奈米黏土與金屬氫氧化物對於EVA及EPDM複合材料之阻燃與機械特性相乘效應研究

Synergistic Effect of Nanoclay and Metal Hydroxide on Flame Retardancy and Mechanical Properties of EVA and EPDM Composites

顏銀昱(Ynh-Yue Yen)

指導教授 ： 王賢達

國立臺北科技大學/工程學院/工程科技研究所/博士(2013年)

https://doi.org/10.6841/NTUT.2013.00747

摘要

此研究聚焦在有機黏土與金屬氫氧化物，應用在乙烯-醋酸乙烯酯及三元乙丙橡膠對阻燃特性與機械特性的相乘效應探討。燃燒試驗以LOI、UL-94、Cone Calorimeter及Smoke Density Chamber 做評估，比較不同比例黏土對於阻燃型EVA及EPDM複合材料之燃燒特性及機械特性影響。
結果顯示，添加EVA/ATH/C1或EVA/MH/C2奈米複合材料，對LOI值有明顯提升，可以達到V-0等級。EPDM/ATH/C2及EPDM/ATH/C3奈米複合材料，LOI雖沒明顯提升，但仍可通過V-0等級。由Cone實驗得到最大熱釋放率(pk-HRR)在EVA/金屬氫氧化物複合材料中，有效降低了28%到47%，在EPDM/ATH複合材料中，更是有效降低了51%到65%。最大煙濃度(Dm)在EVA/金屬氫氧化物複合材料中，降低了16%到25%，在EPDM/ATH複合材料中，只減少3%到12%。由TGA分析顯示，添加奈米黏土對於EVA及EPDM複合材料的熱安定性都隨著奈米黏土添加量增加而有所提昇。
由各項實驗數據顯示，添加奈米黏土不僅可提升熱安定性，對於阻燃性也有所提升，原因是有機黏土具有火焰阻絕性，在燃燒過程中會形成焦炭層以降低發熱量，能有效的阻隔氧氣及熱傳遞，達到最佳的防火相乘效應。
對於機械性質，拉斷時抗張強度，EPDM奈米黏土複合材料比EPDM複合材料提高2倍；EVA奈米黏土複合材料也因奈米黏土添加而提升。伸長率部份，EPDM奈米複合材料提升了4%到12%。EVA奈米黏土複合材料也因奈米黏土添加而有所提升。

關鍵字

金屬氫氧化物 ； 奈米黏土 ； 乙烯-醋酸乙烯酯 ； 三元乙丙橡膠 ； 相乘效應 ； 阻燃機構 ； 煙濃度測試儀

並列摘要

This study focused on the flame retardancy of ethylene-vinyl acetate copolymer (EVA) and ethylene-propylene-diene terpolymer (EPDM) and in combination with metal hydroxide and nanoclay. Fire tests, such as limiting oxygen index (LOI), flammability (UL-94), cone calorimeter, and smoke density chamber were employed to evaluate the effect of composition variation for the metal hydroxide and the nanoclay in EVA composites and EPDM composites.
The experimental results showed that when the nanoclay of 1wt% or 2wt% was substituted for aluminum hydroxide or magnesium hydroxide in EVA blends, the LOI value was significantly improved while the V-0 rating was maintained, and when the nanoclay of 2wt% or 3wt% was substituted for the aluminum hydroxide in EPDM blends, the LOI value was a little improved but while the V-0 rating was maintained. The data obtained from the cone calorimeter test indicated that the peak heat release rate (pk-HRR) of EVA/metal hydroxide composites was reduced by about 28% to 47%, and pk-HRR of EPDM/aluminum hydroxide composites was reduced by about 51% to 65%. The smoke density data (maximal smoke density, Dm) of EVA/metal hydroxide composites showed a reduction by about 16% to 25%. The Dm of EPDM/aluminum hydroxide composites was reduced by about 3% to 12%, The thermogravimetric analysis (TGA) data also showed that the nanoclay increased the thermal stability and char residue of the EVA and EPDM samples. Hence, it is suggested that the metal oxide layer on the burning surface is reinforced by the formation of silicate layer, which is both structured and compacted and acts as the insulation, and the newly formed layer responds to the synergistic effect of flame retardancy as well as smoke suppression observed in the EVA and EPDM blends.
The strength of EPDM/ATH/nanoclay composite was 2.0 times higher than that of EPDM composite. The elongation at break of EPDM/ATH/nanoclay composite increased 4%-12% as compared with EPDM/ATH composite, EVA/metal hydroxide/nanoclay composite exhibited better tensile strength and elongation at break than the corresponding EVA/metal hydroxide composite, and 2 wt% of the nanoclay inside the composite would cause the maximum of mechanical properties.

並列關鍵字

Metal hydroxide ； Nanoclay ； EVA ； EPDM ； Synergistic effect ； Flame retardancy ； Nanoclay ； Smoke density chamber.

參考文獻

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