Study on Rheology and Release Kinetics of Chuanqi Ophthalmic Microemulsion in situ Gel

[Objectives] To study the rheology and release kinetics of Chuanqi ophthalmic microemulsion in situ gel,so as to provide references for its future study and development. [Methods]The fluid properties and linear viscoelastic regions of this preparation were investigated by MCR 102 rheometer. The release kinetics of Chuanqi ophthalmic microemulsion in situ gel was evaluated by modified Franz diffusion cell method,the ligustrazine and ligustilide were selected as the indictors,and semi-permeable membrane was used as a barrier,sampling time point was 0. 5,1,2,4,6,and 8 h respectively. [Results]Chuanqi ophthalmic microemulsion in situ gel was a pseudoplastic fluid and it had a linear viscoelastic region. Taking the shear stress as the indicator,the linear viscoelastic region was 0-302. 74 Pa; taking the strain as the indicator,the linear viscoelastic region was 0-7. 45%. At the critical point,the storage modulus( G') = the loss modulus( G″) =2 976. 60 Pa,critical shear stress was 302. 74 Pa and critical strain was 7. 45%. The average cumulative release of ligustrazine of 6 samples within 8 h was 33. 71 μg,the average cumulative release rate reached 90. 08%,and the release kinetics followed Higuchi equation. The average cumulative release of ligustilide of 6 samples within 8 h was 68. 46 μg,the average cumulative release rate reached 84. 32%,and the release kinetics followed the zero-order kinetics equation. [Conclusions] Chuanqi ophthalmic microemulsion in situ gel has excellent viscoelasticity and its strain is reversible in a certain range. The release kinetics of ligustrazine is the result from synergistic effect of its physicochemical properties and matrix skeleton,while the release kinetics of ligustilide is mainly affected by its physicochemical properties.

RHEOLOGICAL MODIFICATION OF EPOXY RESINS WITH NANO SILICA PREPARED BY THE SOL-GEL PROCESS

Nano silica-modified epoxy resins were synthesized by the sol-gel process, The materials have the morphological structure of nano particales dispersed in the epoxy matrix. The dispersed phase formed a physical network in the resin and thus influenced the rheological behavior greatly. However, the nano silica did not show a significant influence on the mechanical properties of the cured resins.

基于砂浆流变性能的自密实混凝土制备方法研究

通过测定机制砂掺量、胶砂比和粉煤灰掺量因素下砂浆剪切应力随着剪切速率的变化规律,根据宾汉姆流体模型线性拟合,结果得到的屈服应力和塑性黏度指导砂浆组分优化,并基于砂浆-粗骨料两相悬浮原理制备自密实混凝土(SCC)。试验结果表明:混合使用超细砂与机制砂、增大胶砂比及掺入粉煤灰都可以有效地改善砂浆流变性,制备强度等级为C50的SCC时,机制砂用量为40%、胶砂比为1.0、粉煤灰掺量为30%的砂浆具有较小的屈服应力和适宜的塑性黏度,其对粗骨料的动力传输能力及包裹性也最佳,制备的SCC表现出优良的工作性能。

羟丙基双淀粉磷酸酯糊液的屈服应力及触变性研究

为研究羟丙基双淀粉磷酸酯(Hydroxypropyl distarch phosphate,HPDSP)糊液的屈服应力和触变性行为,本文以不同链支比的玉米淀粉(CS)和蜡质玉米淀粉(WS)为原料的HPDSP为研究对象,讨论了HPDSP糊液在不同温度条件下的临界质量分数、屈服应力及触变特性。结果表明,HPDSP在5℃时的稀溶液-半稀溶液、半稀溶液-浓溶液临界质量分数分别为3wt%和6wt%。5wt%时玉米淀粉-羟丙基双淀粉磷酸酯(CS-HPDSP)和蜡质玉米淀粉-羟丙基双淀粉磷酸酯(WS-HPDSP)的屈服应力与温度相关性较低,而6wt%时两者屈服应力随温度升高(至85℃)显著下降了69.52%和77.95%(P<0.05)。HPDSP的触变性受质量分数和温度影响,5℃时,5wt%的CS-HPDSP和WS-HPDSP几乎无触变性,6wt%时触变环面积分别为163.49和85.00 Pa/s,随温度升高至85℃,两者分别降低86.38%和92.18%。WS-HPDSP的三段式触变性测定(Three interval thixotropy test,3iTT)展示出的触变性均小于CS-HPDSP,具有较好的稳定性。综上,与CS-HPDSP相比,WS-HPDSP的屈服应力和触变性更小。本文为HPDSP在食品中作为增稠剂的实际应用提供了理论依据。

