共混改性用粉末SBR的制备

用丁苯胶乳制备了粉末ＳＢＲ。探讨了防粘剂品种及用量、分散剂用量、凝聚温度以及凝聚剂滴加速率对粉末橡胶粒径的影响。结果表明，糊状聚氯乙烯树脂的防粘效果优于滑石粉，粉末橡胶粒径随防粘剂和分散剂用量的增加而减小。提高凝聚温度、粉末橡胶粒径增大。     

选择性激光烧结用尼龙1212粉末的制备

为得到适用于选择性激光烧结的原材料，降低选择性激光烧结用尼龙1212生产成本，用溶剂沉淀法制备了尼龙1212粉末，讨论了溶剂种类、溶解温度、成核温度等因素对尼龙1212粉末粒度和形貌的影响。通过显微镜、扫描电子显微镜、粒度分析、差示扫描量热法等对制备的尼龙1212进行了表征，结果表明采用溶剂沉淀法可有效地制备出分散良好且粒径在20～80μm范围内的尼龙1212球形粉末，其最佳制备工艺条件为：乙醇作溶剂、溶解温度为160℃，将成核温度控制在130℃。对自制尼龙1212和市售选择性激光烧结用尼龙1212进行了松装密度、熔体流动速率、拉伸及弯曲等性能表征，发现两者的粉末性能和制件性能接近，其中自制尼龙1212的弯曲强度和弯曲弹性模量略高于市售尼龙1212，已达到了选择性激光烧结对原材料的要求，能烧结出光滑制件，其尺寸精度可达到±0.1 mm。     

非硫黄调节型粉末CR的制备与性能

采用凝聚包覆法制备非硫黄调节型粉末CR，研究包覆剂的玻璃化温度(L)和用量对粉末CR性能的影响，并对粉末CR的粒子形貌进行了分析。结果表明，采用L为55．3或84．2℃的包覆剂制备的粉末CR的平均粒径较小，且粒径分布较窄；随包覆剂用量的增大，粉末CR的平均粒径减小，硫化胶的物理性能提高SEM分析表明，粉末CR的宏观粒子由多颗细小的初级粒子聚集而成，宏观粒子中存在大小不一的空洞，这些空洞有利于粉末CR的快速干燥。     

硝苯地平聚乳酸缓释微球的制备

采用溶剂蒸发法,以聚乳酸为载体、二氯甲烷为溶剂、聚乙烯醇为分散剂制备了具有缓释功能的硝苯地平微球。研究结果表明微球粒径随搅拌速度的提高而减小;当聚乳酸用量一定时,溶剂体积增大,微球的粒径减小。扫描电子显微镜观察微球的外观为一光滑的圆球,平均粒径为18.9μm。释放研究表明载药微球具有控释功能,释放时间长达50h。     

可控粒径纳米硫化镉的制备

采用溶剂热法,通过改变实验条件,得到影响粒径的主要因素和影响规律;在此基础上,制备了平均粒径范围是2.5～105 nm的六方球形纳米硫化镉。结果表明,硫源和镉源、S/Cd物质的量比和溶剂用量是影响粒径的主要因素。不同硫源、镉源适用于制备不同粒径范围的纳米硫化镉,采用TAA、乙酸镉并改变S/Cd配比和溶剂体积可制备出平均粒径在2.5～21.6 nm的纳米硫化镉;采用硫脲和硝酸镉并改变S/Cd配比可制备出平均粒径在38.5～105 nm的纳米硫化镉;纳米硫化镉的粒径随S/Cd物质的量比的增大而增大;随溶剂用量的增加而增大;反应温度对纳米硫化镉的粒径没有影响。纳米硫化镉的可控粒径的制备方法对纳米硫化镉的制备、研究与应用具有着重要的参考价值。     

可控粒径纳米硫化镉的制备

采用溶剂热法,通过改变实验条件,得到影响粒径的主要因素和影响规律;在此基础上,制备了平均粒径范围是2.5～105 nm的六方球形纳米硫化镉。结果表明,硫源和镉源、S/Cd物质的量比和溶剂用量是影响粒径的主要因素。不同硫源、镉源适用于制备不同粒径范围的纳米硫化镉,采用TAA、乙酸镉并改变S/Cd配比和溶剂体积可制备出平均粒径在2.5～21.6 nm的纳米硫化镉;采用硫脲和硝酸镉并改变S/Cd配比可制备出平均粒径在38.5～105 nm的纳米硫化镉;纳米硫化镉的粒径随S/Cd物质的量比的增大而增大;随溶剂用量的增加而增大;反应温度对纳米硫化镉的粒径没有影响。纳米硫化镉的可控粒径的制备方法对纳米硫化镉的制备、研究与应用具有着重要的参考价值。     

