INFLUENCE OF SHAMPOO ON THE MECHANICAL PROPERTIES OF HUMAN HAIRS1)

头发的弹性和抵抗意外拉断的能力是人们非常关注的指标。为了迎合这一需求,有些厂商推出了具有所谓“强韧”发质功效的洗发水,但其实并不清楚是否真能使头发变“强韧”。为此,针对市场上常见的一种标称具有“强韧”功效的洗发水,通过拉伸力学实验对头发洗护前后的力学性能进行了对比研究。结果表明,用洗发水处理后的头发,屈服应力下降,意味着头发更容易过早进入塑性变形;抗拉强度、最大应变减小,意味着头发抵抗外力拉断的能力下降;杨氏模量下降,说明头发抵抗弹性变形的能力变差。综上,所研究的洗发水对“强韧”发质没有帮助。 关键词: 头发,洗发水,力学性能,强度,韧性     

系数倍率和卡尔曼滤波紫外分光光度法同时测定发洗剂中的苯酚、间苯二酚和水杨酸

用系数倍率和卡尔曼滤波紫外分光光度法同时测定发洗剂中苯酚、间苯二酚、水杨酸的含量，苯酚、间苯二酚、水杨酸的线性回归方程分别为：A=0．00546 0．01762X，r=0.9999；A=0．00245 0.01606X，r=0．9999；A=-0.00748 0.02491X．r=0．9999。回收率分别为97．8％～102.3％、99．9％～102．3％、99．3％～103．2％。     

Substantivity and After‐Rinsing Hair Growth Promotion of Cationic Microparticles of Minoxidil

Cationic minoxidil (MXD) particles were prepared by passing a suspension containing MXD and distearyldimethylammonium chloride (DSDMAC) through a high pressure microfluidizer, operating at 500 bar to 1000 bar. The size of the particles is a few micrometers and the surface charge was+42 mV to+44 mV. The cationic MXD particles were included in a hair cleansing shampoo, of which a major detergent is sodium lauryl ether sulfate (SLES). On an UV spectrophotometer, the turbidity of the cationic MXD particles suspension increased with increasing amount of the anionic surfactant. At the same time, the surface charge of the cationic MXD particles was neutralized around equi‐molar ratio of SLES/DSDMAC, and the value became negative in the excess amount of SLES. These mean that DSDMAC adsorbed on MXD particles is complexed with SLES in the hair shampoo by an ionic interaction. Interestingly, even though the MXD particles contained in a shampoo exhibited negative surface charge, the skin‐retentive amount of MXD was appreciable and the after‐rinsing hair growth promotion effect was remarkable. One of possible mechanisms is that SLES would be desorbed from the complexed MXD particles during the rinsing step, and the charge of the particles might change from a positive value to a negative one, leading to an ionic interaction between the cationic particles and negatively charged skin.     

火焰原子吸收分光光度法测定洗发液、护发液中的铅

建立了一种准确测定洗发、护发用品中铅含量的火焰原子吸收分光光度检测方法,样品用硝酸-高氯酸-硫酸于高温下消解后,在优化的仪器操作条件下进行含量测定,在0~10.00μg/mL内,线性方程为A=0.017 9c 0.001 4,相关系数为0.999 5。4种样品3个不同添加水平试验铅的回收率为86.4%~100.7%,测量结果的相对标准偏差为1.3%~2.2%,铅的检出限为0.017μg/g。     

洗发液中有效物含量的测量不确定度评定

按照QB/T 1974-1994标准评定了检测洗发液中有效物含量的测量不确定度。从实验仪器、试剂、标准物质、操作及实验室环境等方面分析了不确定度的来源,对不确定度各分量进行分析、计算并进行合成。洗发液中有效物含量的测量不确定度主要来源于测量重复性和氯化物含量的测定。在试剂纯度、仪器设备的精度满足实验要求的情况下,有效物含量的相对扩展不确定度为0.12%。