X射线衍射法测定滑石粉中石棉成分

使用X射线衍射法,通过石棉的2θ特征峰进行判断,分析滑石粉中可能存在的石棉成分。结果表明,样品中不含温石棉、铁石棉和青石棉,并对温石棉和绿泥石进行了有效区分。方法快速,灵敏,可有效用于滑石粉中石棉的测定。     

基于GB/T 23263-2009鉴定含滑石粉的化妆品中的石棉

<正>石棉是天然纤维状硅酸盐类矿物的总称^[1],基本成分是水合硅酸镁(3MgO·3SiO₂·2H₂O),其纤维对人体危害很大,长期吸入会引起石棉肺、肺癌等疾病,我国《化妆品安全技术规范》(2015年版)已将石棉列为禁用物质^[2]。滑石粉是一种含水镁硅酸盐矿物,被广泛应用于化妆品(如爽身粉、眼影、粉底液等)及个人护理产品中。滑石粉化学结构稳定,但其原料中常伴有石棉杂质,可能影响人体健康。因此,有效准确地检测化妆品中的石棉,对于提高化妆品的品质     

粉状化妆品及原料中石棉测定方法发布

针对媒体对婴幼儿爽身粉中含有禁用物质石棉的报道和我国目前尚无化妆品及其原料中石棉测定方法的现状,国家食品药品监督管理局组织有关专家对含滑石粉的粉状化妆品及其原料中石棉测定方法进行了论证,并于日前印发了《粉状化妆品及其原料中石棉测定方法》(暂定),要求各省(区、市)卫生、食品药品监管部门(药品监督管理局)参照执行。粉状化妆品及原料中石棉测定方法发布@高     

微波消解-电感耦合等离子发射光谱法测定面粉中滑石粉的含量

采用微波消解-电感耦合等离子发射光谱法(ICP-AES)测定了面粉中的滑石粉含量.采用氢氟酸、硝酸处理样品,使滑石粉中的镁转化成Mg2+,Mg含量在5～50 mg/L范围内与光谱强度线性相关,线性相关系数为0.9994.测定结果的相对标准偏差为3.18%～7.80%(n=6),回收率为91.2%～102.4%.     

X-射线衍射内标法定量滑石粉中的温石棉

对比α-氧化铝、氧化镁、硅粉三者的结晶属性,选择晶相良好且与温石棉特征峰无重叠的单质硅为内标物,建立温石棉衍射吸收标准曲线,该曲线在温石棉含量0%～9.3%具有较好的回归性。使用曲线分析已知温石棉含量的分析样品,测得温石棉含量为1.70%,与理论值(温石棉添加量:1.68%)的相对误差RE为0.99%。分析该方法检出限与定量限分别为0.10%和0.30%。与以金属基底建立曲线的石棉定量方法相比,内标法有较好灵敏度和准确度,是一种准确可靠的石棉定量方法。     

傅里叶变换-红外光谱法快速测定面粉中滑石粉

提出了应用衰减全反射(ATR)傅里叶变换-红外光谱(FT-IRS)法快速检测面粉中混入的滑石粉,测定中采用中红外检测器。根据滑石粉的标准红外光谱图并为避免面粉的吸收干扰,选择滑石粉在3 674.96 cm-1及668.16 cm-1两处的特征吸收峰作为判定面粉中是否含有滑石粉的依据,并且其吸收强度随滑石粉含量的增加而增加。由于面粉中滑石粉质量分数低于0.5%和0.2%时,分别在上述两吸收峰波长处已不呈现吸收,方法中将1%(质量分数)作为滑石粉的检出限。此外,根据吸收峰的吸收强度可估算出滑石粉的含量。方法中选用的主要仪器工作条件为:①扫描范围为4 000～650 cm-1;②分辨率为8 cm-1;③扫描信号累加次数为32;④衰减全反射压力常数为100。     

