纖維素納米晶基功能復(fù)合材料的制備與應(yīng)用研究
發(fā)布時間：2018-10-26 17:42
【摘要】：本文采用真空抽濾的方法,并通過控制不同的條件制備了具有一系列不同顏色的纖維素納米晶基彩色膜,并借助掃描電鏡(SEM),原子力顯微鏡(AFM),紅外(IR), X-ray衍射(XRD),圓二色譜(CD)等表征手段對彩色膜的內(nèi)部結(jié)構(gòu)進(jìn)行了研究,并探索了復(fù)合膜其它的性能。通過對硫酸酸解纖維素的制備條件的探索,我們分別制備了針尖狀的微晶纖維素納米晶和棉漿纖維素的納米晶,發(fā)現(xiàn)棉漿纖維素納米晶的平均粒徑比微晶纖維素納米晶的平均粒徑要稍微大些。然后將納米晶溶液真空抽濾成膜后,表征了膜的熱性能和內(nèi)部結(jié)構(gòu),酸解前后纖維素的晶型不會發(fā)生變化,但是由于酸解過程中接上了磺酸根基團(tuán)使得熱穩(wěn)定性降低。我們對纖維素納米晶溶液進(jìn)行短時間超聲和長時間超聲后得到了纖維素納米晶的無色膜和彩色膜,這種彩色膜面積大、表面光滑平整、透明性好、無裂紋,而且膜的顏色隨著入射光角度的不同而發(fā)生變化。通過SEM對其垂直斷面和斜截面進(jìn)行表征,發(fā)現(xiàn)彩色膜內(nèi)纖維素納米棒是手性向列相螺旋結(jié)構(gòu),又借助CD曲線證實是左手行結(jié)構(gòu),因此膜具有彩色。還通過控制超聲時間、纖維素納米晶懸浮液的體積和真空度制備了一系列不同顏色和不同厚度的彩色膜。我們還設(shè)計了兩種不同的路線制備了氧化石墨烯(GO)/纖維素納米晶(CNC)的雜化膜,研究了第二組份GO與CNC相容性的不同對得到的CNC膜顏色和性能的影響。實驗證明,和CNC形成穩(wěn)態(tài)溶液制備的GO/CNC膜是無彩色的,而和CNC形成亞穩(wěn)態(tài)溶液體系制備的GO/CNC膜是有彩色的。將GO/CNC雜化膜化學(xué)還原后,GO/CNC彩色膜內(nèi)的有序結(jié)構(gòu)沒被破壞,在還原后依然是具有彩色的。而且這兩種膜展現(xiàn)出良好的導(dǎo)電性。鑒于以上的工作,我們又將具有導(dǎo)電性的二維片層石墨烯(TRG)與一維的纖維素納米晶復(fù)合后得到了一種具有金屬光澤的彩色膜,我們改變超聲時間和TRG的含量制備了不同顏色的TRG/CNC彩色膜。這些膜不僅具有導(dǎo)電性,而且我們發(fā)現(xiàn)這些彩色膜對水分具有非常強烈的響應(yīng)性。我們從膜的結(jié)構(gòu)上對這種水響應(yīng)性進(jìn)行了研究,認(rèn)為TRG的加入不僅改變了纖維素納米棒的液晶結(jié)構(gòu)的螺距,而且TRG還起到染色劑的作用吸收水分,因而使得TRG/CNC復(fù)合膜對水具有極強烈的響應(yīng)性。
[Abstract]:Cellulose nanocrystalline color films with a series of different colors were prepared by vacuum filtration method and controlled under different conditions. Scanning electron microscope (SEM), atomic force microscope (AFM),) and infrared (IR), (IR) were used to prepare the color films. The internal structure of the color film was studied by X-ray diffraction (XRD), circular dichroism (CD) and other properties of the composite film were explored. By exploring the preparation conditions of sulfuric acidolysis cellulose, we have prepared apical microcrystalline cellulose nanocrystals and cotton pulp cellulose nanocrystals, respectively. It is found that the average particle size of cellulose nanocrystals in cotton pulp is slightly larger than that of microcrystalline cellulose nanocrystals. After vacuum filtration of nanocrystalline solution, the thermal properties and internal structure of the membrane were characterized. The crystalline form of cellulose did not change before and after acidolysis, but the thermal stability was decreased due to the addition of sulfonic acid group in the process of acidolysis. We get colorless and color films of cellulose nanocrystals after short and long time ultrasound. The color films have large area, smooth and smooth surface, good transparency and no cracks. And the color of the film varies with the angle of incident light. The vertical and oblique sections were characterized by SEM. It was found that the cellulose nanorods in the color film were chiral nematic helical structure and proved to be left-handed by means of CD curve, so the film had color. A series of color films with different color and thickness were prepared by controlling ultrasonic time, volume and vacuum degree of cellulose nanocrystalline suspension. We also designed two different routes to prepare hybrid membranes of graphene oxide (GO) / cellulose nanocrystalline (CNC). The effects of the compatibility of the second component GO and CNC on the color and properties of CNC films were studied. The experimental results show that the GO/CNC films prepared by the steady-state solution formed with CNC are colorless, while the GO/CNC films prepared by the metastable solution system formed by CNC are colourful. After the chemical reduction of GO/CNC hybrid film, the ordered structure of GO/CNC color film was not destroyed and was still colored after reduction. Moreover, the two films exhibit good electrical conductivity. In view of the above work, a color film with metallic gloss was obtained by combining the electrically conductive two-dimensional graphene (TRG) with one-dimensional cellulose nanocrystals. We prepared different color TRG/CNC color films by changing ultrasonic time and TRG content. These films are not only electrically conductive, but also highly responsive to water. We studied the structure of the membrane and found that the addition of TRG not only changed the pitch of the liquid crystal structure of cellulose nanorods, but also played the role of dyeing agent to absorb water. Therefore, the TRG/CNC composite membrane is highly responsive to water.
