Synthesis of dental resins using diatomite and nano-sized SiO2 and TiO2

The mechanical properties of dental composites were improved by porous diatomite and nano-sized silica (OX-50) used as co-fillers.The resin composites,filled with silanized OX-50 and silanized diatomit...     

电泳沉积海藻酸钠/碳纳米管修饰高模碳纤维表面

采用纳米材料增加碳纤维（CF）的表面粗糙度及活性官能团,不仅可以改善CF增强复合材料的界面结合状态,而且不会对CF本体造成损伤,是一种极具发展潜力的新型CF表面改性手段。使用电泳沉积技术（EPD）将碳纳米管（CNTs）沉积在高模CF表面,然后与环氧树脂（EP）复合,制备了单向纤维增强层压板（CF/EP复合材料）。使用万能拉力机测试CF/EP复合材料的层间剪切强度（ILSS）,结果表明,在电压为6 V时制备的CF/EP复合材料的ILSS为58.9 MPa,与未经EPD处理的CF/EP复合材料（ILSS=52.2 MPa）相比提高了12.8%。同时,通过EPD制备了海藻酸钠与CNTs共沉积修饰的高模CF,海藻酸钠的加入增加了CNTs与CF表面的黏附性及氧含量,提高了纤维表面对树脂基体的浸润性。当CNTs的质量浓度为0.3 mg/mL、海藻酸钠的质量浓度为1 mg/mL、EPD电压为8 V时,所制备的CF/EP复合材料的ILSS可达68.3 MPa,与未经EPD处理的CF/EP复合材料相比提高了30.8%。     

电泳沉积海藻酸钠/碳纳米管修饰高模碳纤维表面

采用纳米材料增加碳纤维（CF）的表面粗糙度及活性官能团,不仅可以改善CF增强复合材料的界面结合状态,而且不会对CF本体造成损伤,是一种极具发展潜力的新型CF表面改性手段。使用电泳沉积技术（EPD）将碳纳米管（CNTs）沉积在高模CF表面,然后与环氧树脂（EP）复合,制备了单向纤维增强层压板（CF/EP复合材料）。使用万能拉力机测试CF/EP复合材料的层间剪切强度（ILSS）,结果表明,在电压为6 V时制备的CF/EP复合材料的ILSS为58.9 MPa,与未经EPD处理的CF/EP复合材料（ILSS=52.2 MPa）相比提高了12.8%。同时,通过EPD制备了海藻酸钠与CNTs共沉积修饰的高模CF,海藻酸钠的加入增加了CNTs与CF表面的黏附性及氧含量,提高了纤维表面对树脂基体的浸润性。当CNTs的质量浓度为0.3 mg/mL、海藻酸钠的质量浓度为1 mg/mL、EPD电压为8 V时,所制备的CF/EP复合材料的ILSS可达68.3 MPa,与未经EPD处理的CF/EP复合材料相比提高了30.8%。     

氧化石墨烯增强环氧树脂复合材料的制备及其力学性能研究

以天然石墨为原料，利用改进的Hummers法制备氧化石墨烯，并对其进行X-射线衍射（XRD）和傅里叶变换红外光谱（FT-IR）表征。之后利用一种新型的有机溶剂三缩水甘油基对氨基苯酚（TGPAP）作为相转移剂和表面活性剂，将氧化石墨烯（GO）从水溶液转移到环氧树脂基体中，去除水分，加入固化剂进而得到混合液，最后利用浇铸法得到复合材料。通过万能测试拉力机对复合材料的拉伸性能和弯曲性能进行测试，结果表明氧化石墨烯的加入能够有效增强复合材料的力学性能：在添加0.1%（质量分数）的氧化石墨烯时，复合材料拉伸强度达到最大值77.29 MPa，与不添加氧化石墨烯相比提高了26.60%；在添加1.0%的氧化石墨烯时，拉伸模量达到最大值2 451.99 MPa，与纯环氧树脂相比提高了21.69%。     