滑石粉和PLA-g-MAH对聚乳酸结晶性能和熔体强度的改善

采用混沌混炼单螺杆挤出机,制备马来酸酐接枝聚乳酸(PLA-g-MAH),进而制备PLA/滑石粉(5%,10%和20%,质量分数)和PLA/滑石粉(20%)/PLA-g-MAH(5%和10%)复合材料.复合材料样品中滑石粉的分散状态良好,滑石粉含量高达20%时未发生团聚.20%滑石粉和10%PLA-g-MAH使复合材料中PLA的α晶含量明显增加,结晶度提高至31.6%.在175℃下,PLA样品的熔体强度仅为3.6 mN,20%滑石粉明显提高了PLA的熔体强度(11.6 mN),这是由于分散较均匀的片状滑石粉对PLA熔体起增强效应并可提高PLA结晶速率,对PLA结晶有促进效应.与PLA样品对比,PLA/滑石粉(20%)/PLA-g-MAH(5%)复合材料的杨氏模量和冲击强度分别提高了51.7%和16.9%.     

微波消解-电感耦合等离子体原子发射光谱法同时测定滑石粉中的硅及其他元素的含量

正滑石粉的主要成分是含水硅酸镁,具有润滑、抗粘、助流、耐高温等优良特性~([1]),在食品~([2])、医药~([3])、汽车~([4])、造纸~([5])等方面应用广泛,滑石粉中各组分的含量对其理化性能以及人的身体健康有着重大的影响~([6])。因此,研究滑石粉中无机元素检测方法具有重要意义。目前滑石粉中无机元素分析方法有化学分析     

P3/4HB和滑石粉复合增韧填充PLA的研究

通过熔融共混法制备了可完全生物降解的聚乳酸/聚(3-羟基丁酸-co-4-羟基丁酸共聚酯)/滑石粉(PLA/P3/4HB/滑石粉)复合材料,利用万能试验机、扫描电子显微镜、熔体流动速率仪、差示扫描量热仪及热失重分析仪等测试研究了偶联剂处理以及滑石粉含量对PLA/P3/4HB/滑石粉复合材料的力学性能、界面相容性、熔体流动性和结晶性能的影响。结果表明,当滑石粉填充量较少时,偶联剂处理对复合材料的性能影响不大,但当滑石粉填充量较高时,经过偶联剂处理后的滑石粉能显著提高复合材料的熔体流动速率和冲击强度,PLA/P3/4HB/处理滑石粉复合材料的拉伸强度也保持在36.9MPa以上,结晶性能也有所提升,复合材料具有良好的综合性能。     

使用SEM/EDS快速鉴别建筑材料和保温材料制品中的石棉

建立了一种使用扫描电镜和能谱联用鉴别建筑材料、保温材料等制品中石棉的方法。先用扫描电镜对比了六种石棉标准品的形貌特征,再对照标准品的能谱结果,证明可以通过钙、镁、硅三种元素的含量鉴别石棉种类。用该方法对待测样品中纤维物质进行分析,结果显示纤维中含有钙、镁、硅三种主要元素,其摩尔比与阳起石和透闪石的化学组成吻合,由此判断样品中含有这两种石棉。     

ELECTRORHEOLOGICAL PROPERTIES OF TALC POWDER/SILICONE OIL SUSPENSIONS UNDER DC FIELDS

In this study, the electrorheological （ER） behavior of suspensions prepared from d50 = 2.4 lam talc powder, dispersed in insulating silicone oil （SO） medium was investigated. Sedimentation stabilities of suspensions （c = 5 wt%） prepared using these talc powder powders were determined to be 78 days. The ER activity of all the suspensions was observed to increase with increasing electric field strength, concentration and decreasing shear rate. The shear stress of talc powder suspensions increased linearly with increasing concentrations of the particles and with the applied electric field strength. Electric field viscosity of all the suspensions decreased sharply with increasing shear rate and showed a typical shear thinning non-Newtonian visco-elastic behavior. Effects of frequency on the ER activity of talc powder/SO system were also investigated.     

The influence of fillers on thermophysical properties of adhesives

The influence of powder fillers (boron nitride, aluminum powder, processed asbestos) on the thermal conductivity and linear thermal-expansion coefficient of epoxy adhesives has been investigated. It has been shown that the use of powder fillers makes it possible to develop polymer compositions with a high thermal conductivity.     

A new approach to the problem of kaolinite interference in the determination of chrysotile asbestos by means of x-ray diffraction

In the determination of chrysotile asbestos by means of powder x-ray diffraction, a mathematical approach is used to overcome the problem of kaolinite interference. The overlapped peaks are deconvoluted by using least-squares and simplex optimization procedures.     

