500～700μm直径双层空心微球制备技术研究

采用聚苯乙烯微球臭氧化改性技术和搅拌桨叶轮结构优化技术,提高聚苯乙烯（PS）与聚乙烯醇（PVA）之间的作用强度,优化体系容器内的流场运动环境,制备了500～700 μm直径的PS-PVA双层空心微球,并考察了液滴初始密度与溶剂密度匹配关系对最终PVA涂层均匀性的影响。结果表明,固化温度为37 ℃、溶剂-液滴初始密度差在0.010 g/cm³附近及固化温度为20 ℃、溶剂-液滴初始密度差在0.015～0.020 g/cm³附近能获得较好的PVA壁厚均匀性。     

预处理温度对聚碳硅烷粒子炉内成球性的影响

本文以聚碳硅烷(PCS)为原料,采用炉内成球技术制备直径200~400μm、壁厚3~5μm的SiC空心微球,探讨微球制备的最佳条件,并在此基础上研究不同预处理温度对PCS成球产率及品质的影响。结果表明,炉内载气温度为500℃、He与Ar比例为3∶1时PCS的成球产率较高,且微球的球形度、同心度、表面光洁度均最好。此外,由于预处理过程去除了PCS中的低分子量聚碳硅烷和其他小分子,同时使其聚合度升高,提高了PCS的热稳定性和陶瓷化产率。因此,在最佳炉内成球条件下,PCS的成球率随预处理温度的升高而升高,所得微球的表面粗糙度却随之降低。经350℃预处理后的PCS粒子成球率最高,且微球的球形度和表面质量最佳。     

聚合物空心微球密度匹配法制备工艺研究

以聚苯乙烯（PS）为成球材料,研究了聚合物空心微球密度匹配法制备工艺中的油相（O相）有机溶剂各及配比、O相固化温度及时间、各相溶液中固体颗粒杂质、球内封装水（W1相）的置换等因素对产品微球质量的影响。制得了直径100－500μm、壁厚2－20μm、球形度≥99％、同心度相对偏差≤5％、表面粗糙度≤20nm的PS空心微球。     

内表面掺硫聚苯乙烯空心微球初步研制

以聚苯乙烯磺酸钠（PSS）为掺杂源,采用乳液微封装法制备内表面掺S的聚苯乙烯（PS）空心微球。XPS测量表明,微球内表面存在明显的S元素。利用低能X射线照相技术研究了不同掺杂源浓度下干燥时重力和表面张力对掺杂均匀性的影响,当掺杂源浓度降为0.2%时,得到了内表面掺杂S均匀的PS微球,微球直径为200～800μm,直径300μm的微球中掺杂层S原子面密度为8.57×10⁶μm^－2。     

干凝胶法制备空心玻璃微球的炉内成球过程分析

基于干凝胶粒子炉内成球过程的分解实验结果及各阶段中间产物的分析测试结果,通过对干凝胶法制备空心玻璃微球工艺的传热、传质和运动的过程分析,将干凝胶法制备空心玻璃微球炉内成球过程合理简化为吸热、封装、气泡形成及聚并、精炼、冷却5个阶段。吸热阶段的升温速率以及发泡剂的分解温度和发泡效率、精炼阶段的精炼时间和温度、冷却阶段的冷却速率是影响干凝胶法制备空心玻璃微球工艺和空心玻璃微球最终质量的关键因素。     

乳液微封装技术制备聚苯乙烯空心微球

介绍了乳液微封装技术制备不同直径空心聚苯乙烯微球的工艺技术,着重研究了表面活性剂、电解质、水溶性聚合物对多重乳液的稳定性、微球的直径以及微球表面光洁度的影响。在选定的实验参数下,制备得到直径150～3000μm,壁厚0.8～15μm,表面粗糙度Ra约为4nm,微球同心度≥95%的空心聚苯乙烯微球。     

壁厚1μm以下薄壁空心玻璃微球制备工艺研究

叙述了采用液滴法制备壁厚1μm以下薄壁空心玻璃微球生产工艺。系统地研究了玻璃溶液配方、玻璃溶液浓度、发泡剂的加入量、液滴炉各温区温度、抽气速度等因素的变化对生产空心玻璃球壳壁厚及直径的影响,确定了生产1μm以下超薄壁空心玻璃球壳的工艺条件。采用该工艺,首次成功地生产出直径φ150～250μm,壁厚小于1μm的空心玻璃球壳,微球表面光洁度及同心度都能较好地满足物理实验要求。     

