| Summary: | 碩士 === 元智大學 === 化學工程與材料科學學系 === 104 === Nowadays, laptop cover with excellent electrical insulation, flame retardancy, characteristics of plasticity, formability, and strength are demaned to load, sting, and protect the electrical chips in laptop. The most common laptop covers in market are classified into metal materials such as aluminum-magnesium alloy, and engineer plastic such as ABS, PC/ABS. However, the cost of metal material is too high that can not be applied widely. In addition, the plastics are still used in the cover of mid-laptops currently that can not be thin and light due to its limitated strength. Based on this reason, polymer substracts can be used in laptop cover because of its flexbility and lightness. But polymer substracts are required to modify for better rigidity.
In this study, rigridity of polymers has been enhanced by adding inorganic nanopowders like SiO2 and CaO. Besides, halogen-free flame retardant (bis(diphenyl phosphorus, RDP) was added to PC + GF 20 wt% and PC + GF 30 wt% + SiO2 + CaO with 10 wt% RDP could pass UL 94 flame vertical flame test as V-0 level. Therefore, this study by adding steel strong inorganic nanopowders of SiO2 and CaO in a polymer substrate (PC), whereby the modified polymer reached. In this study, in accordance with the percentage by weight of 0.5, 1.0 and 2 wt%, SiO2 and CaO were sequentially added to PC + GF 20 wt% and among PC + GF 30 wt%, by a screw extruction machine of shear stress and high temperature and pressure, finished after the hot melt extrusion form, and then through the granulation, pre-drying, injection molding and cutting (thickness 1.2, 1.4 and 1.6 mm) and other steps, you can get the final product.
From FE-SEM microphots, the CaO and SiO2 nanoparticles have been well-distributed in the PC + GF 20 wt% and PC + GF 30 wt% composites, and no aggregated particles have been observed. Mechanical properties of the material, then by ASTM standard tensile, bending and impact tests were analyzed, can be found when PC + GF 20 wt% test piece thickness of 1.4 mm, at the amount of 1.5 wt%, doped SiO2 CaO representing the universality to good effect. Stretching the CaO, the flexural are higher SiO2 44 MPa, and 19.1 N/mm2, its trends compared PC + GF 20 wt% specimen obvious. Mixed aspect ratio of CaO and SiO2.
Additionally, 1.5 wt% SiO2 can be mixed with for optimizing the mixed ratio between the two, both of stretching (116.3 and 72.3 MPa), bending (137.1 and 118.0 N/mm2) and impact strength (37.2 and 40.9 kJ/m2) is highest other addition. Finally fixed thickness 1.4 mm and CaO/SiO2 added amount 1.5 wt%, compare the amount of GF 20 and 30 wt% of the stretch (116.3/72.3 and 88.9/68.2 MPa), bending (137.1/118.0 and 130.6/115.6 N/mm2 ) and impact strength (37.2/40.9 and 34.9/23.6 kJ/m2), can be found in the strength of the effect is generally higher than 20 wt% of 30 wt% higher. GF high levels can be learned, SiO2 and CaO for stretching the substrate, the effect of improving the bending strength and the impact of the less significant.
Thermal analysis test by TGA, that results in PC + GF 20 wt% added 1.5 wt% SiO2, Its pyrolysis temperature, 538.7oC added CaO 1.5 wt%, Its pyrolysis temperature 488oC, SO2 high contrast ratio than CaO 50oC, the glass transition temperature by DSC decrease of RDP concentration.
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