氧化石墨烯/苯甲酸钠复合成核剂协同改性PA6纳米复合材料的性能

先用水热法合成氧化石墨烯(GO)/苯甲酸钠(Sb)复合成核剂(GO-Sb),然后用熔融共混法制备尼龙6(PA6)/GO-Sb纳米复合材料,研究了分别添加GO和Sb、同时添加GO-Sb对PA6纳米复合材料的形态、力学和热性能的影响。结果表明：GO与Sb之间存在静电相互作用和π-π共轭,Sb的加入能促进PA6中γ晶的形成。GOSb作为异相成核剂均匀分散在PA6中,使PA6纳米复合材料的结晶温度、结晶度和热变形温度提高。PA6-GOSb(100/0.05/0.25)纳米复合材料的拉伸强度和冲击强度分别比纯PA6提高了69.9%和157.1%。PA6-GO-Sb(100/0.05/0.25)纳米复合材料的拉伸强度、冲击强度和弹性模量分别比PA6-GO-Sb(100/0.3/0)纳米复合材料提高了13.6%、186.4%和52.6%。与纯PA6(k=0.238 W/m·k)相比,PA6-GO-Sb(100/0.3/0)纳米复合材料(k=0.536 W/m·k)的热导率提高了125.2%,PA6-GO-Sb(100/0.05/0.25)纳米复合材料(k=0.854 W/m·k)的热导率提高了258...     

g-C_(3)N_(4)/CeO_(2)/BiOBr三相复合材料的制备及其可见光催化降解RhB性能EI北大核心

以多孔层状g-C_(3)N_(4)为基体,引入沉淀法所得的CeO_(2)/BiOBr复合材料,经超声搅拌制得具有异质结结构的g-C_(3)N_(4)/CeO_(2)/BiOBr三相复合材料。采用X射线衍射、扫描电子显微镜、透射电子显微镜、X射线光电子能谱、紫外-可见光漫反射光谱、光致发光光谱等方法对g-C_(3)N_(4)/CeO_(2)/BiOBr进行了成分、结构和光学性质表征。结果表明:g-C_(3)N_(4)/CeO_(2)/BiOBr三相复合材料呈三明治层状堆叠结构,界面结构构建良好,光响应性能优异,各相分布均匀且结晶程度较高。当Ce∶Bi摩尔比为1∶1,g-C_(3)N_(4)质量分数为15%时所得三相复合材料表现出最高的光催化活性,RhB降解率高达99%,降解速率是纯相CeO_(2)的86倍、纯相BiOBr的3倍。此外,经过4次循环后,复合材料的RhB降解效率依然保持在89%,表现出良好的稳定性。     

超高分子量聚乙烯/石墨烯纳米复合材料的制备及其热性能的研究

为了提高超高分子量聚乙烯的热性能,本文通过溶液共混的方法利用氧化石墨烯改性不同分子量的超高分子量聚乙烯,然后利用红外测试(FTIR)、X射线衍射测试(XRD)、扫描电镜测试(SEM)、差热扫描量热分析仪(DSC)和热失重分析(TG)的方法对超高分子量聚乙烯/石墨烯纳米复合材料的结构、表面形态和性能进行了研究.通过分析测试表明氧化石墨烯在超高分子量聚乙烯/石墨烯纳米复合材料中的分散性良好,氧化石墨烯的添加量为0.3%时,石墨烯/超高分子量聚乙烯的复合材料的热稳定性等性能最好,与原材料相比提高了3℃.     

BMI树脂/氧化石墨纳米复合材料的制备及表征

本文以烯丙基缩合多核芳香烃(GOPNA)树脂与双马来酰亚胺(BMI)共聚制备BMI树脂,通过溶液插层的方法制备BMI树脂/氧化石墨纳米复合材料.采用X射线衍射(XRD)、透射电镜(TEM)、热重分析(TGA)研究了复合材料的结构和性能,采用电子万能试验机研宛了复合材料的力学性能.研究表明,该复合材料为刺离型纳米复合材料...     

