Adrian Barylski  Joanna Maszybrocka  Marian Kupka  Krzysztof Aniołek  Sławomir Kaptacz 《应用聚合物科学杂志》2015,132(31)

PTFE with a 15% addition of graphite was subjected to irradiation using an electron beam of 10 MeV energy with absorbed doses of 26, 52, 78, 104, and 156 kGy. The effect of electron‐beam irradiation on the mechanical, sclerometic, and tribological properties, the crystallinity degree, and the morphology of the polymer surface was examined. It was found that the modification through irradiation entailed a gradual increase in the degree of crystallinity, which had a direct influence on the mechanical properties. An increase in the hardness, Young's modulus, and compressive strength of the polymer irradiated with an electron beam was also demonstrated. The electron‐beam irradiation reduced the value of components of the work‐of‐indentation, showing the growing resistance to deformation. An analysis of the scratch test parameters showed a reduced depth of penetration of the indenter into the material, proportionally to the irradiation value, at relatively constant values of the scratch depth after scratching load removal. A stereometric analysis of the scratch traces on the material allowed to determine coefficients of the wear micromechanism, β, and resistance to wear, W_β. It was found that after irradiation (especially with a dose of 4 × 26 kGy), a significant quantity of the material showed traces of ploughing, which meant a positive effect on the wear mechanism. The value of the wear resistance coefficient W_β for PTFE subjected to the absorbed irradiation dose increased intensively, which portended a significant reduction of the tribological wear compared to the nonirradiated material. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42348.  相似文献   

    

Piotr Krl  Joanna Wojturska 《应用聚合物科学杂志》2003,88(2):327-336

A classical method was utilized for determination of free isocyanates to study the kinetics of a model reaction of 2,4‐ and 2,6‐tolylene diisocyanate (TDI) with 1‐butanol, which was run in the reaction medium of liquid aliphatic hydrocarbons. Such conditions made it possible to find rate constants and activation energy values for the second‐order reactions under isothermal conditions. Those reactions can be employed to produce isocyanate prepolymers, which make intermediates for downstream polyurethanes. The findings are commented upon against the background of earlier kinetic data that can widely be found in the research reports published. Further, part of our work utilized the findings to provide interpretation of kinetic parameters for analogous reactions, the kinetic data being found in the presence of styrene—the monomer employed when producing polyurethane–polyester interpenetrating polymer network (IPN) systems. The hypothesis was put forward that styrene and isocyanate component(s) could react at the final stages of the process when the system becomes short in the hydroxyl substrate. That hypothesis was based on disturbances observed in the reactivity of ? NCO groups (in 2,4‐TDI) in the reaction system studied. The rate constants and activation energy values were determined and presented for the urethanization reaction of 1‐butanol. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 327–336, 2003  相似文献   

    

Eric J. Bosze  Justin Carver  Sheila Singson  Joanna McKittrick  Gustavo A. Hirata 《Journal of the American Ceramic Society》2007,90(8):2484-2488

White-light emission was achieved by activating yttrium oxyorthosilicate with two rare-earth elements, (Y_{1− m − n} Ce _m Tb _n )₂SiO₅. Ce³⁺ strongly absorbs at λ _ex =358 nm and produces a broad, mainly blue emission with a tail that extends out to 600 nm (orange), and transfers energy efficiently to Tb³⁺, which produces strong green-line emissions at 550 nm and some red emission around 650 nm. At λ_{e x} =358 nm, chromaticity coordinates of the optimally activated (Y_0.9625Ce_0.0075Tb_0.03)₂SiO₅ were found to be x =0.266, y =0.365 with a color temperature 8512 K. Upon mixing in another red-emitting phosphor, (Y_0.955Bi_0.005Eu_0.04)₂O₃, the chromaticity and color rendering index values were improved.  相似文献   

    

Joanna Tsang  Sarah Leung  Xiao‐ming Tao  Marcus Chun‐wah Yuen  Pu Xue 《Polymer International》2007,56(7):827-833

Textile strain sensors were made from polypyrrole‐coated stretchable fabrics by a method of screen printing with chemical vapor deposition. The effect of polymerization temperature on the sensing performances was studied. It was found that polymerization at low temperature significantly improved the electrical conductivity, strain sensitivity and environmental stability of the fabric sensors. The conductive fabrics were characterized using X‐ray diffraction, thermogravimetry, contact angle measurements, particle size analysis, scanning electron microscopy and scanning probe microscopy. Powders of pure polypyrrole prepared by the same fabrication method were characterized for a better understanding of the polypyrrole coating. Copyright © 2007 Society of Chemical Industry  相似文献   

    

Boguslaw Czupry&#x;ski  Joanna Paciorek‐Sadowska  Joanna Liszkowska 《应用聚合物科学杂志》2006,100(3):2020-2029