超微虾壳粉对草鱼鱼糜凝胶品质的影响

为提高草鱼鱼糜的凝胶特性,改善其品质,以鲜活草鱼为试验原料,添加虾壳粉,探究不同添加量的虾壳粉(0.25%、0.5%、0.75%、1%、1.25%)对草鱼鱼糜凝胶质构特性、凝胶特性、流变性等的影响。结果表明,与对照组相比,添加虾壳粉会显著降低草鱼鱼糜凝胶的白度和色泽评分(P<0.05),但其质构特性显著增大(P<0.05),持水性显著升高(P<0.05),结合水含量显著增加(P<0.05)。感官评价和电子鼻分析结果表明,当虾壳粉在最适添加量0.5%时,可以显著改善鱼糜凝胶的风味和品质。因此,添加适量虾壳粉能增强鱼糜凝胶的网络结构和持水能力,得到具有较好风味和品质的鱼糜制品,研究结果可为生产高品质的鱼糜产品提供理论依据。

不同乳酸菌发酵黄浆水对酸浆豆腐凝胶特性及其品质的影响

目的研究不同乳酸菌发酵黄浆水对酸浆豆腐凝胶特性及其品质的影响,探究酸浆豆腐的凝固机制,提高酸浆豆腐的品质稳定性,量化生产工艺参数。方法以大豆为原料,分别以鼠李糖乳杆菌、耐高温鼠李糖乳杆菌、混合菌(乳酸链球菌乳亚种、嗜热链球菌和耐高温鼠李糖乳杆菌)发酵黄浆水制成的酸浆作为凝固剂制作豆腐,测定豆腐的凝胶强度、持水性、出品率、色差、质构特性、感官评价、流变特性、水分分布、二级结构、三级结构、表面疏水性和微观结构等指标。结果混合菌酸浆诱导的豆腐质构特性最好,具有较高的凝胶强度、持水性和储能模量,分别为579.63g、69.93%和8166.4Pa,感官评分最高。而耐高温鼠李糖乳杆菌酸浆诱导的豆腐凝胶强度和持水性比鼠李糖乳杆菌酸浆诱导的豆腐高。鼠李糖乳杆菌酸浆诱导的豆腐则硬度较低,为1481.38 gf,水分流动性较大。表面疏水性结果显示,混合菌酸浆诱导的豆腐表面疏水性较低,为268.75%,三级构象最为紧密,鼠李糖乳杆菌酸浆豆腐表面疏水性较大,为469.29%,三级构象较为松散。扫描电镜结果显示,混合菌酸浆豆腐呈致密均匀的三维网状结构,耐高温鼠李糖乳杆菌酸浆豆腐凝胶较为连续,孔隙较大,鼠李糖乳杆菌酸浆豆腐凝胶网络结构较松散。结论混合菌酸浆可使豆腐具有较好的凝胶特性和品质,为酸浆豆腐的品质提高提供了理论和技术支持。

氯化钠对鲢鱼糜体系3D打印性能及凝胶特性的影响

目的:提高鲢鱼糜体系3D打印性能及凝胶特性。方法:通过优化3D打印参数,将3D打印过程与材料流变性质及3D打印性能关联起来。探究氯化钠添加量对鲢鱼糜的流变性能、3D打印性能、凝胶强度、水分特性以及微观结构的影响。结果:氯化钠的加入以剂量依赖的方式降低了鲢鱼糜的耗散模量,但能显著提高材料的剪切恢复性能,还可以降低鱼糜体系的蒸煮损失,提高鱼糜体系的持水性。当氯化钠添加量为2.5%时,鲢鱼糜具有最佳凝胶强度和最为致密的微观结构。结论:添加适量氯化钠可提高鱼糜产品的3D打印性能和凝胶特性。