TiB2含量对原位自生TiB2/2219铝基复合材料组织与性能的影响

利用混合盐高温反应法制备了原位自生TiB2/2219铝基复合材料铸锭. 通过光学显微镜、扫描电镜、X射线等显微组织表征方法以及弹性模量、室温拉伸和室温摆锤冲击实验等测试手段,研究了TiB2含量对原位自生TiB2/2219铝基复合材料组织和性能的影响. 研究表明,当TiB2质量分数由0提高到5%时,TiB2颗粒尺寸和TiB2/2219铝基复合材料铸锭的平均晶粒尺寸逐渐减小,固溶时效态的TiB2/2219铝基复合材料板材的弹性模量和强度显著上升,但延伸率和冲击韧性下降. 当质量分数为5%时,TiB2/2219铝基复合材料板材的弹性模量、抗拉强度、屈服强度和延伸率分别达到88.7 GPa、（474.2±2） MPa、（400.6±1） MPa和（4.7±0.1）%.     

Synthesis of PCL/MWCNT by One-Pot with Microwave-Assistant and Its Mechanical Properties

Polycaprolactone/multi-walled carbon nanotubes nano composite (PCL/MWCNT) was synthesized by a one-pot process with microwave-assistance. The fractured structures, crystalline behaviors and thermal properties of the nanocomposites were investigated with an electronic microscope, an X-ray diffraction device, an infrared spectroscopy, and a differential scanning calorimeter, respectively. A universal testing machine was used to study the mechanical properties of the composites. The results showed that when the content of MWCNT was 0.3 % (m/m), the tensile strength and elongation at break reached the maximum values, and increased from 7.5 MPa and 125 % of neat PCL to 14.8 MPa and 387 %, respectively. With an increase of the MWCNT content, the Young’s modulus continuously increased from 121.5 MPa of PCL to 285.6 MPa. When the MWCNT content was 0.5 % (m/m), the Young’s modulus was ca. 1.4 fold over that of neat PCL, indicating that the addition of MWCNT resulted in simultaneous enhancement of strength, toughness and modulus remarkably.     

碳纳米管增强环氧树脂基复合材料的制备及其力学性能

通过对多壁碳纳米管进行表面处理,用超声分散和模具浇注成型法制备了碳纳米管/环氧树脂纳米复合材料。研究了碳纳米管含量和表面处理对碳纳米管/环氧树脂复合材料力学性能和断面形貌的影响,分析了碳纳米管对环氧树脂的增强机理。结果表明,随着碳纳米管含量的增加,碳纳米管/环氧树脂复合材料的拉伸强度和弯曲强度及模量先增加后减小;当碳纳米管的质量分数为0.5%时,复合材料的拉伸强度、弯曲强度和弯曲模量分别达到最大值69.8MPa、136.9MPa和3.72GPa,比纯环氧树脂提高了33.9%、29.3%和4.8%;当碳纳米管的质量分数为1.5%时,拉伸模量达到最大值2050.5MPa,比纯环氧树脂提高了7.3%。     

VARTM制备麻纤维增强环氧树脂复合材料研究

通过对黄麻纤维热处理、碱处理、硅烷偶联剂处理和异氰酸酯处理进行表面改性,并对改性黄麻纤维布进行热压工艺处理,最后采用VARTM成型工艺制备黄麻纤维增强环氧树脂复合材料,并对其性能进行了系统研究.通过扫描电镜(SEM)分析表明,热处理和碱处理的黄麻纤维增强环氧树脂复合材料的界面粘结未得到明显改善,而通过硅烷偶联剂和异氰酸酯处理的黄麻纤维增强环氧树脂复合材料的界面粘结性能得到了显著的提高.将硅烷偶联剂和异氰酸酯处理的黄麻纤维布通过热压处理不仅可以增加复合材料中黄麻纤维体积含量,而且可以提高复合材料的综合性能,复合材料力学性能研究表明,经硅烷偶联剂处理后的黄麻纤维增强复合材料拉伸强度、模量和弯曲强度分别提高了18.6%,71.4%和50.2%.经异氰酸酯处理的黄麻纤维增强复合材料的拉伸强度、模量和弯曲强度分别提高了16.3%,34.0%和50.3%.     

