PVC塑化木粉及其吸水性

将木粉和PVC共混，同时加入相容剂POE—MAH，三者经挤出机挤出形成化学反应相容。生成PVC塑化木粉。研究了该塑化木粉的吸水性。研究表明：体系中PVC比例增加、木粉比例减小时。临界含水量变小，即吸水性变小。     

转矩流变仪在测定PVC树脂塑化性能方面的应用

介绍了运用附带数据处理机的流变仪PL2000-6分析通用PVC树脂的流变行为,通过“相关程序”研究了国内外同牌号PVC树脂的熔融曲线,发现国产PVC树脂和进口产品在塑化性能方面存在着一定的差距。     

PVC物料挤出塑化的浅议

本文围绕PVC物料挤出塑化质量中的内在质量，从挤出机结构与发展、PVC物料在挤出机中挤出塑化的历程与机理、配方与工艺等三方面对PVC物料挤出塑化进行了较详细的讨论，阐述了提高塑化质量的相应措施。     

PVC树脂粒度分布对加工性能的影响

采用筛分法对PVC树脂进行分级处理,研究了PVC树脂粒度分布对塑化性能、热老化白度和初期着色性的影响,发现提高树脂的颗粒集中度和规整度有利于提高PVC树脂的综合性能。     

PVC异型材塑化质量的探讨

从PVC树脂在塑化过程中的转化、工艺温控曲线与PVC异型材的塑化质量、配方设计与PVC异型材的塑化质量、挤出机性能与PVC异型材的塑化质量等四方面对PVC异型材塑化质量进行了讨论,阐述了保证PVC异型材塑化质量的措施和方法。     

低聚合度PVC树脂性能研究

简要介绍了国内外低聚合度聚氯乙烯(PVC)树脂的牌号、性能和用途.深入剖析了低聚合度PVC树脂的相对分子质量及其分布、颗粒形态、皮膜结构等特点,并研究了低聚合度PVC树脂的塑化性能.结果表明.树脂平均相对分子质量小,分布指数宽,树脂皮膜薄,亚无皮结构的树脂利于塑化.易于加工.     

聚氯乙烯树脂塑化曲线分析评价及熔融性能最佳测试条件的选择

本文用附带数据处理机的流变仪PLD—651型测定聚氯乙烯树脂塑化性能。所得塑化曲线进行分析;指出曲线中各个特征值的物理意义及实用价值。并对同一种型号不同样品特征值加以对比,评价其塑化性能。探讨和优选了熔融性能的最佳测试条件,仅供使用Braben-der塑化仪的同行们参考。     

助剂对PVC/MBS体系塑化性能和流变性能的影响

测试了助剂对PVC/MBS体系塑化性能及流变性能的影响。结果表明:①改性树脂AS的加入,能够明显改变PVC/MBS体系的塑化行为,缩短塑化时间,类似于PVC内润滑剂的流变效果,当AS用量提高到4份时,PVC/MBS体系表现出塑化过快、塑化扭矩过高的特征;②随着润滑剂用量的增加,PVC/MBS体系的塑化扭矩降低,塑化时间延长;试验温度升高,PVC/MBS体系的黏度减小,平衡扭矩降低。     

利用图象分析仪测定颜料粒径及其分布

将图象分析仪引入涂料及涂层中颜料粒子的粒径及其分布的测定过程中，叙述了测定步骤，指出了此法的优缺点。     

激光粒度仪测定PTA粒径分布

介绍了激光粒度仪测定PTA粒径分布的分析方法 ,通过试验确定了分析条件 ,并与筛分法分析结果进行了对比。该方法简捷、快速、重现性好 ,适用于PTA产品的粒度分析。     

Influence of emulsifiers on particle size and particle size distribution of PVC latex synthesized by miniemulsion polymerization

We synthesized poly(vinyl chloride) (PVC) latexes via miniemulsion polymerization using a mixture of cetyl alcohol (CA) and sodium lauryl sulfate (SLS). A vinyl chloride miniemulsion is easily prepared by conventional mechanical stirring. Experimental design methods were applied to investigate the effects of composition and polymerization conditions on average particle size (APS) and particle size distribution (PSD) of the latexes produced. The APS of the latexes produced ranged from 0.4–0.7 μm. When the APS of the latex produced was above 0.7 μm, the resulting latex was highly unstable. The emulsifier ratio (CA/SLS) was the most prominent factor influencing APS and PSD.     

