St-MMA-AA三元无皂共聚胶乳性质的研究Ⅰ.胶粒形态、大小及分布

以苯乙烯（Ｓｔ）、甲基丙烯酸甲酯（ＭＭＡ）为主单体,丙烯酸（ＡＡ）为功能单体进行了无皂乳液批量共聚合,用ＴＥＭ和ＱＥＬＳ观测了胶粒结构形态、大小及分布,探讨了功能单体ＡＡ浓度、引发剂ＡＰＳ含量、体系ｐＨ值、聚合温度及Ｓｔ／ＭＭＡ配比对胶粒形态、大小的影响。结果表明,Ｓｔ－ＭＭＡ－ＡＡ三元无皂共聚胶粒呈核－壳结构,随「ＡＡ」增大。粒径减小,分散系数增大;随「ＡＰＳ」守大,粒径出现最大值,分散系数增大;随ｐＨ值调节剂ＮａＨＣＯ３浓度增大及ＭＭＡ比例增大,粒径变化复杂,且分散系数也相应变化;随聚合温度提高,粒径增大,分散系数增大。     

中空乳胶粒子的制备——碱处理

通过间歇无皂种子乳液聚合,制得具有一定交联度的聚（苯乙烯（St)－丙烯酸丁酯（BA)-甲基丙烯酸（ＭＡ）复合乳液。将稀释后的乳液进行碱－酸阶段处理,得到了粒度的一的、中空结构的乳胶微粒。主要研究了在碱处理过程中ＰＨ值,温度、时间对粒子的空径（粒子中空的大小）粒径及表面冯羧基含量的影响。结果表明,碱处理条件为ＰＨ＝１２．５,t=3h,T=90℃时形成的胶粒粒子的空径最大。     

胶乳型互穿聚合物网络研究：Ⅲ.环氧树脂／聚丙烯酸酯Sem …

通过ＩＲ，ＤＳＣ，ＴＧ，ＴＥＭ溶胀比测定等方法，对丙烯酸丁酯－苯乙烯－甲基丙烯酸甲酯（ＢＡ－Ｓｔ－ＭＭＡ）交联共聚物的结构和ＥＰ／Ｐ（ＢＡ－Ｓｔ－ＭＭＡ）Ｓｅｍｉ－ＬＩＰＮ（ＥＰ为环氧树脂）的结构，热稳定性，溶胀性及乳胶膜的吸水性，乳胶粒开形态进行了研究。结果表明：ＢＡ－Ｓｔ－ＭＭＡ共聚物中主要是无规共聚物，也含有嵌段或接枝共聚链段，但并不太长；当该Ｓｅｍｉ－ＬＩＰＮ受热时，其中的ＥＰ因未交联而先     

胶乳型互穿聚合物网络研究 Ⅲ.环氧树脂/聚丙烯酸酯Semi-LIPN的结构与性能

通过ＩＲ、ＤＳＣ、ＴＧ、ＴＥＭ、溶胀比测定等方法，对丙烯酸丁酯－苯乙烯－甲基丙烯酸甲酯（ＢＡ－Ｓｔ－ＭＭＡ）交联共聚物的结构和ＥＰ／Ｐ（ＢＡ－Ｓｔ－ＭＭＡ）Ｓｅｍｉ－ＬＩＰＮ（ＥＰ为环氧树脂）的结构、热稳定性、溶胀性及乳胶膜的吸水性、乳胶粒形态进行了研究。结果表明，ＢＡ－Ｓｔ－ＭＭＡ共聚物中主要是无规共聚物，也含有嵌段或接枝共聚的链段，但并不太长；当该Ｓｅｍｉ－ＬＩＰＮ受热时，其中的ＥＰ因未交联而先行分解；ＥＰ的加入使乳胶膜的吸水性降低；在乳胶粒的测试过程中，由于分散程度不同还观察到了网络结构。     

