耐高電壓正溫度係數(PTC)高分子複合材料之研究

Study on the Over-Voltage Resistance of Positive Temperature Coefficient (PTC) Polymeric Composites

蔡清山(Ching-Shan Tsai)

指導教授 ： 黃繼遠

大同大學/工程學院/材料工程學系所/博士(2009年)

摘要

耐高電壓正溫度係數(positive temperature coefficient, PTC)導電複材，是由聚乙烯(PE)、導電碳黑(CB)及無機阻燃劑(氫氧化鎂或氫氧化鋁)摻混而成。探討碳黑添加量之滲濾效應、電漿處理時間、電漿處理瓦數、起始劑(DCP)、低密度聚乙烯(LDPE)經接枝馬林酸酐(MA)(LDPE-g-MA)及60Co γ-ray照射，在提升PTC強度，及抑制負溫度係數(negative temperature coefficient, NTC)效應為目標之影響。並且，藉由掃描式電子顯微鏡(SEM)、膠體含量、示差熱分析儀(DSC)、動態機械等分析，對複材之交聯性質進行討論。再藉由測試標準(YD/T 741-95)法，對複材之耐高電壓特性進行量測，並由老化及再現性測試，對複材之結構穩定性進行分析。
高密度聚乙烯(HDPE)/CB/氫氧化鎂組成之複材，其滲濾效應理論可由碳黑含量，在33.7 wt%時，電阻驟降而被合理解釋。HDPE經電漿處理可使複材之室溫體積電阻率降低及PTC強度增加，乃利用1,1-diphenyl-2-picryhydrazyl (DPPH)方法，量測PHDPE之自由基含量，發現電漿處理條件為20W, 1min時，可保有最大自由基含量(1.14×10-6 mol g-1)。以PHDPE搭配DCP及60Co γ-ray照射，劑量在20 Mrads所形成之複材，NTC效應可完全被抑制，且PTC強度也可明顯增加兩個數量級。此研究可將複材之照射劑量降低到20 Mrads以下，且可由照射劑量控制複材PTC行為之反應溫度，從120.9 °C 到 107.8 °C。當複材組成為PH(201)DC33.7M28-20，可成功通過耐高電壓測試，且具極佳結構穩定性。為增加複材之加工特性，在相同組成下，以氫氧化鋁(顆粒尺寸為1.4 μm)取代氫氧化鎂(顆粒尺寸為10 μm)，由結果發現，複材經電漿前處理，配合DCP及60Co γ-ray照射，其PTC強度明顯增加3.26個數量級，NTC效應並可完全被抑制。此研究可將複材之照射劑量降低到20 Mrads以下，且由照射劑量控制複材PTC行為反應溫度，從126.3°C 到 112.1 °C。當複材組成為PH(201)DC33.7A28-20時，也成功通過耐高電壓測試，且具極佳結構穩定性。
在低密度聚乙烯(LDPE)/CB/氫氧化鋁組成之複材，探討LDPE-g-MA對複材交聯之影響。由結果發現，在LDPE-g-MA(4.0 wt%)之複材，其PTC強度明顯增加1.56個數量級，且NTC效應可完全被抑制。隨LDPE-g-MA含量從2.0 wt%增加到10.0 wt%時，複材之交聯度可從53.56 %增加到60.63 %，複材之結晶度會從41.79 %降低到31.25 %，且複材之tanδ值也會隨之降低。當複材組成為LD0.5M4C33.7A28，也成功通過耐高電壓測試，且具極佳結構穩定性。
在線性低密度聚乙烯(LLDPE)/CB/氫氧化鋁組成之複材，其LLDPE與不同含量的起始劑(DCP)產生化學交聯反應。由結果發現，在DCP含量(0.10 wt%)之複材，其PTC強度明顯增加1.89個數量級，且NTC效應可完全被抑制。DCP含量從0.03 wt%增加到0.50 wt%時，複材之交聯度可從37.26 %增加到53.87 %，複材之結晶度會從35.67 %降低到29.24 %，且複材之tanδ值也會隨之降低。當複材組成為LLD0.10C33.7A28，也成功通過耐高電壓測試，且具極佳結構穩定性。

關鍵字

正溫度係數(PTC)效應 ； 負溫度係數(NTC)效應 ； 碳黑 ； 高密度聚乙烯 ； 低密度聚乙烯 ； 線性低度聚乙烯 ； 交聯 ； 60Co γ射線 ； 電漿處理 ； 接枝 ； 耐高電壓 ； 老化 ； 氫氧化鎂 ； 氫氧化鋁

