Novel nanocomposites based on epoxy resin/epoxy-functionalized polydimethylsiloxane reinforced with POSS

• Published in: Composites. Part B, Engineering Engineering, 2015-06, Vol.75, p.226-234
• Main Authors: Florea, N.M., Lungu, A., Badica, P., Craciun, L., Enculescu, M., Ghita, D.G., Ionescu, C., Zgirian, R.G., Iovu, H.
• Format: Article
• Language: English
• Subjects: A. Nano-structures; A. Polymer-matrix composites (PMCs); Aggregates; Atomic force microscopy; B. Thermomechanical; D. Electron microscopy; Dispersions; Hardness; Morphology; Nanocomposites; Nanostructure; Polyhedral oligomeric silsesquioxanes (POSS); Thermal stability
• ISSN: 1359-8368; 1879-1069
• DOI: 10.1016/j.compositesb.2015.01.043

The purpose of the present study is to develop novel nanocomposites based on diglycidylether of bisphenol A (DGEBA) combined with diglycidylether-terminated polydimethylsiloxane (DG-PDMS), reinforced with 10 wt.% (mono-/octa) epoxy POSS nanocages (MEP or OEP-POSS). DG-PDMS and POSS compounds were covalently incorporated into DGEBA resin via copolymerization of epoxy groups. The effect of both DG-PDMS and POSS nanoparticles on the curing reaction, glass transition temperature (Tg), thermal stability, hardness and morphology of DGEBA/DG-PDMS ± POSS nanocomposites were studied by DSC, FTIR, DMA, TGA, SEM/EDX, AFM and contact angle measurements. SEM/EDX and AFM results prove that OEP-POSS is well dispersed within DGEBA/DG-PDMS polymer matrix, while MEP-POSS forms large POSS aggregates. The thermo-mechanical properties of POSS based nanocomposites are also in good correlation with morphology features. MEP-POSS based nanocomposite with heterogeneous dispersion of POSS aggregates exhibits lower Tg value and thermal stability in comparison with OEP-POSS nanocomposite which exhibits a nanoscale dispersion of the POSS cages. The obtained Tg of OEP-POSS based nanocomposite increases with 31 °C in comparison with the unreinforced matrix. Moreover, this nanocomposite shows the highest storage modulus (E′) and hardness.