功能性化学助剂对SBS改性沥青工艺及性能的影响研究

在SBS改性沥青体系中加入酰胺类功能性化学助剂,通过功能性化学助剂的化学成键作用,SBS与基质沥青实现较好的互溶,使SBS改性沥青的高低温性能、5℃延度、储存稳定性及耐老化性能均得到大幅改善.同时与传统SBS改性沥青相比,功能性化学助剂的加入能够降低沥青改性加工温度,缩短沥青改性加工时间,节约生产成本,提高生产效率.     

不同方法强化超临界CO2萃取的最新研究进展

本文阐述了不同强化手段对超临界CO2萃取效率的影响,介绍了夹带剂、超声波、电场等高新技术与超临界CO2萃取耦合技术的研究现状,并指出了存在的问题和应用前景。     

低相对分子质量溴化聚苯乙烯的合成

以低相对分子质量、相对分子质量分布窄的聚苯乙烯为原料,合成低相对分子质量溴化聚苯乙烯;讨论溴化剂用量对溴化聚苯乙烯溴含量的影响;通过溶剂复配提高催化剂的溶解性,制备高溴含量溴化聚苯乙烯;用热失重分析溴化聚苯乙烯的热稳定性。     

活化液助溶剂对再生脱硝催化剂性能的影响

为了考察助溶剂对活化液的催化剂再生性能的影响,将某燃煤电厂失活退役的脱硝催化剂在相同清洗工艺下处理,随后分别浸入以草酸、乙醇胺作为助溶剂配制的活化液中,得到两个再生催化剂。采用XRF、氮气物理吸附法、原位吡啶吸附、NH₃-TPD、Raman、XPS、H₂-TPR以及固定床脱硝反应器等表征手段对新鲜样品、失活样品以及再生样品进行表面理化性质、脱硝性能测试评价。结果显示,脱硝催化剂失活的主要原因是飞灰中的碱金属K、Na造成催化剂的比表面积和孔容下降、表面Lewis酸性位数量减少、V⁵⁺比例下降、活性VO_x减少及氧化还原性能下降。同时发现,两个再生催化剂在等量活性组分钒条件下,脱硝性能却表现出较大差异,乙醇胺助溶活化液再生的样品Ethanol-cat性能恢复至新鲜催化剂的97%以上,而草酸助溶活化液再生的样品Oxalic-cat却几乎无再生效果,这是因为两种活化液中的活性组分钒状态不同,乙醇胺助溶活化液中钒离子可有效恢复失活催化剂的酸性位数量、V⁵⁺比例、活性物种VO_x     

Study on syntheses and characterizations of polymethylphenethylsilane, polymethylcyclohexylsilane and their copolymers

Ｄｕｒｉｎｇｔｈｅｌａｓｔ10ｙｅａｒｓ,ｃｏｎｓｉｄｅｒａｂｌｅｗｏｒｋ[1,2]ｈａｓｂｅｅｎｐｅｒｆｏｒｍｅｄａｎｄｒｅｖｉｅｗｅｄｏｎｐｏｌｙｓｉｌａｎｅｓｙｎｔｈｅｓｉｓ.Ｔｈｅｓｅｐｏｌｙｍｅｒｓａｐｐｅａｒｖｅｒｙｉｎｔｅｒｅｓｔｉｎｇａｓｒｅｓｉｓｔｓｆｏｒｍｉｃｒｏｌｉｔｈｏｇｒａｐｈｙ,ｔｈｅｐｒｅｃｕｒｓｏｒｓｆｏｒｃｅｒａｍｉｃｓｏｒｅｖｅｎａｓｃｏｎｄｕｃｔｉｎｇｍａｔｅｒｉａｌｓ.ＴｈｅｙａｒｅｇｅｎｅｒａｌｌｙｓｙｎｔｈｅｓｉｚｅｄｂｙＷｕｒｔｚｔｙｐｅｃｏｕｐｌｉｎｇｏｆｓ…     

超临界二氧化碳萃取天津冬菜中呈色物质的初步研究

以超临界CO2为溶剂提取天津冬菜中的呈色物质。选用L9(34)正交表,以萃取物A550吸光度平均值为指标,分别考察有无夹带剂存在时,温度、压力、CO2流量对萃取效率的影响。结果表明:压力与温度是萃取的主要影响因素;以水作为夹带剂可有效提高天津冬菜中呈色物质的萃取效率。     

Effects of solvent adsorption on solution properties of poly(vinyl alcohol)/dimethylsulfoxide/water ternary systems

In this study, the solvent adsorption phenomena of poly(vinyl alcohol) (PVA) in cosolvent mixtures of dimethylsulfoxide (DMSO; solvent 1) and water (solvent 2) were investigated. Typically, this cosolvent mixture could form hydrogen‐bonded DMSO/(water)₂ complexes, involving one DMSO and two water molecules. Because of the complex formation in the cosolvent mixtures, PVA chains preferentially adsorb water molecules at DMSO mole fraction X₁ < 0.33, but preferentially adsorb DMSO molecules at X₁ > 0.33. The preferential adsorption of DMSO (a good solvent for PVA) could cause the relatively extended conformation of PVA chains in solutions because of the increase in excluded volume effect. Because of various interactions between PVA chains and cosolvent mixtures, the aggregation and gelation behaviors of PVA solutions were significantly affected by the composition of cosolvent mixture. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3211–3217, 2004     

用含夹带剂丙酮的超临界CO2快速膨胀法制备灰黄霉素的微细颗粒

Griseofulvin (GF) is an antifungal drug whose pharmaceutical activity can be improved by reducing particle size. In this study the rapid expansion of supercritical solution (RESS) was employed to micronize GF.Carbon dioxide with cosolvent acetone was chosen as a supercritical mixed solvent. The solubility of GF in super-critical CO2 with cosolvent acetone was measured using a dynamic apparatus at pressures between 12 and 32 MPa,temperatures at 313, 323 and 333 K and cosolvent concentration at 1.5, 3.0, 4.5 and 6.0% (by mole). The effect of pre-expansion pressure, extraction temperature, spraying distance, nozzle size and concentration of cosolvent on the precipitated particles was investigated. The results show that the mean particle size of griseofulvin precipitated by RESS was less than 1.2μm. An increase in pre-expansion pressure, extraction temperature, spraying distance and concentration of cosolvent resulted in a decrease in particle size under the operating condition studied. With the decrease of nozzle diameter the particle size reduces. The crystallinity and melting point of the original material and the processed particle by RESS were tested by X-ray diffraction (XRD) and differential scanning calorimetry (DSC).No evident modification in the crystal habit was found under the experimental conditions tested. The morphology of particles precipitated was analyzed bY scanning electron microscopy (SEM).     

高炉渣中铝、铁的浸出研究

以钢铁厂高炉渣为原料,采用酸浸法和助浸法研究铁、铝浸出率.结果表明:高炉渣为非晶相玻璃体结构,当H2SO4浓度5 mol/L;酸渣比20:1;反应时间60 rmin,反应温度100℃时,高炉渣中铁、铝的浸出率为30.59％.添加助溶剂Na2CO3有助于提高高炉渣中铁、铝浸出率,在Na2CO3/高炉渣质量比为0.3时,铁、铝的浸出率为46.87％,此时,高炉渣晶体结构改变,表面凹凸不平并粘附不同形状的细小颗粒,吸附性孔道增多,利于混凝吸附的进行,并进一步提出强化浸出建议.