XG-g-P(AA-co-AMPS)/膨润土复合材料对Hg~(2+)的吸附研究

采用丙烯酸(AA)和2-丙烯酰胺基-2-甲基丙磺酸(AMPS)和为聚合单体,制备了一种新型XG-g-P(AA-co-AMPS)/膨润土复合材料,研究了不同温度下复合材料对Hg2+的吸附行为,并根据吸附等温线分析了其吸附热力学性质,借助SEM、FT-IR和XRD对其结构进行了相关表征。结果表明:XG-g-P(AA-co-AMPS)/膨润土复合材料主要通过配位吸附等方式吸附Hg2+,吸附Hg2+后材料的结晶度下降。     

三聚氰胺聚磷酸盐/次磷酸铝对高密度纤维板阻燃和力学性能的影响

本工作采用人造板热压工艺技术,将三聚氰胺聚磷酸盐( MPP)和次磷酸铝( AHP)作为阻燃剂引入高密度纤维板( HDF)中,制备MPP/AHP-HDF复合材料.采用弯曲强度、冲击强度、极限氧指数(LOI)、锥形量热仪等来评价阻燃剂对复合材料性能的影响.研究结果表明:随着阻燃剂添加量的增加,复合材料的弯曲强度、冲击强度明显下降,通过复合材料断面形貌可以看出阻燃剂与基体间界面粘接较差,界面应力传递效率低,故而阻燃剂的引入导致复合材料力学性能下降.随着阻燃剂添加量的增加,复合材料的LOI逐步增大,当阻燃剂添加量达到15%时,复合材料的LOI达到40% ,而热释放速率峰值和总的热释放量呈下降趋势,这是因为MPP和AHP在燃烧过程中可以有效促进裂解产物成炭,而且MPP还产生很多不燃气体,进而稀释了可燃性气体的浓度,从而提高复合材料的阻燃性能.     

聚二联噻吩和聚三联噻吩的固相法合成与性能

以二噻吩(BT)和三联噻吩(TT)为单体,FeCl3为氧化剂,在不同n(FeCl3)/n(单体)比例下,通过固相反应法合成出了聚(二噻吩)(poly(BT))和聚(三噻吩)(poly(TT))。并以傅立叶变换红外光谱、紫外可见吸收光谱、X射线衍射、热重分析和透射电镜等测试方法对聚合物进行了表征,研究了不同n(FeCl3)/n(单体)比例对聚合物结构与性能的影响。结果表明,n(FeCl3)/n(BT)为4∶1和n(FeCl3)/n(TT)为8∶1时,所得聚合物相对于其它比例下的聚合物表现出了较高的分子量、共轭程度和热稳定。其中,poly(TT)的分子量、共轭程度、热稳定、结晶性等特性随单体与FeCl3比例发生明显变化,但在微观形貌上无明显变化,而poly(BT)则随单体与FeCl3比例变化结果与poly(TT)相反,只是在微观形貌上产生了一定的差异。     

SiC(N)/LAS纳米陶瓷复合材料的介电特性

采用LAS玻璃粉末和激光诱导法制备的纳米SiC(N)粉体,通过热压烧结法制备了SiC(N)/LAS纳米陶瓷复合材料,研究了该复合材料在8.2~12.4GHz频率范围内的微波介电特性。结果表明,SiC(N)/LAS的介电常数主要受纳米SiC(N)粉体含量的控制,此外还与烧结温度有关。随着烧结温度的提高,复合材料介电常数和介电损耗均随之增大。SiC(N)/LAS对电磁波的损耗作用明显优于同体积分数的纳米SiC(N)与石蜡混合体,这与烧结过程中形成的碳界面有关。     

钛酸钾晶须增强双马来酰亚胺树脂体系的研究

以钛酸钾晶须(TKw)为增强剂,以N,N'-二胺基二苯甲烷型双马来酰亚胺(BMI)/O,O'-二烯丙基双酚A(BA)树脂作为基体,制备了晶须增强热固性树脂基体复合材料.研究了晶须对树脂体系凝胶特性的影响,同时利用红外光谱分析研究了晶须对体系固化反应性的影响;考察了晶须的表面处理方法、含量及复合工艺对树脂体系力学性能和热性能的影响;通过扫描电子显微镜(SEM)分析了材料的弯曲及冲击断口形貌.研究结果表明,在晶须添加质量分数约为15%左右,所制备的复合材料的综合性能较佳.     

偶联剂表面处理纳米SiO2填充CE/BMI体系的力学性能

本文研究了纳米二氧化硅(nano-SiO2)的含量对nano-SiO2/氰酸酯(CE)/双马来酰亚胺的预聚体(BMI)复合材料力学性能的影响;测量了用不同的硅烷偶联剂处理的nano-SiO2对水和甘油的相对接触角,利用Fowkes-Good几何方程计算了nano-SiO2的表面自由能,考察了经不同硅烷偶联剂处理的nano-SiO2对nano-SiO2/CE/BMI复合材料力学性能的影响.并通过扫描电镜分析nano-SiO2在基体中的分散性及增韧机理.结果表明,nano-SiO2对CE/BMI有增韧增强效果,当nano-SiO2含量为2.0wt%时复合材料的冲击、弯曲强度均最好;硅烷偶联剂处理可以增强纳米nano-SiO2的疏水性并降低其表面能,改善了其在基体中的分散性,有利于提高nano-SiO2/CE/BMI复合材料的冲击强度.     

