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1.
环氧化SIS的合成及表征   总被引:3,自引:1,他引:2  
在甲苯中,利用过甲本酸对SIS进行了环氧化反应,并通过红外光谱、核磁共振、凝胶渗透色谱、透射电镜等分析方法对环氧化SIS的结构进行了表征,同时也对环氧化SIS的力学性能进行了测试。结果表明,在SIS环氧化过程中伴随有副反应发生,分子链炭生了部分降解;异戊二烯链段上双键的反应活性大小依次为:顺-1,4-结构,反-1,4-结构,由于环氧基团的引入,环氧化SIS的极性增强,内聚强度增加。  相似文献   

2.
稻壳合成β-SiC晶须的中试研究及产品分析   总被引:2,自引:0,他引:2  
本文对稻壳合成SiC晶须(简称SiCw)的烧结中试进行了研究,验证了两种催化剂制度下的生产工艺,生产出两种形貌、结构特征不同的SiCw,并同美国、日本生产的SiCw在形貌结构、杂质含量等方面进行了比较。研究表明:中试生产的稻壳SiCw质量达到了国外同类产品的水平,并对SiCw的生长机理进行了探讨  相似文献   

3.
对用国内技术建设的万吨级聚合装置生产的5种牌号产品:线型SBS1301,SBS1401和星形SBS4303,SBS4402及充油33%的星形SBS44522进行了性能剖析。结果表明,国产SBS的物理性质、热氧稳定、玻璃化转变温度、微观结构和相态结构与国外同类产品相当,M_n可以达到预期要求,说明该开发技术是成功的。  相似文献   

4.
CSH凝胶结构的探讨   总被引:8,自引:1,他引:8  
甘新平 《硅酸盐学报》1996,24(6):629-634
针对CSH凝胶中的孔结构特点进行了研究。利用各种测试方法的不同特点来研究各种不同干燥条件CSH凝胶的孔形态。这些测试方法包括:SAXS法、压汞法、氮气吸附法、有机溶剂吸附法等。对SAXS方法进行了较详细的研究,结果表明:用ASAXS方法来研究CSH凝胶的孔结构确定是一种很有效的实验手段,并对引进基体相电子密度起伏的可能原因进行了探讨。  相似文献   

5.
PS热塑弹性体环氧化对胶粘剂性能的影响   总被引:3,自引:2,他引:1  
张军营 《粘接》2000,21(1):5-8
通过对苯乙烯类热塑性弹体SBS、SIS、ESBS、ESIS的溶度参数进行估算入手,从理论上讨论了环氧化对苯乙烯热塑性弹性体胶粘剂的本体强度,增粘剂的互溶行为的影响,通过胶粘剂性能的测试探讨了SBS环氧化后对胶接性能的影响。  相似文献   

6.
本文对稻壳合成SiC晶须(简称SiCw)的烧结中试进行了研究,验证了两种催化剂制度下的生产工艺,生产出两种形貌、结构特征不同的SiCw,并同美国、日本生产的SiCw在形貌结构、杂质含量等方面进行了比较。研究表明:中试生产的稻壳SiCw质量达到了国外同类产品的水平,并对SiCw的生产机理进行了探讨。  相似文献   

7.
增韧SMA的制备及与PC的共混改性   总被引:9,自引:2,他引:7  
周文  潘恩黎 《塑料工业》1998,26(4):122-123
研究了SBS增韧SMA树脂体系,采用二次共混工艺,用15%(质量)的SBS可以很好地增韧SMA树脂;用增韧的SMA树脂与PC进行共混,考察了体系的力学性能和微观相结构,制备出综合力学性能良好、加工性能优于纯PC的共混材料。当增韧SMA/PC为20/80时,共混材料的力学性能与纯PC相近,达到了预期改性PC的目的。  相似文献   

