Toughening of silane modified bis‐phenol‐A epoxides

Abstract

The fracture toughness of two alkoxysilane modified bis-phenol-A (BPA) epoxides were compared at three different temperatures. Organosilanes were utilized to synthesize the modified epoxides; 3-aminopropyl triethoxysilane reacted with the telechelic oxirane (aminosilane functionalized epoxide, ASE); and 3-(triethoxysilyl) propyl isocyanate reacted with the secondary hydroxyl group of the repeat unit (isocyanatesilane functionalized epoxide, ISE). Prehydrolyzed and condensed tetraethyl orthosilicate (TEOS oligomers) and TiO 2 were added to modified epoxides along with an amine hardener. The films were evaluated using DSC, TGA, tensile, and fracture toughness. During film formation, there were two competing chemical pathways: one based on in situ inorganic reactions of silanes and silicates, and the other based on organic reaction of amine crosslinker with epoxide groups. The aminosilane modified epoxides (ASE) indicated higher compatibility with TEOS oligomers or TEOS oligomers/TiO 2 than the isocyanate-silane modified epoxides as smaller agglomerates observed with AFM and SEM images. Theses interactions made ASE tougher, as there was an improvement in the fracture toughness, tensile modulus, and impact strength. This study found that the toughness varied at different temperatures (À50, 20, and 60 C).

Lignosulfonate/silica hybrid nanoparticles as a novel biobased filler in polybenzoxazine matrix

“…Regarding the content of TEOS, no differences were observed using NP 0.3 or 0.6 probably due to counter-effects between the differences in size, morphology, and TEOS content. Although a higher concentration of TEOS tends to increase the toughness of thermosetting materials, 51 smaller particles are able to interact better with the benzoxazine matrix, also enhancing the mechanical resistance of the crosslinked materials. 52 Regarding poly(SA-dfda/NP) systems, the mechanical behavior is similar to the BA-a-based materials.…”

Effects of fatty acid modified epoxy resin on long‐chain epoxy and its physical properties

“…Thus, resistance to external forces is improved. 13 However, these toughening agents are usually physically blended with the epoxy resin, This leads to phase separation, which affects the structure and morphology of cured epoxy matrix. Additionally, since the toughening agent is not dispersed uniformly in the epoxy compositions, the interface is unstable.…”

Synthesis of poly(hydroxyethyl methacrylate)‐b‐poly(propylene glycol)‐b‐poly(hydroxyethyl methacrylate)reactive block copolymer with controlled reactivity for toughening multifunctional epoxy resin

“…Recently, block copolymers are used to toughen epoxy resins since the reduction in modulus, transparency, and glass transition temperature are mitigated due to the effective toughening effects by the relatively low concentration (≤5 wt%) of block copolymers 1–6 . In comparison with the systems of the epoxy resins toughened by traditional rubbers, thermoplastics, and nanoparticles, 7–14 interactions between the epoxy resin and block copolymer can be controlled by the molecular design of the block copolymer 15–24 …”

“…copolymer can be controlled by the molecular design of the block copolymer. [15][16][17][18][19][20][21][22][23][24] Usually, two kinds of block copolymers, unreactive and reactive block copolymers, are used to toughen epoxy resins. [25][26][27][28][29] As a result, various ordered or disordered nanostructures or microstructures such as spherical domains, wormlike structure, lamellar morphology, core/ shell cylinders, and bilayer vesicles are formed in block copolymer modified epoxy resins.…”