Application and Study of Mesoporous Silica Coated Multiwall Carbon Nanotubes-Epoxy Nanocomposites in Semiconductor Packaging

Abstract

The objectives of this research are the preparation and characterization of mesoporous silica coated multi-wall carbon nanotubes/epoxy nanocomposites for application to the semiconductor encapsulant materials There two parts in this dissertation The first part of this dissertation demonstrates the effect of mesoporous silica coated multi-wall carbon nanotuebs (CNTs@MS) on the mechanical and thermal properties of epoxy nanocomposites CNTs@MS was prepared using sodium silicate as the silica source and gelatin as the surface-activation agent The effects of CNTs@MS on the mechanical and thermal properties of epoxy composite are investigated The electron microscopy images and Fourier transform infrared spectra demonstrate integral coating of the mesoporous silica on the CNTs Because of the polar silica shell the CNTs@MS exhibited uniform dispersion in epoxy-based nanocomposite The thermal and mechanical properties of nanocomposites were characterized using dynamic mechanical analysis (DMA) thermo-mechanical analysis (TMA) and thermal conductivity measurement These results show that the storage modulus and thermal conductivity increased along with the amount of CNTs@MS (0 25 0 5 1 0 and 2 0 wt%) The coefficient of thermal expansion decreased gradually because the dipole–dipole interactions between the silica and epoxy polymer and confinement space of the mesoporous structure reduced the thermal mobility of the epoxy polymer inside the mesopore space In the second part of this dissertation we studied silane modification on CNTs@MS for improving compatibility and dispersity in epoxy matrices The mesoporous silica shell with silanol groups on the CNTs provides a platform to attach silane molecules (e g 3-glycidoxy propyltrimethoxysilane GPTMS) that enable the CNTs@MS to be incorporated into the epoxy matrix at a content of up to 20 wt % The viscosities of the CNTs@MS and GPTMS modified CNTs@MS epoxy composites are much lower than that of the CNTs epoxy and then the voids in the GPTMS modified CNTs@MS epoxy composites are most significantly reduced The addition of the CNTs@MS and GPTMS modified CNTs@MS into the epoxy composite can improve the mechanical and thermal properties The results show that the GPTMS modified CNTs@MS improved the filler-epoxy matrix interaction and has better compatibility in epoxy than the CNTs@MS As the surface compatibility and interaction strength increase in the epoxy matrix the enhancement in storage modulus thermal conductivity and reduction in the coefficient of thermal expansion are in the following order: GPTMS-modified CNTs@MS > CNTs@MS >> CNTs

Date of Award	2016 Jan 18
Original language	English
Supervisor	Hong-Ping Lin (Supervisor)