8.
SiO_2纳米粒子的制备、测定及其分散性的研究   总被引:6,自引:0,他引:6  
论述了制备SiO2纳米粒子的最佳条件,对其分散性、粒径、形状的影响因素进行了研究,并用IR、DLS和TEM等测试手段进行了测定  相似文献   

9.
本文研究了滑石粉填充HIPS/SBS体系中,钛酸酯偶联剂的最佳用量,不同份数的滑石粉对HIPS/SBS/滑石粉复合材料的力学性能影响,并对复合材料的形态结构进行了讨论.  相似文献   

10.
郝凤岭 《吉化科技》1996,4(4):32-34
通过紫外、红外、质子核磁共振等波谱手段对SIS进行了结构分析,并建立了测定SIS中结合苯乙烯含量的波谱分析方法。  相似文献   

11.
The hold-up of fine particles in the packed bed of dense particles in the multisolid pneumatic transport bed was experimentally examined. In the experiments, three types of fine particles were used including FCC particles (65 μm), glass beads (105 μm) and fine sand (155 μm), while three types of dense particles were used including aluminum particles (5.50 mm and 6.96 mm) and iron oxide particles (11.08 mm). The hold-up of fine particles in the packed bed of dense particles was found to be higher by a factor as large as 6 compared with that observed in systems without dense particles. An interaction coefficient between fine particles and dense particles was defined based on the momentum balance equation of fine particles in the packed bed. This interaction coefficient, which is empirically correlated, was utilized to account for the hold-up of fine particles in the packed bed.  相似文献   

12.
纳米/微米粒子复合技术在火炸药中的应用(Ⅰ)   总被引:7,自引:1,他引:6  
报道了利用纳米/微米粒子复合技术制备纳米/微米复合燃烧催化剂、氧化剂与可燃物复合粒子,催化剂与氧化剂复合粒子以及炸药复合粒子等过程中的子粒子与母粒子的粒子复合设计原理及实际应用中的理论与实际问题,为纳米及微米粒子在火炸药中的应用设计提供理论指导。  相似文献   

13.
Many aerosols in the environment are hygroscopic and grow in size once inhaled into the humid respiratory tract. The deposited amount and the distribution of the deposited particles among airways differ from insoluble particles of the same initial diameter. As particles grow in size, diffusive behavior tends to diminish while impaction and sedimentation effects increase. A multiple-path model for deposition of hygroscopic particles in the respiratory tract was developed for symmetric and asymmetric lung geometries by implementing particle size change in a model of insoluble particle deposition in lungs. Particle growth by molecular diffusion of water vapor to the particle surface was formulated. The growth model included temperature depression, solute, Kelvin, and Fuchs effects. Particle growth during travel time in each lung airway was computed. Average loss efficiency per airway was calculated by incorporating contributions from particles of various sizes acquired in that airway. A mass balance on the number of particles that entered, exited, deposited, or remained suspended was performed per airway to obtain regional and local deposition fractions of particles in the lung. The deposition fractions calculated for salt particles showed a drop for submicrometer particles in the tracheobronchial region and a significant increase in deposition for micrometer particles or larger. Consequently, very few fine and coarse salt particles reached the alveolar region to be available for deposition. Overall, lung deposition of ultrafine particles decreased for salt particles. Deposition for fine and coarse salt particles in the lung was larger than that of insoluble particles of the same initial particle size.  相似文献   

