热塑性聚氨酯／纳米铜复合材料的制备与表征

选择热塑性聚氨酯（PU）为基体材料,用自制纳米铜颗粒代替铜丝或铜管等块体铜,采用机械共混的方法制备了一种全新的宫内节育器（IUD）材料——聚氨酯／纳米铜复合材料,并采用红外光谱（FFIR）分析、X射线衍射（XRD）分析、扫描电镜分析（SEM）、力学性能测试、热重分析等表征方法对自制纳米铜粉和复合材料的结构及性能进行了表征。结果表明,利用液相还原法成功制备了纳米级铜粉,聚氨酯／纳米铜复合材料的拉伸强度、撕裂强度随着纳米铜含量的增加略有增加,热稳定性随着纳米铜含量的增加稍有降低,为下一步复合材料铜离子的可控释放研究工作提供了很好的基础。     

聚合后期加入纳米复合材料制备改性PVC树脂

在纳米水滑石（HT）表面共聚适量的丙烯酸六氟丁酯（HfA）和甲基丙烯酸甲酯（MMA）,制得HfA／MMA／HT纳米复合材料（以下简称纳米复合材料）,并对纳米复合材料的组成进行了优化;还研究了VCM聚合时纳米复合材料的用量对试样热稳定性和抑烟性能的影响。结果表明：①不同HfA、MMA含量的纳米复合材料均能提高试样的冲击强...     

纳米高岭土/橡胶复合材料的性能研究

研究纳米高岭土／橡胶（SBR，NR，BR和EPDM）复合材料的物理性能和热稳定性能，并用透射电子显微镜、X射线衍射、红外光谱和热重分析法对高岭土／橡胶复合材料进行分析。结果表明，与白炭黑／橡胶复合材料相比，纳米高岭土／橡胶复合材料回弹性、拉伸性能和热稳定性较好，撕裂强度和定伸应力稍差；高岭土片层厚度为纳米级、分散性良好、片状粒子与橡胶大分子在纳米尺度紧密结合以及纳米高岭土片层在橡胶基体中分离且定向平行排列，是复合材料具有优良物理性能和热稳定性的重要原因。     

聚乙烯／亚麻纤维复合材料的性能研究

研究了亚麻纤维的含量和增容剂MAH-g-PE对聚乙烯／亚麻纤维复合材料各项性能的影响。结果表明：随着亚麻纤维含量增大,复合材料力学性能、硬度和维卡软化温度提高,但材料熔体粘度增大。添加MAH-g-PE提高了复合材料的热稳定性,降低了材料吸水性;且添加MAH-g-PE的材料吸水后,其拉伸强度高于未添加MAH-g-PE的材料。     

天然橡胶/固相法改性纳米碳酸钙复合材料的微观形态与力学性能

研究了天然橡胶（NR）／硬脂酸包覆型纳米碳酸钙（CCR）复合材料和NR／固相法改性纳米碳酸钙（M-CCR）复合材料的微观形态、力学性能、耐老化性能和热稳定性能等。结果表明,与CCR相比,M—CCR在NR中的分散性更好,界面结合形态得到了改善;NR／M—CCR复合材料的力学性能、耐老化性能和热稳定性能显著提高,且当M—CCR用量少于10份时,NR／M—CCR复合材料的综合性能最佳。     

双马来酰亚胺/环氧树脂/纳米SiO2复合材料的制备与性能研究

研究了纳米二氧化硅（SiO2）的含量对双马来酰亚胺（BMI）/环氧树脂(EP)/2,2′二烯丙基双酚A(DBA)/纳米SiO2复合材料的耐热性能、力学性能和吸水性能的影响。结果表明,当纳米SiO2的含量为2.0 %(质量分数,下同)时,BMI/EP/DBA/纳米SiO2复合材料具有较高的强度和良好的韧性,其拉伸强度、弯曲强度和缺口冲击强度比BMI/EP/DBA复合材料分别提高了22.8 %、39.0 %和37.8 %;同时,纳米SiO2含量为 2.0 %时,BMI/EP/DBA/纳米SiO2复合材料具有优异的耐热性,其玻璃化转变温度、初始热分解温度和最大热分解温度分别为204、 410、451 ℃。     