溶剂法制备尼龙11粉末工艺研究

用溶剂法制备了尼龙11粉末,并讨论了溶剂配比、工艺温度、恒温时间等因素对其粒径的影响。试验表明最佳工艺为尼龙树脂∶溶剂=1∶6、140℃恒温反应2h,产品200目(75μm)通过率可达到90%以上,基本保持了尼龙11树脂原有的物理性能。     

单分散微米级PMMA微球的制备

以聚乙烯吡咯烷酮(PVP)为分散剂,乙醇和水为反应介质,偶氮二异丁腈为引发剂,甲基丙烯酸甲酯(MMA)为单体,采用分散聚合工艺,制备了单分散微米级PMMA微球。研究了乙醇/水介质的配比、反应温度、分散剂用量、单体用量、引发剂用量对PMMA微球粒径和粒径分布的影响。结果表明,PMMA微球粒径随乙醇用量的增加先增大后减小;随反应温度的升高先增大后减小,粒径分布先变窄再变宽;随单体用量的增加先增大后减小,随引发剂用量的增加而增大;随PVP用量的增加而减小,粒径分布先变窄再变宽。     

抗氧剂对选择性激光烧结尼龙12热稳定性的研究

采用溶剂沉淀法制备了用作选择性激光烧结的尼龙12粉末,利用热失重(TG)对粉末材料的热性能进行了表征。将添加不同抗氧剂的尼龙12粉末进行热空气老化试验,利用色差计测定了尼龙12粉末的黄色指数随老化时间的变化情况;并研究了抗氧剂种类及用量对不同粉末成型试样力学性能的影响。结果表明,主抗氧剂受阻酚1098和辅抗氧剂亚磷酸酯2921T共同作用对尼龙12热稳定性有很大的改善作用。当主、辅抗氧剂比例为2:1、抗氧剂总用量为0.5%时,抗氧化作用最好。     

群青颜料的球磨及改性研究

采用实验室自制球磨机,以乙醇为溶剂对群青颜料进行球磨,制备了不同粒径的群青颜料色浆,用于随后的改性研究.分析了球磨时间、球料比、色浆浓度、分散剂用量、磨球大小和级配对群青颜料粒径及其分布的影响.用硅烷偶联剂3-氨丙基三乙氧基硅炕(APTEs)对不同粒径群青颜料进行表面改性,探讨了改性颜料粒径大小与体系稳定性、印花性能的关系.实验结果表明,颜料粒径越小,体系分散稳定性越好;改性后颜料耐酸性随粒径减小而降低;印花织物的干摩擦牢度随粒径减小而升高,但湿摩擦牢度随粒径减小有降低的趋势.     

静电纺丝工艺参数对PMMA／富勒烯纤维形貌的影响

采用甲苯与二甲基甲酰胺（DMF）混合溶液做溶剂,以静电纺丝法制备了含有富勒烯（C60）的聚甲基丙烯酸甲酯（PMMA）纤维,利用扫描电镜观察了纤维的形貌,分析了PMMA的质量分数、溶剂比、纺丝电压、收集距离等对纤维形貌及平均直径的影响。结果表明：PMMA溶液的浓度以及溶剂比对纤维的形貌起着主导作用,当二者变化时,纤维结构变化较大。纤维的平均直径随着PMMA浓废、纺丝电压的增大而增大;当甲苯/DMF体积比增大时,纤维平均直径先增大后减小;纤维形貌受收集距离的影响较小。     