炉内成球法制备SiC空心陶瓷微球

采用干凝胶法,以聚碳硅烷（PCS）为原料,通过炉内成球技术制备了SiC空心陶瓷微球。并利用TG、IR、SEM、XRD等方法对陶瓷微球进行了成键结构、表面形貌等分析,讨论了有机聚合物的陶瓷化过程机理。结果表明,干凝胶成球技术能利用经纯化处理的聚碳硅烷在500~600 ℃下得到SiC空心陶瓷微球,采用乙醇作为发泡剂可使PCS凝胶粒子得到良好发泡效果,提高载气中氦气含量至50%~80%可提高干凝胶粒子在吸热阶段的升温速率,微球经辐照后在850 ℃下碳化生成以β-SiC为主要相结构的球壳,球壳具有较好的表面平整度。     

低温冷冻靶用聚合物泡沫球壳研制

利用三羟甲基丙烷三丙烯酸酯（TMPTA）的溶液聚合反应，结合多次乳化技术，制备出了惯性约束聚变低温冷冻靶用泡沫空心微球，密度约为50mg/cm^3，微球直径150－300μm，最大球径可达400μm以上，球形度好于955，泡沫蜂窝直径2－5μm。     

空心玻璃微球热扩散法充Ar

采用热扩散法研究高温高压充Ar技术。研究结果表明，当温度低于500℃时，玻璃微球球内基本检测不到Ar；在600℃高温条件下可实现微量Ar气的渗透；在外压1.0MPa、24h条件下，球内Ar最高含量为0.003MPa；延长充气时间和增加外压均不能使微球内Ar量增加；随着充气温度升高，微球表面粗糙度由原来的不到20nm增加到50～100nm，微球损失也增大；在600℃、1.0MPa条件下，玻璃微球开始出现形变或破裂，微球损失超过50％。     

用于ICF的非晶SiC微球制备及微观结构研究

以四甲基硅烷、反式二丁烯和氢气为工作气源,采用化学气相沉积-高温热解法成功制备了壁厚约21μm的非晶SiC微球。利用能量色散X射线光谱仪、X射线光电子能谱仪、X射线衍射仪、Raman光谱仪、扫描电子显微镜、白光干涉仪和X射线照相机对SiC微球的化学成分、结晶状态、表面形貌与粗糙度以及密度与球形度等进行了测量和分析。结果表明:在无氧环境下,通过450~900℃的高温热解及致密化可将在聚α甲基苯乙烯芯轴上沉积的掺硅碳氢聚合物涂层转变成致密的SiC微球。SiC微球呈非晶态,其C/Si原子比约为1.3,主要含有C—Si键和C=C键,微观结构呈无规则状且颗粒分布均匀,密度、球形度和壁厚均匀性分别为2.62 g/cm~3、99.8%和96.8%。     

间歇跳动法制备微球α-C:H涂层

采用低压等离子体化学气相沉积方法,以反式二丁烯和氢气作为工作气体,利用间歇跳动模式,在直径为(280±50) μm的聚乙烯醇 聚苯乙烯（PVA PS）双层球表面制备出了30 μm 厚α C:H涂层。利用原子力显微镜（AFM）、干涉显微镜和X光照相技术分别对涂层表面形貌、球形度和同心度进行表征,结果表明：当涂层厚度为30 μm时,表面均方根粗糙度低于30 nm;球形度与同心度均优于99%。利用热重分析和傅里叶变换红外光谱仪对其热稳定性和价键结构进行表征,结果表明,α C:H涂层主要存在sp3  C—H键,在280 ℃以下,结构成分非常稳定,达到450 ℃后,则完全石墨化。     

微粒定位技术研究

在直径25mm的石墨垫上镀膜或粘贴制作微定位标记，进行SEM-SEM、SIMS-SIMS、SEM-SIMS之间的微粒定位。SEM-SEM之间的微粒定位偏差约为10μm，而SEM-SIMS和SIMS-SIMS之间的微粒定位精度偏差约为15μm。实验表明：粘贴制作微定位标记和矩阵定位算法的组合是一种简便、适应性强、成本低和有效的微粒定位和再定位方法。     

醋酸乙烯酯辐射乳液聚合Ⅲ 聚合产物及其水解产物的结构与性能

本文测定了辐射引发乳液聚合所得聚醋酸乙烯酯(PVAC)及其水解产物聚乙烯醇(PVA)的立规结构,序列结构,结晶度,溶解度,断裂强度,伸长率,钢—钢粘结强度,热转变温度等,并与化学法聚合产物的相应结构与性能作了比较,发现辐射法产物具有头—头结构含量较低,结晶度大,粘接强度较高等特点,并讨论了结构与性能之间的关系。     

