Influence of the Powder on the Properties of the Liquid Crystal Emulsions

The purpose of study was to evaluate the effect of four powder including titanium dioxide,bismuth oxychloride,silica,and kaolin on the properties of the liquid crystal emulsions.The results show that the addition of titanium dioxide and bismuth oxychloride had no obvious effect on the liquid crystal structure.In addition,the addition of Kaolin and silica have an effect on the stability of the liquid crystal structure.Sensory evaluation and Texture analyzer results shown that the addition of titanium dioxide and bismuth oxychloride had no obvious effect on the spreadability of liquid crystal system.The addition of silica and Kaolin was increased the hardness and adhesive of the liquid crystal system.Rheological experiments shown that the kaolin system had lower structural stability.the system with titanium dioxide,bismuth oxychloride,and silica has good stability.This paper provides data support for the application of powders in the formulation of liquid crystal system,which aims to provide a data basis for the preparation and applications of liquid crystal emulsion.

Oil-in-water nanoemulsions loaded with lycopene extracts encapsulated by spray drying:Formulation,characterization and optimization

Lycopene is very susceptible to degradation once released from the protective chromoplast environment.In this study,oil-in-water(O/W)nanoemulsions coupled with spray drying technology were applied for the encapsulation and stabilization of lycopene extracted from tomato waste.Tomato extract was obtained by ultrasound-assisted extraction.Nanoemulsions were prepared by a high-speed rotor stator using isopropyl myristate as the oil phase and Pluronic F-127 as the emulsifier for the aqueous external phase.The effect of emulsification process parameters was investigated.Spray drying of the produced emulsions was attempted to obtain a stabilized dry powder after the addition of a coating agent.The effect of different coating agents(maltodextrin,inulin,gum arabic,pectin,whey and polyvinylpyrrolidone),drying temperature(120-170℃),and feed flow rate(3-9 ml·min^(-1))on the obtained particles was evaluated.Results revealed that the emulsion formulation of 20/80(O/W)with 1.5%(mass fraction)of Pluronic F-127 as stabilizer in the aqueous phase resulted in a stable nanoemulsion with droplet sizes in the range of 259-276 nm with a unimodal and sharp size distribution.The extract in the nanoemulsion was well protected at room temperature with a degradation rate of lycopene of about 50%during a month of storage time.The most stable emulsions were then processed by spray drying to obtain a dry powder.Spray drying was particularly successful when using maltodextrin as a coating agent,obtaining dried spherical particles with mean diameters of(4.87±0.17)μm with a smooth surface.The possibility of dissolving the spray dried powder in order to repristinate.The original emulsion was also successfully verified.

SOAPLESS EMULSION COPOLYMERIZATION IN THE PRESENCE OF BARIUM SULFATE POWDER

To investigate soapless emulsion copolymerization in the presence of a solid phase, copolymerization experiments were carried out for the styrene-butyl acrylate-K_2S_2O_8-water system by using barium sulfate powder,which is assumed to be chemically inert.Reaction conditions were varied with respect to barium sulfate powder quantity,initiator concen- tration and temperature.These factors were investigated with respect to the effect on reaction rate and conversion,polymer particle number and diameter,and latex stability.

The Effect of Different Levels of Sunflower Head Pith Powder on Some Emulsion Attributes of Mechanically Deboned Chicken Meat

In this study, the effect of sunflower head pith powder at various concentrations （0.0, 0.5, 1.0, 1.5, 2.0%） on the emulsion properties of mechanically deboned chicken meat （MDCM） was investigated in a model system. For this purpose, fresh and frozen MDCM samples were used for preparing the oil/water （O/W） model emulsion systems, pH values of slurries and emulsions, emulsion capacity （EC）, stability （ES） and viscosity （EV） of the prepared model system emulsions were analyzed. Protein, fat, ash, dry matter contents and pH value of MDCM were 14.85, 14.93, 0.99, 30.45% and 6.7, respectively. It was found that the pith powder addition significantly （P 〈 0.01） decreased the pH values of slurries. On the other hand, the effect of pith powder addition on pH values of emulsions was insignificant （P 〉 0.01）. The highest EC value was reached when 1% of pith powder added. ES values of the emulsions reached a maximum level at 1.5% pith powder level. Fresh MDCM emulsions had higher EV values than did frozen MDCM emulsions at 10, 20, 50 rpm.

