Preparation and properties of addition curable silicone resins with excellent dielectric properties and thermal resistance

Abstract

A new addition curable silicone resin (ASiR) system with excellent dielectric and thermal properties was developed, which consists of only two components: poly(methylphenylvinylsiloxane) (PMPVSi) and an end‐capped hydrogen‐functionalized hyperbranched polysiloxane (EHFHPSi). PMPVSi is synthesized by a green and controllable process; EHFHPSi is first synthesized via A2 + B3 approach, and then end‐capped by hexamethyldisiloxane (HMDS). Three formulations were designed to investigate the optimum stoichiometry. Results show that cured ASiR resins have greatly different dielectric and thermal properties because of the different chemical structure of cured networks resulting from the different stoichiometries. The resin with a suitable stoichiometry has not only excellent dielectric properties including extremely low dielectric constant (2.96 at 1 Hz) and loss (0.0003 at 1 Hz) as well as good stability on frequency, but also outstanding thermal resistance, exhibiting great potential to be used as a new kind of high‐performance resins for many cutting‐edge industries, especially the microelectronic and insulation fields. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers

An Investigation of Structure–Property Relationships in Silicone‐Based Dielectric Electroactive Elastomers by Varying Stoichiometric Imbalance of the Network

“…By changing the formulation parameters, such as imbalance of the active functional groups, the molecular weight of the prepolymers, cross‐linker type, and filler addition, different network structures can be achieved . Among all parameters, the effect of stoichiometric imbalance on the network structure and on the corresponding mechanical or electrical performances already attracted substantial interest . However, to the best of our knowledge, the aspects of mechanical and electrical performances, which may in fact closely interrelate with each other through the polymer network structure, have mostly been investigated separately in different studies.…”

Two Branched Silicone Resins with Different Reactive Groups: A Comparative Evaluation

“…It is found that DB values of VISR and ALSR are slightly higher than one of the traditional hyperbranched polymers. 20,36,37 This phenomenon may have resulted from the intramolecular cyclization of silanols in the process of random condensation polymerization so that it seems to increase the DB value.…”

“…In general, liquid silicone polymers can be solidified by the aid of three different curing mechanisms, namely, free radical coupling reaction, polycondensation, and hydrosilylation. − Hydrosilylation is one of the key curing ways for preparing organosilicon materials in both industry and academia because this curing process proceeds at low temperature (60–150 °C) compared to the polycondensation type required for 200 °C and even more and can avoid the formation of bubbles and voids from volatile liberation that often occur in the conventional condensation process . Hydrosilylation cross-linking is an addition reaction between unsaturated bonds (e.g., CHCH 2 ) and silicon–hydrogen (Si–H) bonds derived from silicone polymers in the presence of a platinum complex catalyst (Scheme ).…”

Isomeric Silicones: Reactive Phenylsilsesquioxane-Based MT Resins and Comments Concerning the Structure of the Phenylsilsesquioxane Homopolymer

“…We report here our initial studies of MT copolymers, an obvious isomeric class of silicones (Figure a) that has been neglected in the literature for reasons that are not apparent. There are literature reports that use an MT resin as a component in more complex resins, report M-terminated silsesquioxane polymers, and characterize volatile MT oligomers by GCMS, as well as several patents − that claim these isomeric materials; however, there is no literature that addresses the structure, or in particular, how to control the structure of these resins. Our interest in this isomer developed during recent studies with MQ copolymers, when it became apparent that the MT system would offer a much richer structural spectrum than can MQ.…”