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高取代度羟乙基纤维素可利用异丙醇溶液进行精制,根据高取代度HEC中灰分及其在异丙醇中的溶解速度和溶解度不同,通过实验确定了最佳的精制工艺条件:洗涤次数为2次,每次洗涤时间为20min,洗涤液用量为每克HEC需10mL异丙醇溶液,每次洗涤时洗涤液的用量均相同。本实验还设计了产品及废洗涤液中异丙醇回收的实验装置,具有很好的工业参考价值。 相似文献
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探讨多种无机和有机添加剂的分子量、用量、溶剂用量及蒸发时间,确立了氰乙基纤维素/三醋酸纤维素共混膜的制膜参数。实验表明,共混膜的渗透选择性、耐酸、耐碱和耐微生物分解性能优于单一膜材料。 相似文献
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先以NaOH/H2O2水溶液对蔗渣进行预处理,再用预冷至-12℃的7%NaOH/12%尿素水溶液对预处理蔗渣进行分离,获得结构蓬松的蔗渣再生纤维素。以蔗渣再生纤维素为原料,以氯乙酸钠为醚化剂,在85%乙醇水溶液中,采用一次碱化、二次醚化的工艺,制备了羧基取代度达1.45的羧甲基纤维素钠(CMC)。利用红外光谱(FTIR)、扫描电镜(SEM)、X-射线衍射(XRD)、热重分析(TGA)等手段对样品的结构进行了表征,并研究了羧甲基纤维素钠样品的黏度性能。 相似文献
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The change in the water permeability, glass transition temperatures, and mechanical properties of ethyl cellulose with different degrees of substitution are presented. Studies of the hydroxyl group content on the polymer chains indicate that the mechanical properties of a free film decrease as the hydroxyl group content increases. This is thought to be due to the lower solubility of ethyl cellulose with a lower degree of substitution, as determined by the interaction constant in ethanol and the ability of the film with a high hydroxyl group content to hold more water. Furthermore, an increase in hydroxyl group content increases water permeability. Finally, a study of spray‐coated pellets has been performed and reveals a similar effect. The higher the hydroxyl group content, the higher the release rate and, at the same time, the decrease in Vickers hardness. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 529–535, 1999 相似文献
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用紫外光谱、X射线衍射和DSC、偏光显微锐、相差显微镜和电镜等方法研究了乙基纤维素-聚苯乙烯共混体系的相溶性。结果表明该体系为部分相溶体系。 相似文献
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The influence of the composition of a multicomponent solvent on the surface morphology and diameter distribution of ethyl cellulose fibers produced by electrospinning technology was investigated. The results showed that the average diameter of the fibers using the multicomponent solvent was thinner than when using either of the two components and the diameter distribution of the fibers became narrower. Tiny tubercles formed on the fiber surface, which may improve the specific surface area and broaden the applications. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1292–1297, 2005 相似文献
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目前微胶囊红磷大多采用原位聚合法制备,工艺较为复杂,使用的囊壳原料可能对环境造成危害。为解决这一问题,本文以可降解材料乙基纤维素(EC)为壁材,无水乙醇为壁材溶剂,蒸馏水为壁材非溶剂,采用相分离法制备微胶囊红磷,并利用FTIR、SEM及XPS表征微胶囊红磷的形态及包覆效果,同时对样品的热稳定性、吸湿性及感度进行测定,以此确定最佳工艺条件。实验结果表明:经EC包覆后的红磷样品表面粗糙,包覆率随乙基纤维素添加量的增多而升高,最高可达94.8%;EC囊壳能有效提高红磷的热稳定性及安定性,降低吸湿率。在保证红磷正常使用不受影响的前提下,取0.6g乙基纤维素、2g红磷为最佳工艺条件,包覆率达93.2%;制备的微胶囊红磷样品热稳定性提高,着火点升高至310℃;10d后吸湿率降低至6.8%,较普通红磷降低约16.8%;微胶囊红磷摩擦感度降至34%,较未处理红磷降低52%。采用相分离法在常温、中性条件下制备EC包覆微胶囊红磷,工艺简便,材料绿色环保,制备的微胶囊红磷样品具有良好的使用性能。 相似文献