Structure-dependent re-dispersibility of graphene oxide powders prepared by fast spray drying

The graphene oxide powder(GOP)obtained from the spray drying process often exhibits poor redispersibility which is considered due to the partial reduction of GO sheets.The reduction of drying temperature can effectively increase the redispersibility of GOP,but result in a decreased drying efficiency.Herein,we found that the redispersibility of GOP is strongly affected by its microstructure,which is determined by the feed concentration.With the increase of feed concentration,the GO nanosheet assembly varies from the disordered stacking to relatively oriented assembly,making the morphology of the GOP transform from balllike(the most crumpled one)to flakelike(the least crumpled one),and the 0.8 mgml 1 is the threshold concentration for the morphology,structure,and redispersibility change.Once the feed concentration reaches 0.8 mg ml 1,the appearance of the nematic phase in droplet ensures the relatively oriented assembly of GO sheets to form the layered structure with a low crumpling degree,which greatly improves the polar parts surface tension of the solid GOP,making the GOP easier to form hydrogen bonding with water during the redispersion process,thus stabilizing dispersion.This work provides useful information for understanding the relationships between the morphology,microstructure,and final redispersibility of GOPs.

Effect of Polyvinyl Alcohol with a Thiol End Group on the Properties of Polyacrylic Dispersions and Spray-dried Powder

The emulsion polymerization of highly shear-stable copolymer dispersions of methyl methacrylate and butyl acrylate were carried out using poly （vinyl alcohol） with a thiol end group （PVA-SH） as protective colloid. The dispersions can be transformed into corresponding redispersible powder via a spray dryingcooling process. On-line FT-IR monitoring shows that grafting polymer of PVA-g-PMMA was formed mainly at the stage-1 of the emulsion polymerization. TEM images show, the PVA-SH shell was fragmentary when adding SDS at initial stage and integrated when adding at particle growing or final stage. The particle size turns to be smaller when delayed adding SDS surfactant. Triethanolamine, a co-regulator of PVA-SH, controlled the M to 50 000-70 000 and reduced the PDI to 1.5-1.7. The acrylic dispersions with 0.8wt%-1.5wt% PVA-SH1 can be spray-dried into super dispersible polymer powder （SDPP）, which can easily disperse in water and form recon- stituted dispersions with an average particle size smaller than 1 micron.

负压条件对T2/Q235爆炸焊接复合板界面的影响

为了探究负压条件对T2/Q235爆炸焊接复合板界面的影响,选用硅藻土敏化的低爆速粉状乳化炸药作为焊接专用药,T2为覆板,Q235为基板分别在100、60、20kPa环境压力下进行爆炸焊接试验;采用金相分析等方法研究了复合界面的形貌特征和元素组分,采用数值模拟进一步揭示了负压爆炸焊接机理。结果表明,负压条件会增大粉状乳化炸药的装药密度,但爆速变化不大,20kPa条件下猛度比常压条件下提高8.4%;随着环境压力的降低,复合板界面波高和波长逐渐增大,20kPa条件下波高比常压下增加了49%,波长增加了23%;负压条件下T2/Q235结合面氧元素含量低于常压环境;数值模拟结果表明,T2/Q235界面波随着炸药的装药密度变大而增大,与实验结果一致。在爆炸焊接时密度为0.8g/cm^(3)(20kPa)比0.711g/cm^(3)(常压)炸药碰撞速度提高了16.3%,碰撞压力提高了66.3%。研究表明,负压相比于常压条件提高了爆炸焊接的炸药能量利用率。

