壳聚糖Schiff碱的制备及其对金属离子吸附性能研究

文章采用微波辐射技术制备戊二醛交联壳聚糖水杨醛Schiff碱,探究其对铜离子的吸附性能。通过红外光谱仪,热分析仪和扫描电子显微镜对其结构及性能进行一系列表征,同时通过正交实验法考察其反应温度、时间、吸附动力学等影响因素对交联产物吸附性能的影响。扫描电镜分析表明交联改性后壳聚糖的表面明显发生变化,比壳聚糖更加松散,在吸附完成后改性壳聚糖的表面变得严密。由分析热失重可知改性壳聚糖热分解反应是258℃。由吸附动力学曲线可以得出改性壳聚糖对铜离子的吸附符合二级吸附动力学方程。     

一种简单的Cu/PA12复合粉体制备方法

以KH550、CH_3CH_2OH、AgNO_3和H_2O为原料,制备活化液,实现同时改性和活化PA12粉体,结合化学镀铜工艺,基于"两步法"工艺制备Cu/PA12复合粉体,借助扫描电镜、红外、X射线衍射等分析手段研究PA12粉体表面活化和化学镀机理。结果表明:KH550分子中氨基可吸附Ag~+形成直线结构;PA12粉体经活化后形成吸附银颗粒的硅烷包裹在颗粒表面的结构;活化的PA12粉体表面结构可以催化化学镀沉积面心立方铜颗粒,即制备Cu/PA12复合粉体,且随化学镀时间的增加,镀层结晶性能变好,镀层致密度提高。     

Cu/Al纳米流体的制备及导热性能

以柠檬酸钠和β-糊精为稳定剂、以抗坏血酸为还原剂,采用化学还原法制备Cu/Al复合纳米粒子,以水-乙二醇为基液,制备不同质量分数的Cu/Al复合纳米流体。利用XRD、SEM、TEM对Cu/Al复合纳米粒子的相结构和微观形貌进行表征,采用紫外-可见分光光度计和热物性分析仪测试Cu/Al复合粒子纳米流体的稳定性和导热性;研究了不同铜盐前驱体、不同浓度的铜盐对Cu/Al复合纳米相结构和形貌的影响;研究了分散剂种类及纳米粒子添加量对纳米流体稳定性和导热性影响。结果表明,以醋酸铜为前驱体,采用还原法制备的Cu/Al纳米复合粒子具有核壳结构,大小均匀,粒径约为50 nm;以柠檬酸钠为稳定剂,质量百分数为0.1%,0.3%,0.5%复合Cu/Al纳米流体均具有良好的分散稳定性;纳米流体的导热系数随着添加物用量增加而提高,当Cu/Al纳米复合粉体的质量分数为0.5%时,室温下纳米流体的导热系数相对于基液可提高39.6%。     

超声波作用下纳米Al203粉体化学镀Cu的研究

在超声波作用下,对100nm左右的Al2O3粉体进行化学镀铜,从化学镀铜热力学和动力学两方面对其机理进行探讨.同时借助X射线衍射判断其成分组成,用SEM观察镀覆结果,结合EDAX光电子能谱仪对其进行表面元素分析.结果表明:引入超声波可以实现纳米Al2O3粉体的化学镀铜,以EDTA-2Na为配位剂,并加入亚铁氰化钾为稳定剂,可以有效地消除或减少复合粉体中的Cu2O,可以一次镀覆得到铜含量为5%～90%的Cu-Al2O3复合粉体.     

超声波作用下纳米Al2O3粉体化学镀Cu的研究

在超声波作用下,对100nm左右的Al2O3粉体进行化学镀铜,从化学镀铜热力学和动力学两方面对其机理进行探讨。同时借助X射线衍射判断其成分组成,用SEM观察镀覆结果,结合EDAX光电子能谱仪对其进行表面元素分析。结果表明：引入超声波可以实现纳米Al2O3粉体的化学镀铜,以EDTA-2Na为配位剂,并加入亚铁氰化钾为稳定剂,可以有效地消除或减少复合粉体中的Cu2O,可以一次镀覆得到铜含量为5％～90％的Cu—Al2O3复合粉体。     

