Carnauba Wax Particles: Investigation of Dripping and Cold-Extrusion Processes

Solid lipids are commonly used as carrier systems for encapsulation processes. However, formulations containing only solid lipids tend to form a highly ordered crystal lattice, which can expel the active compound during long-term storage, due to the dynamics of polymorphic transitions. Regarding the aspects of particle production, the cooling step of the melted lipid is essential for determining the type of formed crystals. This work aimed to analyze the effects of the crystallization step on the physicochemical properties of lipid particles. Carnauba wax (CW) particles with a relatively high melting point (T_m = 78 °C) were produced by the dripping method, based on melting-crystallization steps, and by cold extrusion, which uses temperatures lower than the melting point of the lipid. Then, the physical properties, thermal behavior, and X-ray of CW particles were analyzed. The particles obtained by dripping and extrusion presented mean sizes of 3.7 and 1.5 mm, respectively. All particles presented a similar thermal behavior (T_m = 78 °C; ΔH = 200 J g⁻¹) and crystalline arrangement of the lipids. However, the dripping system presented an operational problem of clogging, requiring efficient thermal insulation, whereas the extrusion is a cost-effective, time-saving, and eco-friendly method.     

Determining Boron Speciation with an Inductively Coupled Plasma Optical Emission Spectrometer

A method of differentiating elemental B from oxidized B using inductively coupled plasma optical emission spectrometry (ICP‐OES) is presented. The method was developed and validated on weapons grade BKNO₃.     

ICP-OES法测定硅钙钡合金中主量和微量元素

用ICP-OES光谱仪进行了硅钙钡合金中主量和微量元素含量的研究,确立了最佳的样品处理条件和仪器分析条件,实现了对硅钙钡合金中硅、钙、钡、铁、铝及其微量元素的联合测定,并通过准确度和精密度实验,验证了该方法的可行性。该方法具有操作简便,结果准确,分析速度快等优点。     

天然蜡及合成蜡酸值测定方法研究

对天然蜡和合成蜡酸值测定方法进行了探讨,填补了国内标准的空白。利用无毒的混合溶剂(95%乙醇与120号溶剂油体积比为1∶4)代替了二甲苯,不但降低了对人体的危害,而且该方法适用范围广,测定结果标准偏差低。考察了取样量、溶剂量及指示剂量对酸值测定的影响,实验结果表明,取样量对酸值较大的样品的结果影响较小,溶剂量对酸值测定影响不大,指示剂量对酸值较大的样品的分析结果影响较小,该方法重复性好,精密度高。     

ICP—OES法测定钛合金中A1元素含量的不确定度评定

将钛合金样品用10mL1：1硫酸溶解后,用ICP—OES法对其中A1元素含量进行测定,测得样品中W（A1）=6．91％。对测定过程中的不确定度来源进行了分析,依据不确定度评定的步骤,计算得到了各分量标准不确定度及合成标准不确定度,W（A1）测定结果的扩展不确定度为U=0．17％,K=2。     

Wax composition of sunflower seed oils

Waxes are natural components of sunflower oils, consisting mainly of esters of FA with fatty alcohols, that are partially removed in the winterization process during oil refining. The wax composition of sunflower seed as well as the influence of processing on the oil wax concentration was studied using capillary GLC. Sunflower oils obtained by solvent extraction from whole seed, dehulled seed, and seed hulls were analyzed and compared with commercial crude and refined oils. The main components of crude sunflower oil waxes were esters having carbon atom numbers between 36 and 48, with a high concentration in the C₄₀−C₄₂ fraction. Extracted oils showed higher concentrations of waxes than those obtained by pressing, especially in the higher M.W. fraction, but the wax content was not affected significantly by water degumming. The hull contribution to the sunflower oil wax content was higher than 40 wt%, resulting in 75 wt % in the crystallized fraction. The oil wax content could be reduced appreciably by hexane washing or partial dehulling of the seed. Waxes in dewaxed and refined sunflower oils were mainly constituted by esters containing fewer than 42 carbon atoms, indicating that these were mostly soluble and remained in the oil after processing.     

相反转工艺制备巴西棕榈蜡乳液的粒径调控

分别采用经过相反转过程的水入蜡乳化法和直接将蜡加入水中进行乳化的蜡入水乳化法2种工艺制备蜡乳液,测试所得蜡乳液粒径及分布等性能,分析乳化剂选择及复配、乳化剂用量、蜡水质量比、搅拌速度、乳化温度和时间等因素对蜡乳液粒径及其分布的影响。试验结果显示:采用相反转工艺,以乳化剂Span-80、Tween-80和助乳化剂十二烷基硫酸钠组成乳化剂体系,在乳化剂的用量为蜡质量的20%、蜡水质量比为1∶5、乳化温度为90℃、搅拌速度大于1 500 r/min,乳化时间为40 min条件下,能够得到平均粒径小于100 nm的蜡乳液。透射电镜照片显示蜡乳液粒子形状为球形。     