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In this study, biodegradable blend of Poly (Ethylene‐co‐Vinyl Acetate) (EVA) and Ethyl Cellulose (EC) were prepared. Ethylene vinyl alcohol (EVOH) copolymer was used as an interfacial compatibilizer to enhance adhesion between EVA and EC. The melt blended compatibilized biocomposites were examined for mechanical and thermal properties as per the ASTM standards. It has been found that the EC has a reinforcing effect on EVA leading to enhanced tensile strength and also impart biodegradability. Thus, a high loading of 50% EC could be added without compromising much on the mechanical properties. Analysis of the tensile data using predictive theories showed an enhanced interaction of the dispersed phase (EC) and the matrix (EVA). The compatibilizing effects of EVOH on these blends were confirmed by the significant improvement in the mechanical properties comparable with neat EVA as also observed by SEM microscopy. The TGA thermograms exhibits two‐stage degradation and as EC content increases, the onset temperature for thermal degradation reduces. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
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在EC/PS共混体系中,EC的临界浓度与共混组成无关,都是30%。组分在溶液中发生微观相分离。无论组成比多少,在EC相畴中均能形成滴状织构。观察到有混合组成的第三种相畴,它的存在有助于增加相溶性。在大多数组成比的共混物的EC相中,剪切时均能观察到条带织构。 相似文献
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通过差热分析和拉伸试验研究了醋酸丁酸纤维素CAB-35-1与聚丙烯酸乙酯(PEA)物理共混、半一互穿网络共混体系的相容性和力学性能,并用扫描电镜观察了共混物的形态。 相似文献
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超临界CO2抗溶剂法制备乙基纤维素微球试验 总被引:5,自引:0,他引:5
通过自行设计的超临界CO2微球制备装置,利用乙基纤维素丙酮混合溶液,制备了粒径偏差较小、表面光滑与球形度较好的乙基纤维素微球,采用正交试验讨论了温度、压力、溶液质量浓度、CO2流量对微球粒径与粒径分布的影响,分析了进气与进液方式对试验过程的影响。试验结果表明:改变工艺参数,可在较大范围内调控微球大小,所制微球平均粒径为0.2—2.6μm,粒径偏差为0.07—0.85μm;溶液质量浓度是主要影响因素;不同的汽液接触方式也将影响微球的大小。 相似文献
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Fei Li Wei Cui Zhaobo Tian Jie Zhang Songmo Du Zhanglin Chen Shijia Zhang Kexin Chen Guanghua Liu 《International Journal of Applied Ceramic Technology》2022,19(6):2957-2962
Si3N4 powders were prepared by combustion synthesis with 1- and 3-μm α-Si3N4, β-Si3N4 diluent and BN inert diluent. The maximum temperatures of samples with boron nitride (BN) as a diluent are about 1500–1600°C lower than that of samples with α-Si3N4 and β-Si3N4 as diluents are about 1600–1800°C. Moreover, the newly formed α-Si3N4 contents in the synthesized products with BN as diluent over 90 wt% are much higher than those with α-Si3N4 and β-Si3N4 as diluent about 20–40 wt%. The strip-like α-Si3N4, rod-like β-Si3N4 grains, and radiative shaped grains can be observed in the synthesized products. Finally, the effect of the diluent on the α-phase content of combustion synthesized Si3N4 is discussed, which provides key guidance for preparing Si3N4 powders with high α-phase content. 相似文献
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通过可逆加成断裂链转移聚合法(RAFT)将脱氢枞酸(2-甲基丙烯酰氧基异丙醇基)酯(DAGMA)单体接枝到乙基纤维素上合成了全生物质基两亲性的乙基纤维素-聚脱氢枞酸(2-甲基丙烯酰氧基异丙醇基)酯共聚物(EC-g-PDAGMA),并制备了聚合物自组装胶束。利用核磁共振氢谱(1H NMR)、凝胶色谱仪(GPC)对聚合物的结构进行了表征,证实成功合成了EC-g-PDAGMA。由于脱氢枞酸的引入,EC-g-PDAGMA接枝共聚物具有明显的紫外吸收性能。利用动态光散射(DLS)和透射电子显微镜(TEM)对聚合物自组装胶束的粒径、胶束溶液的Zeta电位和形貌进行了表征。结果表明,EC-g-PDAGMA共聚物在选择性溶剂THF/H2O中能够进行自组装形成规整的球形胶束,并且其大小随着聚合物浓度和分子链长而变化,粒径分布较窄,同时胶束具有良好的储存稳定性。 相似文献