乳液型清蜡剂的研究进展及发展趋势

油田清蜡剂在原油开采过程中具有举足轻重的地位。目前油田清蜡剂主要有油基清蜡剂和水基清蜡剂两种,但各有缺点。乳液型清蜡剂是近些年发展起来的新型清蜡剂,它既具有油基和水基清蜡剂的优点,又克服了它们的缺点,从安全、无毒、高效的特点来看,乳液型清蜡剂具有良好的发展前景。目前有关乳液型清蜡剂的综合性报道较少。综述了乳液型清蜡剂的作用机理和研究进展,分析了乳液型清蜡剂的优点和存在的不足,并提出其未来的发展方向及趋势。     

A novel approach to prepare large-scale and narrow-dispersed latex particles by emulsion polymerization based on particle coagulation mechanism

In order to understand the mechanism of narrow particle size distribution of the final latex during particle coagulation, a series of experiments were performed to investigate the effect of polymer nature on particle coagulation capability. In particular, thermodynamics and kinetics in aqueous phase were considered to illustrate the detail process of particle coagulation. The final particle size decreased with the increasing side chain length of alkyl methacrylate from 181.5 nm in MMA to 131.6 nm in EMA, 119.3 nm in PMA, and 115.1 nm in BMA, indicating that the particle coagulation capability was proportional to the hydrophilicity of polymer. With increasing polymer hydrophilicity, the affinity between surfactant molecules and particle surface decreased, thus enhancing the particle coagulation capability. Moreover, the critical length of oligomer radical also increased with increasing hydrophilicity and the efficiency of radical capture decreased, thus increasing the saturation of monomer concentration in the inner part of particle, promoting particle coagulation. Combining these results and the La Mer Diagram, a novel approach was developed to prepare large-scale, narrow-dispersed, and high solid content polymer latex based on particle coagulation mechanism. Three criteria, namely, rapid nucleation, fast coagulation, and a long growth period, should be met to produce latex with a narrow particle size distribution.     

The Impact of Polyoxyethylene Sorbitan Surfactants in the Microstructure and Rheological Behaviour of Emulsions Made With Melted Fat From Cupuassu (<Emphasis Type="Italic">Theobroma grandiflorum</Emphasis>)

Cupuassu fat is a good candidate for partial substitution of cocoa butter in many products, including emulsions. However, for such use it is necessary to know the characteristics of the products prepared with cupuassu fat. Therefore, the main goal of this work is to characterize emulsions prepared with cupuassu fat using the surfactants Tween^® 60, Tween^® 80 and Tween^® 85 as emulsifiers. The emulsions were prepared at 43 °C with addition of 0.5 or 1.5 % (w/v) of surfactant and compared with an emulsion without surfactant. All emulsions were analysed by conductivity, stability, pH, optical microscopy, rheology and oxidative stability. It was verified that the emulsions prepared with Tween^® 60 and Tween^® 80 have higher stability, smaller droplet size and higher apparent viscosity. Also, these properties are positively influenced by the concentration of the surfactant. On the other hand, emulsions prepared with Tween 85 or without surfactant reached unsatisfactory results. The rheological behaviour of the emulsions was adequately described by both Herschel-Bulkley and Mizhari-Berki models revealing pseudoplastic character. These emulsions also present strong gel behaviour, with storage modulus higher than loss modulus. In conclusion, cupuassu fat can be used as oil phase for emulsions products and this characterization helps to understand their behaviour in order to increase their use in food industry.     

AE型高爆速高稳定性乳化炸药的研究

本文介绍一种高爆速高稳定性的雷管感度的AE型乳化炸药的配方和制造工艺。该炸药具有配方简单新颖,原料来源广泛,制造工艺简单,成本低廉,爆轰性能良好以及贮存稳定等特点。因此生产该类型炸药可获得较显著的技术效果和经济效益。     

炸药乳化动力学唯象模型的建立及乳化器的设计

通过对乳化炸药乳胶基质形成过程中典型状态与动力学过程的划分与分析,提出了乳化动力学唯象模型。并阐述了能量输运中的高内相比、高粘度体系乳胶粒子的发展变化,建立了机械强制乳化的理想工作态。最后对合理设计高效的和接近理想工作态的准理想乳化器进行了探讨。     

