共查询到19条相似文献,搜索用时 62 毫秒
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以离子液体(ILs)氯化1-丁基-3-甲基咪唑(BMIMCL)为反应介质,无催化剂均相合成了高取代度的高直链玉米淀粉醋酸酯,利用红外光谱(FT-IR)、核磁共振(1H-NMR)、X射线衍射(XRD)和热重分析(TGA)对不同取代度(DS)的淀粉醋酸酯进行表征。结果表明,在BMIMCL中,无催化剂条件下,高直链玉米淀粉可与醋酸酐发生较好的均相反应,所合成的淀粉醋酸酯不存在淀粉原有的颗粒结构和结晶结构。并且,随着取代度的增加,XRD曲线中9°处的弥散峰增强,其热稳定性逐步提高。 相似文献
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甲基丙烯酸与木薯淀粉接枝共聚反应研究 总被引:16,自引:0,他引:16
以硝酸铈铵为引发剂,以南方地区特有的木薯的淀粉与部分中的和甲基丙烯酸接枝共聚。研究了单体转化率,淀粉接枝率和接枝效率与甲基丙烯酸浓度。引发剂浓度,反应温度和时间,甲基丙烯酸中和度之间的关系。 相似文献
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淀粉-丙烯酸接枝共聚新工艺研究 总被引:20,自引:1,他引:19
研究了淀粉接枝丙烯制备高吸水树脂的新工艺,结果表明,在淀粉接枝丙烯酸的共聚物中填充一定量的糊化淀粉,进行热交联,由于二者的协同作用,使树脂的吸水率不仅不降低而且还略有提高,树脂中淀粉含量明显增加,成本大幅度降低,有利于高吸水树脂的推广应用。 相似文献
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以离子液体1-丁基-3-甲基咪唑氯盐([C4mim]Cl)作为反应介质,在不使用任何催化剂的情况下,实现木质素的乙酰化。研究了反应时间、反应温度及乙酸酐/OH物质的量比等因素对乙酰化木质素接枝率的影响。结果表明,乙酰化木质素的接枝率随乙酸酐/OH物质的量比的增大而升高,当反应温度达到90℃、酰化时间为2 h时,接枝率最高。采用红外光谱(FT-IR)、核磁共振(13C-NMR)、热重分析(TGA)及扫描电镜(SEM)对乙酰化木质素进行了表征。测试表明,乙酰化木质素的FT-IR和13C-NMR谱图中出现明显的乙酰基特征峰,且其热稳定性得到明显提高,粒度较改性前减小。 相似文献
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淀粉接枝丙烯腈吸水树脂的微波合成 总被引:7,自引:0,他引:7
在大学生的化学实验课中开设了“淀粉接枝丙烯腈吸水树脂的微波合成”实验。学生对此实验非常感兴趣,文中探讨了实验中淀粉糊化。接枝共聚,皂化步骤对此实验的影响。 相似文献
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改性淀粉与乙烯基单体的接枝共聚反应 总被引:8,自引:0,他引:8
以过硫酸铵为引发剂研究了物理改性淀粉分别与醋酸乙烯酯和丙烯酸的接枝共聚反应。红外光谱验证了接枝共聚反应的发生。探讨了单体浓度,引发剂浓度,淀粉浓度,反应温度和反应时间等因素对接枝效率的影响。实验结果证明,淀粉与醋酸乙烯酯接枝共聚反应的最佳条件是:单体浓度为3.90mol/L,引发剂浓为7.67mmol/L,反应温度为70℃,反应时间为3h;淀粉与丙烯酸接枝共聚反应的最佳条件是:单体浓度为2.50mol/L,引发剂浓度为3.0mmol/L,反应温度为60℃,反应时间为3h。 相似文献
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淀粉/BA-VAc接枝共聚物的合成及应用研究 总被引:19,自引:0,他引:19
以过硫酸铵为引发剂,研究了玉米淀粉与丙烯酸丁酯和醋酸乙烯酯接枝共聚合反应的规律。实验结果表明,单体浓度0.97mol/L,引发剂浓度9.1×10-3mol/L,反应温度68℃,反应3h时,反应体系的接枝率较高。通过红外光谱和X射线粉末衍射对接枝共聚物进行了结构分析。笔者以该接枝共聚物为基料,采用计算机辅助法设计出最优工艺配方,在国内首次研制生产出性能优异的功能性粘接材料 相似文献
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The effects of kenaf and poly (methyl methacrylate grafted kenaf on the thermal and dynamic mechanical properties of poly (vinyl chloride), PVC and ethylene vinyl acetate, EVA blends were investigated. The PVC/EVA/kenaf composites were prepared by mixing the grafted and ungrafted kenaf fiber and PVC/EVA blend using HAAKE Rheomixer at a temperature of 150 °C and the rotor speed at 50 rpm for 20 min. The composites were subjected to Differential Scanning Calorimetric (DSC), Thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), Fourier transform infrared (FTIR) and Scanning Electron Microscopy (SEM) studies. The DSC data revealed that the crystallinity of the EVA decreased with the addition of 30% grafted and ungrafted kenaf fibers. TGA and derivative thermogravimetric (DTG) curves displayed an increase in the thermal stability of the composites upon grafting of the fiber. Studies on DMA indicate that the Tg of the PVC and EVA in the PVC/EVA/kenaf composites has been shifted to higher temperature with the addition of the kenaf fiber. The presence of PMMA on the surface of grafted kenaf fiber was further confirmed by the analytical results from FTIR. The morphology of fractured surfaces of the composites, which was examined by a scanning electron microscope, showed the adhesion between the kenaf fiber and the PVC/EVA matrix was improved upon grafting of the kenaf fiber. 相似文献
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将具备优良化学稳定性及高电导率的双三氟甲烷磺酰亚胺锂(LiTFSI)溶于1-乙基-3-甲基咪唑双三氟甲磺酰亚胺盐(EMIM-TFSI)离子液体中制成LiTFSI-EMIM-TFSI电解液,加入环氧乙烯基酯树脂(VER)中对其进行改性。结果表明,添加了上述电解液后的锂离子电解液/环氧乙烯基酯树脂(LiTFSI-EMIM-TFSI/VER)体系可通过FTIR检测到离子液体的特征吸收峰。随着电解液含量的增加,LiTFSI-EMIM-TFSI/VER体系的孔隙率逐渐增大,沟壑与片层结构逐渐增多。这一变化有利于锂离子的传导,提高体系的电学性能,同时可在一定程度上改善树脂的塑性和韧性,提高LiTFSI-EMIM-TFSI/VER体系的力学性能。在本实验中,当电解液含量为40wt%时,LiTFSI-EMIM-TFSI/VER体系多功能性得以最好地实现。 相似文献
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The kinetics of crystal growth of hydroxyapatite [Ca5(PO4)3OH, HAP], the thermodynamically most stable calcium phosphate phase, on a commercially available carboxylated (1%) vinylchloride (83%) vinyl acetate (13%) copolymer was investigated at relatively low ionic strength, at 37 °C and pH 7.4. Stable supersaturated solutions were seeded with HAP seed crystals as reference and with the polymer in powder form. Well defined induction times preceded the growth of HAP on the polymeric substrate. The induction times measured were inversely proportional to the solution supersaturation. The rates of crystallization both on HAP and on the polymer were measured at conditions of constant supersaturation. HAP growth took place on both substrates and the parabolic dependence of the rates of crystal growth on the relative solution supersaturation suggested a surface diffusion controlled mechanism. The rates of HAP crystal growth on the polymeric substrate were found to depend on the amount of the seed material suggesting selective overgrowth of HAP. A possible explanation for this selectivity is the development of active growth sites through the formation of surface complexes of the calcium ions with the dissociated carboxyl groups. 相似文献