添加复合稀释剂的低爆速乳化炸药的制备及性能

以玻璃微球和滑石粉共同作为稀释剂制备一种低爆速乳化炸药。观察不同质量分数的玻璃微球和滑石粉对乳化炸药形貌的影响,并对乳化炸药的爆速、猛度、空中爆炸冲击波压力及储存稳定性进行测试。实验结果表明,随着滑石粉质量分数的增加,乳化炸药的形貌由乳胶状逐渐向颗粒状转化,爆速呈线性下降,对玻璃微球质量分数为5%、10%、15%的乳化炸药,测得最低爆速分别为3440、2740、2188 m/s。而随着滑石粉质量分数的增加,猛度、空中爆炸冲击波峰值超压均呈非线性下降,当滑石粉控制在一定量时,冲击波正压作用时间变化不大,乳化炸药储存稳定性较好。这种低爆速乳化炸药成本低廉、爆轰性能可调、储存稳定性好,具有较好的实用性。

VAE乳胶粉与偏高岭土聚合物改性防水砂浆性能研究

为了提高普通砂浆抗渗性能,提出了一种将有机聚合物与无机矿物相结合、并内掺有机硅赋予普通砂浆优良抗渗性能的试验研究。通过对防水砂浆抗压强度、抗折强度、抗渗强度、吸水率的测定分析,得到了高性能的聚合物改性防水砂浆。研究结果表明:(1)可再分散乳胶粉在水泥砂浆中形成的膜结构,会显著降低抗压强度而提高抗渗强度,适宜掺量应为水泥质量的3%;(2)偏高岭土具有的火山灰活性,可与水化产物发生二次反应,但应注意掺量与力学性能的关系,不宜大于6%;(3)聚硅氧烷在砂浆中形成的有机硅憎水基团,可以赋予防水砂浆优良憎水性,从而提高抗渗强度降低吸水率,掺量为0.5%时综合性能最优;(4)聚合物改性防水砂浆在具有良好力学性能的同时,抗渗强度从最初的1.0 MPa升至2.3 MPa,吸水率从7.7%降至5.2%,各项性能均远超国家规范对聚合物防水砂浆的要求。该研究成果可为防水砂浆的推广使用及改性研究提供参考。

碳酸钙颗粒表面改性及其稳定的石蜡Pickering乳液

用丁烷四羧酸、油酸和丙烯酰胺原位复合调控碳酸钙表面特性,并用改性碳酸钙颗粒制备了高固含量的石蜡Pickering乳液。用红外光谱、扫描电镜、热失重法、水接触角法和表面电位法等对改性碳酸钙的表面组成结构和形貌进行表征,并用光学显微镜和激光共聚焦显微镜对Pickering乳液形貌进行表征。试验结果表明:脂肪酸与丙烯酰胺抑制碳酸钙晶粒的生长,丁烷四羧酸钙以介孔超分子结构覆盖在碳酸钙表面,明显降低了碳酸钙的亲水性。改性碳酸钙颗粒中,纯碳酸钙60%,脂肪酸钙40%。改性碳酸钙粒径约为250 nm,水接触角为84.7°,表面电位为-23.5 mV。用改性碳酸钙制备了水包油型固含量70%的石蜡Pickering乳液。

Pickering乳液自组装CL-20/n-Al/F2605复合空心微球的制备与性能

高能量、高爆热的六硝基六氮杂异伍兹烷(CL-20)/Al复合物由于自身的高感度而限制了在炸药领域的广泛应用。为制备高能量和高安全性的CL-20/Al含能复合材料,采用Pickering乳液法制备了空心球形CL-20/n-Al/F2605(氟橡胶)复合物,并对Pickering乳液稳定性、复合物表面结构、热分解、燃烧及安全性能进行了分析。结果显示:当2 mL乙酸乙酯中溶解的CL-20固体质量为0.10~0.14 g、油水质量比在1:5~1:7之间、超声时间小于30 min、静置时间小于120 min时,形成的乳液稳定性好。该复合物表面结构粗糙,中位径d_(50)为73.17μm,各组分复合均匀。复合物的热分解峰温和活化能分别为236.7℃、164.6 kJ/mol,n-Al和F2605降低了CL-20分解过程中21.2%的活化能。复合物平均线性燃速为7.14 cm/s;特性落高H_(50)为39.5 cm,和原料CL-20相比提升了26.5 cm,安全性能得到提高。

