Preparation of micron‐size monodispersed PS/P(St/MAA) microspheres by seeded dispersion polymerization

Uniform polystyrene (PSt) particles with the size of 1.9 μm were first prepared via dispersion polymerization, and then used as the seeds in a second‐stage dispersion copolymerization of styrene (St) and methacrylic acid (MAA) to produce carboxyl‐carrying microspheres. The PSt seed particles were swollen by monomer mixture of St and MAA, including an oil‐soluble initiator 2,2′‐azobisiso‐butyronitrile (AIBN), before polymerization. Finally, uniform PS/P(St/MAA) (polydispersity index, PDI = 1.02) microspheres with the size of 2.2 μm were obtained. The average particle size and size distribution of the final microspheres were investigated. MAA contents between 54 and 97 mg/g were detected from the PS/P(St/MAA) particles produced under different conditions. Dispersion medium has great influence on the kinetics of polymerization, due to its effect on the partitioning of monomers, solvents, and initiator in the particle phase, probably as well as on the conformation of the dispersion agent on the surface of the particles. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3586–3591, 2006     

新型真空耙式干燥机的开发

通过对常规真空耙式干燥机存在问题的剖析，经多年实验研究，研制开发出了高效、节能的新型真空耙式干燥机，并得到了工业生产验证。     

弹性聚四氟乙烯／聚氨酯复合薄膜性能的研究

在聚四氟乙烯树脂（PTFE）中加入热塑性弹性体聚氨酯（TPU），制备出了有弹性的微孔复合薄膜，有效地改进了唧双向拉伸薄膜受力后的回复性。在复合薄膜中，加入经偶联剂处理的纳米二氧化硅，有利于TPU在PTFE中的均匀分散，从而提高复合薄膜的弹性。随着TPU含量的增加薄膜回复性也提高，双向拉伸倍率的增大可以导致薄膜回复性能有所下降，SEM分析证明了在PTFE中加入TPU可以增大复合薄膜的微孔尺寸。     

国内外聚碳酸酯市场及需求分析

聚碳酸酯(PC)综合性能好,其消费与生产增长举世瞩目,在世界五大通用工程塑料中占有重要地位。国内PC生产及消费量虽不大,但潜在市场不可忽视,发展与开拓工程塑料,特别是PC的应用与生产的开发,是我国化学和石化工业发展需要之一。     

Crystallization behavior of carbon nanotubes‐filled polyamide 1010

The nanocomposites of polyamide1010 (PA1010) filled with carbon nanotubes (CNTs) were prepared by melt mixing techniques. The isothermal melt‐crystallization kinetics and nonisothermal crystallization behavior of CNTs/PA1010 nanocomposites were investigated by differential scanning calorimetry. The peak temperature, melting point, half‐time of crystallization, enthalpy of crystallization, etc. were measured. Two stages of crystallization are observed, including primary crystallization and secondary crystallization. The isothermal crystallization was also described according to Avrami's approach. It has been shown that the addition of CNTs causes a remarkable increase in the overall crystallization rate of PA1010 and affects the mechanism of nucleation and growth of PA1010 crystals. The analysis of kinetic data according to nucleation theories shows that the increment in crystallization rate of CNTs/PA1010 composites results from the decrease in lateral surface free energy. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3794–3800, 2006     

Study on the floatation mechanism and floatation performance for the floatation cyclone of natural inlet air

A novel structure floatation cyclone of natural inlet air has been designed, and its structural characteristics and floatation principle have been analyzed. The velocity and pressure distributions within the flow field of the floatation cyclone have been studied by Navier-Stokes equations. Based on the flow characteristics of the mixture of fine coal and water, reasonable boundary conditions are decided and the equations are modified, so that the final equations can describe the real flow state of the flow field of the floatation cyclone. The boundary surface position between float coal and tailings is determined and there is an air cylinder in the central region of the floatation cyclone. The research reveals the floatation mechanism of the floatation cyclone. The floatation results can be greatly improved by regulating the structural dimensions of cyclone. The experimental results show that the floatation cyclone is very effective for the floatation of fine coal grains.     

湿法磷酸固-液体系混沌混合与浸出强化行为

湿法磷酸浸出过程中，传统刚性搅拌桨的作用方式主要是剪切作用，容易形成对称性流场结构，降低搅拌效率。实验考察了桨叶类型、离底高度、搅拌速度、柔性钢丝绳长度、柔性钢丝直径对磷矿浸出率及最大Lyapunov指数(LLE)的影响。实验结果表明：刚柔组合桨通过刚-柔-流的耦合作用，改善流场的结构，提高了流体混沌混合效果。当搅拌转速225 r/min，浸出时间120 min，离底高度h=T/4，柔性钢丝绳直径d= 0.42r，柔性钢丝绳长度L=1.3T时，刚柔组合桨的最大Lyapunov指数达到0.09071，磷矿浸出率提高了10.8%。另外，在相同的功耗(P _v=9890 W/m³)条件下，刚柔组合桨使反应器内的悬浮均匀度和渣中磷含量分别降低了40.8%和17.67%，有效地改善了晶体的形貌，提高了磷石膏的过滤性能，强化了颗粒的混合与浸出。     

定向凝固纯铜组织性能研究

采用高真空多功能定向凝固及悬浮熔炼设备,以不同凝固速度制备纯铜试样,并对定向凝固纯铜试样的显微组织和机械性能进行了分析研究.通过实验获得了定向凝固纯铜的组织性能.当凝固速度小于500μm/min时,定向凝固的纯铜试样横、纵截面的晶粒形貌都是等轴晶,晶粒内存在孪晶,凝固速度较小时,其孪晶组织数量较多.当凝固速度大于500μm/min时,定向凝固的纯铜试样横截面的晶粒形貌是等轴晶,而纵截面的晶粒形貌是柱状晶,晶粒内基本不存在孪晶组织.定向凝固纯铜的室温机械性能是:当凝固速度在50μm/min的条件下,试样的抗拉强度约153 MPa,较普通铸造纯铜试样的低,而屈服强度约91.8 MPa,延伸率约80.12%,都优于普通铸造纯铜试样.透射电镜分析表明,纯铜定向凝固过程中形成的孪晶B=[110].     

天线座扭转振动固有频率分析

文中以某转台式天线座为研究对象,首先,采用拉格朗日法创建了考虑系统中电机、减速器和安装平台势能及各主要零部件动能的扭转振动动力学模型,并得到了可用于固有频率计算的解析表达式;其次,基于ADAMS建立了面向实体的动力学模型并进行仿真分析,求得的固有频率与理论分析结果吻合。该方法可为天线座的动态性能分析提供参考。     

中国水资源空间均衡评价与空间关联性分析

为科学认知中国水资源空间均衡现状和空间分布特征,在对水资源空间均衡内涵进行解析的基础上,构建了水资源空间均衡评价指标体系,以中国333个地级行政区和4个直辖市为研究对象,对全国各地区水资源空间均衡状态进行了评价和空间关联性分析。结果表明:各省级行政区空间均衡状态存在空间差异大的特点,全国31个省级行政区(不包括港澳台)有17个处于空间不均衡状态,主要分布于东三省、华北平原、河西走廊、华南部分地区和新疆南部;各研究单元空间均衡状态存在一定的聚集性,主要表现为高值聚集和低值聚集两种形态,也散布有小范围的低高聚集、高低聚集形态。