阻燃改性木粉/聚苯乙烯复合装饰材料的性能

以含聚磷酸铵（APP）阻燃剂的木粉增强体制备复合材料。利用热重分析测试、极限氧指数测试、衰减全反射红外光谱分析、力学性能测试研究了阻燃改性复合材料对木粉/聚苯乙烯(PS)复合材料的阻燃性能和力学性能的影响。结果表明：相比未改性的木粉/聚苯乙烯复合材料,用APP改性木粉/聚苯乙烯复合材料改善了木塑复合材料的耐热性和阻燃性。当添加5%-20%APP含量时,最大热损失速率由13.02%·min-1降低到11.63%·min-1,热降解性能提高;成炭率和LOI值提高,阻燃性能增强。但是与未添加APP的复合材料相比,添加20%APP时,抗弯强度由71.3MPa降低到54.2MPa, 降低了24%; 拉伸强度从35.3MPa降低到24.8MPa, 降低了30%,APP的加入使复合材料的力学性能降低。     

芳香型聚胺醚及其连续玻纤增强复合材料的性能研究

以双酚A二缩水甘油醚（DGEBA）和对甲氧基苯胺为单体制备了芳香型聚胺醚,并通过原位聚合的方法制备了连续玻纤增强热塑性聚胺醚（GF/PHAE）复合材料。研究了DGEBA/对甲氧基苯胺体系的反应特性、动态黏度、熔体流动速率（MFR）、耐热性及聚胺醚浇注体和GF/PHAE复合材料的力学性能,采用红外光谱法（FT-IR）对聚胺醚进行了结构分析,并借助SEM分析了GF/PHAE复合材料的断面形貌。研究结果表明：DGEBA/对甲氧基苯胺体系在25 ℃下放置85 min后黏度为2100 mPa•s,黏度较低有利于纤维的浸润;聚胺醚为可熔融的热塑性聚合物,反应时间5 h、反应温度140 ℃下制备的聚胺醚熔融指数较低为1.4 g/10min;聚胺醚的玻璃化转变温度（Tg）为86.7 ℃,起始分解温度为310.2 ℃;聚胺醚浇注体的弯曲强度126.9 MPa,弯曲模量10.2 GPa;当玻纤体积分数为59.3%时,GF/PHAE复合材料弯曲强度1327.2 MPa,弯曲模量21.8 GPa,层间剪切强度86.2 MPa;SEM断面分析表明聚胺醚对玻璃纤维具有良好的界面黏接。     

氟金云母填充环氧树脂复合材料研究

分别用标准氟金去母和改性氟金云母填充环氧树脂，制得了氟金云母／环氧树脂复合材料，对其力学性能进行了测试，并用扫描电子显微镜对其微观组织和形态进行了观察分析，研究了氟金云母的性质，质量分数同该复合材料力学性能之间的关系，结果表明：改性氟金云母对环氧树脂具有较好的增强作用，当其质量分数为10％时，复合材料的弯曲强度可提高50％，弹性模量可提高100％，标准氟金云母虽然可提高弹性模量，但却使弯曲强度下降。     

Effect of graphite powder as a forming filler on the mechanical properties of SiCp/Al composites by pressure infiltration

(38vol% SiCp + 2vol% Al₂O_3f)/2024 Al composites were fabricated by pressure infiltration. Graphite powder was introduced as a forming filler in preform preparation, and the effects of the powder size on the microstructures and mechanical properties of the final composites were investigated. The results showed that the composite with 15 μm graphite powder as a forming filler had the maximum tensile strength of 506 MPa, maximum yield strength of 489 MPa, and maximum elongation of 1.2%, which decreased to 490 MPa, 430 MPa, and 0.4%, respectively, on increasing the graphite powder size from 15 to 60 μm. The composite with 60 μm graphite powder showed the highest elastic modulus, and the value decreased from 129 to 113 GPa on decreasing the graphite powder size from 60 to 15 μm. The differences between these properties are related to the different microstructures of the corresponding composites, which determine their failure modes.     

