Long-Term Thermal Aging of Modified Sylgard 184 Formulations

Abstract

Primarily used as an encapsulant and soft adhesive, Sylgard 184 is an engineered, high-performance silicone polymer that has applications spanning microfluidics, microelectromechanical systems, mechanobiology, and protecting electronic and non-electronic devices and equipment. Despite its ubiquity, there are improvements to be considered, namely, decreasing its gel point at room temperature, understanding volatile gas products upon aging, and determining how material properties change over its lifespan. In this work, these aspects were investigated by incorporating well-defined compounds (the Ashby–Karstedt catalyst and tetrakis (dimethylsiloxy) silane) into Sylgard 184 to make modified formulations. As a result of these additions, the curing time at room temperature was accelerated, which allowed for Sylgard 184 to be useful within a much shorter time frame. Additionally, long-term thermal accelerated aging was performed on Sylgard 184 and its modifications in order to create predictive lifetime models for its volatile gas generation and material properties.

3D Printed Chromophoric Sensors

“…These thermal stability properties are given in Table 4. The composites fall within a 26 • C range for Td5% (400-426 • C), which shows an improvement of at least 30 • C compared to regular Sylgard 184 (a Td5% of 370 • C was demonstrated in our own laboratory results in and literature) [56,62,63]. The TdMax of the composites is more varied, where the range spans 266 • C (499-665 • C).…”

“…The densities of the 0.5 wt.% samples were approximately 1.06 g/cm 3 . As noted in previous literature, some mechanical properties correlate with the structure of the polymer network and its degree of crosslinking [56,58,59], thus the Shore A Hardness values for the samples are presented along with the network swelling values and specific crosslink densities for the sensors in Table 3. In general, solvent swelling is inversely related to the density of crosslinks in a network, so lower swelling values indicate that the crosslink density is greater.…”

“…The Flory-Rehner equation for a phantom network was applied because it models the PDMS and toluene system well [54,55]. The specific crosslink density p x , in units of moles of crosslinks per gram of material, is the reciprocal of the average molecular weight of the polymer between crosslinks M c , which was derived in previous work [56]. It is a function of the polymer volume fraction ϕ p , the Flory-Huggins polymer-solvent interaction parameter χ, the polymer density ρ p (which is taken as the density of the composite), and the molar volume of the solvent v m,s (for toluene, this value is 106.2 mL/mol) (Equation ( 1)).…”

Modulus and adhesion of Sylgard 184, Solaris, and Ecoflex 00‐30 silicone elastomers with varied mixing ratios

“…In general, these commercial systems may also include adhesion promoters or other fillers, like silica in Sylgard 184. 34,35 However, there are significant changes in the amount of free extractable chains as we modify the mixing ratios from the factory recommendation. For example, at a low frequency modulus of $30 kPa, the amount of extractable material is ≈ 24%, 26%, and 55% for the Sylgard 184 (35:1), Solaris (5:1), and Ecoflex (1:1), respectively.…”

Phenyl effect on properties evolution of silicone networks under isothermal and dynamic high temperature aging

“…27 Post-crosslinking reactions are commonly supposed to occur. More recently, accelerated aging studies have been carried out on Sylgard 184 to create predictive lifetime models of materials properties 28 and to characterize the degradation mechanisms of room temperature vulcanization (RTV) phenylsilicone rubbers vulcanized with different crosslinkers (tetraethoxysilane, tetraproposysilane and polysilazane). 29 Such studies are motivated by the wide use of polysiloxanes and the increasing needs for them to withstand higher temperatures.…”