- 學位論文
低密度聚乙烯/乙烯-丙烯橡膠摻混電子束交聯發泡
Low density polyethylene/ethylene-propylene rubber blends foam crosslinked by electron beam
摘要
低密度聚乙烯屬結晶性物質，受外力作用時易有形變之問題產生，其發泡材料應用於鞋類材質時回復率不佳。本研究針對此一現象作改善探討，主要以添加無定型的橡膠材質來改善此一缺點。橡膠的選擇為同屬聚烯烴類的乙烯-丙烯橡膠，藉由不同的低密度聚乙烯與乙烯-丙烯橡膠摻混比例，利用雙滾輪混練機製成塑膠薄板後，以電子束照射裝置使高分子材料內部形成交聯的網狀結構，接著以烘箱加熱使化學發泡劑裂解產生氣體，形成發泡體。發泡試片以SEM觀察，探討分析橡膠含量對泡孔型態的影響。以TGA探討發泡助劑對化學發泡劑的影響，並測試泡體密度、抗拉強度、延伸率、壓縮強度、永久壓縮變形率、尺寸安定性等相關性質。實驗結果顯示，低密度聚乙烯與乙烯-丙烯橡膠最佳摻混比例為70：30。兩者固定摻混比例為70/30時，進一步探討不同的照射累積劑量對發泡體各項性質的影響，發現凝膠率的範圍在30~50%時可使化學發泡劑有最大的效用。
並列摘要
LDPE (Low density polyethylene) has a simple chemical structure. It could be recycled and regenerated easily, most of its combustion products are carbon dioxide and water. This study, LDPE was blended with EPR (ethylene-propylene rubber) and irradiated by electron beam under heat to make foam materials. The mixing of amorphous rubber into LDPE resulted LDPE, a semi-crystal material, to have better resiliency. Seven LDPE/EPR blends with different EPR contents ranging from 0 to 100 weight percent were foamed. The microcellular morphology of the foam was investigated using a scanning electron microscope. The effects of decomposition promoter on chemical blowing agent were measured via thermo-gravimetric analysis. The density, tensile strength, elongation at break, compressive strength and compression set of foam were according to the ASTM D-3575 procedures. The LDPE/EPR blend with a weight ratio of 70/30 and a gel fraction ranging from 30% to 50% was found to be an optimum condition for making foam materials.