膨胀石墨的剥离和酯化及其在聚乙烯醇薄膜中的应用
发布时间：2018-08-22 08:12
【摘要】：本文基于水热剥离法,以膨胀石墨为原料和阳离子表面活性剂为插层剂制备出氧化石墨烯,分别探讨了在水和乙醇介质中水热剥离的效果。选用乙醇为分散体系的剥离后的膨胀石墨与三氯氧磷的进行酯化反应。并将酯化处理后的膨胀石墨添加到聚乙烯醇(PVA)浇注薄膜中,探讨了复合处理的PVA膜的阻燃性能。利用X射线衍射、红外光谱、拉曼光谱和冷场扫描电镜、热失重分析等探讨了水热处理与酯化处理膨胀石墨的晶体结构、表面化学结构、形貌和力学性能等,并初步研究了剥离与酯化处理后的石墨对聚乙烯醇力学增强作用以及阻燃性能的增强。实验得出以下主要结论:1、水热剥离过程中,乙醇为剥离介质时,阳离子表面活性剂CTAB对膨胀石墨的剥离效果最好,97.6%层叠的石墨层,并出现了明显的非晶结构(剥离作用),即无规分散的氧化石墨烯,1.8%膨胀石墨层间距增大(插层结构)。水作剥离介质时,同样,表面活性剂CTAB剥离后的效果最好,非晶剥离与未改变部分各占87.6%和12.4%,但未出现插层的现象。2、经水热处理后的膨胀石墨表面形成大量含氧官能团,主要是羟基、羧基。无论是在乙醇中还是在水作介质中,表面活性剂处理后的膨胀石墨在100-240℃范围内出现明显失重,失重率大约在30-75%之间,其中,表面活性剂1227和CTAB处理时失重明显。且处理后的膨胀石墨明显提高了PVA膜的拉伸断裂强度。3、三氯氧磷与膨胀石墨中的羟基发生了酯化反应。热失重分析的结果表明:酯化后的膨胀石墨在200-600℃范围内出现失重,失重率大约在50-60%,引起失重的主要原因应该与磷酸酯受热分解密切相关。微型量热仪(MCC)测试结果表明,经酯化处理后的膨胀石墨在燃烧过程中由于磷酸酯的脱水而形成了碳层。酯化处理后的膨胀石墨改善了PVA薄膜的阻燃性能。本文的特色与创新之处:(1)先后对膨胀石墨进行水热剥离和酯化处理,并将其应用于改善聚乙烯醇的阻燃性能。(2)结合拉曼光谱和XRD技术对剥离后的膨胀石墨微观结构进行表征,水热剥离不仅使膨胀石墨产生剥离(形成非晶结构)和插层效果(石墨层间距增大),而且使石墨层尺寸明显减小。
[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，
本文编号：2196514
[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，
本文编号：2196514
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