發(fā)布時(shí)間：2018-08-04 11:22

【摘要】：木質(zhì)素是自然界中豐富的可再生有機(jī)資源,廣泛存在于植物纖維原料中,在自然界中蘊(yùn)藏量?jī)H次于纖維素,是世界上第二位最豐富的有機(jī)物。其含碳量較高,因此可作為碳纖維的原料進(jìn)行利用。本論文的研究?jī)?nèi)容和成果包括以下三部分:(1)以堿性木質(zhì)素為主要原料,與聚環(huán)氧乙烷(又名聚氧化乙烯,PEO)混合溶于甲酸中,通過(guò)靜電紡絲的方法來(lái)制備木質(zhì)素基復(fù)合納米纖維并通過(guò)預(yù)氧化和碳化處理得到木質(zhì)素基碳化纖維。討論了溶液濃度,接收距離,正極電壓和滾筒轉(zhuǎn)速對(duì)紡絲纖維形態(tài)的影響。結(jié)果表明,質(zhì)量分?jǐn)?shù)為20%為最佳紡絲濃度。最佳紡絲工藝參數(shù)為負(fù)電壓為-2kV,正電壓為20kV,接收距離為15cm,滾筒轉(zhuǎn)速為1000r/min。并對(duì)纖維及原料進(jìn)行了傅里葉變換紅外光譜儀分析(FTIR)和熱分析(TG和DSC),表明木質(zhì)素與PEO之間形成了氫鍵作用,纖維原絲中木質(zhì)素和PEO兩者沒(méi)有發(fā)生相分離。(2)為了防止碳化過(guò)程中纖維發(fā)生熔融而失去纖維形態(tài),需要對(duì)復(fù)合纖維進(jìn)行預(yù)氧化處理。實(shí)驗(yàn)試探了預(yù)氧化過(guò)程中空氣含量、升溫速率和溫度對(duì)纖維的影響。結(jié)果表明,本實(shí)驗(yàn)最佳預(yù)氧化工藝為,室溫以2℃/min的速率升溫至300℃,保溫120min。之后,對(duì)復(fù)合纖維進(jìn)行了碳化處理在升溫速率為5℃/min條件下,分別在600℃,700℃,800℃和900℃保溫300min進(jìn)行碳化處理。使用掃描電子顯微鏡(SEM)、熱重分析(TG)、元素分析儀、X射線(xiàn)衍射儀(XRD)、拉曼光譜儀(Raman)、電導(dǎo)率測(cè)試和電化學(xué)測(cè)試對(duì)預(yù)氧化纖維和碳化纖維的微觀形貌、碳元素含量、纖維晶型、碳層有序度以及纖維導(dǎo)電性進(jìn)行了表征。結(jié)果表明,本實(shí)驗(yàn)所采用的溫度范圍內(nèi),碳化纖維均為亂層石墨結(jié)構(gòu),碳結(jié)構(gòu)均為無(wú)定型碳,隨著溫度的增高,C含量增高,導(dǎo)電性變大。900℃碳化纖維的電導(dǎo)率為4.316S/cm,比電容為35F/g。(3)以堿性木質(zhì)素為主要原料,與PEO和乙酸鎳(C_4H_6NiO_2·4H_2O)混合溶于甲酸中,通過(guò)靜電紡絲的方法來(lái)制備復(fù)合納米纖維并通過(guò)預(yù)氧化和碳化處理得到木質(zhì)素基功能化碳纖維。在空氣中以2℃/min的升溫速率在300℃下保溫120min的條件下進(jìn)行預(yù)氧化,在氮?dú)夥諊��?℃/min,800℃保溫300min的條件下進(jìn)行碳化處理,使用SEM、TG、DSC、EDS、XRD、Raman、表面電阻分析儀和電化學(xué)工作站對(duì)碳化纖維的微觀形貌、纖維晶型、碳層有序度、導(dǎo)電性能進(jìn)行表征。結(jié)果表明:碳化之后纖維表面出現(xiàn)了顆粒狀物質(zhì),Ni元素主要分布在纖維表面,碳化纖維均為亂層石墨結(jié)構(gòu),碳結(jié)構(gòu)均為無(wú)定型碳,碳化之后乙酸鎳轉(zhuǎn)化為了NiO和Ni,與不含Ni的碳化纖維相比,纖維的電導(dǎo)率變大為3.698S/cm,比電容也增大為59F/g。
[Abstract]:Lignin is a rich renewable organic resource in nature. Lignin is the second most abundant organic substance in the world. Because of its high carbon content, it can be used as the raw material of carbon fiber. The research contents and achievements of this thesis include the following three parts: (1) the basic lignin was mixed with polyethylene oxide (PEO) and dissolved in formic acid. Lignin based composite nanofibers were prepared by electrospinning and the lignin based carbonated fibers were obtained by preoxidation and carbonization. The effects of solution concentration, receiving distance, positive voltage and rotary speed on fiber morphology were discussed. The results showed that the optimum spinning concentration was 20%. The optimum spinning parameters are negative voltage of -2kV, positive voltage of 20kV, receiving distance of 15cm, rotary speed of 1000r / min. The fiber and raw materials were analyzed by Fourier transform infrared spectroscopy (FTIR) and thermal analysis (TG and DSC), showed that the hydrogen bond between lignin and PEO was formed. Lignin and PEO were not separated from each other. (2) in order to prevent the fiber from melting and lose the fiber morphology during carbonization, the composite fiber should be preoxidized. The effects of air content, heating rate and temperature on fiber during preoxidation were investigated. The results show that the optimum preoxidation process is that the temperature is raised to 300 鈩，

本文編號(hào)：2163824