PMMA—MAA／PS复合乳胶粒的形态

用种子乳液聚合合成了具有微空形态的ＰＭＭＡ－ＭＡＡ／ＰＳ复合乳液；认为种子聚合物的分子量是影响其迁移性及复合乳胶粒形态的重要因素；讨论了交联剂，乳化剂对第二阶段聚合地点及粒子形态的影响。     

交联剂对乳胶粒成孔的影响

通过连续法无皂种子乳液聚合技术和碱酸分步处理法,合成了一系列不同含酸量、骨架为ＰＳｔ的多孔结构乳胶粒,考察了交联剂种类及用量对聚合反应、乳胶粒交联程度及乳胶粒成孔的影响。表明二乙烯基苯（ＤＶＢ）是该聚合反应体系合适的交联剂,发现乳胶粒的交换程度及不饱和酸的种类与用量是影响其成孔的关键因素。     

Ｓt—MMA—AA三元无皂共聚胶乳性质的研究：Ⅱ．胶乳中—ＣＯＯＨ分布

以苯乙烯（Ｓt)、甲基丙烯酸甲酯（ＭＭＡ）为主单体、丙烯酸（ＡＡ）为功能单体进行了无皂乳液批量共聚合。用电导滴定法测定了羧基在胶乳中的分布,讨论了功能单体ＡＡ浓度、引发剂ＡＰＳ含量、体系ＰＨ值,聚合温度及Ｓt/MMA比例对胶乳中－ＣＯＯＨ分布的影响。结果表明,随ＡＡ浓度增大,表面羧基百分比减小、而包埋百分比增大、胶粒表面羧基密度增大。引发剂ＡＰＳ浓度、MAＭＡ比例及聚合温度的提高,不利于羧基分布在乳胶粒表面、胶粒表面羧基密度减小。体系ＰＨ值增大,有利于羧基位于胶粒表面、表面羧基密度有所增加。     

P(MMA-BA-MAA)／P(MMA-BA-VP)共聚物复合体系的氢键相互作用

通过乳液共聚合分别合成了两种具有互补结构的共聚物乳液：聚（甲基丙烯酸甲酯－丙烯酸丁酯－甲基丙烯酸聚Ｐ（ＭＭＡ－ＢＡ－ＭＭＡ）和聚（甲基丙烯酸甲酯－丙烯酸丁酯－乙烯基吡咯烷酮）Ｐ（ＭＭＡ－ＢＡ－ＶＰ）。通过^1H-NMR测定,研究了共聚物组成与单体投料组成的关系;通过ＦＲ－ＩＲ、ＤＳＣ、表 及力学性能测试,研究了Ｐ（ＭＭＡ－ＢＡ－ＭＭＡ）／Ｐ（ＭＭＡ－ＢＡ－ＶＰ）共聚物复合体系氢键相互作用及其对聚合物性能的影响,结果表明Ｐ（ＭＭＡ－ＢＡ－ＭＭＡ）／Ｐ（ＭＭＡ－ＢＡ－ＶＰ）共聚物复合体系存在氢键相互作用,氢键相互作用导致复合体系表面降低、拉伸强度提高。     

PBA／αMS－AN核壳乳液共聚反应的研究

以聚丙烯酸丁酯（ＰＢＡ）为核，用石油化工副产物α－甲基苯乙烯（αＭＳ）代替通常使用的苯乙烯（Ｓｔ）或甲基丙烯醚甲酯，利用其成本低，本身不易均聚，但易与丙烯腈（ＡＮ）共聚的原理用其共聚物作为壳层，采用分段乳液聚合法，得到了具有ＰＢＡ／αＭＳ－ＡＮ核壳结构的高分子复合乳液。通过大量实验确定了聚合反应配方及加科方式，通过红外分析法（ＩＲ）、透射电镜法（ＴＥＭ）、差热分析法（ＤＳＣ）等手段，对该共聚物结构进行了表征，确认了该共聚物为核壳型结构。     