The method of boroorganic compounds preparation by esterification of boric acid and glycols has been presented. The obtained compounds tri(2‐hydroxybutyl)borate, tri(hydroxythiodiethylene)borate, tri[(3‐chloro‐2‐hydroxy‐1‐propoxy)‐1‐methylpropyl]borate, and tri[3‐chloro‐2‐hydroxy‐1‐propoxy)thiodiethyl]borate were used to produce the rigid polyurethane–polyisocyanurate (PUR‐PIR) foams. The foams were prepared by one‐stage method and the amount of borates added varied, within the range from 0.0 to 0.4 of chemical equivalent. The method of preparation, determination of foaming parameters, and methods of testing of the physicochemical properties of PUR‐PIR foams as well as their results have been presented. A special emphasis was put on reduction of the foam flammability. It was found that application of the obtained compounds as polyolic components has a favorable effect on the properties of the produced rigid PUR‐PIR foams. The obtained rigid PUR‐PIR foams were characterized by a higher compressive strength, lower brittleness, considerably reduced flammability, and higher content of the closed cells. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2020–2029, 2006  相似文献   

    

Piotr Krl  Joanna Wojturska  Gennadiy A. Statyukha  Denis M. Skladannyy 《应用聚合物科学杂志》2005,97(5):1855-1867

Modern statistical analysis methods were employed to investigate and evaluate the effect of chemical composition on mechanical properties of interpenetrating polymer network (IPN) formulations that had been synthesized of polyurethane and unsaturated polyester resin (cross‐linked with styrene). Experiments run according to the mathematical plan made a basis for empirical models derived from the Sheffe polynomials. The models were utilized to optimize the chemical composition of IPN from the viewpoint of achievable mechanical parameters, to assess changes of those properties over the whole theoretically possible scope of quantitative compositions, and to investigate the effects of individual components and their possible interactions. The findings supported a thesis on complex interactions between polymeric components of IPN; they can be the reason for tangled polyurethane, unsaturated polyester, and linear polystyrene polymer networks, and ultimately they can be responsible for the formation of immiscible phases within the plastics produced. Data were also obtained which make it possible to evaluate potential mechanical properties of synthesized IPN compounds as coating materials and engineering plastics. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1855–1867, 2005  相似文献   

    

David K. Hood  Laurence Senak  Steven L. Kopolow  Michael A. Tallon  Yoon Tae Kwak  Drupesh Patel  John McKittrick 《应用聚合物科学杂志》2003,89(3):734-741

Structural insights into a novel, molecular‐composite poly(vinyl pyrrolidone) consisting of a soluble, film‐forming poly(vinyl pyrrolidone) (PVP) polymer and in situ formed, minute, crosslinked, nanoscale, insoluble poly [poly(vinyl pyrrolidone)] (PPVP) polymer particles are reported. A technique for determining the PVP molecular weight and PPVP weight fraction by gel permeation chromatography/multi‐angle light scattering (MALS) is described. Particle size studies by quasi‐elastic light scattering and field flow fractionation/MALS demonstrate that the nanoscale, insoluble polymer particles are nominally 370 and 325 nm in diameter, respectively. Rheological experiments on this dispersed system yield a complex macroscopic behavior. Atomic force microscopy images confirm a substantial heterogeneous nature for a film cast from this molecular‐composite material. Finally, this polymeric molecular composite in film form exhibits, among many other interesting properties, a dramatic enhancement in water resistance, as demonstrated by a simple image water resistance test for an ink‐jet printing application. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 734–741, 2003  相似文献   

    

Andrzej Kołodziej  Mieczysław Jaroszyński  Bożena Janus  Tadeusz Kleszcz  Joanna Łojewska  Tomasz Łojewski 《Chemical Engineering Communications》2013,200(8):932-949

Catalytic wire gauzes have been used for many years for ammonia oxidation. The flow and transfer properties of stacked gauzes, however, have not been sufficiently examined in the literature. This study presents an experimental program designed to characterize the pressure drops observed across stacked woven and knitted wire gauzes. This work generated an extensive database of measurements and reveals that each gauze requires its own correlation equation. Furthermore, previously published general models were not able to describe all four cases with high accuracy. After surveying the literature, we present some modifications to the models based on our collected experimental results.  相似文献   

    

Magdalena Wirkowska‐Wojdyła  Joanna Bryś  Agata Górska  Ewa Ostrowska‐Ligęza 《European Journal of Lipid Science and Technology》2014,116(11):1546-1552

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Zuzanna Żołek‐Tryznowska  Joanna Izdebska  Małgorzata Gołąbek 《Coloration Technology》2014,130(4):314-318

For the first time, the use of ionic liquids as additives for printing inks in order to improve the wettability of the printing base by the ink is presented. The aim of this work was to study the influence of ionic liquids on the selected properties of water‐based printing ink and the prints. The contact angles of the printing inks on the printing base were measured. Modified flexographic inks were laboratory printed on polypropylene plastic film. The impact of small amounts of various ionic liquids on printing ink colour was examined in terms of the optical density of the full‐tone area, the colour parameters (L*, a*, b*, CIE), the total colour difference, and the gloss of the dried ink film. The influence of ionic liquids on the ink contact angle, the optical density, and the L*a*b* coordinates is discussed. In general, the investigated ionic liquids improve the wettability of water‐based flexographic printing ink, with an acceptable total colour difference. The optical density is increased for printing inks containing ionic liquids in comparison with the original flexographic printing ink, Process.  相似文献