蛇纹石/La复合粉体的制备及其摩擦性能

分别采用水溶液沉淀法和乙醇溶液沉淀法制备了蛇纹石/La复合粉体,并分别在120℃（脱除吸附水）和700℃（蛇纹石脱除羟基）对复合粉体进行了干燥和煅烧热处理。利用X射线衍射法、扫描电子显微镜、能谱分析表征了复合粉体的物相组成、微观形貌。利用MM-10W型多功能摩擦磨损试验机对复合粉体的摩擦性能进行了评价。结果表明：蛇纹石/La复合粉体中,La化合物呈纳米颗粒,并包覆在蛇纹石表面;700℃煅烧将导致蛇纹石/La复合粉体物相变化和摩擦性能变差;120℃干燥处理的蛇纹石/La复合粉体具有良好的减摩-抗磨性能,摩擦因数较未添加者降低22.48%以上。     

低光泽PP复合材料的制备及性能研究

采用无机粉体、氢化苯乙烯-丁二烯嵌段共聚物(SEBS)对聚丙烯(PP)进行复合改性,研究了共混物的表面性能和力学性能,探讨了加工条件、皮纹对材料光泽度的影响。研究发现:加入无机粉体能够有效降低材料光泽度,其中云母、滑石粉效果最好,但划痕处发白现象明显,同一类粉体对光泽度的控制性能和划痕发白现象呈正相关;SEBS能够明显降低复合材料光泽度,并且划痕发白现象不明显;滑石粉、SEBS体系能够对复合材料表面光泽度的降低、韧性的提高起到协同作用,并且对材料其他关键性能未出现拮抗作用。     

粉体对泡沫灭火剂发泡能力和热稳定性影响研究

研究了纳米二氧化硅、硅微粉、石墨、纳米级铜粉对于蛋白泡沫的发泡能力及热稳定性的影响,并且测试了形成的复合泡沫的热稳定性,结果表明：将耐烧粉体直接添加进灭火泡沫中有望增强其抗烧能力和灭火性能。在常温下纳米二氧化硅以及纳米级铜粉能与蛋白泡沫较好的结合为复合泡沫,添加测试粉体后复合泡沫的热稳定性均有明显增强,其中添加纳米二氧化硅和纳米级铜粉的复合泡沫整体性能良好,无泡沫排液和聚并现象,可以起到良好的隔热作用。     

铜改性凹凸棒石/纳米二氧化钛复合粉体的微观结构

以四氯化钛作前驱体,采用酸碱中和并流法制备了以铜改性凹凸棒石为载体的表面包覆纳米氧化钛的复合粉体.用高分辨透射电镜和X射线衍射(X-ray diffraction,XRD)对该纳米复合粉体的微观结构进行观察和分析.实验结果显示:二氧化钛以3～6nm的晶体颗粒粘附在一维纳米棒状的凹凸棒石表面.凹凸棒石和氧化钛均各自相互分离,没有团聚现象发生.纳米复合粉体中的氧化钛为单一类型的锐钛矿相,其XRD衍射峰和JCPDS的锐钛矿特征衍射峰一致.凹凸棒石的主要特征衍射峰位置没有发生较大变化.铜以多价态的形式存在于凹凸棒石表面.该复合粉体对大肠杆菌和金黄色葡萄球菌的24h抑菌率分别达到了99.52%和99.15%.     

铜锡改性纳米二氧化钛光催化氧化还原性能的研究

在复合半导体基础上，采用超声浸渍法对催化剂表面作进一步铜改性，制备了铜锡改性的纳米二氧化钛光催化剂CuOx-SnO2／TiO2，考察了表面铜改性、二氧化锡复合对催化剂光催化氧化还原性能的影响．结果表明，表面铜改性和复合都有利于提高催化剂光催化氧化还原能力，二者间表现出相互增强的作用．结合XRD、XPS、TEM等催化剂表征结果，对铜锡改性纳米二氧化钛光激发机制进行了讨论，提出了二氧化碳光催化还原的可能机制．     

