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  • 學位論文

具溫感性、熱可交聯性聚(異丙基丙烯醯胺)共聚物及其導電碳黑複合材料之製備,靜電紡纖維,性質與形態分析

Thermo-responsive and Thermally Curable Poly(N-isopropylacrylamide) Copolymers and their Carbon Black Conductive Composites: Preparation, Electrospun Nanofibers, Characterization, and Morphology

指導教授 : 邱文英

摘要


本研究目的在於製備以具溫感性、熱可交聯性聚(異丙基丙烯醯胺)共聚物及其導電碳黑複合材料,並探討其在膠體以及奈米纖維不同型態下的性質及應用。 論文內容共分為兩大部分。第一部份包含第二、三章。第二章中探討具溫感性、熱可交聯性聚(異丙基丙烯醯胺)共聚物的製備與溫度感應性質以及共聚物水膠特性。使用熱可交聯性單體N-(methylol acrylamide) (NMA) 與N-isopropylacrylamide (NIPAAm) 在水中溶液藉由自由基反應聚合反應合成熱可交聯性poly(NIPAAm-co-NMA)共聚物,並施以不同的熱交聯時間與交聯溫度。在本研究中探討含不同NMA比例以及不同交聯條件之poly(NIPAAm-co-NMA)共聚物,其交聯程度(Gel fraction)、膨潤程度(Swelling ratio)以及低臨界相轉變溫度(Lower Critical Solution Temperature, LCST) 等性質。結果顯示少量的NMA熱可交聯型單體引入,即可使poly(NIPAAm-co-NMA)交聯,而NMA含量以及交聯的程度,對共聚物水膠的特性有顯著的影響。第三章主要製備Poly(NIPAAm-co-NMA)的奈米纖維以及探討在奈米纖維型態下此共聚物的特性。應用靜電紡絲的方式將poly(NIPAAm-co-NMA)共聚物在水以及甲醇中進行靜電紡,探討不同的溶劑特性,溶劑濃度,以及靜電紡參數對共聚物靜電紡絲型態上的影響。另外比較在水膠狀態以及在奈米纖維型態下的poly(NIPAAm-co-NMA)共聚物其性質的差異。 第¬二部份包含第四、五章,探討導電碳黑複合材料的特性。第四章中藉由在poly(NIPAAm-co-NMA)中引入酸化後的碳黑來製備具有溫度感應性的導電薄膜,結果顯示該導電薄膜除了外在溫度以及含水量會影響表面阻抗之外,當溫度高於低臨界相轉變溫度之後會有明顯的表面阻抗下降,另外,該薄膜也具有可逆性的溫度感應特性。 第五章則利用靜電紡絲製程製備溫度感應性之導電性奈米纖維,並探討在不同的碳黑比例下該溫感導電型複合材料的型態,交聯後的奈米纖維可以在水中保持穩定的特性與型態。在電紡纖維型態下,僅需要較低的碳黑比例就可以達到與薄膜型態相同的導電度,並且奈米導電纖維對於溫度與濕度的反應靈敏度也比薄膜型態高。 本研究之原創性及成果貢獻在於: 1.首次在異丙基丙烯醯胺(NIPAAm)中利用引入熱可交聯性單體進行共聚合反應, 並且藉由熱可交聯性單體的比例以及熱交聯條件,控制該共聚合物的溫度感應 性、澎潤性、以及交聯度。 2.利用靜電紡絲技術製備poly(NIPAAm-co-NMA)奈米纖維,並藉由該共聚物熱可交聯的特性,使該奈米纖維經過熱交聯後,可以維持共聚物奈米纖維的型態以及其特性。 3.利用Poly(NIPAAm-co-NMA)的溫度感應性,成功製備具溫度及濕度感應性之導電性複合薄膜以及奈米纖維。經過熱交聯後的該複合材料以及纖維,可以使碳黑粒子穩定地存在共聚物薄膜及奈米纖維中。

並列摘要


In this study, the thermo-responsive and thermal crosslinkable poly(N-isopropylacrylamide-co-N-methylol acrylamide), poly(NIPAAm-co-NMA), copolymer and its conductive composites of poly(NIPAAm-co-NMA) with carbon black in the morphologies of films, hydrogels or nanofibers were prepared. There are two parts in this research. The first one includes Chapter 2 and Chapter 3. In Chapter 2, it shows the preparation and characteristics of the thermo-responsive and thermal crosslinkable oly(NIPAAm-co-NMA) and the properties of hydrogels for the copolymers. Poly(NIPAAm-co-NMA) was copolymerized by thermally curable monomer N-(methylol acrylamide) (NMA) and N-isopropylacrylamide in water by initiators and then applied various curing time or temperature for thermal curing. The properties of gel fraction, swelling ratio, and lower critical solution temperature (LCST) were evaluated for the ratio of NMA and the curing conditions of the poly(NIPAAm-co-NMA) copolymers. The results showed the copolymer could be cured at low NMA ratio. The introduction of a crosslinking structure,NMA, into the temperature-responsive polyNIPAAm controlled the swelling capability and the properties of the crosslinked hydrogels. In Chapter 3, thermo-responsive nanofibers were successfully prepared via electrospinning. Poly(NIPAAm-co-NMA) in methanol or water was used as the solution for preparing the electrospinning nanofibers. Thermal curing process was then applied on the copolymer nanofibers for thermal crosslinking and the crosslinked nanofibers could keep the fiber morphology and the copolymer characters while soaking in water. The properties of the copolymers in the morphologyof hydrogel or nanofibers were further investigated. The second part includes Chapter 4 and Chapter 5, in which the properties of conductive composites with carbon black were studied. The acid-treatment carbon black was introduced into poly(NIPAAm-co-NMA) in Chapter 4 to prepare the temperature-dependent conductive films. It was found that the surface resistance of the conductive films not simply affected by the amount of water content, but also appeared significant drop when the temperature was higher than the LCST. It is noted that the poly(NIPAAm-co-NMA)/CB composites exhibited both temperature-dependent electric resistance and reproducible thermal-responsive characteristics. In Chapter 5 the temperature-dependent conductive composite nanofibers were prepared by electrospinning. The morphologies of the nanofibers with different carbon black loading were evaluated and the crosslinked nanofibers were with good stability in water. The composites in nanofibers showed the lower percolation ratio and higher surface resistance response rate than the copolymer in films.

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