聚苯胺/MCM-41介孔分子筛导电复合材料的制备及其表征

利用MCM-41介孔分子筛单分散孔道特性作为"纳米反应器",在其孔道内合成聚苯胺.讨论了HCl浓度、(NH4)2SO8浓度和聚合温度对复合材料导电性的影响,得到最佳的聚合条件:HCl:1.5mol/L,(NH4)2SO8:1.0mol/L,聚合温度:15℃,此时的电导率为0.61s/cm.在最佳合成条件下,对聚苯胺/MCM-41介孔分子筛导电复合材料进行SEM、红外光谱分析.     

PF/MCM-41纳米复合材料的制备及其耐热性

采用原位聚合结合共混工艺制备了PF／MCM-41纳米复合材料，研究了耐热性．结果表明，当MCM-41粉的含量为20％时，PF／MCM-41纳米复合材料中MCM-41粉的分散性及有机-无机两相间的界面结合良好；与纯PF比较，复合材料的质量损失达到50％（质量分数）时的温度提高约70℃，分解结束时的温度提高约100℃．介孔MCM-41中的纳米级孔道能有效地限制其内树脂分子链的自由运动，是PF／MCM-41复合材料耐热性提高的机理．同时，其纳米级厚度的孔壁具有极好的耐热性和绝热性，在快速升温的条件下能延缓孔内树脂分子的热分解及分解产生的小分子产物的释放．     

超临界CO2方法制备环氧树脂/纳米介孔MCM-41复合材料

采用超临界方法先将环氧树脂低聚物引入介孔MCM-41的一维孔道内,再与基体溶液共混,制备出环氧树脂／MCM-41纳米复合材料．研究了复合材料的拉伸性能与填充复合颗粒含量的关系．结果表明,超临界的方法确实可将环氧树脂低聚物分子链引入到MCM-41的孔道,并占据孔道的绝大多数空间．环氧基团进入介孔的孔道中并使孔口处的环氧基团与基体环氧产生了较强的界面相互作用,增加了两者的相容性．填充含量较低的复合颗粒就能提高复合材料的拉伸性能．     

Polybutylacrylate/poly(methyl methacrylate) Core-Shell Elastic Particles as Epoxy Resin Toughener: Part I Design and Preparation

Polybutylacrylate (PBA)/poly(methyl methacrylate) (PMMA) core-shell elastic particles (CSEP), whose rubbery core diameter ranged from 0.08 μm to 1.38μm, were synthesized by using conventional emulsion polymerization, multi-step emulsion polymerization, and soapless polymerization. Allyl methacylate (ALMA) and ethylene glycol dimethacrylate (EGDMA) were selected as crosslinking reagents for core polymerization. Methacrylic acid (MAA) was used as functional co-monomer with methyl methacrylate as shell component. The content of vinyl groups in PBA rubbery core increased with the amount of crosslinking reagents. The core-shell ratio affected great on the morphology of the complex particles. Furthermore, the amounts of carboxyl on the surface of core-shell particles, copolymerized with acrylic acid, were determined by potentiometric titration. Results showed that methylacrylic acid was distributed mostly on the surface of particles.     

8-羟基喹啉锌/碳微球复合材料的合成表征及发光性能

利用流变相反应法制备了碳微球(CMSs)负载8-羟基喹啉锌(Znq2)的复合材料.通过场发射扫描电子显微镜、X射线衍射仪、热重分析仪、X射线光电子能谱仪、傅里叶红外光谱仪和荧光分光光度计等对Znq2/CMSs复合材料结构和发光性能进行了表征和分析.结果表明:Znq2以非共价键形式负载于直径均匀的CMSs(300～400...     

Thermal stability of in situ synthesized (TiB + La2O3)/Ti composite

Thermal stability of in situ synthesized (TiB + La₂O₃)/Ti composite is investigated. The phase analysis is identified by X-ray diffraction. Microstructure of the melted and forged titanium matrix composites (TMCs) after heat treatment is characterized by means of optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The room temperature tensile properties after an additional thermal exposure at 873 K, 923 K or 973 K for 100 h are tested. After the thermal exposure, the strength of specimen increases and ductility decreases. This is attributed to precipitation of ordered α₂ phase (Ti₃Al) and S₁ (silicide) in the titanium matrix composites after the thermal exposure.     

Raspberry-like and other hexagonal close-packed morphologies of P(St-MMA-AA) particles obtained from different emulsifiers for photonic applications.

