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Curing System (curing + system)
Selected AbstractsThermally dissociable pseudo -polyrotaxane as a supramolecular shrinkage suppressor for epoxy,amine curing systemJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 6 2008Yukio Isobe Addition of pseudo -polyrotaxanes (PPRtxs) consisting of cyclodextrins (CDs) and amine-terminated polyethers to epoxy,amine curing system remarkably suppressed the volume shrinkage on the curing reaction. The PPRtx underwent thermal dissociation with creation of free volume, which efficiently contributed to the suppression of volume shrinkage. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.] [source] Heat transfer for pultrusion of a modified acrylic/glass reinforced compositePOLYMER COMPOSITES, Issue 1 2002Mariasun Sarrionandia Experimental values of the temperature on the wall and into the die were obtained for the pultrusion of a modified acrylic resin. The equation of continuity, and energy balance, coupled with a kinetic expression for the curing system, are solved using difference method to calculate the temperature and the conversion profiles in the thickness direction in a rectangular pultrusion die. The effects of the process variables (e.g. pulling rate, die temperature, die thickness and content of fibers) on the performance of the pultrusion are evaluated. [source] Microstructure-properties correlations in dynamically vulcanized nanocomposite thermoplastic elastomers based on PP/EPDMPOLYMER ENGINEERING & SCIENCE, Issue 3 2007Ghasem Naderi Thermoplastic vulcanized (TPV) nanocomposites were prepared in a laboratory mixer using EPDM, polypropylene of different viscosities, maleic anhydride modified polypropylene, an organo-clay, and a sulfur-based curing system. Based on the obtained results from X-ray diffraction, transmission electron microscopy (TEM), scanning electron microscopy (SEM), differential scanning calorimeter, and mechanical properties, the microstructure of the prepared nanocomposites was found to be sensitive to the viscosity difference between the two phases and the clay content. X-ray diffraction and TEM images of the TPV nanocomposites showed that clay was nearly exfoliated and randomly distributed into the polypropylene phase. The SEM photomicrographs of the dynamically vulcanized thermoplastic elastomer samples showed that the rubber particles were dispersed through the polypropylene in form of aggregates and their size increased with the introduction of clay. The nanoscale dimensions of the dispersed clay resulted in a significant improvement of the tensile modulus of the TPV nanocomposite samples, from 20 to 90% depending on clay content and the viscosity ratio of PP/EPDM. In the PP nanocomposites, the clay layers act as nucleating agents, resulting in higher crystallization temperature and reduced degree of crystallinity. Moreover, the oxygen permeability in the TPV nanocomposites was found to be lower than in unfilled but otherwise similar materials. POLYM. ENG. SCI., 47:207,217, 2007. © 2007 Society of Plastics Engineers. [source] Effects of curing systems and polysulfonamide pulp on the curing characteristics, mechanical properties, and swelling behavior of ethylene,propylene,diene elastomer compositesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2010Xiaolong Jia Abstract The effects of three curing systems and polysulfonamide (PSA) pulp on the curing characteristics, mechanical properties, and swelling behavior of ethylene,propylene,diene elastomer (EPDM) composites were investigated. The maximum torque value and the optimum curing time were highest for EPDM composites cured with a peroxide system, and they were closely followed by those cured with a sulfur system. In comparison with those cured with peroxide and phenolic resin systems, EPDM composites cured with the sulfur system showed higher mechanical properties and dimensional stability. With increasing PSA pulp content, the maximum torque value of the EPDM composites increased, whereas the optimum curing time of the composites decreased. The orientation percentage of the PSA pulp in the EPDM composites was maximum at 30 phr pulp, as determined from green strength measurements. In the longitudinal direction along which the pulp was oriented, the EPDM composites showed higher tensile strength as well as lower elongation and swelling ratios. Also, with increasing PSA pulp content, the tensile strength of the EPDM composites decreased up to 10 phr pulp and subsequently increased, whereas the elongation and swelling ratio of the EPDM composites decreased linearly. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Synthesis and characterization of hyperbranched-poly(siloxysilane)-based polymeric photoinitiatorsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 10 2006Qing-Fa Si Abstract Three UV-sensitive, hyperbranched-poly(siloxysilane)-based polymeric photoinitiators, bearing an alkyl phenone moiety linked to the surface of the hyperbranched polymer, were synthesized via the hydrosilylation of hyperbranched poly(siloxysilane) and modified UV-sensitive compounds. Hyperbranched poly(siloxysilane) was prepared via the polyhydrosilylation of the AB2 -type monomer methylvinyldichlorosilane. The chemical structures of the polymeric photoinitiators were characterized with 1H, 13C, and 29Si NMR, elemental analysis, Fourier transform infrared, differential scanning calorimetry, UV spectrophotometry, and thermogravimetric analysis. The UV-curing behaviors of the blends of the hyperbranched polymeric photoinitiators with UV-curable epoxy acrylate (EA) resin were determined by Fourier transform infrared, and the results showed that the initiation efficiency of the polymeric photoinitiators was excellent and that the thermostability of the EA/polymeric photoinitiator curing systems was higher than that of the EA/photoinitiators. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3261,3270, 2006 [source] Comparative study of continuous-power and pulsed-power microwave curing of epoxy resinsPOLYMER ENGINEERING & SCIENCE, Issue 10 2000Bao Fu Three epoxy reaction systems, diglycidyl ether of bisphenol A (DGEBA) with curing agents meta phenylene diamine (mPDA), diaminodiphenyl methane (DDM), and diaminodiphenyl sulfone (DDS), were cured with both pulsed-power and continuous-power microwave curing systems. Isothermal curing was conducted at three different temperatures for each reaction system with both pulsed-power and continuous-power microwave curing systems. Extent of cure was measured with Fourier Transform Infrared Spectroscopy (FTIR). The temperature characteristics, incident and reflected power patterns, and the reaction rates were compared between the two curing approaches. The incident power and reflected power of both curing processes were observed to reveal reaction status. Continuous-power microwave curing produced noticeably higher reaction rates than pulsed-power microwave curing. [source] UV curing kinetics and mechanism of a highly branched polycarbosilaneAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 1 2009Houbu Li Abstract The UV curing process in both air and nitrogen atmosphere for the highly branched polycarbosilane system was investigated by differential scanning photo calorimeter. The UV cured products were characterized by Fourier-transform infrared spectrometry (FTIR). By comparison with the FTIR results of the uncured liquid mixture and the cured samples, the possible cross-linking reactions were determined. The kinetics of the curing systems was studied. The rate constant k was calculated based on the experimental results. The activation energies in different curing conditions were obtained. According to these results, it was learned that the mechanism for the UV curing in nitrogen was controlled by the photolysis of photoinitiator. Comparably, the UV curing process in air was complicated. It was affected by not only the photolysis of photoinitiator, but also oxygen and tripropane glycol diacrylate. Copyright © 2008 John Wiley & Sons, Ltd. [source] | ||||||||||