Synthesis and characterization of organic-inorganic hybrid clay filled and bismaleimide—siloxane modified epoxy nanocomposites

Abstract

Organic-inorganic hybrids involving organo-modified montmorillonite (OMMT) clay and tetraglycidyl diamino diphenyl methane epoxy (TGDDM) were prepared via in situ polymerization by the homogeneous dispersion of various percentages (1-5% w/w) of clay in epoxy matrix resin. The resulting homogeneous epoxy-clay hybrids were modified with 10 wt% of hydroxyl terminated polydiemthyl siloxane (HTPDMS) using γ-aminopropyltriethoxysilane (γ-APS) as coupling agent in the presence of tin catalyst. The siliconized epoxy-clay prepolymers were further modified separately with 15 wt% of bismaleimide (BMI) monomers and cured with diaminodiphenylmethane. The reactions involved during the curing process between epoxy resin, siloxane and BMI were confirmed by using FTIR and DSC curing analysis. The differential scanning calorimetry (DSC) show that the significant increase in glass transition temperatures in the clay filled hybrid epoxy systems than that of neat epoxy resin. The data obtained from thermal studies indicates that the appreciable improvement in hybrid systems was due to the incorporation of MMT clay, BMI and siloxane into epoxy systems. Scanning electron microscopy (SEM) of the hybrid systems show that the homogenous morphology. X-ray diffraction analysis of the clay hybrid systems shows that the amorphous diffraction patterns and the peaks are broadened and nearly disappeared after 24 h swelling, suggesting the formation of exfoliated structure.

Design and Development of Novel Flexible Bismaleimide Toughened Multi-Walled Carbon Nanotube Reinforced Epoxy Nanocomposites

“…The glass transition temperatures (Tg) of the conventional DGEBA epoxy system, BMIDPE/DGEBA epoxy and MWCNT/BMIDPE/DGEBA epoxy systems were determined from DSC analysis and are listed in Table 1 and Fig. -3 MWCNT with the crosslink density and thus the access of the molecules of epoxy resin DGEBA is hindered, which results in a higher degree of cross-linking and as a consequence a higher Tgvalue [46][47][48] .…”

“…The thermal stability and degradation temperature of BMIDPE into DGEBA epoxy matrices were augmented as the concentration of BMIDPE were increased. The cross-linked structure and the entangled network of BMIDPE/DGEBA epoxy resin systems which delayed the degradation temperature caused by the BMIDPE moiety 48 . Furthermore, the incorporation of COOH-MWCNTs into epoxy matrices boosted thermal stability since nanocomposites act as a heat-proofing and mass transport barrier to the volatile products generated during decomposition.…”

Thermal and electrical behavior of hybrid thermosets based on epoxy and maleimide resins cured with p‐aminobenzoic acid

“…The obtaining of the mixtures by chemical reactions involves the use of certain substances who can participate in forming simultaneous chemical bonds between the two comonomers during thermal cross‐linking. In this sense, the most used compounds are diamines …”

Dynamics and thermal properties of epoxy resin cured by new diamino disiloxanes

“…Among the developed methods to enhance the toughness of epoxy resins, the chemical modification of epoxy resins by introducing flexible segment to improve the molecular chains activity between crosslinking sites of the cured epoxy resin has been an important route. Generally, the introduction of flexible segment into epoxy resins can be achieved by either synthesis of epoxy resins containing flexible segments, or use of curing agents containing flexible structure units . The unit of SiOSi with good flexibility and high resistance to thermal oxidation has drawn intensive attention in the modification of epoxy resin.…”

“…The unit of SiOSi with good flexibility and high resistance to thermal oxidation has drawn intensive attention in the modification of epoxy resin. However, most of work is focused on the use of siloxane polymers or oligomers as modifiers, limited attention has been paid on the use of siloxaneyl monomers . In addition, though siloxanes containing amine groups were used as curing agents of epoxy resins in the past few decades, there has no report on the use of siloxaneyl unit containing aromatic diamine compound as curing agent so far.…”