Reinforcement of a Rubbery Epoxy Polymer by Mesostructured Silica and Organosilica with Wormhole Framework Structures

Abstract

Mesostructured forms of silica (denoted MSU‐J) and aminopropyl‐functionalized silica (denoted AP‐MSU‐J) with wormhole framework structures are effective reinforcing agents for a rubbery epoxy polymer. At loadings of 2.0–10 wt %, MSU‐J silica with an average framework pore size of 14 nm (65 °C assembly temperature) provides superior reinforcement properties in comparison to MSU‐J silica with a smaller average framework pore size of 5.3 nm (25 °C assembly temperature), even though the surface area of the larger pore mesostructure (670 m2 g−1) is substantially lower than the smaller pore mesostructure (964 m2 g−1). The introduction of 5.0 and 10 mol % aminopropyl groups in the wormhole framework walls decreases the textural properties in comparison to the pure silica analogs. AP‐MSU‐J organosilicas increase the tensile strength as well as the strain‐at‐break of the rubbery epoxy mesocomposites in comparison to MSU‐J silica as a reinforcing agent. The improved toughness provided by the aminopropyl functionalized mesostructures is attributable in part to covalent bond formation between the mesostructured silica walls and the cured epoxy matrix and to a more ductile mesostructure framework in comparison to a pure silica framework. An organosilica derivative containing 20 mol % aminopropyl groups, but lacking a mesostructured framework, provides little or no improvement in polymer tensile properties, demonstrating that an ordered porous network is essential for polymer reinforcement. In general, the reinforcement benefits provided by mesostructures with larger framework pores are superior to those provided by smaller pore derivatives, most likely because of more efficient polymer impregnation of the particle mesopores. The presence of a mesostructured form of the organosilica is essential for improving the mechanical properties of the epoxy polymer.

Phase separation of organic/inorganic hybrids induced by calcination: A novel route for synthesizing mesoporous silica and carbon materials

“…For examples, ionic liquids are successful to template mesoporous silicas [27,28]; novel organic-silica surfactants are designed to synthesize mesoporous materials [29]; a series of non-surfactant molecules such as sugar, citric acid, cyclodextrins, hyperbranched polyglycerol, and organic supermolecules have been also developed to fabricate mesoporous silicas [30][31][32][33][34][35][36]. Notably, the above-mentioned syntheses of mesoporous silica are performed in aqueous solutions.…”

Studies on Preparation and Property Researches of EP/SiC Thermal Conductivity Composites

“…Epoxy resins have been widely applied as matrix of coatings, adhesives and composites because of their high mechanical and adhesion properties, excellent dimensional and thermal stabilities and environmental stability, good electrical insulation property, low cost and shrinkage rate and ease of forming [1][2][3][4][5][6] . However, high thermal conductivity is desirable need for appreciable levels of thermal conductance in circuit boards, heat exchangers, appliances, and machinery.…”

Curing behavior and thermal and mechanical properties enhancement of tetraglycidyl-4,4′-diaminodiphenylmethane/4,4′-diaminodiphenylsulfone using a liquid crystalline epoxy

“…As far as the toughness is concerned, this is a good method but usually results in an accompanying reduction in modulus and poorer thermomechanical properties due to incorporation of a more flexible network structure, or a phase separation in the modified resin system. Although this problem has been solved somewhat by simultaneous curing of epoxy resin with rubbery network, this area needs to be explored further . Therefore, improving the toughness of epoxy resins without compromising but rather improving the related thermal and physical properties is a challenge.…”