Electrospinning of polycarbonate urethane biomaterials

Polycarbonate urethane (PCU) nano-fibers were fabricated via electrospinning using N,N- dimethylformamide (DMF) and tetrahydrofuran (THF) as the mixed solvent. The effect of volume ratios of DMF and THF in the mixed solvent on the fiber structures was investigated. The results show that nano-fibers with a narrow diameter distribution and a few defects were obtained when mixed solvent with the appropriate volume ratio of DMF and THF as 1∶1. When the proportion of DMF was more than 75% in the mixed solvent, it was easy to form many beaded fibers. The applied voltage in the electrospinning process has a significant influence on the morphology of fibers. When the electric voltage was set between 22 and 32 kV, the average diameters of the fibers were found between 420 and 570 nm. Scanning electron microscopy (SEM) images showed that fiber diameter and structural morphology of the electrospun PCU membranes are a function of the polymer solution concentration. When the concentration of PCU solution was 6.0 wt-%, a beaded-fiber microstructure was obtained. With increasing the concentration of PCU solutions above 6.0 wt-%, beaded fiber decreased and finally disappeared. However, when the PCU concentration was over 14.0 wt-%, the average diameter of fibers became large, closed to 2 μm, because of the high solution viscosity. The average diameter of nanofibers increased linearly with increasing the volume flow rate of the PCU solution (10.0 wt-%) when the applied voltage was 24 kV. The results show that the morphology of PCU fibers could be controlled by electrospinning parameters, such as solution concentration, electric voltage and flow rate.     

相反转法制备超细Bi-Pb-Sn-Cd易熔合金粉

用相反转法将含分散剂的水滴加到熔融的Bi-Pb-Sn-Cd易熔合金液中,制备了一系列超细合金粉,使超细粉的制备与表面修饰同步进行,系统研究了制备过程中温度、搅拌速度和分散剂浓度对超细合金粉粒径的影响。实验结果表明,随着水在合金液中含量的增加,体系发生相转变,合金从连续相逐渐破裂成分散相而形成超细金属粉,同时改性剂以物理吸附的方式对超细金属粉进行表面改性;制备温度、搅拌速度和分散剂浓度对合金粉粒径有明显影响,以浓度为1%的油酸钠为分散剂,温度为85℃,搅拌速度为1750r.min-1,可制得平均粒径为0.3μm的超细Bi-Pb-Sn-Cd合金粉。为获得满意粒径和表面改性效果的超细合金粉,必须将制备温度、搅拌速度和分散剂浓度控制在适当的范围。     

Radiation preparation of ultrafine carboxylated styrene–butadiene rubber powders and application for nylon 6 as an impact modifier

Ultrafine carboxylated styrene–butadiene rubber(CSBR) powders were prepared by using gamma irradiation and following spray‐drying method. The influences of dose rate, absorbed dose, and sensitizer content on the crosslinking density of CSBR latices were studied in detail. Then the ultrafine CSBR powders were used to toughen nylon 6. The toughness and thermal properties of nylon 6/CSBR blends were measured by using notched lzod impact test and differential scanning calorimetry and thermogravimetry, respectively. Results showed that the crosslinking density of CSBR increased with increasing of dose and sensitizer content, and it is independent on dose rate. The notched Izod impact strength of nylon 6 under room temperature increased after incorporation of irradiation crosslinked CSBR powders with appropriate crosslinking density. The morphology of higher impact nylon 6/CSBR blends indicated that the finer dispersion existed with dispersed particles of 150‐nm diameter. Fracture morphology of nylon 6/CSBR blend suggested that the shear yielding in matrix is the primary toughening mechanism for nylon 6/CSBR blends. The crystallinity of nylon 6/CSBR blends decreased slightly compared with pure nylon 6, whereas the addition of CSBR powders had little influence on the thermal stability of nylon 6. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3040–3046, 2002     

Al2O歧化法制备微细Al2O3/Al复合粉体

真空条件下,以Al2O3和Al为原料,通过Al2O歧化法制备微细Al2O3/Al复合粉体.XRD和SEM分析表明:在反应温度为1200～1400℃时,随着温度的升高,粉体中氧化铝含量升高;冷凝温度约为550～750℃时,复合粉体中的氧化铝包括稳定晶型和不稳定晶型;冷凝温度约为1100～1300℃时,复合粉体中的氧化铝全部为稳定晶型;冷凝温度约为550～650℃时,复合粉体的平均粒径小于0.5μm;冷凝温度约为750℃时,铝熔化、微粒团聚;冷凝温度约为1100～1200℃时,铝形成铝珠,氧化铝为不规则状、平均粒径小于2μm;冷凝温度约为1300℃时,氧化铝为片状.因此,通过选取合适的反应温度、冷凝温度,可以控制Al2O3/Al复合粉体中氧化铝的含量、晶型和粒径.     