聚氨酯/蒙脱土纳米复合材料

综述了聚氨酯／蒙脱土纳米复合材料的制备、结构表征和热力学性能，对制备过程进行了热力学分析，并对其发展前景进行了讨论。聚氨酯／蒙脱土纳米复合材料是一种新型的有机／无机纳米复合材料。在无机材料含量远低于常规填充量的情况下复合材料就可以具有较好的力学性能、阻隔性，热稳定性能也显著提高。     

汉麻杆芯粉填充SBR的研究

研究了废旧的生物质材料汉麻杆芯粉（HP）对所填充丁苯橡胶（SBR）复合材料加工性能、热稳定性、力学性能以及吸水性能的影响。结果表明,较小尺寸的HP对橡胶的加工工艺影响不大,填充后的硫化胶力学性能获得改善,但热稳定性和吸水性有所下降,偶联剂改性明显改善了填充效果。     

纳米水滑石对PVC热稳定性和烟密度的影响

研究了纳米水滑石（nano—HT）对聚氯乙烯（PVC）热稳定性和燃烧烟密度的影响。采用原位聚合并熔融加工得到PVC／纳米水滑石复合材料，纳米水滑石在PVC基体中分散均匀，分散尺度小于100nm。随着纳米水滑石含量增加，PVC／nano—HT复合材料的热分解温度和刚果红变色时间增加，热稳定性提高；分散均匀的纳米水滑石对PVC具有良好的抑烟效果，当PVC／nano—HT复合材料中纳米水滑石含量为1．25％和2．5％时，最大烟密度分别比空白PVC低40％和60％左右。     

埃洛石纳米管对线形低密度聚乙烯的改性作用

采用天然纳米材料埃洛石纳米管（HNTs）通过普通的塑料加工方法制备了线形低密度聚乙烯/埃洛石（LLDPE/HNTs）纳米复合材料,研究了用偶联剂KH550改性HNTs前后纳米复合材料的力学性能、阻燃性能和热稳定性.结果表明：HNTs的加入能明显提高LLDPE的阻燃性能,增加LLDPE的拉伸强度,但引起冲击强度和5%～10%热失重温度的明显下降 用KH550改性HNTs能进一步提高HNTs的阻燃效果,并提高复合材料的冲击强度和热稳定性.     

Preparation of Cu/OMMT/LLDPE nanocomposites and synergistic effect study of two different nano materials in polymer matrix

Cu/OMMT (organo-montmorillonite)/LLDPE (linear low-density polyethylene) nanocomposites were prepared via melt mixing combined with melt extruding process. X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectra, scanning electron microscope (SEM), and transmission electron microscopy (TEM) were employed to characterize the resultant nanocomposites. The results showed that the OMMT layers were exfoliated and the nano-Cu particles were distributed uniformly in the polymer matrix. And the introduction of nanofiller into LLDPE matrix had little effect on the crystallinity of the polymer. The salt spray tests showed that OMMT and nano-Cu could improve the anticorrosion properties of LLDPE matrix, respectively. And the coexistence of OMMT and nano-Cu in Cu/OMMT/LLDPE nanocomposites could produce a synergistic effect on enhancing the anticorrosion properties. Furthermore, the co-incorporation of OMMT and nano-Cu into the polymer matrix also increased the thermal-oxidative stability and mechanical properties of LLDPE matrix significantly, as compared with the Cu/LLDPE and OMMT/LLDPE nanocomposites due to the synergistic effect. The bactericidal properties evaluation showed that the bactericidal ability of Cu/OMMT/LLDPE increases with nano-Cu content effectively.     

