Papers by Keyword: Silicone Resin

Abstract: One component room temperature vulcanized (RTV) silicone resin was prepared by combination of a kind of polydimethylsiloxane-b-phenylsilsesquioxane copolymer with crosslinker and catalyst. The effects of feeding order on properties of cured silicone resin were studied in detail. When hydroxyl terminated polydimethylsiloxane was added in three times and the D/T ratio was 2.0~2.3 during synthesis, the cured resin with the hardness over 20Shore D had the better elastic-plastic properties and heat resistance than the other two feeding orders. The tensile strength was over 3MPa and the elongation at break was above 75%. The T_d5% was 416.6°C.The silicone resin also had good radiation resistance. At the radiation dose of 1500kGy, there was no obvious defect observed in the material, and the tensile strength increased to 6.83MPa, while elongation at break decreased to 26%.

Abstract: Silicone resins are manufactured and supply in various delivery forms since decades. The impregnation of large electrical machines demonstrates a main application in the field of electrical insulation technology at the moment. Silicone resins are characterized by outstanding resistance to heat stress at high temperatures in general. Experience has shown that they are also very stable against exposure to UV radiation. Based on the expected very good property profile, Wacker Chemie AG developed a solvent-free, low-viscosity silicone resin for use as a binder for castable and moldable products. The article presents the chemical composition of silicone resins, the resulting properties of the resin and selected results of the extensive work for the evaluation of possible fillers and filler mixtures as well as first experience with the processing.

Abstract: The most common reason for the appearance of cracks or delamination of plaster is their too high strength - higher than the strength of the substrate, their low flexibility and high shrinkage during curing. The article presents a study on influences of natural and synthetic polymers with different chemical composition of the physical properties of category CS II mortars. Polymer additives in the form of dry powders were selected for testing. Studies were carried out in two versions: with constant consistence and with a constant w/c ratio maintained. It has been found that modifying mortars with synthetic polymers improves their flexibility and flexural tensile strength. The shrinkage is dependent on the ability of the synthetic polymer to liquefy fresh mortar where the tests were conducted maintaining constant consistence. Similar relationships were determined for cellulose ethers. Also in this case, the increase in the contents of the cellulose ethers increases their tensile strength and decreases the shrinkage. It was found that the impact of cellulose ethers on the shrinkage depends on their surface activity.

Abstract: This paper investigates the magnetic and electrical properties of iron silicone resin soft magnetic composites. Scanning electron microscopy, energy dispersive X-ray spectroscopy analysis, distribution maps and density measurements confirm that the particles surface layer contains a thin layer of silicone resin with complete coverage of powders surface. The thickness of silicone resin film is averagely 120nm according to the results of transmission electron microscopy. Magnetic measurements show that the silicone resin insulation has a greater heat resistance than the conventional phosphate insulation, which enables stress reliving during annealing at higher temperature (600°C) without a large increase in magnetic loss. The results of annealing at 600°C show that the electrical resistivity increased from 8μΩ·m for SOMALOY^TM samples to 55μΩ·m for the silicone insulated composites produced in this work.

Abstract: Ready-to-use mortars based on organic binders are increasingly widely applied in renovation of historic buildings. Thispaper contains an analysis of the impact of silicone-organic polymers of various chemical structures, used for silicone plasters production, on water vapour permeability in the produced render. The results were obtained by means of experiments. The Sd value of cured render formed from plasters containing different quantities of the analysed silicone-organic polymers at a different quantity of organic resin was studied. Statistical methods based on Statistical methods based on multiple regression were used to describe the S_d value dependence on the change in contents of the analysed polymers. It was discovered that the changes in the contents of organic resin in the plaster formula have a greater impact on the coat water vapour permeability in the cured render than the changes in the contents of polysiloxanes. The intensity of polysiloxanes impact on the S_dvalue depends on their chemical structure, and on the kind of substituents related to the siloxane skeleton in particular.

Abstract: Coating systems consist of acrylic polyol resin and silicone intermediate resins were tested for their corrosion resistance properties. The corrosion protection property of the coating was evaluated by using Electrochemical Impedance Spectroscopy (EIS) which showed that system with 70 % of acrylic has the highest corrosion resistance. The maximum value of corrosion resistance obtained was found to be 1.40 x 10⁹ Ω on the 30^th day for the 70 % of acrylic sample. The glass transition temperature (T_g) obtained using the Differential Scanning Calorimetry (DSC) were in the range of 23 °C to 65 °C. It showed that all samples are suitable for decorative paints, general industrial coatings and floor care coatings. The functional groups and also the cross-linking between the organic resins were analyzed using Fourier Transform Infra-Red Spectroscopy.

Abstract: Silicone paints were prepared by mixing as-synthesized silicone resin, pigments, fillers and other additives. The effects of the solvent, addition of pearlescent powder, addition of KH550, addition of butyl titanate and temperature on the performance of high-temperature-resistance silicon paints or coatings were studied. The results showed that the optimal coating was cured at room temperature and had no cracks after 10 times cold and hot alternation in the condition of 500oC~cold water. The pencil hardness and the adhesion of coating reached 3H and 1 level, respectively.

Abstract: Organosilicone paints were prepared by mixing as-synthesized silicone resin, pigments, fillers and other additives. Through scraping and baking, the thick film coating on the treated aluminum alloy was obtained. The optimum range of P/B (weight ratio of the pigment/binder) was determined to be 0.75:1 by investigating the influence of the P/B on the liquidity and thickness of the coating, indicating that the thickness of the coating reached 500μm. When mica powder, talc powder, nanometer titanium dioxide, sub-micron titanium dioxide, sphere silicon fine powder and lipophilic silica content were 15 wt%, 15wt%, 15wt%, 10wt%, 20wt% and 3 wt % of solid mass of silicone resin, respectively, the coating had good gloss and no holes were occurred on the surface. And there were no bubbles or shrinkage cavities in the obtained coating when the leveling agent S43, defoamer 900 and dispersant 670 content were 0.7 wt%, 0.1wt% and 0.3wt% of the total mass of paint, respectively.

Abstract: A kind of silicone modified by epoxy resin was synthesized by chemical reaction which were characterized and confirmed with FIIR. The changes of the contact angle, glass transition temperature and microstructure of the resin modified with epoxy were studied. The results showed that there was little change on the contact angle of the resin film, there was a slight increase on Tg of the resin and homogeneous phase structure was remained after modification. It was also found that while the content of the epoxy was increased, the roughness of microstructure of the epoxy modified silicone resin was increased and the surface contact angle was rose.

Abstract: In this paper, the surface tension components of three silicone resins were determined with an advanced contact angle technique, which was composed of dynamic cycling contact angle and axisymmetric drop shape analysis (ADSA). The interfacial properties of three silicone/quartz glass fiber composites were measured through interfacial shear strength (IFSS) testing experiment. It was found that the Lifshitz–van der Waals component was the main surface tension component for all of the silicones. There is a perfect linear relationship between the interfacial tension and the IFSS. With the increase of the Lifshitz-van der Waals component, the interfacial tension and the IFSS of composites increased. Therefore, the Lifshitz-van der Waals component is the most important parameter for explaining the interfacial shear property of silicone/glass fiber composites.