| Summary: | 碩士 === 逢甲大學 === 材料與製造工程所 === 93 === Abstract
The composites filled with ceramic powder, α-Al2O3, were widely applied in electronic devices, such as semiconductor seal material, dissipation pad, thermal pad, thermal grease etc. In this paper, commercialized α-Al2O3 were used as fillers to enhance the thermal heat conduction of composites by dispersing them in PP resin with the mixing equipments.
Two types of α-Al2O3 were dispersed in the PP resin respectively by single and twin screw extruder. The thermal conductivity of composites mixed with single screw extruder was higher than the one processed with twin screw extruder. It can be explained that the single screw extruder possess lower shear force. SEM photos illustrated that poor dispersion preserving the original particle size of α-Al2O3 that caused much agglomeration. The more agglomeration was found to have better conduction and therefore to generate higher thermal conductivity. Comparison between the large (45μm) and small (5.7μm) particle sizes of α-Al2O3, dispersed in PP resin respectively, the thermal conductivity of the larger size is better than that of small ones, but the thermal conductivity of the two intermixed samples are significantly exceed that of individual sized samples. The reason is regarded as that the specified ratio of smaller size particles acts as the bridges among larger ones, which improves the thermal conductivity of composites.
In other physical and characteristic analysis, the polypropylene blended with α- Al2O3 has lower tensile strength, thermal stability, but has higher flexural modulus, impact value; however, the flammability and morphology of crystallization of the PP resin didn’t show significant changes.
|
|---|