【學(xué)位授予單位】：青島科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TB332
[Abstract]:Cellulose nanocrystalline color films with a series of different colors were prepared by vacuum filtration method and controlled under different conditions. Scanning electron microscope (SEM), atomic force microscope (AFM),) and infrared (IR), (IR) were used to prepare the color films. The internal structure of the color film was studied by X-ray diffraction (XRD), circular dichroism (CD) and other properties of the composite film were explored. By exploring the preparation conditions of sulfuric acidolysis cellulose, we have prepared apical microcrystalline cellulose nanocrystals and cotton pulp cellulose nanocrystals, respectively. It is found that the average particle size of cellulose nanocrystals in cotton pulp is slightly larger than that of microcrystalline cellulose nanocrystals. After vacuum filtration of nanocrystalline solution, the thermal properties and internal structure of the membrane were characterized. The crystalline form of cellulose did not change before and after acidolysis, but the thermal stability was decreased due to the addition of sulfonic acid group in the process of acidolysis. We get colorless and color films of cellulose nanocrystals after short and long time ultrasound. The color films have large area, smooth and smooth surface, good transparency and no cracks. And the color of the film varies with the angle of incident light. The vertical and oblique sections were characterized by SEM. It was found that the cellulose nanorods in the color film were chiral nematic helical structure and proved to be left-handed by means of CD curve, so the film had color. A series of color films with different color and thickness were prepared by controlling ultrasonic time, volume and vacuum degree of cellulose nanocrystalline suspension. We also designed two different routes to prepare hybrid membranes of graphene oxide (GO) / cellulose nanocrystalline (CNC). The effects of the compatibility of the second component GO and CNC on the color and properties of CNC films were studied. The experimental results show that the GO/CNC films prepared by the steady-state solution formed with CNC are colorless, while the GO/CNC films prepared by the metastable solution system formed by CNC are colourful. After the chemical reduction of GO/CNC hybrid film, the ordered structure of GO/CNC color film was not destroyed and was still colored after reduction. Moreover, the two films exhibit good electrical conductivity. In view of the above work, a color film with metallic gloss was obtained by combining the electrically conductive two-dimensional graphene (TRG) with one-dimensional cellulose nanocrystals. We prepared different color TRG/CNC color films by changing ultrasonic time and TRG content. These films are not only electrically conductive, but also highly responsive to water. We studied the structure of the membrane and found that the addition of TRG not only changed the pitch of the liquid crystal structure of cellulose nanorods, but also played the role of dyeing agent to absorb water. Therefore, the TRG/CNC composite membrane is highly responsive to water.
【學(xué)位授予單位】：青島科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TB332
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