引发剂对硅烷化杨木单板/聚乙烯薄膜 复合材料性能的影响

为分析引发剂对硅烷偶联剂的协同效应,以高密度聚乙烯(HDPE)薄膜为胶黏剂,乙烯基三甲氧基硅烷(A-171)和引发剂过氧化二异丙苯(DCP)为杨木单板的改性剂,制备硅烷化杨木单板/HDPE薄膜复合材料。分别采用力学试验机、动态力学分析仪(DMA)和冷场发射扫描电子显微镜分析引发剂DCP用量(0、0.05%、0.10%、0.15%)对复合材料物理力学性能的影响。结果表明:在引发剂DCP的诱导下,硅烷化杨木单板与HDPE薄膜发生了化学交联反应,形成了优良的胶接结构,硅烷化杨木单板/HDPE薄膜复合材料的力学性能、耐水性能和耐高温破坏性能都显著增强。当引发剂DCP添加量达到0.15%时,复合材料的胶合强度、木破率、静曲强度和弹性模量值分别由1.02 MPa、2%、60.10 MPa、5 102 MPa增加至2.07 MPa、95%、77.20 MPa、6 822 MPa; 吸水率和吸水厚度膨胀率分别由77.80%和5.79%降低至53.75%和4.09%。DMA结果显示,复合材料的耐高温破坏能力随DCP添加量的增加而改善,当DCP用量由0增至0.15%时,复合材料在130 ℃时的储能模量保留率由44.19%提高到88.34%,胶接界面层失效的温度点从147 ℃提高至197 ℃。     

Mechanical and Thermal Properties of Apocynum and Ramie Fiber Mat Reinforced Polylactic Acid Composites

With the increasing awareness of environmental protection and rational utilization of resources, natural fiber reinforced composites have shown broad development prospects. Apocynum fiber, known as the "king of wild fiber", not only has moisture absorption, air permeability, and good mechanical properties but also has many health-related advantages such as antibacterial properties. In this study, four types of needle-punched Apocynum fiber and ramie fiber mat reinforced polylactic acid(PLA) composites were fabricated. Mechanical and thermal properties of the composites were tested and analyzed. The results showed that compared with those of the ramie fiber finish needle-punched mat reinforced composites, the tensile strength and the tensile modulus of Apocynum fiber finish needle-punched mat reinforced composites had increased by 15.3% and 60.1%, respectively. In comparison, the bending strength and the bending modulus were decreased by 21.8% and 7.6%, respectively. Moreover, compared with the Apocynum fiber finish needled-punched mat reinforced composites and the ramie fiber finish needle-punched mat reinforced composites, the Apocynum 50/ramie 50 finish needle-punched mat reinforced composites had the best tensile and bending properties. The after-fracture morphology was detected by a scanning electron microscope(SEM). The thermal properties of the composites were also characterized. It was found that the thermal properties of the four types of composites showed very similar behaviors.     

不饱和树脂/石墨烯复合材料的制备及性能

采用球磨法制备不饱和聚酯树脂/石墨烯纳米复合材料,并对其力学性能、动态力学性能和导电性能进行研究.结果表明:石墨烯微片经过球磨被剥离成厚度低于5层的石墨烯;制备的不饱和聚酯树脂石墨烯复合材料与纯的不饱和聚酯树脂相比,当石墨烯的质量分数为0.5%时,复合材料的拉伸强度、杨氏模量、弯曲强度均达到最大值,分别提高44.99%,47.67%和55.08%;复合材料的冲击性能基本不受石墨烯加入的影响;且复合材料的渗滤阀值为6%.     