PBA/PMMA型核壳结构增韧剂的合成及表征

采用传统乳液聚合、无皂乳液聚合及其扩径聚合的方法,得到了粒径从０．０７８ｕｍ至１．３８ｕｍ的窄分布的ＢＡ（丙烯酸丁酯）为主单体的ＰＢＡ橡胶核,然后,进行ＰＭＭＡ的壳层种子接枝乳液聚合,得到ＰＢＡ／ＰＭＭＡ核壳结构胶乳,乳液经破乳过滤干燥后得到核壳结构增韧剂,发现随着橡胶相交联剂用量的增加,ＰＢＡ胶粒表现双键含量增加;核壳复合粒子表观羧基的含量可以用电位滴定法获得。实验表明,进行壳层混合单体（ＭＭＡ、ＭＡＡ）接枝时羧基主要分布在胶粒的浅层;核壳比对复合粒子的形态有较大影响。利用ＬＳ激光粒径仪测得胶粒的大小及其分布;同时,ＴＥＭ照片显示了核壳粒子的形态和尺寸。     

超微粒子设计技术及应用

本文综述了目前进行微粒子设计的几种主要方法 ,并对设计出的各种具有不同功能的超微粒子的应用作了介绍     

Effect of crystallization parameters and presence of aqueous extract of Nigella Sativa on growth inhibition of calcium oxalate monohydrate particles

For the first time, nucleation kinetics, crystal growth and agglomeration of calcium oxalate monohydrate (COM) are studied as a crystal growth inhibitor with and without Nigella Sativa(NS) extract. The induction period was determined under different supersaturation ratios ranging from 1.63 to 4.51 at 37°C using the conductivity method. Based on the classical homogeneous nucleation theory; the critical nucleation parameters were evaluated at higher supersaturation ratio. The calculated surface energy was increased from 7.97?mJ/m² without additive to 10.31?mJ/m² with NS extract. However, the nucleation rate at a supersaturation ratio of 3.26 corresponding to 5.44 with the NS extract was decreased from 3.9?×?10²⁹ nuclei/cm³.s (without additive) to 1.3?×?10²⁹ nuclei/cm³.s with NS extract addition. The number of molecules required for the formation of a stable nucleus was calculated with and without NS extract at different supersaturation ratios. The crystallite sizes of the formed crystals without and with the additive are 93 and 51?nm, respectively. Scanning electron microscopy (SEM) photomicrographs show the formation of small crystals and less aggregated with the NS inhibitor compared with the baseline (without the inhibitor). This study can help us with a clear understanding of the inhibition mechanism of an aqueous NS extract on COM crystals.     

颗粒统计平均粒径及其分布的表征

讨论了颗粒形状和大小的表示、粒径测定、平均粒径和粒径分布的表征等问题,用实例比较了３种粒径分布较典型的乳液样品的各种平均粒径差异;根据粒子数计算公式的含义分析和统计平均粒径的物理意义,认为用于计算粒子数的平均粒径应为体均粒径,提出有关的一些建议。     

Equipment for the Spectral Characterization of High-Temperature Particles

The spectral radiant characteristics of plume particles of a solid rocket engine are important in the design of the engine specific impulse, ablative material, and plume flame hiding. These parameters are measured from tests of the engine. Some equipment has been established to realize particle heating, uniform particle distribution, and measurements based on an FTIR spectral instrument. The equipment is based on SiC heating and is divided into a warm-up chamber and a measurement chamber to improve the particle temperature stability. A special design of uniform particle distribution combined with an acoustic levitation device is used to determine the particle falling speed. The spectral characteristics and the transmission rate of the particles have been measured by using the system including a standard blackbody, an assembled optical system, and an FTIR spectrometer. The measurements of particle concentration and temperature are given in detail. The instrument specifications are as follows: temperature range – 60–1500 °C; spectral range – 0.60–25 μm; and particle dimension range – 10–500 μm. Paper presented at the Seventh International Workshop on Subsecond Thermophysics, October 6–8, 2004, Orléans, France.     

