基于超分子结构共掺杂纳米复合薄膜的制备与荧光特性

为改善功能分了的特性,提出一种基于金属纳米粒子-偶氮染料复合物共掺杂超分子结构功能材料的设计新方法.并依照此方法制备出复合材料,观测了其显微结构,测量了其紫外-可见光吸收,研究了该超分子结构复合体系的荧光特性.实验发现,由于金属银纳米粒子的掺杂,使得超分子结构复合体系中功能分子甲基橙在溶液态体系的荧光强度增强近5倍,而在两种不同结构(共混结构和包覆结构)的薄膜态超分子结构体系中,其荧光强度分别被猝灭15%和20%.研究结果表明,复合膜中采用超分子结构完全能够改善功能分子的特性.     

光谱法研究PA612/TPU熔融共混体系相互作用

采用熔融共混制备尼龙(PA)612/热塑性聚氨酯(TPU)复合材料,通过广角X射线衍射仪(WAXD)和傅里叶变换红外光谱仪(FTIR)研究了PA612和TPU之间的相互作用。WAXD结果表明,TPU的加入影响了PA612的结晶完善度,且随着TPU含量的增加,PA612的结晶度逐渐降低。FTIR的结果证实了共混样品中PA612与TPU形成了新的氢键,且熔融共混过程中两组分之间有少量化学反应发生。     

TiC和AlN材料制备中的重力行为研究(Ⅰ)

为了研究失重环境对液相烧结AlN复合材料的影响,在抛物线飞行飞机上,以碳钛燃烧反应 形成的高温作为实验热源,进行了失重实验和AlN复合材料、TiC材料制备中重力行为研究. 利用抛物线飞行时产生的不同重力环境,研究了不同重力水平对碳钛燃烧反应的影响.研究 结果显示,重力水平的差异导致燃烧温度不同,样品的不同取向下重力对燃烧反应的影响不同. 关键词： 微重力 化学炉 TiC     

基于Metglas/PFC磁电层状复合材料的电能无线传输系统

本文完整推导了无直流偏磁条件下, 磁致伸缩材料和压电材料黏接而得的磁电层状复合材料输出电压、电流、磁电系数表达式, 制备了多个样品并实现了电能无线传输系统. 对样品的测试结果验证了理论分析的正确性. 进一步试验结果表明: 磁电层状复合材料的输出具有倍频特性, 材料长度与谐振频率成反比, 谐振状态下样品可在20 Oe的磁场中输出接近100 V (有效值)开路电压, 样品最大传输功率为520 mW (此为该传输方式下公开报道的最大功率), 功率密度为1.21 W/cm³, 样品最大传输效率达35%, 30°以内的偏转角度对材料的输出无显著影响. 试验结果表明, 基于Metglas/PFC磁电层状复合材料是小体积、 小功率、 对传输效率不甚敏感的电能无线传输应用的一种非常有前景的实现方式. 关键词： 磁电复合材料 无线能量传输     

甘氨酸燃烧法合成纳米ZnO-MgO及其紫外光发射

利用甘氨酸燃烧法制备了ZnOMgO纳米复合材料,并在不同温度进行热处理.通过X射线衍射、扫描电子显微镜和傅里叶变换红外吸收谱,对其升温过程中的结构变化进行了表征,研究了热处理温度对样品室温光致发光行为的影响.结果表明,复合材料的发光性能与纯ZnO相比有很大改善,经900℃热处理的纳米复合材料,其发射谱由一个强紫外发射带(峰值385nm)构成;当热处理温度低于900℃时,发光强度随热处理温度的升高而增强,进一步将热处理温度升至1000℃时发光强度又明显降低.发光强度主要受ZnO、MgO纳米晶的粒子尺寸、结晶完善程度,尤其是受两相纳米粒子之间相互作用的影响.同时发现选择合适的甘氨酸与硝酸根离子的摩尔比,对改善样品紫外发光特性也很重要.     

用ICP-AES方法测定淀粉中铅、砷的含量

采用ICP-AES(电感耦合等离子体发射光谱)法,以硝酸镍作为基体改进剂,对淀粉中的铅、砷含量进行了测定;探讨了样品灰化方法及灰化原子化温度、基体改进剂对测定结果的影响.实验结果表明,用ICP-AES方法测定淀粉样品中铅、砷一类有害重金属含量,数据、结果的重现性好,方法简便易行、测定结果准确.     

