Thermally and mechanically enhanced epoxy resin‐silica hybrid materials containing primary amine‐modified silica nanoparticles

Abstract

In this article, a series of hybrid materials consisted of epoxy resin matrix and well-dispersed aminomodified silica (denoted by AMS) nanoparticles were successfully prepared. First of all, the AMS nanoparticles were synthesized by performing the conventional acid-catalyzed sol-gel reactions of tetraethyl orthosilicate (TEOS), which acts as acceded sol-gel precursor in the presence of 3-aminopropyl trimethoxysilane (APTES), a silane coupling agent molecules. The as-prepared AMS nanoparticles were then characterized by FTIR, 13 C-NMR, and 29 Si-NMR spectroscopy. Subsequently, a series of hybrid materials were prepared by performing in situ thermal ring-opening polymerization reactions of epoxy resin in the presence of as-prepared AMS nanoparticles and raw silica (RS) particles (i.e., pristine silica). AMS nanoparticles were found to show better dispersion capability in the polymer matrices than that of RS particles based on the morphological observation of transmission electron microscopy (TEM) study. The better dispersion capability of AMS nanoparticles in hybrid materials was found to lead enhanced thermal, mechanical properties, reduced moisture absorption, and gas permeability based on the measurements of thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and gas permeability analysis (GPA), respectively.

Relationships between nanostructure and dynamic-mechanical properties of epoxy network containing PMMA-modified silsesquioxane

“…The microdomain sizes are even a little bit larger than that observed for epoxy/PMMA network, suggesting the presence of epoxy resin inside the domains, increasing their size. This result is consistent with the low condensation degree of PM3 determined from 29 Si NMR, which should induce a reaction between the hydroxyl groups present in the partially condensed SSO-PMMA and the anhydride used as the hardener. This phenomenon promotes good chemical affinity between the hybrid and epoxy, favoring epoxy penetration in the microdomains.…”

“…Then, 100 parts of DGEBA was added. The mixture was stirred, degassed, poured into an open silicon mold and cured at 80°C for 3 h, followed by a post curing treatment at 110°C for 3 h. 29 Si MAS solid state nuclear magnetic resonance (NMR) spectra of the hybrid materials were recorded on a Bruker DRX-300 (7.05 Tesla) spectrometer equipped with an 4 mm ZrO 2 rotor, operating at 4000 Hz and 1000 scans. The chemical shifts positions are referenced to kaolinite.…”

“…The structural features of the silsesquioxane moieties of the Silsesquioxane-PMMA (SSO-PMMA) hybrids prepared in this study were investigated by 29 Si MAS Figure 2 presents a typical spectrum of the hybrid compound containing 56% of MMA (PM1). The MMA content in the PM1 comes from the methacrylate moiety in the silane precursor, since there was no added MMA.…”

“…Consequently an improvement of thermal, oxidative and dimensional stability as well as mechanical performance of many polymeric resins is usually achieved. Mono-and multi-functionalized silsesquioxanes containing epoxy [7,[19][20][21][22][23][24][25][26][27], amino [28][29][30][31][32], mercapto [33], maleimido [34,35], and isocyanate groups [36] have been successfully employed in the preparation of epoxy resin-based hybrid materials. Mono-functionalized silsesquioxanes are prepared by corner capping reaction of a trisilanol with a functionalized trialkoxy silane, and results in POSS molecules grafted onto the epoxy matrix [14].…”

Controversial effects of fumed silica on the curing and thermomechanical properties of epoxy composites

“…Thus, the dispersion of nanoparticles in a polymer matrix has a significant impact on the properties of nanocomposites. Methods to improve the dispersion of nanoparticles into the matrix include, but are not limited to, mechanical mixing and ultrasonic dispersion [8,10], surface modification of nanoparticles [10,22,23] and sol-gel process [24,25]. On other hand, thermal analysis techniques are usually employed in the study of thermal stability, curing reactions, glass transition and thermomechanical properties.…”