14.
Aspects of the self-assembly of particles, which uses nanometer or micrometer sized building blocks to bridge the gap between microscopic and macroscopic scales, are reviewed. Particle self-assembly has been the focus of considerable research in recent years because it can lead to superstructures with a complexity inaccessible by molecular self-assembly, and functionalities entirely different from or superior to those of the primary particles. Examples in molecular self-assembly suggests that anisotropic interactions could be useful in promoting particle self-assembly, with the exception of colloidal crystallization, which requires particles of uniform size and shape. Anisotropic particles prepared by surface modification of precursor particles are often rigid and submicron or micron sized, and thus relatively strong isotropic van der Waals interactions tend to resist self-assembly into regular superstructures. In addition, the relatively large contact area between particles needed for a sufficient binding enthalpy to stabilize a superstructure is difficult for rigid spherical particles. In contrast, flexible anisotropic polymeric particles dispersed in solvents have been shown to self-assemble into various superstructures. The flexibility of primary anisotropic particles enables them to fuse and stabilize into a superstructure. Some flexible and multi-component particles that are isotropic in common solvents can undergo deformation and sufficient material redistribution to anisotropically self-assemble into regular superstructures in selective solvents. The self-assembly is also driven by anisotropic interactions, which is induced during self-assembly rather than in the particles as synthesized. This review focuses on recent achievements in soft particle self-assembly and describes briefly the advancements in rigid particle self-assembly. The presentation is divided into discussion of self-assembly by the colloidal crystallization of isotropic rigid particles, anisotropic rigid particles, anisotropic soft particles and isotropic soft particles, in that order.  相似文献   

15.
Fluoroelastomer (FKM) rubber containing different weight percentage of in-situ generated nanosilica particles have been prepared by sol-gel method using tetraethoxysilane (TEOS) as precursor and n-butyl amine as catalyst. FKM rubber with precipitated silica particles have also been prepared to compare the effect of in-situ generated nanosilica particles and precipitated silica particles on the physico-mechanical properties of FKM rubber. It is interesting to note that the FKM rubber containing in-situ generated nanosilica particles display excellent tensile stress-strain properties, rheological properties and thermal properties in comparison to the FKM rubber containing precipitated silica particles. The better performance of the in-situ generated nanosilica particles has been attributed to the good dispersion of in-situ generated nanosilica particles in FKM rubber matrix when compared to the precipitated silica particles. The fourier transform infrared (FTIR) spectroscopy clearly confirms the existence of chemical interaction between the FKM rubber chains and the in-situ generated nanosilica particles which leads to the good dispersion of the nanosilica particles in the rubber matrix. Strain sweep studies confirm the presence of more rubber-filler interaction in FKM rubber filled with in-situ generated nanosilica particles. On the other hand, strain sweep studies confirm the presence of more filler-filler aggregation in FKM rubber filled with precipitated silica particles. The dispersion of the in-situ generated nanosilica particles and precipitated silica particles in the surface and bulk of FKM rubber has been studied by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). Selected samples have been cured to understand the effect of curing on the efficiency of in-situ generated nanosilica particles and precipitated silica particles on the physico-mechanical properties of FKM rubber.  相似文献   

16.
蔡杰  钟文琪  袁竹林 《化工学报》2015,66(11):4342-4349
细长颗粒气固两相流研究已成为气固两相流研究的重点问题之一。而各种细长颗粒在流场中的受力、运动模型构建以及细长颗粒/流场间的耦合关系的构建是细长颗粒两相流数值模拟研究的难点之一。在已经基于刚体动力学原理构建了细长粒子气固两相流单向耦合模型的基础上,结合基于κ-ε模型的球形粒子-流场气固间耦合关联式,并改进细长颗粒间碰撞模型,从而构建了细长颗粒气固两相流动多向耦合数值模拟平台。并且采用此平台对某一实际流化床内的细长粒子气固两相流场进行了数值模拟研究。研究表明,不同时间细长颗粒在流场内的停留位置具有较强的随机性;细长颗粒在流化运动过程中伴随有较明显的取向选择性;细长颗粒的存在会导致当地流场的速度、压强均有较为明显的下降。  相似文献   