(NaZSM-5)-AgI主体-客体纳米复合材料的研究

用热扩散法成功地把AgI组装于NaZSM5的孔道中,对制备的样品(NaZSM5)AgI进行了化学分析、粉末XRD分析、化学吸附、红外光谱表征,研究了所制备的样品固体扩散漫反射吸收光谱及发光性质.化学分析表明,AgI已进入NaZSM5主体中.粉末XRD分析显示了组装AgI后NaZSM5沸石骨架依然存在,红外光谱表明了(NaZSM5)AgI样品骨架振动与NaZSM5的骨架振动有细微差别,这主要是由组装了AgI引起的.吸附研究说明了AgI已进入NaZSM5的孔道.固体扩散漫反射吸收光谱表明,主体NaZSM5对制备的主体客体样品光吸收几乎没有影响,(NaZSM5)AgI的吸收光谱受AgI尺寸大小的影响.发光研究表明,制备的样品能带隙很高,辐射过程很强,(NaZSM5)AgI样品系具有发光功能的复合材料.     

多重衰减全反射-红外光谱法在复合材料表面分析中的应用

应用衰减全反射-傅立叶变换红外光谱技术(FTIR-ATR)分析三种不同类型复合材料成分,并运用扫描电镜和光电子能谱方法对结果进行了确证,确定了:1.复合材料密封膜HNP由聚丙烯、(乙烯-乙酸乙烯酯)共聚物和聚酰胺三层材料组成;2.纤维复合膜中间层的粘结材料为聚四氟乙烯;3.金属复合包装膜中聚合物材料为(偏二氯乙烯-丙烯酸酯)共聚物。实验表明FTIR-ATR技术在复合材料表层和夹层中高分子材料成分的分析应用中有明显的优势,简化了繁杂的分离纯化样品工作,方法简单、易于操作。文中对使用FTIR-ATR技术进行定性分析中的若干问题提出探讨。     

高氯酸萃取-连续流动法测定烟草中的淀粉含量

淀粉是烟草中较难测定的成分之一.为了快速准确地测定烟草中的淀粉含量,研究了高氯酸萃取-连续流动法测定烟样中淀粉含量的方法,即每0.1g烟草样品用1.0mL 50%的乙醇和1.2mL 72%高氯酸萃取烟草样品中的淀粉,通过自动化学分析仪(滤光片波长660nm)测定淀粉含量.采用本法测定了云南烤烟烟叶、杀青烟叶、白肋烟和香料烟的淀粉含量,平均回收率为96.71%,相对标准偏差在1.79%-5.58%之间.与传统的酸解法和酶解法比较,本法操作步骤简单、检测成本低、快速准确.     

乙基苯胺的转动光谱及分子结构（英文）

本文使用傅里叶变换微波谱仪研究了乙基苯胺类物质(邻乙基苯胺,间乙基苯胺,对乙基苯胺)的分子结构.由于此类分子含氮原子(I~(14)N=1),因此跃迁谱线中都呈现出核四级裂分.通过比较实验测定得到的分子结构,可总结苯胺环上不同位置乙基的取代对氨基及分子整体结构的影响.     

Designing and Characterization of Poly(L-Lactide)/Poly(ϵ-Caprolactone) Multiblock Copolymers

A series of poly(L-lactide)/poly(?-caprolactone) (PLA/PCL) biodegradable multiblock copolymers was synthesized by a two-step process and characterized. Ring-opening polymerization was used to prepare a series of HO-PLA-PCL-PLA-OH copolymers initiated by hydroxyl-terminated PCL. Then the triblock copolymers and 1,6-hexamethylene diisocyanate (HDI) were reacted with different copolymer/HDI weight ratios. Consequently, a series of PLA/PCL multiblock copolymers with designed molecular chain structure was obtained. Gel permeation chromatography (GPC), Fourier transform infrared (FTIR) spectroscopy, and ¹H NMR were used to characterize these copolymers and the results showed that the designed PLA/PCL copolymers had been synthesized. Dynamic mechanical analysis (DMA) was applied to characterize their thermal properties. Stress–strain curves showed that a PLA/PCL copolymer with adjustable mechanical properties had been achieved.     