水性苯丙吸波涂层的制备与性能研究

吸波涂料是一种能够吸收和衰减入射电磁波的功能涂料,而水性吸波涂料更具有环保健康的特点。选择炭黑和羰基铁粉作为复合吸波剂,加入水性苯丙乳液中制备成本较低的复合吸波涂层。首先测试了炭黑和羰基铁粉的电磁参数,并计算得出成分为12%炭黑和70%羰基铁粉,厚度为2mm时吸波性能最佳,反射损耗优于-5dB的有效吸收频宽达到9.9GHz,反射损耗峰值达到-28.6dB。然后制备了含12%炭黑和70%羰基铁粉,厚度为2mm的苯丙吸波涂层,测试分析了苯丙吸波涂层的吸波性能以及涂料相关性能。

珠蛋白水解物对肌球蛋白大豆油乳液理化性质的影响

文章研究珠蛋白水解物对肌球蛋白大豆油乳液理化性质的影响。结果表明:与血球蛋白粉和珠蛋白相比,珠蛋白水解物具有较高的溶解度(P<0.05),但铁离子质量比较低(P<0.05);相比于血球蛋白粉和珠蛋白,珠蛋白水解物降低了肌球蛋白大豆油乳液的分层指数和粒径(P<0.05),提高了肌球蛋白大豆油乳液的乳化活力指数和乳化稳定性(P<0.05)。微观结构表明,与血球蛋白粉和珠蛋白相比,珠蛋白水解物有利于形成更小、更均匀的液滴。与空白组相比,珠蛋白水解物、珠蛋白和血球蛋白粉均促进肌球蛋白大豆油乳液中过氧化物和硫代巴比妥酸的生成(P<0.05),但珠蛋白水解产物加速脂质氧化的效果最弱(P<0.05)。研究结果表明珠蛋白水解物有效地增强了肌球蛋白大豆油乳液的物理稳定性,且对脂质氧化的不利影响最小,在食品工业中具有潜在的应用价值。

提升水性涂料耐盐雾性能方法浅析

论证了不同材料对水性涂料耐盐雾性能有着很大影响,如丙烯酸乳胶、聚氨酯乳液、有机硅树脂、云母粉及耐盐雾助剂的使用,均可以提高产品耐盐雾性。主要研究水性涂膜在盐雾箱中1080 h的表现,确认不同材料对耐盐雾性能的提升有如何影响,在此基础来改善汽车钢板或者电泳板材料耐腐蚀性能,并在常温固化的情况下满足产品其他所需性能。

不同引发体系合成有机硅-聚苯乙烯核壳结构微球的研究

以羟基硅油、苯乙烯为主要原料,采用半连续乳液聚合方法制得具有核壳结构的有机硅-聚苯乙烯聚合物乳液,将其进行喷雾干燥制得聚合物粉末,考察了3种不同引发体系对聚合物乳液稳定性和单体转化率的影响,并对其进行了红外光谱、透射电子显微镜分析。结果表明,3种引发体系均成功合成了有机硅-聚苯乙烯共聚物,且制得的聚合物乳液有较明显的核壳结构和较好的稳定性;采用过硫酸铵、亚硫酸氢钠和过氧化二苯甲酰组成的复合引发体系(APS+NaHSO3+BPO)制备的聚合物乳液单体转化率最高,可达93.24%。对由APS+NaHSO3+BPO复合引发体系制备的聚合物粉末进行了扫描电镜和热失重表征,结果显示,在-50~180℃内有机硅-聚苯乙烯粉末没有明显的失重峰,在500~580℃区间内,粉末热失重达61.91%,表明该聚合物具有良好的耐高低温性能,可在较宽温度范围内使用并仍旧保持良好的性能。