Fabrication and characterization of OMMt/BMI/CE composites with low dielectric properties and high thermal stability for electronic packaging

Thermostable nanocomposites based on interpenetrating polymer network bismaleimide/cyanate ester (BMI/CE) copolymer, derived from bisphenol A dicyanate, 4,4′-bismaleimidodiphenyl methane, and doped by 1–5 wt% organo-modified 2D montmorillonite (OMMt) nanoparticles were synthesized and characterized using a dielectric strength tester, concept 40 impedance analyzer, scanning electron microscope (SEM), dynamic mechanical analysis, and thermogravimetric analysis techniques. OMMt improves the dispersibility, alignment and interfacial strength of these nanocomposites, the electrical conductivity increase with increasing OMMt loading, and a suitable addition of OMMt can enhance the mechanical properties and dielectric property of BMI/CE copolymer. SEM analysis shows distinct characteristics of a ductile fracture of the blends. In addition, the OMMt/BMI/CE nanocomposites have a better thermal stability and a higher thermal conductivity compared to those of BMI/CE resin with the increasing of OMMt content. All of these changes in properties are closely correlated with the OMMt/BMI/CE nanocomposites, which could form an interaction interface structure in the system.     

增韧双马来酰亚胺的性能及其热稳定性

以二苯甲烷双马来酰亚胺和邻－二烯丙基双酚Ａ为共聚单体，制成了增韧的双马来酰亚胺９ＢＭＩ）树脂，并测定了树脂的各种性能，对影响因素作了探讨。还研究了双马来酰亚胺及ＢＭＩ／二烯丙基双酚Ａ固化树脂的热稳定性，提出了交联产物的热分解历程。     

新型双马来酰亚胺基体树脂及其玻璃布层压板的制备与性能

以糠醇、甲苯二异氰酸酯（ＴＤＩ－２０／８０）和二苯甲烷双马来酰亚胺（ＢＭＩ）为原料,采用由Ｄｉｅｌｓ－Ａｌｄｅｒ加成反应合成的含有氨酯键的新型双马来酞亚胺ＢＭＵ－Ｔ作为二苯甲烷双马来酰亚肢的增韧改性剂．通过ＢＭＵ－Ｔ与二苯甲烷双马来酰亚胺以不同比例简单混合得到增韧改性的新型双马来酰亚胺基体树脂;用丙酮和乙二醇单甲醚作为混合溶剂制备了贮存稳定性能优良的树脂溶液和玻璃布预浸料。压制得到的玻璃布层压板具有良好的力学性能和电气性能．１５５℃下的弯曲强度保留率可以达到９０％以上,而且对甲苯、饱和氯化钠水溶液及１０％的盐酸具有很好的耐腐蚀性能。     

增韧双马来酰亚胺树脂及其玻璃布层压板的制备与性能

以糠醇,六次甲基二异氰酸酯和二苯甲烷双马来酰亚胺通过Ｄｉｅｌｓ－Ａｌｄｅｒ反应合成了含有氨酯宾新型双马来酰亚胺ＢＭＵ－Ｈ．用ＢＭＵ－Ｈ作为二苯甲烷双马来酰亚胺ＢＭＩ的增韧改性剂,ＢＭＵ－Ｈ与二苯甲烷双马来酰亚胺不同比例简单混合得到增韧改性的新型双马来酰亚胺树脂。     

二元双马来酰亚胺共混聚合物的结构与热性能研究

用两种不同类型的双马来酰亚胺进行共混聚合改性研究，研究其热性能与固化的关系，用＾１Ｈ ＮＭＲ，ＩＲ和ＴＧ－ＤＴＡ对其结构和固化度进行表征，并确定了树脂的固化参数。     

聚乳酸/石墨/多壁碳纳米管复合材料的制备及性能

通过共溶剂法制备了由石墨(GN)和多壁碳纳米管(MWCNTs)掺杂的聚乳酸(PLA)纳米复合材料,借助扫描电镜等手段,研究了MWCNTs用量对复合材料微观结构、热稳定性、导热和导热性能及介电性能的影响。结果显示,MWC-NTs和GN在PLA基体中形成了稳定的导电和导热网络结构,从而导致复合材料具有较低的导电和导热逾渗阈值,其值约为MWCNTs/GN=0.5/1。MWCNTs和GN均匀分散和协同增强效应促使复合材料热稳定性、导热和导电性能明显提高。与纯PLA相比,填料在逾渗阈值附近的复合材料的初始分解温度提高了近16℃,导热系数提高了1倍,体积电阻降低了109数量级。     

