發(fā)布時(shí)間：2018-08-31 13:26

【摘要】：由于亞微米尺寸的膠體微粒具有獨(dú)特的結(jié)構(gòu)與性能,近年來其作為一種新型功能材料受到研究者們?cè)絹碓蕉嗟年P(guān)注。碗狀和籠狀微球均為典型的非球形膠體微粒。碗狀微球由于具有獨(dú)特開口形狀、不對(duì)稱結(jié)構(gòu)、中空腔體及單側(cè)平面而被廣泛應(yīng)用于催化、藥物緩釋、分子印刷、光學(xué)、可控釋放,超級(jí)電容器等方面。而籠狀微球由于具有貫穿內(nèi)外的孔結(jié)構(gòu)及內(nèi)部空腔的特點(diǎn)而廣泛應(yīng)用于藥物貯存與緩釋、催化劑載體、微反應(yīng)容器、吸附等領(lǐng)域。目前制備碗狀及籠狀微球的方法很多,但依然存在所制備微粒尺寸不均、孔道調(diào)控困難以及難以大量制備等問題。本文運(yùn)用高溫?zé)峤夥?可簡(jiǎn)單高效地大量制備碗狀微球和籠狀碳微球。這對(duì)于拓展碗狀及籠狀微球的制備方法及應(yīng)用等方面具有重要的意義。第二章中,我們通過在空氣氣氛中高溫?zé)峤廛浐擞矚さ木郾揭蚁?PS)微球,制備了碗口一致朝上的規(guī)整排列的正六邊形碗狀微球,并探究了煅燒條件及交聯(lián)度對(duì)碗狀微球形貌的影響。研究發(fā)現(xiàn),通過大范圍調(diào)節(jié)煅燒溫度,可以得到正六邊形實(shí)心和正六邊形碗狀兩種微球。在270℃~420℃煅燒時(shí),得到的微球均為碗狀,而且隨溫度的升高,碗狀微球的壁厚減小,其開口尺寸則先增大后減小;隨煅燒時(shí)間的增加,碗狀微球的壁厚減小,開口尺寸也呈現(xiàn)與升高溫度相同的規(guī)律;隨升溫速率的增大,其壁厚呈現(xiàn)逐漸增大的趨勢(shì),而其開口尺寸則有一直減小的趨勢(shì)。隨著交聯(lián)度的增大,碗狀微球的壁厚和開口尺寸都增大。但是本章所制備的規(guī)整排列的碗狀微球由于粘連嚴(yán)重,無法形成可分散的微球。我們通過利用在PS微球表面包覆一層二氧化硅的方法,很好的解決了此問題。表面或內(nèi)部帶有孔結(jié)構(gòu)的碗狀微球,由于兼具獨(dú)特的碗狀形貌與孔結(jié)構(gòu)特點(diǎn),大大拓展了碗狀微球的應(yīng)用,因此關(guān)于具有孔結(jié)構(gòu)的碗狀微球是近年來的研究熱點(diǎn)之一。在第三章中,我們受到第二章制備可分散碗狀微球的啟發(fā),通過高溫?zé)峤鈽漭疇頟S-Si O2微球,使其線性內(nèi)核分解并使二氧化硅嵌入到熔脹的交聯(lián)聚苯乙烯殼層中,制備了表面具有凹坑/孔的可分散碗狀微球,并著重研究了煅燒條件對(duì)可分散碗狀微球形貌的影響。研究發(fā)現(xiàn),隨著煅燒溫度的增加,碗狀微球的形貌由雙層碗狀向“單層”碗狀轉(zhuǎn)變,其表面孔/凹坑深度的大小也隨之增加;隨著煅燒時(shí)間的增加,可分散碗狀微球由碗狀與多面體微球共存全部轉(zhuǎn)變?yōu)闉橥霠钗⑶?且碗狀微球的壁厚和孔數(shù)量增加;隨著升溫速率的增加,碗狀微球的形貌由單層碗狀到雙層碗狀再到蘑菇頭狀與多面體微球共存轉(zhuǎn)變,其表面形貌由大孔到少部分凹坑再到無凹坑過渡。在第四章中,我們利用氮?dú)鈿夥罩懈邷靥蓟瘶漭疇頟S-Si O2微球制備了籠狀碳球。在制備過程中,我們對(duì)樹莓狀微球的制備方法和碳化條件進(jìn)行了探索,研究發(fā)現(xiàn),通過添加陽(yáng)離子表面活性劑STAB,可成功制備包覆度較好的樹莓狀復(fù)合微球。并且在碳化條件及碳化模板的選擇研究中發(fā)現(xiàn),對(duì)20 wt%PS微球進(jìn)行后交聯(lián)4h、6h之后,在合適條件下碳化可以得到介孔籠狀碳球。通過采用30wt%PS-STAB-Si O2為制備大孔籠狀碳球的模板,將其在合適條件下碳化制備了具有大孔的籠狀碳球。
[Abstract]:Because of the unique structure and properties of submicron colloidal particles, they have attracted more and more attention as a new functional material in recent years. Both bowl-shaped and cage-shaped microspheres are typical non-spherical colloidal particles. Cage microspheres are widely used in the fields of catalysis, drug release, molecular printing, optics, controlled release, supercapacitor and so on. Cage microspheres are widely used in the fields of drug storage and release, catalyst support, micro-reaction vessel, adsorption and so on because of their pore structure and inner cavity. In this paper, bowl-like microspheres and cage-like carbon microspheres can be prepared simply and efficiently by pyrolysis at high temperature. It is of great significance to expand the preparation methods and applications of bowl-like and cage-like microspheres. Orthogonal hexagonal bowl-shaped microspheres were prepared by pyrolysis of soft core and hard shell polystyrene (PS) microspheres in air atmosphere. The effects of calcination conditions and crosslinking degree on the morphology of the bowl-shaped microspheres were investigated. The hexagonal bowl-shaped microspheres were both bowl-shaped when calcined at 270 ~420, and the wall thickness of the bowl-shaped microspheres decreased with the increase of temperature, the opening size of the bowl-shaped microspheres increased first and then decreased; with the increase of calcination time, the wall thickness of the bowl-shaped microspheres decreased, and the opening size of the bowl-shaped microspheres showed the same rule as the increase of temperature. With the increase of crosslinking degree, the wall thickness and opening size of the bowl-shaped microspheres increase. However, the bowl-shaped microspheres prepared in this chapter can not form dispersible microspheres because of the serious adhesion. The application of bowl microspheres with porous structure has been greatly expanded due to their unique bowl-like morphology and pore structure. Therefore, the research on bowl microspheres with porous structure is one of the hotspots in recent years. In the second chapter, the dispersible bowl microspheres were prepared by pyrolysis of raspberry-like PS-Si O2 microspheres at high temperature. The linear core decomposition of the microspheres was carried out and the silicon dioxide was embedded into the swelling cross-linked polystyrene shell. The dispersible bowl microspheres with pits/pores on the surface were prepared. The effect of calcination conditions on the morphology of dispersible bowl microspheres was studied. It was found that with the increase of calcination temperature, the shape of the bowl microspheres changed from double-layer bowl to single-layer bowl, and the depth of the surface face/pit increased; with the increase of calcination time, the dispersible bowl microspheres changed from bowl-shaped and polyhedron microspheres to bowl-shaped microspheres, and the wall thickness and thickness of the bowl-shaped microspheres increased. With the increase of heating rate, the morphology of bowl microspheres changed from single-layer bowl to double-layer bowl, then to mushroom-head and polyhedron microspheres, and the surface morphology changed from macropores to a few pits and then to no pits. In the preparation process, we explored the preparation methods and carbonization conditions of raspberry-like microspheres. It was found that by adding cationic surfactant STAB, the raspberry-like composite microspheres with better coating degree could be successfully prepared. In the study of carbonization conditions and carbonization template selection, it was found that the 20 wt% PS microspheres were crosslinked after the carbonization. Mesoporous cage carbon spheres were prepared by carbonization under suitable conditions after 4 h and 6 h. The cage carbon spheres with large pores were prepared by carbonization using 30wt% PS-STAB-Si O2 as template.
【學(xué)位授予單位】：鄭州大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TB34

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相關(guān)期刊論文 前2條

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本文編號(hào)：2215123