Studies on Thermal and Mechanical Properties of Epoxy-Silicon Oxide Hybrid Materials

Abstract

Ultrasonic dual mixing (UDM) process involving ultrasonic vibration with simultaneous stirring is used to prepare epoxy-silicon oxide hybrid materials with inorganic nanoscale building blocks by incorporating nanoscale silicon oxide network in epoxy matrix. The silicon oxide network is obtained from tetraethoxysilane (TEOS) by using the in situ sol-gel process. Same epoxy-silica hybrid materials were also prepared by mixing with simple impeller stirring, and its properties were compared with the material of same composition prepared by the UDM process. The epoxy-silicon oxide hybrid materials are characterized by using FT-IR, DSC, FESEM, and XRD techniques. The glass transition temperature, tensile strength, and elastic modulus of the epoxy-silicon oxide hybrid materials treated by UDM process are found comparatively better than those of the materials processed by a rotating impeller. FESEM studies confirm that amount of TEOS varies the distribution and size of silicon oxide network, which remains relatively finer at lower content of TEOS. Significant improvement of thermal and mechanical properties of the neat epoxy is noted in the presence of 3.05 wt.% TEOS content in it is giving rise to the formation of inorganic building block of silicon oxide of size 88 ± 45 nm in the matrix. In this regard, the use of UDM process is found superior to mixing by simple impeller stirring for enhancement of properties of epoxy-silicon oxide hybrid materials. Lowering of properties of the epoxy-silicon oxide hybrid materials with TEOS addition beyond 3.05 wt.% up to 6.1 wt.% occurs primarily due to increase of amount and size (up to 170 ± 82 nm) of the inorganic building block in the matrix.

Corrosion resistance environment durable SWIR-MWIR AR coatings

“…Nevertheless, when the sample is exposed to SO2 salt fog for 24hrs, the entire coating collapsed into flakers (Figure 4 (b)). Since SiO2 and Si are reported stable in the SO2 salt fog environments [16][17][18][19], three factors that bring to our attention are 1) Stability of ZnO in the SO2 salt fog environment, 2) Defects in the coating that may allow SO2 penetration, and 3) Coating stress. ZnO is chemically unstable when exposed to SO2 or H2SO4 as shown below:…”