Banana fiber strands–reinforced polymer matrix composites

Banana fiber (BF)-reinforced low-density polyethylene (LDPE) unidirectional composites were fabricated by the compression molding process with 40 wt% fiber loading. The fibers were modified with methylacrylate (MA) mixed with methanol (MeOH) along with 2% benzyl peroxide under thermal curing method at different temperatures (50–90 °C) for different curing times (10–50 min) in order to have better compatibility with the matrix. The effect of fiber surface modification on the mechanical properties (tensile and impact properties) of the composites were evaluated. Monomer concentration, curing temperature, and curing time were optimized in terms of polymer loading and mechanical properties. The mechanical properties were found to be improved based on the improved interaction between the reinforcement and the matrix. Optimized BFs were again treated with 2–5 wt% starch solutions and composites made of 4% starch treated BF showed the highest mechanical properties than that of MA treated composites. Scanning electron microscopy (SEM) was performed to get an insight into the morphology of the composites. Water uptake and soil degradation test of the composites were also investigated.     

Physical properties of a high molecular weight hydroxyl-terminated polydimethylsiloxane modified castor oil based polyurethane/epoxy interpenetrating polymer network composites

A series of polyurethane (PU)/epoxy resin (EP) graft interpenetrating polymer network (IPN) composites modified by a high molecular weight hydroxyl-terminated polydimethylsiloxane (HTPDMS) were prepared. The effects of HTPDMS content on the phase structure, damping properties and the glass transition temperature (Tg) of the HTPDMS-modified PU/EP IPN composites were studied by scanning electron microscopy (SEM) and dynamic mechanical analysis (DMA). Thermogravimetric analysis (TGA) showed that the thermal decomposition temperature of the composites increased with the increase of HTPDMS content. The tensile strength and impact strength of the IPN composites were also significantly improved, especially when the HTPDMS content was 10%. The modified IPN composites were expected to be used as structural damping materials in the future.     

Electrospun PLA: PCL composites embedded with unmodified and 3-aminopropyltriethoxysilane (ASP) modified halloysite nanotubes (HNT)

Electrospinning is a simple and versatile fiber synthesis technique in which a high-voltage electric field is applied to a stream of polymer melt or polymer solution, resulting in the formation of continuous micro/nanofibers. Halloysite nanotubes (HNT) have been found to achieve improved structural and mechanical properties when embedded into various polymer matrices. This research work focuses on blending poly(ε-caprolactone) (PCL) (9 and 15 wt%/v) and poly(lactic acid) (PLA) (fixed at 8 wt%/v) solutions with HNT at two different concentrations 1 and 2 wt%/v. Both unmodified HNT and HNT modified with 3-aminopropyltriethoxysilane (ASP) were utilized in this study. Fiber properties have been shown to be strongly related to the solution viscosity and electrical conductivity. The addition of HNT increased the solution viscosity, thus resulting in the production of uniform fibers. For both PCL concentrations, the average fiber diameter increased with the increasing of HNT concentration. The average fiber diameters with HNT-ASP were reduced considerably in comparison to those with unmodified HNT when using 15 wt%/v PCL. Slightly better dispersion was obtained for PLA: PCL composites embedded with HNT-ASP compared to unmodified HNT. Furthermore, the addition of HNT-ASP to the polymeric blends resulted in a moderate decrease in the degree of crystallinity, as well as slight reductions of glass transition temperature of PCL, the crystallization temperature and melting temperature of PLA within composite materials. The infrared spectra of composites confirmed the successful embedding of HNT-ASP into PLA: PCL nanofibers relative to unmodified HNT due to the premodification using ASP to reduce the agglomeration behavior. This study provides a new material system that could be potentially used in drug delivery, and may facilitate good control of the drug release process.     

Thermorheological Properties and Thermal Stability of Polyethylene/Wood Composites

The thermal stability, flame retardancy, thermorheological, and mechanical properties of polyethylene/wood flour (PE/WF) composites were characterized. By time–temperature superposition treatment, addition of WF was found to lead to a complexity in the thermorheological behaviors in low-density PE/wood composites. However, high-density PE/wood counterparts showed no obvious thermorheological complexity. The effects of WF and ammonium polyphosphate contents on the thermorheological behavior and thermal stability were also studied. The current work should be of practical significance for the optimization of wood/plastic composite) formulae, as well as for further investigations on correlations between processing and performance of polymer composites.     

