吸濕效應對玻纖複合材料機械性質之影響;The influence of Hygroscopic effect to the mechanical properties of glass fiber composite material

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Title:	吸濕效應對玻纖複合材料機械性質之影響;The influence of Hygroscopic effect to the mechanical properties of glass fiber composite material
Authors:	羅乾豪;Lo,Chian-hao
Contributors:	機械工程研究所碩士在職專班
Keywords:	玻璃纖維複合材料;吸濕;配向性;熱活化;射出成型;機械特性;拉伸性質;模流分析;glass fiber composite material;plasticization;thermal activation;fiber orientation;free volume;moisture absorption effect;moldflow;injection;Nylon 9
Date:	2012-08-24
Issue Date:	2012-09-11 18:17:18 (UTC+8)
Publisher:	國立中央大學
Abstract:	本研究目的在探討不同進膠點的Nylon 9+33%玻纖複合材料在各種吸濕級距下的機械性質變化，並且比較吸濕後玻纖複合材料在常溫與高溫下機械性質之差異。本研究運用商用模流分析軟體，模擬計算中間進膠點與側面進膠點的玻璃纖維配向性以及殘留應力，並依照ASTM D638規範製作兩種進膠方式的試片，分別進行120 h、240 h、360 h、480 h及600 h吸濕實驗，探討不同進膠點在吸濕程度上的差異，接著將吸濕後的試片以鹵素燈照射方式加溫，觀察不同進膠點與濕度損耗的關係。最後將兩種不同進膠點試片分別以上述吸濕級距進行吸濕，再以MTS拉伸試驗機進行拉伸實驗，探討不同進膠點試片在不同吸濕級距下之常溫與高溫拉伸性質之變化，並以掃瞄式電子顯微鏡(SEM)觀察其拉伸破斷面變化。實驗結果顯示，常溫下中間進膠點比側面進膠點試片更容易受到吸濕效應影響，而在高溫時中間進膠點的濕度損耗也比側面進膠點大。在常溫拉伸實驗方面，適當的吸濕時效可以增加中間進膠點的抗拉強度，不過在側面進膠點確無增加效果；在延伸率部分，適當的吸濕時效在兩種試片上均有增加延伸率的效果，中間進膠點在120 h為最高，側面進膠點最高延伸率則是發生在240 h。在高溫時，因為熱活化關係使得吸濕後兩種進膠點的抗拉強度低於常溫，而延伸率則是吸濕後兩種進膠點在高溫時均高於常溫時的延伸率。常溫與高溫下側面進膠點試片的抗拉強度以及降伏強度在各個吸濕級距中均優於中間進膠點，主要是因為側面進膠點玻璃纖維的配向性以及成型後的殘留應力優於中間進膠點，在本研究所進行的各項實驗中證實，在吸濕效應以及拉伸性質上側面進膠方式均優於中間進膠方式。The purpose of this study is to investigate the mechanical properties of Nylon 9+33% glass fiber composite material with different injection locations and moisture absorption levels. The effect of environmental temperature on the mechanical properties is also studied for such a composite material with various moisture absorption levels. A commercial moldflow software is employed to simulate and calculate the fiber orientation and residual stress for center- and side-gate injection. Tensile specimens are made as per ASTM D638 Standard with two injection locations and exposed to steam for 120 h, 240 h, 360 h, 480 h, and 600 h to discuss the moisture absorption effect. After moisture absorption, the specimens are dried at 95oC using halogen lamps to study the relation of moisture releasing ability with injection location. Tensile tests are then performed at room temperature and 95oC using an MTS material testing machine. Scanning electron microscopy (SEM) is applied to characterize the fracture features in the broken specimens.Experimental results show that the center-gate injected specimens are subjected to more moisture effects than the side-gate injected ones and have a greater extent of moisture loss at 95oC. A certain extent of moisture can increase the room-temperature ultimate tensile strength of center-gate injected specimens, but not for the side-gate injected specimens. An proper amount of moisture also increases the room-temperature elongation for both center- and side-gate injected specimens, with a peak value taking place at a moisture absorbing time of 120 h and 240 h for center- and side-gate injected specimens, respectively. The ultimate tensile strength of moisture-absorbed specimens at 95oC is less than that at room temperature regardless of the injection location, due to a thermal activation effect. On the other hand, the high-temperature elongation is greater than the room-temperature one for each given moisture-absorbed level of both center- and side-gate injected specimens. Side-gate injected specimens have better tensile properties than do the center-gate injected ones due to a better fiber orientation quality and less residual stresses. They are also less sensitive to the moisture absorbing effect.
Appears in Collections:	[Executive Master of Mechanical Engineering] Electronic Thesis & Dissertation

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