The effects of the variations of carbon nanotubes on the micro-tribological behavior of carbon nanotubes/bismaleimide nanocomposite

Two kinds of original multiwalled carbon nanotubes (MWCNTs) with different diameters, and one carboxyliated MWCNTs were used to prepare three kinds of MWCNTs/bismaleimide (BMI) nanocomposites. The effects of the diameter, concentration and functional group of MWCNTs used in the composites on the micro-tribological behavior of the MWCNTs/BMI nanocomposites were investigated in this paper. The microhardness, the morphology of the worn surface, the glass transition temperature and dynamic mechanical properties of the MWCNTs/BMI nanocomposites were also measured to figure out the possible main wear mechanism of the composites. Results show that the addition of MWCNTs in BMI resin decreases the friction coefficient of the resin no matter what kind of MWCNTs is added. Moreover, the wear loss rate of all nanocomposites considerably decreases with the increasing of nanotube content until the content reaches 2.5 wt%. Functionalization of MWCNTs changes the main wear mechanism of the MWCNTs/BMI composite from adhesive wear (for pure BMI resin) to abrasive attrition by changing the self-lubricating property of the wore surface, the dispersion of MWCNTs in the BMI matrix, the interfacial strength between MWCNTs and the matrix as well as the internal strength of the materials.     

A COMPARATIVE STUDY OF THE PREPARATION AND CHARACTERIZATION OF AROMATIC AND ALIPHATIC BISMALEIMIDES TO PRODUCE MODIFIED SILICONIZED EPOXY INTERCROSSLINKED MATRICES FOR ENGINEERING APPLICATIONS

A novel hybrid intercrosslinked network of hydroxyl-terminated polydimethylsiloxane modified epoxy and bismaleimides [N,N'-bismaleimido-4,4'-diphenylmethane and 1,6-bis(maleimido)hexane] matrix systems were developed. Epoxy resin was modified with 5, 10, and 15% (wt%) of hydroxyl-terminated polydimethylsiloxane using γ-aminopropyltriethoxysilane as crosslinking agent and dibutyltindilaurate as catalyst. The reaction between hydroxyl-terminated polydimethylsiloxane and epoxy resin was confirmed by IR spectral studies. The siliconized epoxy systems were further modified with 5, 10, and 15% (wt%) of both aromatic and aliphatic bismaleimides separately. The castings and E-glass fiber-reinforced composites prepared were characterized for their mechanical properties. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) of the matrix samples were also performed to determine the glass transition temperature (T_g) and thermal degradation temperature of the hybrid intercrosslinked systems. Data obtained from mechanical studies and thermal characterization indicate that the introduction of siloxane into epoxy resin improves the toughness and thermal stability, with reduction in strength and modulus values. The incorporation of aromatic bismaleimide into epoxy resin improved both tensile strength and thermal properties, whereas it was observed that the incorporation up to 5% of aliphatic bismaleimide into epoxy resin decreased the stress-strain value and above 5% increased the strength properties. However, the introduction of both aromatic and aliphatic bismaleimides (aromatic and aliphatic) into siliconized epoxy resin influenced both mechanical and thermal properties according to the percentage content.     

Morphology,thermal and mechanical properties of PVC/MMT nanocomposites prepared by solution blending and solution blending + melt compounding

Two types of montmorillonite (MMT), natural sodium montmorillonite (Na-MMT) and organically modified montmorillonite (OMMT), in different amounts of 1, 2, 5, 10 and 25 phr (parts per hundred resin), were dispersed in rigid poly (vinyl chloride) by two different methods: solution blending and solution blending + melt compounding. The effects on morphology, thermal and mechanical properties of the PVC/MMT nanocomposites were studied by varying the amount of Na-MMT and OMMT in both methods. SEM and XRD analysis revealed that possible intercalated and exfoliated structures were obtained in all of the PVC/MMT nanocomposites. Thermogravimetric analysis revealed that PVC/Na-MMT nanocomposites have better thermal stability than PVC/OMMT nanocomposites and PVC. In general, PVC/MMT nanocomposites prepared by solution blending + melt compounding revealed improved thermal properties compared to PVC/MMT nanocomposites prepared by solution blending. Vicat tests revealed a significant decrease in Vicat softening temperature of PVC/MMT nanocomposites prepared by solution blending + melt compounding compared to unfilled PVC.