不同性質茂金屬聚乙烯及聚乙烯-醋酸乙烯酯共聚物於超臨界發泡之影響

Metallence Polyethylene(mPE) and Ethylene-Vinyl Acetate Copolymer(EVA) with Different Material Properties Foamed by Carbon Dioxide at Supercritical or Near Supercritical Conditions.

張志仁(Chih-Jen Chang)

指導教授 ： 王賢達

國立臺北科技大學/工程學院/有機高分子研究所/碩士(2011年)

https://doi.org/10.6841/NTUT.2011.00598

摘要

本研究探討有機過氧化物(DCP)為交聯劑對三種茂金屬聚乙烯(mPE) 及一種聚乙烯-醋酸乙烯酯(EVA)混合不同比例的交聯劑，在不同發泡溫度及發泡壓力之下，形成交聯與未交聯的發泡體之影響。三種mPE分別為mPE-A、mPE-B、mPE-C及EVA都有熔點。mPE-A的熔點約42℃，mPE-B的熔點約83℃，mPE-C的熔點約105℃和EVA的熔點約85℃。四種材料和交聯劑反應後，其熔點約下降1℃~3℃。這四種材料的發泡條件為發泡溫度介於50℃~110℃之間和兩種發泡壓力1000 psi及2000 psi， 二氧化碳(CO2)做為發泡劑。固定溫度和壓力之下將這些材料置於模具內部含浸CO2 約60分鐘，接著打開模具洩壓形成發泡體，之後觀察發泡體的外型、量測密度及氣泡大小。
三種mPE之中mPE-A具有最低熔點在發泡壓力1000 psi及2000 psi，其最低發泡密度產生於發泡溫度約65℃；mPE-C具有最高熔點,其最低發泡密度產生於發泡溫度約100℃；mPE-B的熔點介於兩者之間,其最低發泡密度產生於發泡溫度約85℃；而EVA的最低發泡密度產生於發泡溫度約80℃且EVA產生較低的發泡密度的發泡溫度範圍較廣。CO2 在發泡壓力1000 psi低於超臨界壓力時會造成未交聯的三種mPE和EVA發泡體具有較大的平均氣泡泡徑而含交聯劑的三種mPE和EVA發泡體具有較小的平均氣泡大小，而發泡壓力2000psi，CO2 是超臨界態造成四種材料無論是否有交聯的發泡體都具有低於100μm的平均氣泡大小。

關鍵字

茂金屬聚乙烯 ； 聚乙烯-醋酸乙烯酯共聚物 ； 發泡 ； 交聯

並列摘要

This research examines the effect of crosslinking agent, dicumyl peroxide(DCP), at various ratios on three metallence polyethylenes (mPEs) and ethylene-vinyl acetate(EVA) copolymer foams under different foaming temperatures and foaming pressure. Three mPEs named mPE-A, mPE-B, mPE-C, and EVA are used in the research. The four materials have their own melting temperatures. The melting temperature of mPE-A, mPE-B, mPE-C, and EVA is approximately 42℃, 83℃, 105℃, and 85℃, respectively. The melting temperature of four materials can decrease about 1℃ to 3℃ due to reacting with DCP. The foaming conditions for four materials range from 50℃ to 110℃ in foaming temperatures and two foaming pressure of 1000 psi and 2000 psi. Carbon dioxide(CO2) is used as a foaming agent. The materials are saturated with CO2 at a constant foaming temperature and pressure about 60 minutes in a mold. The mold in then opened and pressure in the mold is released after 60minutes to obtain foams for the materials. The shapes of foams are pictured; density and average cell sizes of foams are measured.
When three mPEs are foamed at foaming pressure of 1000 psi and 2000 psi, mPE-A has the lowest melting temperature among three mPEs and the lowest foam density for mPE-A occurs at the foaming temperature of around 65℃. mPE-C has the highest melting temperature and the lowest foam density for mPE-C happens at the foaming temperature of around 100℃. The melting temperature of mPE-B is in-between and the lowest foam density for mPE-B is observed at the foaming temperature of around 85℃. The lowest foam density of EVA is generated at the foaming temperature of around 80℃ and EVA foams shows a wide range having a lowest foam density. Foaming pressure of 1000 psi below supercritical pressure for CO2 can result in a large average cell size for the foams of three mPEs and EVA without DCP and can lead to a small average cell size for three mPEs and EVA with DCP. When foaming pressure reaches 2000 psi, CO2 is under supercritical conditions. The average cell size of the foams for four materials with or without DCP are below 100 μm.

並列關鍵字

metallence polyethylene ； ethylene-vinyl acetate ； foaming ； cross-linking

參考文獻

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