Preparation and structural study of polypropylene–talc gradient materials

Polypropylene (PP)–talc composites with proper spatial gradients were prepared by gradually varying the component ratio of PP and talcum powder during the extrudion process. The gradient variations of composition, structural and physical properties along the radius direction of a cylindrical sample were studied by wide angle x‐ray diffraction (WAXD), thermogravimetric analysis (TG), scanning electron microscopy (SEM) and tensile testing. The WAXD and TG results indicate that the content of either component shows a monotonic change along the radius direction. With increasing radius, a gradually decreased percentage of PP was observed, while that of the talc filler gradually increased. A gradually varying stacking density of the talcum powder in the PP matrix was also observed by the SEM images for the sliced specimens sampled at different positions. As a result of such variations in both component and structure, the physical properties, including the mechanical performance and thermal behaviour of the PP–talc composites, gradually varied along the radius direction. The experimental data show that a polymeric gradient material (PGM), with significantly different structures and properties existing on both sides, can be prepared by using this unique process. Copyright © 2004 Society of Chemical Industry     

超细滑石粉/聚乳酸复合材料的制备与表征

以偶联剂γ-(2,3-环氧丙氧)丙基三甲氧基硅烷(KH-560)处理后的超细滑石粉为增强相,聚乳酸(PLA)为基体,制备了超细滑石粉/PLA复合材料。通过傅里叶变换红外光谱(FT-IR)、电子扫描显微镜(SEM)、X射线衍射(XRD)、光学解偏振法、温度-形变曲线及热失重(TG)对复合材料进行了表征。结果表明,KH-560成功地包覆在滑石粉表面,滑石粉表面与PLA基体发生了化学键合,处理后的滑石粉粒子与PLA基体之间形成了良好的界面。适量的滑石粉能够提高PLA基体的结晶速率和结晶度,当滑石粉添加量增大到一定程度,PLA基体的晶格参数和晶体结构会发生变化。当滑石粉分散良好时,复合材料的玻璃化转变温度(Tg)和热稳定性显著提高。     

Preparation and properties of polyurethane‐coated talcum/polypropylene composite materials

In order to improve the toughness of polypropylene (PP) and expand its applications, a layer of polyurethane (PU) elastomer was coated on the surface of ultrafine talcum powder by an in‐situ synthesis method. In this way, an organic‐inorganic composite particle was formed. Then the surface‐treated talcum powder was mixed with melted PP to prepare PP composite materials through extrusion, granulation, and injection molding. Infrared spectral characterization and energy‐dispersive X‐ray analysis showed that there was a layer of PU elastomer on the surface of the talcum powder. Impact fracture analysis indicated that there was good compatibility between the talcum powder and the PP matrix. With the incorporation of PU elastomer coated on the surface of talcum powder, the toughness of PP was significantly improved, while the tensile strength decreased slightly. The optimum properties of the composite material were obtained when the weight fraction of talcum powder was 20% and the PU coating coverage was 25%. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers     

Tailoring properties and processing of Sylgard 184: Curing time,adhesion, and water affinity

The curing time, surface adhesion, and water absorption characteristics of Sylgard 184 were modified through the addition of catalysts and fillers. Incorporation of small amounts of a platinum-based Karstedt catalyst greatly decreased curing time at room temperature, whereas the addition of talcum powder (talc), polytetrafluoroethylene (PTFE), and NaY zeolite fillers changed surface adhesion and functionality of Sylgard 184. Fourier-transform infrared spectroscopy (FT-IR), rheological and mechanical tests (tensile strength and hardness) were used to quantify the acceleration in the curing time. The surface adhesion was evaluated for aluminum and glass-like substrates using a 90° peel-off test. The interaction between fillers and Sylgard was studied by molecular dynamics simulations, which showed the interaction between NaY and Sylgard is greater than that for PTFE. Water absorption studies indicated that 10 wt% NaY added to Sylgard 184 helped to improve water absorption, whereas incorporation of talc had the opposite effect. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48530.     