纳米Cu电极的制备及其在电催化还原CO_2反应中的应用

Cu电极较之玻碳(GC)电极,更有利于CO2的电还原反应,而电沉积制备的纳米Cu电极可以进一步提高其电催化还原性能。本文考察了电沉积条件,包括沉积时间、H2SO4浓度、沉积电位、Cu2+浓度等对所制备的纳米Cu电极对CO2电还原反应催化性能的影响。针对该反应优化了纳米Cu电极的制备条件,并用SEM表征了其微观形貌。最后还将制备的纳米Cu电极运用于CO2与环氧丙烷的电合成反应,提高了碳酸丙烯酯的反应产率。     

PE-HD/棉秆皮复合材料的制备及其性能研究

采用蒸汽爆破对含水率分别为30 %、40 %、50 %的棉秆皮进行预处理,并与高密度聚乙烯（PE-HD）复合制备PE-HD/棉秆皮复合材料,研究了蒸汽爆破、棉秆皮含量、棉秆皮含水率对PE-HD/棉秆皮复合材料力学性能和密度的影响。结果表明,与未经蒸汽爆破处理的PE-HD/棉秆皮复合材料相比,蒸汽爆破预处理后制备的PE-HD/棉秆皮复合材料的力学性能更好;当棉秆皮含量为30 %时,复合材料的综合力学性能最佳;复合材料的拉伸强度随棉秆皮含水率的增加而提高;复合材料的弯曲强度在棉秆皮含水率为40 %时达到最大值。     

PP/硅灰石/EPDM体系组分与形态结构对冲击韧性的影响

利用双螺杆挤出机制备PP/硅灰石/EPDM三元复合物,通过扫描电镜和冲击实验等研究了该复合物组分变化和形态结构对其力学性能,特别是冲击韧性的影响。控制组分和形态结构可以得到冲击韧性和刚度同时提高的力学性能均衡的复合材料。     

聚氯乙烯/蒙脱土纳米复合材料的研究

采用熔融插层法制备了聚氯乙烯(PVC) /蒙脱土(MMT)纳米复合材料并进行了表征,研究了PVC/MMT纳米复合材料的力学性能。结果表明:PVC进入到有机MMT的片层间形成了纳米复合材料,但PVC不能进入钠基MMT的片层间,形成纳米复合材料;蒙脱土的加入提高了PVC的力学性能,而且PVC/有机MMT纳米复合材料的拉伸和冲击强度总是优于PVC/钠基MMT复合材料;对PVC/有机MMT纳米复合材料而言,复合材料的V型缺口冲击比U型缺口冲击敏感,其力学性能随热处理时间延长而降低,但PVC/有机MMT复合材料比PVC/钠基MMT的抗热性好。     

PBS/剑麻复合材料制备与性能研究

利用蒸汽爆破预处理剑麻纤维(SESF)作为增强体,通过模压成型制备聚丁二酸丁二醇酯(PBS)/SESF复合材料,研究了SESF质量分数对复合材料力学性能的影响。对比了在剑麻纤维质量分数为30%的条件下,和未经预处理的2种剑麻纤维制得的复合材料的力学性能,并通过扫描电镜(SEM)对试样进行观察分析。结果表明,随着SESF质量分数的增加,复合材料的拉伸强度先增大后减小,在SESF质量分数为30%时达到最大值,比纯PBS的提高了15.5%;弯曲强度和弯曲模量均随剑麻纤维质量分数的增大而提高,其中弯曲强度在SESF质量分数为30%时的比纯PBS的提高了132.5%;断裂伸长率和冲击强度随着SESF质量分数的增加而降低。     