Application of dsc to study crystallization kinetics of polypropylene containing fillers

The present work is concerned with the comparison of nucleating efficiency of various organic and inorganic fillers of isotactic polypropylene: talc, chalk, wood flour, nano clay particles, carbon black, chitosan in the form of powder of the same content equal to 5 mass%. The kinetics of isothermal crystallization of isotactic polypropylene in the composite systems was evaluated by using DSC. Avrami equation was applied to the results. Calculated K and n parameters depend on filler applied. The σσ_e surface free energies were also found. The best nucleating agent found here was talc and carbon black. The organic filler as a chitosan powder forms amorphous inclusions in the composites on which IPP molecules cannot be adsorbed. Their presence disturbs a macromolecular diffusion and delays crystallization process of IPP. This revised version was published online in July 2006 with corrections to the Cover Date.     

PE膜中层状双羟基复合氢氧化物的红外吸收性能

水滑石;聚乙烯薄膜;PE膜中层状双羟基复合氢氧化物的红外吸收性能     

Contact angle and film pressure: study of a talc surface

Talc samples in both sheet and powder form are studied by adsorption calorimetry and adsorption isotherm techniques. A model is used to determine the solid surface energy, the solid surface tension and the dispersive, acidic, and basic components of these terms. These results are introduced in an approximate equation relating adsorption to contact angle data. Experimental contact angles are in correct agreement with this approach. The Neumann equation of state is used to fit the data and discussed. It appears as a numerical form of the general equation taking into account gas adsorption and film pressure. Behaviors of talc in contact with liquids do not appear very different whether the solid is in sheet or powder form.     

Effect of poly(vinyl alcohol) fine particles as a novel biodegradable nucleating agent on the crystallization of poly(3‐hydroxybutyrate)

The effect of poly(vinyl alcohol)(PVA) fine particles as the nucleating agent on the crystallization behavior of bacterial poly(3‐hydroxybutyrate)(PHB) was studied using differential scanning calorimetry measurements and polarized light microscope observation. The results were compared with the effect of PVA conventionally blended with PHB. The PVA fine particles were found to be able to greatly enhance the crystallization of PHB, while the conventionally blended PVA extremely retarded the crystallization of PHB. The nucleating effect of PVA fine particles is almost comparable to that of the talc powder. Considering the biodegradability and biocompatibility of PVA, the usage of PVA particle as a nucleating agent provides marked benefits over the currently employed nonbiodegradable nucleating agents, such as talc and boron nitride. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44:1813–1820, 2006     

Determination of talc in geological samples by infrared spectrometry

Talc is determined by infrared spectrometry in talc ore and mineral mixtures containing clinochlore chlorite, dolomite and magnesite as major minerals. When the Si-O-Si vibration at 668 cm^?1 is used, the calibration graph is linear up to about 0.5 mg of talc. Band overlap from chlorite is corrected by using the ratio of absorbances at 668 and 3620 cm^?1. Talc (?15%) in talc/carbonate/chlorite mixtures and ore was determined with relatively good precision and accuracy (recovery 91.2–97.4%). The sample sizes were 0.5–1 mg for 40–60% talc and 0.5–1.5 mg for 7.5–15% talc. The recoveries were worse (84.0–94.6%) for < 15% talc. The precision for unknown samples of talc ore varied from 1.5 to 4.0% (n=4).     

Transport properties and microstructure changes of talc characterized by emanation thermal analysis

Thermal behavior of talc samples (from locality Puebla de Lillo, Spain) were characterized by emanation thermal analysis (ETA), DTA and TG. The ETA, based on the measurement of radon release rate from samples, revealed a closing up of surface micro-cracks and annealing of microstructure irregularities of the talc samples on heating in the range 200–500°C. For ground talc sample a crystallization of non-crystalline phase formed by grinding, into orthorhombic enstatite was characterized as a decrease of radon mobility in the range 785–825°C and by a DTA exothermal effect with the maximum at 830°C. ETA results characterized the microstructure development of the talc samples on heating and served to evaluate their radon mobility and transport properties on heating and cooling. Transport properties of the talc samples were evaluated by using ETA experimental data measured during heating to 600 and 1300°C, respectively, and subsequent cooling to room temperature.