Aliphatic amine cured PDMS-epoxy interpenetrating network system for high performance engineering applications—Development and characterization

Abstract

A siliconized epoxy interpenetrating network (IPN) was synthesized from commercially available DGEBA epoxy resin GY250 (Ciba-Geigy, epoxy equivalent = 182-192, viscosity = 9000-12000 cP) and hydroxyl terminated polydimethylsiloxane (PDMS). PDMS and GY250 were thoroughly mixed at 30°C to get the prepolymer. Stoichiometric amounts of PDMS-epoxy prepolymer, γ-aminopropyltriethoxysilane, aliphatic amine curing agent (HY951), and dibutyltindilaurate catalyst, were thoroughly mixed and cast in a mould after evacuating the entrapped air. The cured material was then taken out and post cured at 70°C for 10 h. IPN was characterized by FTIR spectroscopy, SEM, DSC, TGA and viscosity measurements. Incorporation of PDMS in the epoxy matrix increased the viscosity and lowered the exotherm and pot-life. PDMS in IPN increased T g , heat-distortion temperature and reduced the percentage weight loss with increase in temperature. Incorporation of PDMS drastically reduced the tensile and flexural strengths and hardness. By reducing the tensile and flexural modulus, the siloxane moiety effectively reduced the internal stress of IPN thereby improving its impact strength and percentage elongation. PDMS increased the electric potential gradient of IPN to withstand without breakdown. An increase in the tracking index and arc resistance of IPN were observed, because of the presence of Si-O-Si, which minimized the possibility of forming carbonized path. Volume and surface resistivities of IPN also increased with the incorporation of PDMS. The siliconized epoxy IPN, with better impact and thermal resistance, may be used in automobile and aerospace applications to withstand high temperature, and mechanical stress. The PDMS-epoxy IPN may be used for encapsulation, high temperature and high voltage application due to their low shrinkage and lesser internal stress. With the improved electrical characteristics, IPN may be used for high performance electrical insulation, insulator housings, and encapsulation to withstand high voltage, moisture, oxidation, chemical attack, biological attack, outdoor weathering, contamination, electrical, mechanical and thermal stress.

Effects of TiO2 Nanoparticles on the Overall Performance and Corrosion Protection Ability of Neat Epoxy and PDMS Modified Epoxy Coating Systems

“…Silicone polymers are widely used as polydimethylsiloxane (PDMS) which is an inorganic polymer and has the properties of being hydrophobic contributed by its non-polar -CH 3 group that gives the coating low surface energy (Ammar et al, 2017). Massive research works have been conducted in the past few years (Sung and Lin, 1997;Velan and Bilal, 2000;Ahmad et al, 2005) to determine the optimum mixing ratio between epoxy resin and PDMS. It has been agreed that the mixing ratio of 90:10 w/w gives the most optimum performance, especially on the research outcome performed by Ananda Kumar together with his research team (Kumar and Narayanan, 2002;Kumar et al, , 2006Duraibabu et al, 2014).…”

Influence of Epoxy Content on the Properties and Marine Bacterial Adhesion of Epoxy Modified Silicone Coatings

“…The benzene ring bending vibration absorption peaks of ES-30 are at 1610 cm −1 and 1505 cm −1 , indicating that the crosslinked structure of epoxy resin has been successfully introduced into the siloxane structure. The formation process of the molecular structure can be explained as [27], the first stage is the pretreatment reaction between E51 and LT-550. When the two liquids with different viscosities are mixed uniformly, the epoxy group of E51 epoxy and the amino group of LT-550 undergo a ring-opening reaction.…”

“…The principle of the reaction is shown in Figure 2. The second stage is the condensation reaction between the hydroxyl group of PDMS and the ethoxy group of hydrolyzed LT-550 under the catalysis of DBTDL to complete the modification of silicone by epoxy [27]. It was found that the viscosity of the system increased during the mixing process.…”

Durable Hydrophobic Coating Based on Cerium Phosphate Nanorod-Siliconized Epoxy for Corrosion Protection

“…However, the usage was limited due to the porous nature of the coating, hydrophilicity, and less impact strength. 1 Meanwhile, fillerloaded epoxy composite coats yielded an advantage by filling pores. 2 Especially, nanofillers with unique morphology provide homogeneous dispersion thereby restricting the pathways of corrosive species attack.…”