Polyacrylonitrile/Nylon 6 Blends: Preparation and Characterization

Summary: Polyacrylonitrile (PAN) particles with micro‐size ranges (0.15–2 μm) were prepared by emulsion and dispersion polymerizationa and in supercritical carbon dioxide media. The PAN particles were blended with Nylon 6 (PA6) at 220 °C by using a miniature mixer; it was found that melt‐mixing was possible for PAN‐rich compositions as high as 70 wt.‐%. Blends were characterized by scanning electron microscopy, IR, viscosity measurements, differential scanning calorimetry, and dynamic mechanical thermal analysis (DMTA). The size and shape of original PAN particles were retained in PAN/PA6 blends. The useful range to blend PAN particles size was less than 1 μm in terms of shape retention of the PAN particles in blends. Blends with 40 wt.‐% PAN content were found to be melt‐processable. The elastic modulus was higher for PAN/PA6 blends than pure PA6.

SEM photograph of PAN‐SC/PA6 blend with a 40/60 weight ratio.     

Morphology,crystallinity, and electrochemical properties of in situ formed poly(ethylene oxide)/TiO2 nanocomposite polymer electrolytes

A method to produce nanocomposite polymer electrolytes consisting of poly(ethylene oxide) (PEO) as the polymer matrix, lithium tetrafluoroborate (LiBF₄) as the lithium salt, and TiO₂ as the inert ceramic filler is described. The ceramic filler, TiO₂, was synthesized in situ by a sol–gel process. The morphology and crystallinity of the nanocomposite polymer electrolytes were examined by scanning electron microscopy and differential scanning calorimetry, respectively. The electrochemical properties of interest to battery applications, such as ionic conductivity, Li⁺ transference number, and stability window were investigated. The room‐temperature ionic conductivity of these polymer electrolytes was an order of magnitude higher than that of the TiO₂ free sample. A high Li⁺ transference number of 0.51 was recorded, and the nanocomposite electrolyte was found to be electrochemically stable up to 4.5 V versus Li⁺/Li. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2815–2822, 2003     

Effect of nylon 6 on fracture behavior and morphology of tough blends of poly(2, 6‐dimethyl‐1,4‐phenylene oxide) and maleated styrene‐ethylene‐butadiene‐styrene block copolymer

Ternary blends of poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO), nylon 6, and styrene‐ethylene‐butadiene‐styrene block copolymer grafted with maleic anhydride (SEBS‐g‐MA) were prepared via a melt extrusion, and the fracture behavior, morphology, mechanical properties, and rheology were studied. The compatibilization of the blended components was confirmed by differential scanning calorimetry (DSC) analysis. Mechanical properties evaluation demonstrated that incorporation of nylon 6 resulted in an improvement of the tensile strength, but reduction of both the notched Izod impact strength and elongation at break. Transmission electron microscopy (TEM) observation revealed that the network structure of SEBS‐g‐MA domain was gradually destroyed by incorporating the nylon 6. A conversion of SEBS‐g‐MA domain from the network to the irregular dispersed phase took place when the nylon 6 content reached 20 wt %, which resulted in a reduction of the impact strength. Fracture morphology implied that increase of the tensile strength was caused by the plastic deformation of matrix. Rheology investigation indicated that the melt viscosities could be reduced significantly with increasing the content of nylon 6; thus, the processability was improved. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99:3336–3343, 2006     

基于反调和平均的张量形态学算子模型及其在彩色图像边缘检测中的应用

旨在建立基于张量模型的彩色图像形态学算子。通过将HSV彩色空间下的三维向量利用二阶对称正定张量进行建模表示, 提出一种基于反调和平均的彩色形态学算子。在此基础上, 借助于张量相似性度量构造基于参考张量的形态学算子, 该算子能够实现滤波的输入保持。通过基于形态学梯度的边缘检测实验验证模型的可行性和有效性。对比实验表明基于张量的彩色形态学模型相对于原有的向量模型在图像处理中具有更好的结果。     

Imide-aryl ether benzoxazole random copolymers

Novel imide-aryl ether benzoxazole copolymers were prepared and their morphology and mechanical properties investigated. A key feature of these copolymers is the incorporation of a benzoxazole moiety by the use of 2,2′-bis[4-(3-aminophenoxy)phenyl]-6,6′-bibenzoxazole or 2,2′-bis[4-(4-aminophenoxy)-phenyl]-6,6′-bibenzoxazole as co-diamines in polyimide syntheses. The preparation of these diamines involved the nucleophilic aromatic substitution of 2,2′-bis(4-fluorophenyl)-6,6′-bibenzoxazole with either 3- or 4-aminophenol in the presence of K₂CO₃. The diamines were co-reacted with various compositions of pyromellitic dianhydride (PMDA) and 4,4′-oxydianiline (ODA) to synthesize the desired poly(amic acids). Films were cast and cured (350°C) to effect the imide formation, affording films with elongations between 40 and 110% and moduli in the 2000–2750 MPa range. The copolymers exhibited good dimensional (T_g in excess of 300°C) and thermal stability. Wide-angle X-ray diffraction measurements on the copolymers showed that the ordered morphology characteristic of PMDA/ODA polyimide was retained. Improvements in the auto-adhesion were observed, particularly in those copolymers which displayed a T_g.     

挤出机各段温度对开孔型橡塑共混材料性能的影响

研究开孔型橡塑共混材料在不同挤出加工工艺中结构形态及力学性能的变化规律。结果表明，挤出机的机头温度应稍高于发泡剂的分解温度，均化段温度要设在发泡剂分解温度区的低温段，在挤出加工工艺中，要特别注意挤出机均化段温度及机头温度的设定，温度设定不好会使发泡剂无法发挥作用。     

一种三维植物叶片生成算法的研究及实现

不同树种的叶片形态结构也大不相同,根据植物形态学原理和实际观测结果得出刺柏叶的叶片形态特点,得出它们的自相似性。在此基础上采用分形图形学技术,给出刺柏叶的仿射变换矩阵,将叶片的计算机模拟由传统的二维点绘制方法,拓展成三维以面为单位的绘制方法,提高真实感。在OpenGL环境下结合虚拟现实技术可以从各个角度对生成叶片进行多方位浏览。     

基于VF的实验经费管理系统设计与开发

以我校实验经费管理为目标,在我校实验经费量化管理数学模型基础上,运用VF6.0软件,在注重软件操作的交互性、简单性及科学性的基础上,设计并实现了一套管理系统.     

变风量汽车空调的建模与仿真

介绍了变风量空调系统的原理和汽车空调负荷的特点,对变风量空调系统在汽车空调中的应用进行了研究.根据汽车空调负荷的特点,建立了变风量（VAV）空调系统汽车车厢的数学模型,利用仿真软件Matlab对车厢的温度控制系统进行了仿真,得到了系统的响应.