CrN films deposited by ion source-assisted magnetron sputtering

CrN coatings were deposited on Si(100) and piston rings by ion source assisted 40 kHz magnetron sputtering.Structure and composition of the coatings were characterized by X-ray diffraction,atomic force microscopy,scanning electron microscopy and transmission electron microscopy.Mechanical and tribological properties were assessed by microhardness and pin-on-disc testing.The ion source-assisted system has a deposition rate of 3.88 μm/h,against 2.2 μm/h without ion-source assistance.The CrN coatings prepared with ion source assistance exhibited an increase in microhardness(up to 16.3 GPa) and decrease in friction coefficient(down to 0.48) at the optimized cathode source-to-substrate distance.Under optimized conditions,CrN coatings were deposited on piston rings,with a thickness of 25 μm and hardness of 17.85 GPa.     

氘代聚苯乙烯丝的力学特性

在Z-pinch出中子实验的研究中,氘代聚苯乙烯（DPS）丝和氘代聚乙烯丝是理想的固体燃料容器。实验采用微型熔融纺丝法制备出直径为30～100μm的聚合物丝样品。通过对聚苯乙烯（PS）丝以及DPS丝的力学性能研究观测到,当伸长率为1％时,PS丝的应力松弛率较小;在不同的外力作用下,PS丝表现出良好的尺寸稳定性。随着DPS丝直径的减小,其强度和伸长率均增加,当直径减小到100μm以下时,丝强度急剧上升。在较小的外力作用下,DPS丝表现出良好的尺寸稳定性。DPS丝的蠕变及应力松弛行为与PS丝具有相同的变化趋势。     

Preparation of Spherical Bi2O3 Powder by Plasma and Precipitation Processes

Spherical Bi2O3 powder prepared by plasma chemical vapor reaction and aqueous chemical precipitation is studied. The superfine spherical Bi2O3 powder with an average diameter of 1 μm is made by plasma process. During the precipitation process, the micrograph of the Bi2O3 powder can be controlled through the reaction temperature, the rate of addition of the precipitation reagent, the reaction time and the amount of the dispersant. Accordingly, spherical Bi2O3 powder with diameters ranging from 2μm to 3μm is prepared. The spherical Bi2O3 particles have such advantages as uniform size distribution and excellent dispersing property. ZnO varistors made from the resultant powder exhibit properties of a low discharge voltage ratio, great eligibility coefficient measured by a rectangle wave of 2 ins 800 A and good stability in the above characteristics.     

Enhancement of the electrical performance of poly(vinyl) alcohol by doping with chlorophyll and gamma irradiation

The electrical properties of poly(vinyl) alcohol (PVA) have been improved pronouncedly by doping with chlorophyll (Chl) and gamma irradiation. PVA/Chl films have been prepared and irradiated with γ-rays at dose levels of 10, 20, 30, 50, 70, 100, 150, 200 and 250 kGy. The crystalline and chemical structures of the samples have been studied using XRD and FTIR techniques. Also, the direct current electrical conductivity and the dielectric constant and loss have been determined for the proposed samples before and after gamma exposure. It is clearly shown that the electrical conductivity of PVA films was increased two orders of magnitude due to chlorophyll doping and about fifteen times due to gamma irradiation. Considering the dielectric constant and loss, their values were shown to increase significantly due to PVA doping with chlorophyll. The obtained results can be attributed to the existence of the conducting Mg atom, as well as, the conjugated double bonds in the chlorophyll. Moreover, the gamma irradiation of PVA/Chl, over 50 kGy, improves also this electrical performance. Therefore, the study suggests the possibility of the utilization of the gamma irradiated PVA/Chl films in different electronic applications.     

Microanalysis of a ductile iron by microchip laser-induced breakdown spectroscopy

Laser beams with ns pulse width are generally employed as an excitation source in the process of detecting inclusions and elemental segregation on a workpiece surface by microanalysis of the laser-induced breakdown spectroscopy.In addition,the ablation crater interval of laser sampling on the sample surface is generally 20 μm or more.It is difficult to detect the morphology of inclusions smaller than 50 μm in diameter and the micro-segregation of elements.However,in this work,when the laser ablation crater is 10 μm and the sampling resolution of the laser on the sample surface is 5 μm,the morphology and distribution of spherical inclusions (20-60 μm) in ductile iron can be detected according to the difference of the Fe spectrum on the Fe matrix and the spheroidal inclusions.Moreover,the distribution of micro-segregation of Mg and Ti elements in ductile iron was also studied.