Fabrication and joining mechanism of Nano-Cu/Si3N4 ceramic substrates

A novel method for fabricating a nano-Cu/Si₃N₄ ceramic substrate is proposed. The nano-Cu/Si₃N₄ ceramic substrate is first fabricated using spark plasma sintering (SPS) with the addition of nanoscale multilayer films (Ti/TiN/Ti/TiN/Ti) as transition layers. The microstructures of the nano-Cu metal layer and the interface between Cu and Si₃N₄ are investigated. The results show that a higher SPS temperature increases the grain size of the nano-Cu metal layer and affects the hardness. The microstructure of the transition layer evolves significantly after SPS. Ti in the transition layer can react with Si₃N₄ and with nano-Cu to form interfacial reaction layers of TiN and Ti–Cu, respectively; these ensure stronger bonding between nano-Cu and Si₃N₄. Higher SPS temperatures improve the diffusion ability of Ti and Cu, inducing the formation of Ti₃Cu₃O compounds in the nano-Cu metal layer and Ti₂Cu in the transition layer. This study provides an important strategy for designing and constructing a new type of ceramic substrate.     

Dynamic mechanical,mechanical and morphological properties of reactive thermotropic liquid crystalline polymer/unsaturated polyester/glass fibre hybrid composites

Abstract

Unsaturated polyester (UP) reinforced with self-synthesised reactive thermotropic liquid crystalline polymer (TLCP)–methacryloyl copolymer (LCMC) and glass fibre (GF), the hybrid composites of UP/GF/LCMC were prepared by moulding technology. The dynamic mechanical analysis indicated that storage modulus and glass transition temperature (T _g) of hybrid composites increased significantly because of the addition of LCMC. The effect of LCMC content on the mechanical properties of LCMC/UP/GF hybrid composites such as impact strength, specific strength and modulus and load–displacement relationship were also investigated through static mechanical tests. The mechanical properties of hybrid composites increased significantly because of the addition of LCMC. The crystal behaviour analysis of LCMC/UP blend was investigated by X-ray diffraction and polarising optical microscopy. The results showed that the crystal phase and texture structure of LCMC still existed in the blends after blending with UP. The morphology of fracture surfaces of hybrid composites containing different TLCP contents was observed by scanning electron microscopy. The present paper discussed the mechanism for the improvement of dynamic mechanical and mechanical properties.     

Printability,shape-memory,and mechanical properties of PHB/PCL/CNFs composites

Shape-memory polymers have attracted attention as smart implant materials in recent years because they are lightweight, low-cost, easily processable, and because they undergo large deformation. Here, cellulose nanofibers (CNFs) were used as a reinforcement for polyhydroxybutyrate (PHB)/polycaprolactone (PCL) composites to improve mechanical properties. The composites were investigated by rheological tests, differential scanning calorimetry, dynamic mechanical analysis, mechanical property tests, and shape-memory tests. The printability of PHB/PCL/CNFs composites was demonstrated by using them to print interconnected porous structures with a gyroid surface. The results showed that the PHB/PCL (80:20) composites with 1 wt% CNF displayed the best comprehensive mechanical and shape-memory properties. As a functional verification, a model of the self-opening hand was fabricated by 3D printing, and its deformation and recovery capabilities were evaluated.     

Investigation on the Polyamide 6/SEBS-g-MA/Organoclay Nanocomposites with Glycidyl Methacrylate as a Compatibilizer

Polyamide 6 (PA6)/maleated styrene-ethylene/butadiene-styrene copolymers (SEBS-g-MA)/organoclay (DK5) composites with glycidyl methacrylate (GMA) as a compatibilizer were prepared by melt compounding. The influences of maleating, DK5 and GMA on interfacial adhesion and mechanical properties of PA6 composites were investigated in terms of SEM observations, mechanical testing, Molau tests, IR analyses, and rheological behavior. Satisfactorily balanced mechanical properties of the composite could be achieved in the presence of GMA. Both DK5 and GMA retarded the crystallization of PA6. The storage modulus, loss modulus, and complex viscosity of the composites were obviously affected by the addition of DK5 and GMA.