【摘要】：本文基于水熱剝離法,以膨脹石墨為原料和陽(yáng)離子表面活性劑為插層劑制備出氧化石墨烯,分別探討了在水和乙醇介質(zhì)中水熱剝離的效果。選用乙醇為分散體系的剝離后的膨脹石墨與三氯氧磷的進(jìn)行酯化反應(yīng)。并將酯化處理后的膨脹石墨添加到聚乙烯醇(PVA)澆注薄膜中,探討了復(fù)合處理的PVA膜的阻燃性能。利用X射線衍射、紅外光譜、拉曼光譜和冷場(chǎng)掃描電鏡、熱失重分析等探討了水熱處理與酯化處理膨脹石墨的晶體結(jié)構(gòu)、表面化學(xué)結(jié)構(gòu)、形貌和力學(xué)性能等,并初步研究了剝離與酯化處理后的石墨對(duì)聚乙烯醇力學(xué)增強(qiáng)作用以及阻燃性能的增強(qiáng)。實(shí)驗(yàn)得出以下主要結(jié)論:1、水熱剝離過程中,乙醇為剝離介質(zhì)時(shí),陽(yáng)離子表面活性劑CTAB對(duì)膨脹石墨的剝離效果最好,97.6%層疊的石墨層,并出現(xiàn)了明顯的非晶結(jié)構(gòu)(剝離作用),即無(wú)規(guī)分散的氧化石墨烯,1.8%膨脹石墨層間距增大(插層結(jié)構(gòu))。水作剝離介質(zhì)時(shí),同樣,表面活性劑CTAB剝離后的效果最好,非晶剝離與未改變部分各占87.6%和12.4%,但未出現(xiàn)插層的現(xiàn)象。2、經(jīng)水熱處理后的膨脹石墨表面形成大量含氧官能團(tuán),主要是羥基、羧基。無(wú)論是在乙醇中還是在水作介質(zhì)中,表面活性劑處理后的膨脹石墨在100-240℃范圍內(nèi)出現(xiàn)明顯失重,失重率大約在30-75%之間,其中,表面活性劑1227和CTAB處理時(shí)失重明顯。且處理后的膨脹石墨明顯提高了PVA膜的拉伸斷裂強(qiáng)度。3、三氯氧磷與膨脹石墨中的羥基發(fā)生了酯化反應(yīng)。熱失重分析的結(jié)果表明:酯化后的膨脹石墨在200-600℃范圍內(nèi)出現(xiàn)失重,失重率大約在50-60%,引起失重的主要原因應(yīng)該與磷酸酯受熱分解密切相關(guān)。微型量熱儀(MCC)測(cè)試結(jié)果表明,經(jīng)酯化處理后的膨脹石墨在燃燒過程中由于磷酸酯的脫水而形成了碳層。酯化處理后的膨脹石墨改善了PVA薄膜的阻燃性能。本文的特色與創(chuàng)新之處:(1)先后對(duì)膨脹石墨進(jìn)行水熱剝離和酯化處理,并將其應(yīng)用于改善聚乙烯醇的阻燃性能。(2)結(jié)合拉曼光譜和XRD技術(shù)對(duì)剝離后的膨脹石墨微觀結(jié)構(gòu)進(jìn)行表征,水熱剝離不僅使膨脹石墨產(chǎn)生剝離(形成非晶結(jié)構(gòu))和插層效果(石墨層間距增大),而且使石墨層尺寸明顯減小。
[Abstract]:In this paper, graphene oxide was prepared with expanded graphite as raw material and cationic surfactant as intercalation agent based on hydrothermal stripping method. The effect of hydrothermal stripping in aqueous and ethanol media was discussed respectively. The exfoliated graphite with ethanol as dispersion system was esterified with phosphorus oxychloride. After esterification, expanded graphite was added to the polyvinyl alcohol (PVA) cast film, and the flame retardancy of the composite treated PVA film was discussed. The crystal structure, surface chemical structure, morphology and mechanical properties of expanded graphite treated by hydrothermal treatment and esterification were investigated by X-ray diffraction, infrared spectroscopy, Raman spectroscopy, cold field scanning electron microscopy and thermogravimetric analysis. The mechanical enhancement and flame retardancy of graphite treated by peeling and esterification on polyvinyl alcohol were studied. The main conclusions are as follows: 1. When ethanol is used as the stripping medium, the exfoliation effect of cationic surfactant CTAB on expanded graphite is 97.6%. An obvious amorphous structure (exfoliation) was found, that is to say, the distance between the expanded graphite layers (intercalation structure) was increased by 1.8% of the randomly dispersed graphene oxide. When water is used as the stripping medium, the effect of surfactant CTAB is the best. The amorphous exfoliation and the unchanged part account for 87.6% and 12.4% respectively, but there is no intercalation. A large number of oxygen-containing functional groups are formed on the surface of the expanded graphite after hydrothermal treatment. Mainly hydroxyl, carboxyl. Both in ethanol and in water medium, the expanded graphite treated by surfactants has obvious weightlessness in the range of 100-240 鈩，

本文編號(hào)：2196514