High performance epoxy‐layered silicate nanocomposites

Abstract

High performance epoxy‐layered silicate nanocomposites based on tetra‐glycidyl4,4'‐diamino‐dipheny1 methane (TGDDM) resin cured with 4,4'‐diaminodipheny1 sulfone (DDS) have been successfully synthesized. Fluorohectorites modified by means of interlayer cation exchange of sodium cations for protonated dihydro‐imidazolines and octadecylamine were used. Fluorohectorite exchanged with 1‐methy12‐norsteary1‐3‐stearinoacid‐amidoethy1‐dihydro‐imidazolinium ions was immiscible with the epoxy matrix. In contrast, fluorohectorites exchanged with hydroxyethy1‐dihydro‐imidazolinium (HEODI) and riciny1‐dihydro‐imidazolinium ions (RDI) favored the formation of a nanocomposite structure. This is most likely due to the presence of ‐OH groups in their molecular structure, which has a catalytic effect on the polymerization occurring between the silicate layers. The diffusion of epoxy and curing agent molecules between the silicate layers is also promoted. Microscopy observations revealed that the dispersion of the silicate aggregates on a microscale was proportional to the degree of separation of the silicate layers on a nanoscale. Decreased apparent glass transition temperature was observed in all the nanocomposites. Finally, mechanical property studies showed that epoxy‐layered silicate nanocomposite formation could simultaneously improve fracture toughness and Young's modulus, without adversely affecting tensile strength.

Effect of temperature, duration and speed of pre-mixing on the dispersion of clay/epoxy nanocomposites

“…Dispersion using high speed premixing produces clay aggregates with average size of around 0.4 lm and maximum size of 2 lm, and with intergallery distance of 4.03-6.69 nm. Dispersion using a direct pre-mixing method with mechanical stirrer produces clay aggregates of average size around 6 lm and many large aggregates of greater than 25 lm [2,6,8]. Direct pre-mixing carried out by the authors (pre-mixing at below 1000 rpm) produces aggregates with average size around 3-5 lm and many large aggregates more than 23 lm.…”

“…The intercalated or exfoliated forms of nanolayer silicates in many polymer systems have improved stiffness, strength, fracture toughness, fire resistance, barrier properties, and dimensional stability of the material [1][2][3][4][5][6]. The reinforcing ability of nanoclay is due to its high modulus, high strength and high aspect ratio.…”

Viscoelastic properties and residual stresses in polyhedral oligomeric silsesquioxane‐reinforced epoxy matrices

“…In particular, we are interested in the influence of polyhedral oligomeric silsesquioxane (POSS) nanoparticles, [17][18][19] which combine a hybrid inorganic-organic composition with nanosized cage structures. Compared with the layered silicates, [20][21][22][23] POSS nanoparticles are nearly spherical and relatively soft, and because they can be functionalized, the interface can be tailored-an important issue since the interfacial properties become extremely important for polymer nanocomposites because of the large surface to volume ratio of the nanoparticles. In addition, the functionalization can facilitate dispersion.…”

Synthetic, layered nanoparticles for polymeric nanocomposites (PNCs)

“…133 The matrix was tetra-glycidyl 4,4'-di-amino-di-phenyl methane (TGDDM) cured with 4,4'-di-amino diphenyl sulfone (2DS). Once the organoclays were dispersed in the matrix, the gallery increased for FM-ODA, FM-HEODI and FM-RDI, but decreased for the immiscible FM-W75.…”