原位聚合法制备聚乳酸/滑石粉复合材料

用硅烷偶联剂对超细滑石粉（Talc）改性后,采用原位聚合法制备出不同质量分数的聚乳酸/滑石粉（PLA/Talc）复合材料,并采用傅里叶变换红外光谱仪（FTIR）、扫描电子显微镜（SEM）、核磁共振波谱仪（NMR）、热失重分析仪（TG）、偏光显微镜（POM）等方法对复合材料进行表征。结果表明,Talc粒子在复合材料中均匀分散;PLA/含量3 %Talc的复合材料的拉伸强度、冲击强度分别比纯PLA增加了102.56 %和47.83 %,复合材料的热稳定性也明显提高;Talc促进了PLA结晶性能,在一定程度上提高其力学性能,复合材料降解速率比于纯PLA明显加快。     

Enhancement of Mechanical Properties of PA6 Blending with Talcum for Fused Deposition Modeling

The objective of this work is to fabricate polyamide 6 (PA6) composite filament with enhanced mechanical properties and low cost for fused deposition modeling (FDM). The composite filaments are obtained by compounding PA6 and talcum fillers and then single screw extruding. Virgin PA6 and commercial e‐PA6 are set as controls. First, the rheological behaviors and thermal properties of PA6/talc, PA6, and e‐PA6 pellet materials are investigated, including viscosity, melting temperature, crystallinity, and decomposition temperature, which are important parameters for fabricating filament feedstocks. The results show that 10 wt% addition of talcum content accelerates the increase of the viscosity among the processing temperature. Accordingly, virgin PA6 and PA6/talc5 with good flowability are produced and subsequently evaluated by tensile and flexural tests. It is notable that the introduction of talcum increases the diameter constant and shape stability of PA6‐based filament. Also, it is found that both PA6 and Pa6/talc5 filaments exhibit superior tensile properties to the commercial e‐PA6 counterparts. Especially, PA6/talc5 filaments achieve the maximum tensile yield strength of 67.1 MPa and modulus of 3.10 GPa. Finally, auxetic lattice parts are successfully printed via FDM using lab‐made PA6, PA6/talc5, and commercial e‐PA6 filaments, and PA6/talc5 exhibits remarkable loading and energy absorption capability.     

基于碳纳米涂层沉积滑石粉与炭黑协同填充PVC/ABS复合材料的性能研究

通过高温热解聚合物方法将碳纳米涂层沉积到滑石粉的表面,并将其与炭黑协同填充到聚氯乙烯/丙烯腈-丁二烯-苯乙烯共聚物（PVC/ABS）复合材料中,研究了滑石粉与炭黑含量对复合材料电学性能、力学性能、热稳定性与阻燃性能的影响。结果表明,添加3份滑石粉时,炭黑的逾渗值仅为3份,在此添加量下复合材料的拉伸强度提高了14.4%,原因为滑石粉与炭黑在基体内构成了网络结构,滑石粉作为节点在基体内随机位置、随机方向分布,而炭黑可作为连接各个节点的通道。     

滑石粉的成核作用对尼龙66的力学性能及非等温结晶行为的影响

研究了滑石粉,尼龙66样品的力学性能及非等温结晶行,探讨了滑石粉的比表面积和表面改性对尼龙66力学性能和非等温结晶过程的影响。结果表明：滑石粉的加入改善了尼龙66的拉伸性能和弯曲性能,冲击性能下降,表面处理后的滑石粉更有助于尼龙66性能的改善;滑石粉的比表面积对拉伸性能和冲击性能影响不大,对弯曲性能有较大影响;滑石粉的异相成核作用可提高尼龙66的结晶温度,滑石粉比表面积的增加和表面处理更有利于尼龙66结晶温度的提高。     

PP/POE/滑石粉复合材料的制备及其在汽车内饰件中的应用

通过分析聚丙烯(PP)和乙烯-辛烯共聚物(POE)的流变特性,选用熔体黏度相近的材料作为基体,以滑石粉为填料,制备了PP/POE/滑石粉复合材料.研究了螺杆组合、助剂种类对复合材料性能的影响,并利用扫描电子显微镜观察了POE和滑石粉在复合材料中的分散情况,考察了该复合材料在改善汽车内饰件外观中的应用状况.结果表明,合适...     

滑石粉填充聚乙烯母料的流变性能研究

采用毛细管流变仪研究了不同剪切速率下分散剂种类及用量、加工温度、滑石粉含量及粒径以及偶联剂含量对滑石粉填充聚乙烯母料流变性能的影响。结果表明,聚乙烯母料的流变曲线出现"剪切变稀"行为;聚乙烯母料的黏度随分散剂含量增加以及加工温度升高而降低;聚乙烯母料的黏度随母料中滑石粉含量增加而迅速增大;滑石粉粒径减小和偶联剂含量增加使聚乙烯母料的黏度略有下降。