凝胶推进技术研究进展

凝胶推进技术是指在液体燃料中加入合适的胶凝剂形成三维网络以转变为半固体半液体状态,通过控制推进剂流量实现推力可调的一类推进技术。凝胶推进剂具有比冲大、安全性高和易于储存等优良性能。从凝胶推进剂的胶凝剂种类、流变特性、雾化特性、液滴燃烧特性和应用前景等方面进行了梳理和总结,提出了今后研究的重点并展望了未来发展方向,即制备对外界刺激敏感的凝胶推进剂、改善凝胶推进剂供给环境和雾化模式、建立凝胶推进剂液滴燃烧模型、设计和开发适用于空间任务的凝胶微推进系统等。

改性糯米灰浆材料流变性及其结石体力学性能研究

2017年九寨沟“8·8”地震导致火花海钙华坝受损,而针对自然遗产地的加固材料须为生态环保材料,研发的糯米灰浆采用支链淀粉团聚石灰、石膏与硅粉,达到了加固钙华坝的目的。为满足九寨沟钙华地区坝体加固对注浆材料的要求,在传统糯米灰浆中加入外加剂、硅灰、石膏改善其流变性与力学性能。改变糯米灰浆中石灰/石膏质量比(0、0.11、0.25、0.43、0.67),通过常规剪切(0.01~100 s^(-1))与循环剪切(0.01~300 s^(-1))测定流变曲线,分析改性糯米灰浆的流变性与触变性。此外,对改性糯米灰浆结石体的力学特性进行研究,并利用扫描电子显微镜分析结石体的微观结构。结果表明:石灰/石膏质量比由0变化到0.67,浆液最大黏度降低了84.7%~91.3%,其对应剪切速率逐渐增大;改性糯米灰浆属于带屈服值的假塑性流体材料;与Bingham模型相比,Herschel-Bulkley模型能更好地描述改性糯米灰浆的流变性;改性糯米灰浆具有触变性,石灰组份的掺入导致浆液的触变性降低,与黏度受影响规律相仿;触变性受剪切历史控制,呈现出随剪切循环次数的增大而降低的特点;改性糯米灰浆结石体28 d的抗压强度可达9.78 MPa;随着石灰/石膏质量比的增大,改性糯米灰浆结石体的弹性模量逐渐减小,宏观破裂方式由脆性破坏过渡到延性破坏。

Hofmeister效应对大豆分离蛋白凝胶特性和流变学特性的影响

选取不同浓度(0.02、0.04、0.06 mol/L)的4种盐(KCl、NaCl、CaCl_(2)、MgCl_(2)),研究Hofmeister效应对大豆分离蛋白凝胶特性和流变学特性的影响。结果表明:添加盐离子能提高大豆分离蛋白的凝胶强度,但0.04、0.06 mol/L的CaCl_(2)、MgCl_(2)会降低样品的凝胶黏性;在动态流变学测试中,各种盐离子都可以在不同程度上提高样品储能模量G′、损耗模量G″,较高浓度的CaCl_(2)、MgCl_(2)会导致大豆蛋白分子过度聚集,反而使之降低;在温度扫描过程中,CaCl_(2)、MgCl_(2)的添加改变了样品G′、G″的变化趋势,KCl、NaCl则只使G′、G″提高而未改变其趋势;在静态流变学测试中,较高浓度的CaCl_(2)、MgCl_(2)降低了样品的表观黏度和剪切应力,其他样品使二者提高,较高浓度盐离子对表观黏度和剪切应力的影响与Hofmeister序列一致。综上,在本实验中,在特定盐离子浓度(0.04、0.06 mol/L)条件下,大豆分离蛋白样品凝胶特性和流变学特性的变化符合Hofmeister效应。