Physical Properties of Aqueous Solutions of Pectin Containing Sunflower Wax

The aim of this study is to investigate the physical properties of aqueous solutions of pectin (PA) containing sunflower wax (SFW), which are used as a basis for producing edible films. The stability and the rheological and microstructural characteristics of SFW/PA mixtures were evaluated. SFW/PA mixtures formed oil-in-water emulsions that were milky and opaque in appearance and were stable towards phase separation. Polarized micrographs revealed the presence of wax crystals, whose size decreased as pectin concentration increased. The rheological behavior of the aqueous solutions of pectin containing different amounts of SFW were best described by the generalized power law model of Herschel–Bulkley (H–B), which gave the best fit in all the range of shear rate values. Apparent viscosities and yield stress were determined using this model, and both properties increased with increasing pectin content. The apparent viscosity values were between 0.0095 and 0.1031 Pa s. SFW addition resulted in a small decrease in viscosity for emulsions formulated with 1 and 2 % PA, but the opposite effect was observed for emulsions formulated with 3 % PA. In addition, shear stress values were higher for emulsions with higher PA content, but were not affected by SFW addition.     

IPMC无机有机复合材料的制备与表征

以Nafion-117膜为基材制备IPMC无机有机复合材料,并对其性能进行了测试。结果表明,IPMC无机有机复合材料具有较高的电极活性和良好的电化学催化性能,银的引入增强了基膜的热稳定性。     

Biomimetic Modification of Water-Borne Polymer Coating with Carnauba Wax for Controlled Release of Urea

Benefitting from the special structure of the leaf cuticle layer, plants have natural hydrophobicity and anti-fouling abilities. Inspired by the leaf surface structure, a biomimetic modification strategy was raised to improve the surface hydrophobicity of polyacrylate coating for controlled release fertilizer. Double-layer (polyacrylate and carnauba wax) coated fertilizer was obtained after biomimetic modification. The quality of controlled release fertilizer modified with the carnauba wax was greatly enhanced, and the coating material was effectively saved. The surface appearance of polyacrylate-coated fertilizer was improved for the surface blemish was repaired by the loaded carnauba wax. The characterizations by Fourier transform infrared spectroscopy indicated that the hydrogen bonds were formed between the water-based polyacrylate membrane and the carnauba wax layers. By optimizing the content of polyacrylate and carnauba wax, the release duration of the fertilizer was effectively prolonged, which was improved from 1 month to more than 2 months after the biomimetic modification. Therefore, biological wax as an environmentally-friendly natural material that has showed a broad potential in the application of coated controlled release fertilizer.     

氧化微晶蜡的研究

介绍了氧化微晶蜡的研制过程,实验结果表明,在高效的催化剂,适宜的反应温度、反应时间、空气流量下可生产出酸值超过30mg KOH／g的氧化微晶蜡产品。     

硫化物测定的主要影响因素

亚甲蓝分光光度法测定硫化物是非常实用的分析方法。该法操作比较严格,测试结果的准确度受诸多因素的影响,对这些影响因素进行了探讨。主要有试剂的影响;水样保存过程中的影响;样品预处理的影响和样品分析过程中的影响等。     

Determination of phosphorus in biodiesel using FIA with spectrophotometric detection

In this work, a method for the determination of phosphorus in biodiesel (B100) using flow injection analysis with spectrophotometric detection (FIA-SD) is described. Samples were digested using an acid mixture in a heating block. The phosphorus concentrations obtained by the (FIA-SD) method were similar to those obtained by the official method. Recovery tests show results between 98.6% and 101.0% for biodiesel produced from sunflower and between 102.1% and 113.5% for biodiesel produced from castor and soybeans. The limits of detection (LOD) and quantification (LOQ) obtained using the FIA system were 0.14 mg L⁻¹ and 0.46 mg L⁻¹, respectively.     

无机前驱体法制备连续氮化硼纤维及其结构表征

采用无机前驱体法制备氮化硼（BN）纤维,先将熔融B2O3拉丝低温（1000℃）NH3下氮化后高温（1750℃）N2下氮化得到均匀的BN纤维.利用XRD,FTIR,XPS,FE-SEM,HR-TEM,XRF和ICP等测试方法对1750℃氮化温度下的BN纤维物相组成、微观结构、元素成分进行了系统表征.结果表明：经过1750℃二次氮化后的BN纤维物相主要为六方氮化硼（h— BN）,氮化基本完全,纤维直径5～8μm,结构致密但结晶不完全,部分出现无定形BN（a-BN）.     

