Epoxy Elastomers Modified with Silsesquioxane

Abstract

Summary: This study aimed at investigating into possible applications of polyhedral oligomeric silsesquioxanes (POSS) as fillers of epoxy elastomers. Detailed studies were carried out for octakis [(3-glycidyloxypropyl) dimethylosiloxy] octasilsesquioxane (POSS-OG). The elastic epoxy materials consisted of diglycidyl ethers of 1,4-butanediol or 1,6-hexanediol, crosslinked with polyoxypropylenediamine Jeffamine D2000. The results obtained by differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMA), and rheological measurements made it possible to establish the effect of POSS-OG modifier on the properties of the material. The silsesquioxane modifier was found to enhance the elasticity of the resulting polymers and reduced gelation time.

Liquid‐crystalline epoxy thermosets as matrices for ordered nanocomposites—a summary of experimental studies

“…In the article [37] it was also shown that the elastic modulus for structures oriented in a magnetic field increased from 10 9 to 10 10 Pa at temperatures of the order of 2408C. In the materials studied by us, a significant change of the elastic modulus (from 1.1 to 2.5Á10 9 Pa) at similar temperatures could be observed after adding the filler (POSS-OG) to the cured matrix [29].…”

“…In the first part of studies, a series of liquid crystalline epoxy compounds was synthesized; their properties were reported in paper [30]. Subsequently, the research scope was extended by introducing new epoxy monomers with longer aliphatic chains and curing them with the use of different curing agents [28,29,32,36]. The molecular structures of all the synthesized materials along with the temperatures of phase transitions during heating are shown in Table 1.…”

“…The addition of POSS-OG to the liquid crystalline epoxy matrix did not significantly change the curing process, but reduced the glass transition temperature and increased the stiffness of the composite in the glassy state (in the case of monomer composition with DDM amine, the temperature T g dropped from 1108C for plain matrix to 1018C when POSS-OG was added). It was found that the resulting composites had anisotropic properties [29]. Diphenyl aluminum phosphate nanorods, which were added to the LCER composition at the ratio of 2%, did not disturb the crosslinking reaction either.…”

“…In our study, alternatively, diphenyl aluminum phosphate nanorods and octakis-[(3-glycidoxypropyl)dimethylsiloxy]octasilsesquioxane (POSS-OG) were also employed as fillers of liquid crystalline epoxy resins [28,29]. The addition of POSS-OG to the liquid crystalline epoxy matrix did not significantly change the curing process, but reduced the glass transition temperature and increased the stiffness of the composite in the glassy state (in the case of monomer composition with DDM amine, the temperature T g dropped from 1108C for plain matrix to 1018C when POSS-OG was added).…”

“…During our study we synthesized and tested many epoxy resins and investigated their basic liquid crystalline properties [28][29][30][31][32][33][34][35][36]. Curing behavior was studied with various curing agents, for example, amines: 4,4 0 -diaminodiphenylmethane (DDM) or 4-(N,N-dimethylamino)pyridine (DMAP), and pimelic acid (KP), and basic properties of compositions prepared from the synthesized diepoxy monomers were presented in several papers [28,29,[32][33][34][35]. The initial aim was to determine the optimal conditions for curing of the epoxy matrix alone, so as to obtain a solid structure with molecular orientation similar to the one occurring in liquid crystals.…”