A facile one-pot synthesis of Poly(Styrene-methyl-methacrylate-acrylic acid) P(St-MMA-AA) terpolymers by soap seeded emulsion polymerization was examined. Raspberry-like and hexagonal close-packed morphologies were conveniently obtained using Cetyltrimethylammonium bromide (CTAB), Sodium dodecyl sulphate (SDS) and Gum arabic (GA) emulsifiers. The resultant colloidal latex samples were used to fabricate coloured tunable photonic crystals via vertical deposition process. The results showed that the emulsifiers used effectively reduced the polydispersity index (PDI) and zeta potential of the terpolymer samples (Ter-PSDS, Ter-PGA and Ter-PCTAB 0.021, 0.097 and 0.076; –36.20, –35.60 and –32.80, respectively). Thus, the interfacial tension between particles that promote the formation of the stable nanosized photonic crystals is also reduced. The low PDI values are clear indication of monodispersity of the terpolymer samples. Varying the choice of emulsifiers also resulted in changes in the particles sizes as well as the resultant morphologies. The particles diameters of 117.15, 209.20 and 315.00 nm were obtained for Ter-PSDS, Ter-PGA and Ter-PCTAB, respectively. The results showed that Ter-PSDS was the most stable of all terpolymers examined. The fabricated photonic crystals were observed to reflect different wavelengths (Iridescent colours) as the observation angles changed. This could be due to the bandgap resulting from the different morphologies associated with the different emulsifiers. The variation in the colour reflectance with change in the observation angle confirms the photonic potential of the synthesized P(St-MMA-AA) crystals.     

中空玻璃微珠含量对回收聚对苯二甲酸乙二醇酯/聚碳酸酯基复合泡沫材料性能的影响

采用回收聚酯饮料瓶片(R-PET)为主要原材料,以乙烯-丙烯酸甲酯-甲基丙烯酸缩水甘油酯(E-MA-GMA)为增容剂,将硅烷偶联剂KH560处理后的中空玻璃微珠(HGM)与R-PET/PC/E-MA-GMA(70/30/10)在双螺杆挤出机中熔融共混制备复合泡沫材料。通过红外光谱、扫描电镜、差示扫描量热、表观密度、极限氧指数、导热系数和力学性能测试,考察了0~50 phr HGM对复合泡沫材料性能的影响。研究结果表明,HGM改性成功并与基体紧密结合,HGM的加入使RPET的结晶性下降,拉伸强度和冲击强度降低,但是所得的复合泡沫材料的表观密度减小,最小达到0.729 g/cm3,基体的隔热性提高,导热系数减小到0.089 W/(m·K),燃烧过程熔融滴落现象得到改善。     

Synthesis and phase evolution of Si-C-Ti powder derived from poly(methylsilaacetylene) and Ti

Si-C-Ti powder was synthesized by reactive pyrolysis of poly(methylsilaacetylene)(PSCC) precursor mixed with metal Ti powder. Pyrolysis of PSCC/Ti mixture with certain atomic ratio was carried out in argon atmosphere between 1300 °C and 1500 °C. The metal-precursor reactions, and phase evolution were studied using X-ray diffraction and scanning electron microscopy equipped with EDX. Ti₃SiC₂ phase was obtained from reaction of PSCC and Ti for the first time. Ti₃SiC₂ formation started at 1300 °C and its amount increased significantly at 1400 °C. In addition, liquid formed by additive CaF₂ could promote the formation of Ti₃SiC₂ phase.     

六亚甲基二异氰酸酯(HDI)交联壳聚糖与三甲基-烯氯化铵接枝共聚物/聚丙烯腈复合纳滤膜的研究

以壳聚糖与三甲基-烯氯化铵共聚物的水溶液为铸膜液,涂敷在聚丙烯腈超滤膜上,以六亚甲基二异氰酸酯为交联剂,制备了壳聚糖与三甲基一烯基氯化铵共聚物复合阳离子型纳滤膜.着重讨论了交联剂浓度、交联时间、干燥时间等因素的影响,采用单因素实验法确定了最佳的制膜条件:以0.75%(质量分数)的壳聚糖与三甲基-烯氯化铵共聚物水溶液为铸膜液,在50℃下干燥2h.在乙醇、HDI的质量比为50:0.32交联体系中,50℃水浴浸泡交联21h,50℃下热处30min.通过电镜扫描对膜结构进行观察.膜的截留分子量大约为900Da.并且,对该复合膜的性能进行了测试,分别探索了操作压力、料液浓度、料液类型等因素与膜性能的关系.在20℃,流速为30L/h,操作压力为1.2MPa时,对2000mg/L MgCl2、NaCl、MgSO4、CaCl2、Na2SO4、KCl、K2SO4的截留率分别为95.6%、66.4%、80.8%、95.4%、30.7%、53.7%、23.8%;通量分别为6.73、7.35、6.43、6.73、6.12、6.12、6.43L/(h·m-2).对不同类型无机盐的截留顺序为MgCl2≈CaCl2＞ MgSO4＞NaCl＞KCl＞Na2SO4＞K2SO4,呈现阳离子型复合纳滤膜的截留特征.流动电位曲线进一步说明了该复合膜的荷正电性,其电压渗系数β为6.8mV/MPa.