Thermal Performance of Epoxy Composites Enhanced by Adding Al2O3 Fiber/AlN Powder

• Main Authors: Wu Yi-Chun, 吳怡君
• Other Authors: Kao Li-Heng
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/9pyyes

碩士 === 國立高雄應用科技大學 === 化學工程與材料工程系碩士在職專班 === 103 === Because of thermal conductivity of AlN is greater than the Al2O3, but AlN get high cost than Al2O3. If AlN is added to plastic packaging material to get better thermal conductivity, but increase its cost. Therefore, using a lower cost of Al2O3 was prepared in which the fibers to add in order to maintain good thermal conductivity and to reduce costs. This study is using electrospinning method to prepare electrically insulating but high thermal conductivity three-dimensional (3-D) micron network Al2O3 fillers and applied to enhance thermal conductivity of epoxy composites. However, Epoxy Molding Compounds is mostly adding powder, by adding Al2O3 fiber can improve the general added in the gap between the powder and the powder, the thermal conductivity is more beneficial to form heat conduction pathway to improve the polymer composite materials. To improve the common process, plans to add modified 3-D micron network Al2O3 fillers to the epoxy matrix and form the pathway for heat conduct. Al2O3 fibers prepared by calcining temperature 1150 ℃ to removed PVP and also conducive to the formation of hexagonal Al2O3. From the image of SEM, indicate the Al2O3 fillers with 3-D micron network structure and high aspect ratio (> 50), and identified as hexagonal system Al2O3 by XRD (JCPDS 25-1133), and TEM. The specific surface area of Al2O3 fibers is higher than the Al2O3 powder by physical adsorption-desorption analyzer. The experimental conditions of the AlN powder is fixed to 70 wt% in the epoxy resin, To replace 21 wt%, 35 wt% and 49 wt% the ratio of Al2O3 fiber mixed, The thermal conductivity and storage modulus was detected by thermal conductivity meter (Hot-Disk) and Dynamic Mechanical Analyzer (DMA), by Thermal Mechanical Analyzer (TMA) measure the Coefficient of thermal expansion (CTE) of the composite rubbery state. The results from the thermal conductivity meter, the thermal conductivity of epoxy with adding 70 wt% commercial AlN powder is 0.97 W/mK, and thermal conductivity of epoxy with adding the ratio of Al2O3 fiber is 1.3 W/mK、1.1 W/mK、1.2 W/mK, which enhance the thermal conductivity a rate of 385 % to 550 %. The results from Dynamic Mechanical Analyzer (DMA), storage modulus gradually increase by adding more Al2O3 fiber, mainly due to the Al2O3 fiber will fill the gap, that enhance its composite structural strength. By thermal mechanical analyzer (TMA) measured results, epoxy resin without adding filler of the thermal expansion coefficient is 206.2 (ppm/oC), with adding 70 wt% commercial AlN powder of the thermal expansion coefficient is 109.6 (ppm/oC), with adding 21 wt%, 35 wt% and 49 wt% Al2O3 fiber of the thermal expansion coefficient is 113.7 (ppm/oC), 108.5 (ppm/oC), 104.0 (ppm/oC), based on the experiments, adding filler can effectively reduce the thermal expansion coefficient of epoxy resin itself.