四元共聚抗高温耐盐粉体降失水剂的制备及性能研究

以2-丙烯酰胺-2-甲基丙磺酸(AMPS)、N,N-二甲基丙烯酰胺(DMAA)、马来酸酐(MA)和甲基丙烯磺酸钠(SMAS)等为原料,采用反相乳液聚合法并引入非离子型乳化剂异构十三醇聚氧乙烯醚和司班80合成了一种抗高温耐盐四元共聚物粉体降失水剂ADMS。利用FT-IR、NMR、TG和GPC对共聚物的结构和热稳定性进行表征,并对ADMS进行了性能评价。结果表明,4种功能单体均参与了反应,ADMS的重均分子质量达448198,耐温可达320℃;ADMS抗温能力良好,使用温度在30~200℃;200℃时,添加3%ADMS的淡水基水泥浆失水量为48 mL;ADMS抗盐能力良好,在半饱和盐水和饱和盐水基水泥浆中分别添加4%和5%的ADMS可控制失水量在50 mL以内;ADMS对水泥浆稠化时间、水泥石抗压强度等无不利影响。

可再分散乳胶粉掺量对再生无机人造石性能的影响

在相同配合比下,研究不同掺量(0%、0.6%、0.8%、1%)的可再分散乳胶粉对再生无机人造石性能的影响规律。结果表明,随着乳胶粉掺量的增加,再生无机人造石的强度和耐落球冲击性先升后降,吸水率先下降后上升;当乳胶粉掺量分别为0.6%和0.8%时,再生无机人造石的压缩强度、抗折强度和耐落球冲击性最大可分别提高18.46%、16.34%和28%,吸水率最大可降低24.59%。适量的乳胶粉可以提高人造石各材料之间的粘结性能和密实性,而乳胶粉过量会使得对人造石性能的提升作用下降,建议工程应用中可再分散乳胶粉的掺量控制在0.6%~0.8%。

缓释bFGF-PLGA微球制备及其体外释药性质和生物活性的研究

目的 制备bFGF PLGA微球 ,考察其一般性质、体外释药特性和微球中bFGF生物活性保存情况。方法 应用复乳干燥法制备缓释bFGF PLGA微球 (bFGF PLGA Ms) ,并考察其一般性质。采用ELISA法建立用于bFGF含量测定的标准方法和回归方程 ,模拟体内条件研究微球体外释药特性。将bFGF PLGA Ms加入成纤维细胞培养液中 ,MTT法观察细胞增殖情况。结果 微球表面光滑圆整 ,球体均匀度好 ,平均粒径为 (1 5 5 2± 0 0 15 ) μm ,冻干粉剂为白色粉末状 ,再分散性良好 ,临界相对湿度为6 4 % ,CH2 Cl2 残留量低于限量的 1/10 ,微球包封率和载药量分别为 (6 6 4 3± 1 2 4 ) %和 [(2 7 18± 0 5 1)× 10 -3 ]%。微球体外释药规律符合Higuichi方程 :Q =2 5 884 6t1/ 2 - 15 70 5 1(r =0 9975 ) ,突释期内释放度仅为 19 2 6 % ,11d后其释放度达到72 4 7%。培养初期 ,bFGF组A值高于其余两组 ;培养中后期 ,PLGA微球组A值高于其余两组 ,差异均有显著性意义 (q检验 ,P <0 0 5 )。结论 bFGF PLGA微球及其冻干粉剂制备工艺良好 ;微球中bFGF生物活性保存良好 ,体外具有明显缓释作用。

可再分散乳胶粉的作用机理与制备研究进展

介绍了可再分散乳胶粉的作用机理,着重阐述了可再分散乳胶粉的制备方法,对其制备过程中的单体、保护胶体、喷雾干燥工艺等一些关键影响因素进行了讨论。

可再分散乳胶粉的研究进展及应用前景

介绍了可再分散乳胶粉的研究进展、性能特点以及在现实中的应用。随着对可再分散乳胶粉研究的深入,可再分散乳胶粉的应用因其优良的性能已从原来在建筑材料行业的应用扩展至许多新的领域。