Pithecellobium Clypearia Benth Fiber/Recycled Acrylonitrile-Butadiene-Styrene (ABS) Composites Prepared in a Vane Extruder: Analysis of Mechanical Properties and Morphology

The effect of compatibilizer types and concentrations on the mechanical properties and morphology of Pithecellobium Clypearia Benth Fiber (PCBF)/recycled ABS composites prepared by a vane extruder were characterized. In addition, the percentage of compatibilizer was fixed at 8%, and the effect of lubricant concentrations on the mechanical properties and torque behaviors of the composites was also studied. Maleic anhydride grafted ABS (ABS-g-MAH) and maleic anhydride grafted PS (PS-g-MAH) were used as compatibilizers; the lubricant used was Struktol TPW 604 (blend of aliphatic carboxylic acid salts and mono diamides). The composite with 8% ABS-g-MAH showed superior mechanical properties compared to the composite without compatibilizer and the 8% PS-g-MAH compatibilized composites. Compared with PS-g-MAH, ABS-g-MAH was more effective for the composites to improve the interfacial interaction and mechanical properties. The comprehensive mechanical properties of PCBF/recycled ABS composite filled with 4% lubricant were better than the composites without lubricant and the composites with any other content of TPW 604. Moreover, the torque of the composites in an internal mixer decreased with an increasing lubricant content.     

The influence of polymer concentrations on the structure and mechanical properties of porous polycaprolactone-coated hydroxyapatite scaffolds

Polycaprolactone (PCL)-coated porous hydroxyapatite (HA) composite scaffolds were prepared by combining polymer impregnating method with dip-coating method. Three different PCL solution concentrations were used in dip-coating process to improve the mechanical properties of porous HA scaffolds. The results indicated that as the concentration of PCL solution increases the compressive strength significantly increased from 0.09 MPa to 0.51 MPa while the porosity decreased from 90% to 75% for the composite scaffolds. An interlaced structure was found inside the pore wall for all composite scaffolds due to the penetration of PCL. The porous HA/PCL composite scaffolds dip-coated with 10% PCL exhibited optimal combination of mechanical properties and pore interconnectivity, and may be a potential bone candidate for the tissue engineering applications.     

The interface structure of nano-SiO2/PA66 composites and its influence on material's mechanical and thermal properties

The PA66-based nanocomposites containing surface-modified nano-SiO₂ were prepared by melt compounding. The interface structure formed in composite system was investigated by thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). The influence of interface structure on material's mechanical and thermal properties was also studied. The results indicated that the PA66 chains were attached to the surface of modified-silica nanoparticles by chemical bonding and physical absorption mode, accompanying the formation of the composites network structure. With the addition of modified silica, the strength and stiffness of composites were all reinforced: the observed increase depended on the formation of the interface structure based on hydrogen bonding and covalent bonding. Furthermore, the differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) showed that the presence of modified silica could affect the crystallization behavior of the PA66 matrix and lead to glass transition temperature of composites a shift to higher temperature.     

Mechanical and Flame Retardant Properties and Microstructure of Expandable Graphite/Silicone Rubber Composites

Flame-retardant expandable graphite (EG)/silicone rubber (SR) composites were prepared using nano-CaCO₃ particles as reinforcement filler. In addition to mechanical measurements, limited oxygen index (LOI), UL-94 and cone calorimeter tests (CCT), the thermal properties were tested by thermogravimetric analysis (TGA). The results showed that the content and particle size of the EG both had large effects on the flammability and mechanical properties of the EG/SR blends. The composites that contained 25 phr EG (50–80 mu) had excellent LOI values, 47–48, and achieved the UL-94 V-0 level while the pure SR sample had the LOI value of 25 and achieved the UL-94 V-2 level. The data obtained from the CCT indicated that the addition of EG decreased remarkably the heat release rate, smoke emission, and mass loss rate of the composites. SEM microphotographs of the EG/SR composites before and after combustion demonstrated that EG underwent a large volume expansion, and the multiporous char structure blocked heat transfer and protected the substrate from fire.     

Evaluation of thermomechanical properties of epoxy–basalt fibre composites modified with zeolite and silsesquioxane

The aim of this study was to verify the influence of zeolite and silsesquioxane (POSS) addition on thermo-mechanical properties of basalt fiber reinforced epoxy composites. The dynamic mechanical thermal analysis was conducted with different frequencies at bending mode. The mechanical properties were determined at static tensile test and Charpy impact strength method. The structure of composites was determined by scanning electron microscopy. The thermal stability was characterized by thermogravimetric analyses in inert and oxidizing atmospheres. The impact strength and thermal stability of the composites with zeolite and silseqioxane were higher than the reference sample. Thus, these composites can be used as thermally stable materials with high stiffness.