並列摘要

The over-voltage resistance of positive temperature coefficient (PTC) conductive composite that polyethylene (PE) was blended with the conductive carbon black (CB), and inorganic flame retardants, magnesium hydroxide (Mg(OH)2) and aluminum hydroxide (Al(OH)3), was prepared. Effects of the CB content (percolation effect), plasma treatment time, power of plasma, initiator (dicumyl peroxide, DCP), peroxide-initiated grafting maleic anhydride (LDPE-g-MA), and dosage of 60Co γ-ray radiation on the goals of enhansment of PTC intensity and the elimination of negative temperature coefficient (NTC) effect were studied. In addition, the cross-linking of composite was analysed particularly by analyses of scanning electron microscopy (SEM), gel content, differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). The characteristic of over-voltage resistance of composite was measured by test standard of YD/T 741-95. The structural stability of composite was analysed by aging and reproducibility. This study was researched, and conclusions were listed as follows.
In the high-density polyethylene (HDPE)/CB/magnesium hydroxide (Mg(OH)2) composite, the results showed percolation theory was explained the abruptly decreased resistance in the CB content of 33.7 wt%. The room-temperature volume resistivity and PTC effect were improved with plasma treatment. The 1,1-diphenyl-2-picryhydrazyl (DPPH) method was adopted to estimate the free radicals content of PHDPE, which the maximum free radicals content was 1.14×10-6 mol g-1 by plasma treatment at 20 W for 1 min. The composite of PHDPE with DCP, and 60Co γ-ray radiation (20 Mards) eliminated the NTC effect of composites fully, and the PTC intensity of composite markedly increased 2 orders of magnitude. In this work, the irradiating dosage was decreased to 20 Mrads, and the response temperatures (120.9 °C to 107.8 °C) of composite were controlled by irradiating dosages. The composition of PH(201)DC33.7M28-20 successfully passed the over-voltage resistance test, and possessed good structural sability. To increase the processing characteristic of composite, aluminum hydroxide (Al(OH)3, particle size of 1.4 μm) was used to replace Mg(OH)2 (particle size of 10 μm) in the same composition. The results showed that the PTC intensity of composite markedly increased 3.26 orders of magnitude, and the NTC effect of composite eliminated fully in the composite of PHDPE with DCP, and 60Co γ-ray radiation (20 Mards). In this work, irradiating dosages was reduced to 20 Mrads effectively, and the response temperature (126.3 °C to 112.1 °C) of composite was controlled by irradiating dosages. The composition of PH(201)DC33.7A28-20 also successfully passed the over-voltage resistance test, and possessed good structural stability.
In the low-density polyethylene (LDPE)/CB/Al(OH)3 composite was prepared. Effect of cross-linking of peroxide-initiated grafting maleic anhydride (LDPE-g-MA) in composite was studied. The PTC intensity of composite markedly increased 1.56 orders of magnitude, and the NTC effect of composite eliminated fully in the composite with LDPE-g-MA of 4.0 wt%. With increasing of LDPE-g-MA content from 2.0 wt% to 10.0 wt%, the gel content of composites increased up to 60.63 %, the degree of crystallinity of composites decreased up to 31.25 %, and the tanδ of composites decreased. The composition of LD0.5M4C33.7A28 also successfully passed the over-voltage resistance test, and possessed good structural stability.
In the linear low-density polyethylene (LLDPE)/CB/Al(OH)3 composite. LLDPE was chemically cross-linking with various amounts of initiator (DCP). The PTC intensity of composite markedly increased 1.89 orders of magnitude, and the NTC effect of composite eliminated fully in the composite with DCP of 0.10 wt%. With increasing of DCP content from 0.03 wt% to 0.50 wt%, the gel content of composites increased up to 53.87 %, the degree of crystallinity of composites decreased up to 29.24 %, and the tanδ of composites decreased. The composition of LLD0.10C33.7A28 also successfully passed the over-voltage resistance test, and possessed good structural stability.

並列關鍵字

Positive Temperature Coefficient (PTC) ； Negative Temperature Coefficient (NTC) ； Carbon black (CB) ； High-density polyethylene (HDPE) ； Low-density polyethylene (LDPE) ； Linear low-density polyethylene (LLDPE) ； Cross-linking ； 60Co γ-ray radiation ； Plasma treatment ； Initiator ； Grafting ； Over-voltage resistance ； Aging ； Magnesium hydroxide ； Aluminum hydroxide

參考文獻

[4] Doljack, F. A. IEEE Trans Comp Hyb Manuf Tech 1981, 4, 372.

[5] Yacubowicz, J.; Narkis, M.; Benguigui, L. Polym Eng Sci 1998, 30, 459.

[6] Narkis, M.; Ram, A.; Flashner, F. Polym Eng Sci 1978,18, 649.

[7] Lux F. Polym Eng Sci 1993, 33, 334.

[8] Karasek, L.; Sumita, M. J Mater Sci 1996, 31, 281.