17.
多种表征手段结合,研究了新疆油田矿场采出水中固体悬浮颗粒的结构及理化性质,实验结果表明:该矿场采出水中固体悬浮颗粒含量小于80 mg/L,粒径较大颗粒(10μm)占总颗粒的85%以上;加入絮凝剂聚氯化铝后,大量颗粒发生沉降,粒径较大颗粒(10μm)占总颗粒的95%以上,而粒径较小颗粒含量不足5 mg/L;不同粒径分布区间颗粒的Zeta电位不同,较小粒径颗粒(5μm)的Zeta电位较高,溶液状态较为稳定;加入絮凝剂后,Zeta电位降低,导致较小粒径颗粒易于发生沉降;结合电感耦合等离子体发射光谱、X射线荧光及元素分析,可知该固体悬浮颗粒中含有8种非金属元素和22种金属元素,元素C、O、Ca含量最高,加入絮凝剂后,元素Al和一些二价金属元素含量增高;X射线衍射表征技术表明颗粒主要以碳酸钙的方解石和文石以及卤化物形态存在。  相似文献   

18.
When particles are allowed to move over a horizontal surface, the effect of gas flow through them is to increase the distance over which they move, termed their mobility. This has already been shown for cases when gas is continuously passed through a current of particles, but this investigation shows that this is also true when the gas flow is only initially present. Experiments were conducted on a column of fluidised particles that were released into an enclosed channel by the removal of a wall, and the distance travelled by the particles was measured. The behaviour of fine particles (group A in the Geldart classification of fluidised particles) was distinct from that of larger particles.The mobility was modified when they were mixtures of different-sized particles. In particular, when there was no gas flow, the mobility was a maximum when the proportion of fine particles was 30% and the magnitude of this effect increased with the size of the coarser component of the mixture. All the different mixtures of particles acted in a similar manner with increasing mobility for a given gas flow rate with proportion of fine particles until roughly half the mixture was composed of fine particles, and there was then no further increase.  相似文献   

19.
Submicron polystyrene (PS) latex particles were used as seed in seeded dispersion polymerization of methyl methacrylate (MMA) to investigate the particle nucleation and aggregation behavior in this type of polymerization. The PS seed particles were located and tracked during the reaction using a refractive index matching technique. The number of PS seed particles present in the poly(methyl methacrylate) (PMMA) particles was investigated in detail throughout the reaction. The change in the distribution of PMMA particle populations containing different numbers of seed particles indicated that intensive nucleation and aggregation occurred during the early stage of the reaction until a transition point of 8.7% conversion was attained under the reaction conditions studied. The size of the large particles at this point was around 1 μm. These particles were regarded as mature particles that did not aggregate with other mature particles. Meanwhile, immature particle were still generated continuously from the continuous phase. These immature particles could not survive the aggregation process to grow to become mature particle, but instead, were captured by the mature particles. Therefore, the total number of the mature particles remained constant from this point until the end of the reaction. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

20.
To prepare relatively large negatively charged polymer particles in a size range from 0.3 μm to 0.5 μm, having high surface charge densities, the heteroaggregation of small (50–100 nm), highly charged (185 and 421 μeq/g) anionic polystyrene particles onto the surface of larger (317–466 nm) poly(vinylbenzyl choride)‐based cationic (10, 614, and 830 μeq/g) particles was carried out. As a result, particles with different surface charges, having a core‐shell structure, were successfully prepared. First, aggregated particles were formed via heteroaggregation of the lowest surface charge density anionic particles (185 μeq/g) with the lowest surface charge density cationic particles (10 μeq/g). However, the anionic particles in the shell layer desorbed with time owing to the relatively weak interaction between the two particles. Second, aggregated particles comprised of the highest surface charge density cationic (830 μeq/g) and anionic latex particles (421 μeq/g) were formed. However, to prepare a stable system, an excess of the small anionic particles was required, leaving a large number of small particles present in the aqueous phase, which proved difficult to remove. Finally, aggregated particles were formed by heteroaggregation of cationic particles with an intermediate surface charge density (614 μeq/g) with the highest surface charge anionic particles (421 μeq/g). As a result, not only were core‐shell particles formed, but few free small anionic particles remained in the aqueous phase. In this article, the preparation and characterization of each of these aggregates are discussed in terms of particle size, morphology, and extent of incorporation of the functional groups. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

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