystallization for sufficient experimental time to develop morphology close to equilibrium conditions. The thermal properties (e.g. glass transition temperature, melting temperature, crystallinity) according to differential scanning calorimetry and the ionic conductivity obtained from impedance spectroscopy at room temperature (σ _DC ～ 10^?6 S cm^?1) demonstrate insignificant variation with respect to the molar mass of PEO at constant salt concentration. These findings are in agreement with the PEO crystalline structures using X‐ray diffraction and ion ? dipole interaction by Fourier transform infrared results. © 2017 Society of Chemical Industry     

Trends in the chemistry and technology of lipids

A review is given of the annual world production of fats and oils and their increasing availability for edible and nonedible purposes. Trends in some important industrial processes (polymerization, metathesis, oxidation, etc.) are discussed and the applicability of fatty oils as specific and characteristic base materials for the organic chemical industry is compared with developments in the field of petroleum synthetics. To improve the position of fat-intermediates and fat derivatives on the world market, future research should be particularly directed to an optimal use of their specific physical, chemical and biochemical properties, and to an increased coherence between our technological and biochemical knowhow.     

Radical addition-fragmentation chemistry in polymer synthesis

This review traces the development of addition-fragmentation chain transfer agents and related ring-opening monomers highlighting recent innovation in these areas. The major part of this review deals with reagents that give reversible addition-fragmentation chain transfer (RAFT). These reagents include dithioesters, trithiocarbonates, dithiocarbamates and xanthates. The RAFT process is a versatile method for conferring living characteristics on radical polymerizations providing unprecedented control over molecular weight, molecular weight distribution, composition and architecture. It is suitable for most monomers polymerizable by radical polymerization and is robust under a wide range of reaction conditions. It provides a route to functional polymers, cyclopolymers, gradient copolymers, block polymers and star polymers.     

Morphology of composite polymer emulsion particles consisting of two kinds of polymers between which ionic bonding intermolecular interaction operates

The morphology of particles (I) produced by seeded emulsion copolymerization of styrene (S) and sodium p-styrene sulfonate (NaSS) with butyl acrylate (BA)-methacryloyloxyethyl-trimethylammonium chloride (QDM) copolymer particles as seed was examined in comparison with poly(butyl acrylate) (PBA)-polystyrene (PS) composite polymer emulsion particles (II). In an electron microscopic observation, it was observed that II particles had an anomalous shape and the electron densities at different points in the particle were heterogeneous, whereas I particles had an almost spherical shape and the electron densities were homogeneous. The maximum tensile strength and toughnes were much larger in II than I. The dynamic mechanical studies indicate that II film had a macroheterogeneous structure consisting of PS-rich and PBA-rich phases, whereas I film had a microheterogeneous structure. These ressults suggest that there is an effect of intermolecular interaction between polymers of different kinds on the formation of heterogeneous structure in particles consisting of two kinds of polymers.