绿萝卜20种矿质元素的微波消解-ICP-OES测定

利用HNO3/H2O2湿法微波消解制样、再应用全谱直读电感耦合等离子体原子发射光谱法(ICP-OES),对青皮萝卜中的矿物元素组成进行了全面的分析与测定。定量分析了K、S、Ca、P、Na、Mg、Al、Zn、Si、Fe、Ba、Sr、B、Cu、Mn、V、Pb、Cr、Cd、Ti等20种矿物元素,定量结果 RSD值在0.26%~10.5%之间,标准样品回收率在89.0%~109.6%之间。实验结果可为萝卜的应用研究提供基础数据。     

Effects of Candelilla and Carnauba Wax Incorporation on the Functional Properties of Edible Sodium Caseinate Films

The aim of this study was to evaluate the effects of candelilla (CAN) or carnauba wax (CAR) incorporation on functional properties of edible sodium caseinate (CAS) films. Glycerol and Tween-80 were used as the plasticizer and the emulsifier, respectively. The results showed that the incorporation of waxes increased film opacity, total color differences (∆E), and mechanical resistance and reduced film lightness, water vapor permeability (WVP), and elongation at break. Scanning electron microscopy showed heterogeneous structure of emulsion films with regular distribution of lipid particles. A different internal arrangement was observed as a function of the film composition with both layered and incorporated film structure. Films containing candelilla wax exhibited more regular lipid reorganization, which resulted in better water vapor barrier efficacy and mechanical resistance in comparison to control films. The presence of Tween-80 resulted in better dispersion of lipid particles in film-forming solutions and lower water solubility, lightness, film opacity, and water vapor permeability, whereas the total color differences (∆E) were significantly larger and the improvement in mechanical properties was also achieved.     

Formulation and Characterization of Novel Nanostructured Lipid Carriers with Photoprotective Properties Made from Carnauba Wax,Beeswax, Pumpkin Seed Oil,and UV Filters

Pumpkin seed oil (PSO) with carnauba wax and beeswax was used to develop nanostructured lipid carriers (NLC) loaded with a UV filter, Uvinul® A Plus B. The aims of the study were to optimize the concentration of PSO to develop a stable NLC formulation, determine storage stability of the NLC with and without PSO, and the synergistic effect of PSO-NLC with UV filter for photoprotective properties. The physical properties of NLC were optimized based on the mean particle size, polydispersity index, and storage stability. The optimized NLC consisted 10% lipid phase (3.5% carnauba wax, 3.5% beeswax, and 3.0% PSO) and 90% aqueous phase. After optimization, Uvinul® A Plus B was added in the optimized PSO-NLC to produce a photoprotective formulation. Uvinul® A Plus B consisted of both UVA (Diethylamino Hydroxybenzoyl Hexyl Benzoate) and UVB (Ethylhexyl Methoxycinnamate) filters. The NLC produced with PSO and Uvinul® A Plus B had mean particle size of 135 ± 2 nm and showed good physical stability under storage time. Besides that, the NLC produced also proven to have positive effect in enhancing the entrapment efficiency and drug loading, which were 82.86 ± 0.15% and 55.41 ± 0.04%, respectively, and showed sun protection factor value of 16.61 ± 3.45. The results indicated the presence of synergistic effect among the PSO-NLC with Uvinul® A Plus B.     

ICP-OES内标法测定不锈钢中硅含量

建立ICP-OES内标法测定不锈钢中硅元素含量,利用钇元素作为内标物质,有减少元素干扰和基体差异的优点,同时节约实验资源。以盐酸和硝酸的混合酸溶解不锈钢,优化ICP-OES的测试条件,选择检测谱线。本方法简单高效,方法检出限为0.028μg/m,加标回收率为104.6%,可满足产品质量控制的需要。     

The development of a digestion procedure for the determination of metals in gum obtained from deposits in internal combustion engines by ICP-OES

The accurate determination of metals in gum (deposits found in internal combustion engines) is strongly influenced by a selection of the right sample digestion method. The difficult and heterogeneous nature of this kind of sample, and its unpredictable reaction behavior are the major obstacles in getting correct analytical results. The studies were implemented with one sample called “reference sample”. Two digestion procedures were tested in this work. The dry ashing procedure was followed by another dissolution procedure with HF and heating, in order to complete the dissolution of the ash in the samples. The process was performed in 36 h. The second digestion procedure was implemented in closed system (pressurized) with 2 mL of HNO₃ and 2 mL of H₂SO₄. This last one presented a reduction of 80.5% time-consuming in relation to the first one (dry ashing). Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Na, Ni, Pb, Si, and Zn were determined in 14 samples of gum by ICP-OES. The wet closed system digestion procedure showed efficiency in the Cr, Cu, Fe, K, Ni, Pb, Si, and Zn determination. The correlation matrix results contribute to the characterization studies of the gum formation process, as well as the corrosion of the motor parts and fuel quality control.