静电纺丝热塑性聚氨酯纳米纤维的制备

将N,N-二甲基甲酰胺（DMF）和四氢呋喃（THF）按体积比0：4、1：3、2：2、3：1、4：0混合作为溶剂,确定配比后,在不同浓度、电压下对热塑性聚氨酯（TPU）溶液进行静电纺丝。结果表明,DMF与THF的体积比对聚氨酯静电纺丝纤维的形貌、直径及其均匀性有明显影响,当混合溶液体积比为2：2,浓度为0．18g／mL,电压为26kV时,TPU纺丝液纺丝效果最佳,得到最理想的纤维;纤维直径随DMF含量的增多而减小,但当DMF含量过多时,纤维上容易出现液滴,纤维形貌变差;TPU纺丝液浓度增大,纤维直径增大;电压增大,纤维直径减小。     

Spheroidization of SiC powders and their improvement on the properties of SiC porous ceramics

Spherical SiC powders were prepared at high temperature using commercial SiC powders (4.52 µm) with irregular morphology. The influence of spherical SiC powders on the properties of SiC porous ceramics was investigated. In comparison with the as-received powders, the spheroidized SiC powders exhibited a relatively narrow particle size distribution and better flowability. The spheroidization mechanism of irregular SiC powder is surface diffusion. SiC porous ceramics prepared from spheroidized SiC powders showed more uniform pore size distribution and higher bending strength than that from as-received SiC powders. The improvement in the performance of SiC porous ceramics from spheroidized powder was attributed to tighter stacking of spherical SiC particles. After sintering at 1800 °C, the open porosity, average pore diameter, and bending strength of SiC porous ceramics prepared from spheroidized SiC powder were 39%, 2803.4 nm, and 66.89 MPa, respectively. Hence, SiC porous ceramics prepared from spheroidized SiC powder could be used as membrane for micro-filtration or as support of membrane for ultra/nano-filtration.     

Preparation of nylon 66/mesoporous molecular sieve composite under high pressure

Nylon 66/mesoporous molecular sieve (pore diameter: 2.7 nm) composites were prepared by annealing mixtures of nylon 66 and mesoporous molecular sieve (FSM) powders under high pressures and high temperature (FSM content: 0–60 wt %; pressure: 0.5–30 MPa; temperature: 300°C; time: 1 h). X‐ray diffraction and TEM measurements indicated the presence of the pores of FSM in the composite. Above 2 MPa, nylon 66 was charged in the pores of FSM. The fraction of the charged nylon 66 increased with pressure and was independent of the FSM content (pressure: 2–30 MPa; fraction of charged nylon 66: 54–66%). The infrared spectrum of the composite showed the bands based on Si O, C H, N H, CO. DSC measurement indicated that the heat of fusion of nylon 66 crystallite in the FSM pores was low compared with that of nylon 66. The composites prepared above 2 MPa were found to be superior in storage modulus to nylon 66. The modulus increased with an increase in the fraction of charged nylon 66 and the amount of FSM. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3254–3258, 1999     

化学镀法制备纳米镍及其对高氯酸铵热分解的催化作用

采用化学镀镍工艺制备纳米镍粉,用TEM和XRD等分析仪器对纳米镍粉的结构和特性进行表征。所得纳米镍粉不含氧化物质,呈球形,为面心立方晶体,平均粒径约60 nm。采用热分析实验（TG-DTA）研究纳米镍对高氯酸铵热分解的催化作用。结果表明,在高氯酸铵中加入质量分数5%的纳米镍粉,高氯酸铵的低温热分解峰和高温热分解峰分别提前了约17 ℃和72 ℃,纳米镍粉对高氯酸铵热分解催化作用明显。     

BaFe9(Ti0.5Mn0.5)3O19铁氧体粉末的合成及磁性能研究

采用溶胶-凝胶自蔓延法合成了BaFe9(Ti0.5Mn0.5)3O19铁氧体粉末,利用XRD、TEM和VSM对样品进行表征及磁性能研究。结果表明,合成样品为均匀单一的纳米级铁氧体粉末,平均粒径80nm,焙烧温度对磁能影响显著,焙烧温度过高不利于提高样品磁性能。