Rheological, Mechanical, and Thermal Properties of Silane Grafted Layered Double Hydroxide/Epoxy Composites

Abstract

Judicious surface design of a nanofiller is pertinent to exploit its reinforcing competency in polymer composites. Herein, sodium dodecyl sulfate intercalated layered double hydroxide (LDH) was functionalized using 3-aminopropyltriethoxysilane (APTES), which was then dispersed in the epoxy matrix. The grafting of APTES on the LDH surface was confirmed by Fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis. The robustness of the interface reflected the significant improvement of ∼104 and 90% in flexural strength and modulus at 0.25 wt % loading, while the tensile strength and Young̀s modulus were found to increase by ∼44 and 50.8%, respectively. The tangible improvement in interfacial interaction due to the functionlization was further reflected in the enhanced storage modulus and glass transition temperature, Tg, by ∼36% and ∼6 °C, respectively, at 0.25 wt % loading. A rheological study confirmed the Newtonian behavior of the composites in the shear rate range of 0.1–100 s–1.