蛋清蛋白/黄油复合凝胶的特性研究

以蛋清蛋白(egg white protein,EWP)和黄油为原料,按照不同比例(1∶1、1∶2、1∶3、1∶4、1∶5,质量比)进行复配,经热诱导制备EWP/黄油复合凝胶,并分析其质构特性、持水性、乳化性、乳化稳定性、流变特性、扫描电镜及激光共聚焦的变化规律。结果表明,质构特性中的硬度及胶黏性随着黄油添加量的增加而增加,而弹性及内聚性则在EWP/黄油为1∶3(质量比)时达到最高(P<0.05);复合凝胶的持水性随着黄油添加量的增加而增加,在1∶4及1∶5(质量比)时差异不显著(P>0.05);当二者质量比为1∶3时,乳化性及乳化稳定性显著高于其他组(P<0.05);流变结果显示当二者质量比为1∶3时,复合凝胶具有较大的储能模量(G′)及较低的损耗因子tanδ,说明此比例下的黄油提高了复合凝胶的黏弹性;扫描电镜结果表明二者质量比为1∶3时促使复合凝胶形成了更致密紧凑的网络结构,而未添加黄油的蛋清蛋白凝胶则呈现孔洞较大且大小不均匀的结构特征;激光共聚焦结果显示EWP/黄油1∶3(质量比)时网络结构相对均匀,且无析水无孔隙。综上所述,EWP和黄油的质量比为1∶3时可以改善蛋清蛋白的乳化特性及凝胶特性,为后续替代食品中部分乳化盐,以降低食品中钠含量,制备相关低钠食品提供了数据支撑。

食品增稠剂对果酱质地的影响研究进展

果酱是一种常见的水果加工制品,其种类繁多且营养丰富,具有悠久的消费历史和广大的消费受众。传统果酱的质地需要在高糖(55%~75%)、高酸(pH 2.0~3.5)等条件下形成,这对低糖果酱的制作是一种挑战。另外,果酱的质地在贮藏运输等过程中也容易受到破坏,从而影响果酱的品质。食品增稠剂是一类可以增加流体食品黏度、稠度、凝胶强度的食品添加剂,能够促进低糖果酱质地的形成,维持果酱在贮藏运输等过程中的稳定性。本文综述了果酱质地的形成原理和劣变现象,阐述了果胶等多种食品增稠剂以增稠或胶凝的机制在果酱中的应用现状,重点探讨了食品增稠剂对果酱制品感官特性、质构特性、流变特性、微观结构等的影响,并展望了其未来的研究方向,旨在为增稠剂在果酱产业中的开发与应用提供思路。

辅酶Q10柔性脂质体凝胶的制备及其评价

目的将辅酶Q10制备成柔性脂质体凝胶,考察其体外特性与抗衰老效果.方法以卡波姆940为凝胶基质,甘油和丙二醇为保湿剂制备凝胶剂,以皮肤滞留量为指标,采用正交试验设计优化辅酶Q10柔性脂质体凝胶处方,并对其外观形态、体外释放、体外透皮、流变学、抗衰老药效学进行考察.结果辅酶Q10柔性脂质体凝胶处方为:卡波姆940的比例为0.5%,保湿剂的比例为10%,其中甘油与丙二醇为质量比1∶1,三乙醇胺的比例为0.4%;凝胶质地均匀细腻,稳定性良好;体外释放结果表明,辅酶Q10柔性脂质体的体外释放量高于辅酶Q10柔性脂质体凝胶和辅酶Q10市售面霜;体外透皮结果表明,辅酶Q10柔性脂质体的透皮量高于辅酶Q10柔性脂质体凝胶,但皮肤滞留量低于辅酶Q10柔性脂质体凝胶;流变学结果表明,制备的凝胶属于假塑性流体;药效学结果表明,辅酶Q10柔性脂质体凝胶具有增加皮肤的抗氧化活性,增加皮肤胶原纤维含量,延缓皮肤衰老的作用.结论辅酶Q10柔性脂质体凝胶可以提高皮肤抗氧化能力,延缓皮肤衰老.

A Novel Thixotropic Phenomenon——Complex Thixotropic Behavior

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Application of the gel casting process in iron powder metallurgy

The effects of various gel casting process parameters such as the dispersant and solid loading on the rheology of Fe slurries, molding, and sintering behaviors were studied. The relationship between solid loading and viscidity in the process of iron base powder metallurgy was researched to obtain better microstructure and properties. The results showed that the viscosity of Fe slurries is obviously reduced with the increase of the dispersant. The suitable parameters are as follows： the solid loading is 61% and sintering temperature is 1180℃. Iron parts with relatively high density and better properties were obtained by the gel casting process.