激光粒度分析和筛分法测粒径分布的比较

分别采用筛分法和马尔文激光粒度分析仪两种方法对16种颗粒的粒径分布进行了测量。通过比较,发现两种测量手段得到的粒径分布结果存在较大的差异,马尔文激光粒度方法对颗粒粒径的测量结果偏小,受颗粒形状的影响很大;筛分法对微细颗粒的测量误差较大,但对大粒径颗粒的测量较为准确。通过对不同粒径段灰颗粒的显微照相,发现细颗粒的团聚是筛分法测量小颗粒结果偏小的主要原因。     

Water-Soluble Anisotropic Iron Oxide Nanoparticles: Dextran-Coated Crystalline Nanoplates and Nanoflowers

We report a simple phase transfer based synthesis route for two novel anisotropic water soluble iron oxide nanoparticle shapes, namely, nanoplates and nanoflowers. The nanoplates and nanoflowers are initially prepared in an organic solvent via a modified “heat-up” method. Then, the crystalline nanoparticles are rendered hydrophilic via sonication in the presence of dextran and water. These nanoparticles are highly monodisperse and superparamagnetic at room temperature. High resolution transmission electron microscopy indicates that the iron oxides cores are not affected by the phase transfer. Dextran coating is confirmed by dynamic light scattering, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The obtained dextran coverage was 26 wt% for the nanoplates and 37 wt% for the nanoflowers. The nanoplates and nanoflowers were not only water soluble, but also remained stable at different pH (4–7) and in common aqueous buffer solutions. Thorough characterizations of the nonspherical iron oxide nanoparticles indicate that these particles could be useful for potential biomedical applications and magnetic resonance imaging.     

Effect of Vortex Finder Diameter on Flow Field and Collection Efficiency of Cyclone Separators

In this study, aerocyclone separators, with five different vortex finder diameters are simulated using commercially available computational fluid dynamics code Fluent 6.3.26 to analyze flow field pattern and the collection efficiency. It is found that a decrease in vortex finder diameter results in an increase in pressure drop by 47.84% and an increase in the collection efficiency by 9.54%, whereas, the increase in vortex finder diameter leads to a reduction in pressure drop by 23.87% and a decrease in the collection efficiency by 7.70% as compared to the Stairmand high efficiency cyclone. It is also observed that a decrease in vortex finder diameter leads to about 33% increase in axial velocity and about 25% increase in tangential velocity, whereas, an increase in vortex finder diameter results in about 23% decrease in axial velocity and about 12% decrease in tangential velocity as compared to the Stairmand high efficiency cyclone.     

亲水性及疏水性颗粒在水中的分散行为研究

研究了亲水性和疏水性两大类型颗粒在水中的分散规律及颗粒分散行为与表面润湿性、表面电位的关系。对粒间作用势能的计算揭示了颗粒分散的机理     

Particle Characteristics and Analysis Using the Laser-Based Phase Doppler Particle Analyzer (PDPA) and Statistical Method

Particle characterization is an important component in product research and development, manufacturing, and quality control of particulate materials. In this article a laser-based phase Doppler particle analyzer (PDPA) was used to measure particle size and velocity. Two different particles, humid particles and fog particles, were tested using the PDPA. Several tests were conducted under different conditions and all data were analyzed using the statistical method and analysis of variance (ANOVA) to see which factor affects particle performance. The humid particle flow rate has a significant effect on both the particle mean diameter and the particle mean velocity with 90% confidence. The type of oil particle has a significant effect on the particle mean velocity with 90% confidence.     

Particle Characteristics and Analysis Using a Laser-Based Phase Doppler Particle Analyzer (PDPA) and Statistical Method

Particle characterization is an important component in product research and development, manufacturing, and quality control of particulate materials. In this study a laser-based phase Doppler particle analyzer (PDPA) was used to measure particle size and velocity. Two different particles including humid particles and fog particles were tested using the PDPA. Several tests were conducted under different conditions and all data were analyzed using the statistical method and analysis of variance (ANOVA) to see which factor affects particle performance. The humid particle flow rate has a significant effect on both the particle mean diameter and the particle mean velocity with 90% confidence. The type of oil particles has a significant effect on the particle mean velocity with 90% confidence.