Effect of wet screening on particle size distribution and coal properties

Wet screening is one of the methods used to remove fine material from the coal feed to gasification. Sasol Synfuels in South Africa undertook an investigation to quantify fine coal generation in the coal supply to gasification. Coal samples were wet screened in the laboratory and results compared to the normal dry screening procedure. It was found that the fines (−0.5 mm) increased almost five times when the coal was wet screened compared to dry screening. This study was subsequently initiated by Sasol Technology R&D to establish the mechanism of fine coal generation during wet screening, as well as the effect of wet screening on particle size distribution (PSD) and chemical properties of coal. Changes in the PSD and chemical properties of coal from individual coal sources used at Sasol Synfuels were compared. Composite coal samples with a predetermined PSD of all individual coal sources used at Sasol Synfuels were screened under wet and dry conditions. The PSD was again determined after screening, as well as the mineral composition (by X-ray diffraction) of the fines. Results indicated that wet screening caused clay minerals to be removed from the coal structure leading to an increase in the fines. This removal of minerals weakened the coal structure causing further size degradation of coarser fractions.     

水泥粒度分布对其性能的影响

0引言 水泥的粒度分布是其重要的物理指标之一,对水泥的性能有着极其重要的影响。特别是水泥胶砂强度检验方法改用ISO法后,多数水泥企业采取提高粉磨细度的方法,使水泥强度达到标准要求。     

粉煤灰粒度分布对水泥性能的影响

主要研究了不同粉磨时间的粉煤灰密度、比表面积、粒度分布等颗粒特性的变化规律,以及研究了将不同粉磨时间的粉煤灰按30％比例掺人硅酸盐水泥中的水泥性能变化情况.结果表明：随着粉磨时间的增加,粉煤灰颗粒的密度、比表面积和粒度分布都呈有规律的变化;其中粉磨60 min时的粉煤灰水泥性能达到最佳.     

激光粒度仪测量PVC树脂粒径的影响因素

通过激光粒度仪仪器参数设置和不同样品加入量的对比试验,确定了测量PVC树脂粒径分布的Mastersizer 3000型激光粒度仪最佳仪器参数:搅拌速度2 700 r/min、超声时间60 s、遮光度7.0％～9.0％.     

图像分析技术在PVC颗粒粒径大小及分布测定中的应用

利用图像分析技术对PVC透射光镜图像进行处理,引入算术平均粒径、质量平均粒径及粒径分布均匀度等参数.考察了最低检测像素数、灰度值阈值、透明颗粒的处理方法等实验条件对测定结果的影响,建立了PVC颗粒粒径大小及分布的表征方法.利用本方法对相同聚合度、不同生产厂家的4个PVC样品的粒径大小及分布进行了对比分析.     

Determination of particle size distribution of salt crystals in aqueous slurries

A method for determining particle size distribution of water-soluble crystals in aqueous slurries is described. The salt slurries, containing sodium salts of predominantly nitrate, but also nitrite, sulfate, phosphate, aluminates, carbonate, and hydroxide, occur in radioactive, concentrated chemical waste from the reprocessing of nuclear fuel elements. The method involves separating the crystals from the aqueous phase, drying them, and then dispersing the crystals in a non-aqueous medium based on nitroethane. Ultrasonic treatment is important in dispersing the sample into its fundamental crystals. The dispersed crystals are sieved into appropriate size ranges for counting with a HIAC brand particle counter. A preponderance of very fine particles in a slurry was found to increase the difficulty of effecting complete dispersion of the crystals because of the tendency to retain traces of aqueous mother liquor. Traces of moisture produce agglomerates of crystals, the extent of agglomeration being dependent on the amount of moisture present. The procedure is applicable to particles within the 2 – 600 μm size range of the HIAC particle counter. The procedure provides an effective means for measuring particle size distribution of crystals in aqueous salt slurries even when most crystals are less than 10 μm in size.