Influence of Polycarboxylate Superplasticizer on Rheological Behavior in Cement Paste

Molecular structures of polycarboxylate（PCE） superplasticizer significantly affect the rheological properties of cement paste. Consequently, we employed self-synthesized PCE copolymers with different carboxylic densities to investigate their influence on the rheological behavior of cement paste. Three typical rheological models were applied to analyze the rheological properties, including Power-law model, Bingham model as well as Herschel-Buikley model. In addition, the thixotropical performances of cement paste in the presence of PCE with different carboxylic densities were investigated. The results show that the carboxylic density of PCE greatly influences the dispersing performance of PCE superplasticizers. As carboxylic density increases, the dispersing capability of PCE improves, and P（PEG1-AA6） possesses the strongest dispersing capability, the initial fluidity and 1 h fluidity of cement paste are both the highest, and cement paste has the lowest viscosity and the smallest hysteresis loop.

Preparation and Rheological Properties of Vacuum Lubricating Grease

A kind of vacuum lubricating grease was prepared by using perfluoropolyether as base oil,perfluorinated polymer as thickener,and self-made additives.The colloidal stability of the grease was greatly improved by introducing a colloidal structure modifier.The rheological properties of the self-made grease(SMG),such as viscosity versus time,thixotropy,etc.,were studied by a rheometer at different temperatures and were compared with those of foreign brand grease(FBG).The results show that the performance of SMG reached the level of similar FBG,and some properties such as mechanical stability,colloidal stability,extreme pressure and antiwear properties were better.It can be used for long life lubrication of moving parts in a vacuum environment.

Copper base materials prepared by gel-casting process

Gel-casting process was developed as a new molding process in the field of copper base powder metallurgy to manufacture metal parts with excellent performance and complex shapes.Through changing the parameters of gel-casting process,such as dispersant and solid loading,the corresponding effects on the rheology of Cu slurries,molding and sintering behaviors were studied.The results show that the viscosity of Cu slurries was significantly reduced with an increase in dispersant.The most appropriate solid loading was found to be 61% and the sintering temperature was 910°C in these experiments.After the optimization of parameters of gel-casting process,copper composite parts with relatively high density and better properties were obtained.

聚醚脂肪酸类油基钻井液提切剂的研制与应用

针对油基钻井液切力低,易导致沉砂卡钻等严重问题的现状,合成了一种聚醚脂肪酸类油基钻井液用提切剂LQZ。利用红外光谱、热重曲线、凝胶强度和界面扩张流变参数等测试方法,分析了提切剂的结构、热稳定性、凝胶性能和作用机理,同时探究了基础油、油水比、密度和温度对其提切效果的影响。结果表明,该提切剂分子中含有羟基、酰胺基、酯基、醚键,能形成网架结构,提高悬浮能力,且具有快速弱凝胶特点;300℃无明显热分解;加量小于0.85%时有利于乳液稳定性;该提切剂对白油基、柴油基和合成基钻井液体系普遍适用,且白油基中效果最好;当钻井液油水比为8∶2、密度为2.1 g/cm^(3)、190℃时提切效率最佳,动切力、φ6及φ3读数和静切力增长约1倍;与国外同类产品相比,LQZ具有提切不增塑性黏度的优势。LQZ在现场页岩油气井应用时,动切力、φ6及φ3读数和静切力基本增加100%,塑性黏度无明显增长。LQZ能够提高油基钻井液悬浮能力,不显著增加塑性黏度,具有很好的推广应用前景。

Rheological behavior of semi-solid TiB_2 reinforced Al composite

The rheological behavior of the semi-solid Ti B2 reinforced Al-Mg alloy composite slurry was investigated,which is required for the mould filling simulations during the semi-solid processing.Ti B2 reinforced in-situ Al-Mg alloy composite samples were remelted and subsequently brought to the semi-solid temperature regime within the heating chamber of a Searle type rheometer.In order to understand the rheological behavior of composites,three different types of experiment were carried out,namely,steady state test,continuous cooling test and isothermal test.Apart from that,the thixotropic nature of the slurry was confirmed from the obtained hysteresis loops during the experimentation.The results indicate that when isothermally held,the composite slurry exhibits pseudo-plasticity and shows shear-thinning behavior up to the shear rate of 1300 s^-1,and at higher shear rates（1300 s^-1）,it shows a shear thickening tendency,which is probably due to the agglomeration of non-deformable nano-Ti B2 particles.The pseudo-plastic behavior of the slurry was also estimated employing intermittent step changes of shear rate（shear jump test）.