The Effect of Surface Modification of Silica Microfillers in an Epoxy Matrix on the Thermo-mechanical Properties Articles uri icon

publication date

  • July 2008

start page

  • 1443

end page

  • 1459

issue

  • 13

volume

  • 22

International Standard Serial Number (ISSN)

  • 0169-4243

Electronic International Standard Serial Number (EISSN)

  • 1568-5616

abstract

  • Thermo-mechanical and mechanical studies were carried out on silica filled epoxy composites. The effects of the filler with and without surfacemodification were studied. Silica particles were incorporated into the polymer matrix: (i) as received and (ii) surface treated with aminosilane coupling agents, namely 3-aminopropyltriethoxysilane (APTES) and 3-aminopropylmethyldiethoxysilane (APDES). The epoxy matrix consisted of poly (bisphenol A-co-epichlorohydrin) glycidyl end-capped (DGEBA) resin cured with ethylenediamine (EDA). The relaxation temperatures assigned to the glass transition temperatures (Tg) of the composites revealed that the filler both with and without surface treatment greatly affects the polymer network structure. It seems that on filling the epoxy-amine reactive mixture with silica a stoichiometric change in the epoxy/amine mixture occurs, which causes a decrease in the Tg. However, no significant differences were found for the different surface treatments. Assuming the systems were homogeneous a pseudo-fractional free volume was calculated from the superposition in the slow dynamics regime and good correlations between this parameter with the type of surface treatment and with the yield stress were found.

keywords

  • Surface treatments
    Composites
    Epoxy
    Silica fillers