4A分子筛对EVA/APP/PETA复合材料阻燃性能的影响

以聚磷酸铵(APP)和聚对苯二甲酰乙二胺(PETA)复配制备了无卤阻燃乙烯-醋酸乙烯共聚物(EVA)/膨胀型阻燃体系(IFR)复合材料,通过极限氧指数仪、热失重分析仪(TG)和扫描电镜(SEM)分析了4A分子筛对复合材料的阻燃性能、热稳定性能和复合材料残炭表面形貌的影响。结果表明,当4A分子筛添加量为2%时,复合材料的极限氧指数达39%,比未添加4A分子筛的提高了4%,垂直燃烧达到V-0级。SEM表明,4A分子筛的加入提高了样品残炭表面致密度。     

乳化剂种类与乳化炸药压力减敏关系研究

测量了含3种不同乳化剂的乳化炸药受冲击波作用前后的水中爆炸冲击波参数,依据这些参数计算出压力减敏程度.比较3种乳化炸药在冲击波作用后的压力减敏程度,结果表明在各个组分的含量和制造工艺完全相同的情况下,含有乳化剂B的乳化炸药最不容易发生压力减敏;此外,分析了乳化剂种类对乳化炸药压力减敏的影响机理,研究表明,除了敏化剂被破坏,局部破乳是乳化炸药压力减敏的重要原因.     

Analysis of Phytochemical Composition of Camellia oleifera Oil and Evaluation of its Anti-Inflammatory Effect in Lipopolysaccharide-Stimulated RAW 264.7 Macrophages

In China, Camellia oleifera oil (COO) is not only a common edible oil but also a traditional remedy widely applied to ameliorate a variety of illnesses associated with inflammation, such as mouth ulcers, thrush, eczema, etc. However, there has been a lack of relevant biological research on the anti-inflammatory capacity of COO, and the specific bioactive lipid phytochemicals contributing to the anti-inflammatory effect need further research. In this study, the RAW 264.7 macrophages model was used to investigate the anti-inflammatory capacity of COO. Our data showed that 33–200 μg/mL COO markedly inhibited the lipopolysaccharide lipopolysaccharide (LPS)-stimulated nitric oxide (NO.) secretion via the suppression of Nos2 and Cox-2 expression. The enzyme immunoassay confirmed that COO also exhibited a strong suppressive effect on the expression of proinflammatory cytokines such as Tnf-α and Il-6. To further explore the correlation between the anti-inflammatory effects and the lipid phytochemicals in COO, 10 samples were collected and screened for their chemical compositions. It was interestingly demonstrated that the polyphenol extracts of COO play a vital role in its anti-inflammatory properties. In addition, an oil-in-water (O/W) emulsion-based system was also developed to deliver the liposoluble COO into the cells, and the feasibility of this system was confirmed. Our research confirms the anti-inflammatory potential of COO and highlights that the main functional ingredient is polyphenol extracts. This may provide a scientific basis for the comprehensive utilization and development of COO and related functional foods.     

用于FDM的导电ABS/MWCNT复合材料的制备

采用熔融共混法将丙烯腈-丁二烯-苯乙烯共聚物(ABS)与多壁碳纳米管(MWCNT)复合,并对所得的复合材料进行了力学性能、热性能和电学性能分析。结果表明,添加MWCNT能够提高复合材料的力学性能、电导率和耐热性,力学性能在MWCNT添加量为2%时最佳,电导率随MWCNT添加量的增加而增大,MWCNT添加量为4%时,其电导率能达到4.35×10-6S/m。将添加4%MWCNT的复合材料拉丝,然后以三种打印方向进行熔融沉积(FDM)打印,研究了打印试样的力学性能,用扫描电镜(SEM)观察了其断面形貌。结果表明,水平方向打印的试样力学强度最好,侧向打印的试样次之,垂直方向打印的样品由于仅靠丝材的层间黏结,其力学强度比较差,与纯ABS丝材打印试样相比,复合丝材打印试样的拉伸强度和弯曲强度均有明显提高,冲击强度有所下降。