T-800碳纤维湿法缠绕用环氧树脂基体研究

针对制备高性能碳纤维缠绕复合材料的要求,以TDE-85树脂为主体树脂、AG-80树脂为添加树脂,选用混合芳香胺固化剂,研究了一种适合于T-800碳纤维复合材料缠绕成型的树脂基体。结果表明,该树脂的黏度和适用期可满足湿法缠绕成型工艺要求,其浇铸体具有优异的耐热性能与机械性能,而其制备的T-800碳纤维复合材料界面粘接好,缠绕强力环层间剪切强度达到81MPa、拉伸强度高于2500MPa,适合T-800碳纤维的湿法缠绕成型。     

防腐剂预处理玉米秸秆皮/HDPE复合材料 制备及其力学性能研究

将不同防腐剂处理后的玉米秸秆皮(CSF)、高密度聚乙烯(HDPE)塑料和其他添加剂共混,熔融复合后,采用挤出成型制备CSF/HDPE复合材料。考察了玉米秸秆皮添加量、防腐剂种类及其处理浓度对复合材料力学性能的影响,并利用扫描电镜(SEM)和红外光谱(FTIR)对复合材料进行表征。结果表明:经氨溶铜季铵盐(ACQ)处理后,随ACQ浓度增加,复合材料力学性能逐渐降低; 玉米秸秆纤维质量分数为50%、ACQ质量分数为1%时,玉米秸秆皮/HDPE复合材料的力学性能最佳。经硼酸锌(ZB)处理后,随ZB浓度的增加,复合材料拉伸强度逐渐增强; 弯曲强度、弯曲模量、冲击强度均呈现先增大后减小的趋势; 玉米秸秆纤维质量分数为50%、ZB质量分数为2%时,CSF/HDPE复合材料的力学性能最佳。     

动力学控制合成原子精确的银纳米团簇及催化还原4-硝基苯酚

Synthesizing atomically precise Ag nanoclusters (NCs), which is essential for the general development of NCs, is quite challenging. In this study, we report the synthesis of high-purity atomically precise Ag NCs via a kinetically controlled strategy. The Ag NCs were prepared using a mild reducing agent via a one-pot method. The as-prepared Ag NCs were confirmed to be Ag₄₉(D-pen)₂₄ (D-pen: D-penicillamine) on the basis of their matrix-assisted laser desorption ionization time-of-flight mass spectrometric and thermogravimetric characteristics. The interfacial structures of the Ag NCs were illustrated by proton nuclear magnetic resonance and Fourier-transform infrared spectroscopy. The Ag NCs were supported on activated carbon (AC) to form Ag NCs/AC, which displayed excellent activity for the catalytic reduction of 4-nitrophenol with a kinetic reaction rate constant k of 0.21 min?1. Such a high k value indicates that the composite could outperform several previously reported catalysts. Moreover, the catalytic activity of Ag NCs/AC remained nearly constant after six times of recycle, which suggests its excellent stability.     

Ti – Cu– Zr–Fe– Nb ultrafine structur e-dendrite composites with good mechanical properties and biocompat ibility

Ti-Cu-Zr-Fe-Nb ultrafine structure-dendrite composites were designed by inducing Nb and more Ti to a Ti-Cu-Zr-Fe glass-forming alloy composition and prepared by copper mold casting.The composite alloys consist of β-Ti dendrites and ultrafine-structured CuTi₂ and CuTi phases as well as a trace amount of glassy phase.The volume fraction of β-Ti dendrites increases with the increase in content of Nb which acted as the β-Ti phase stabilizer in the alloys.The composites exhibit high compressive yield strength exceeding1200 MPa,maximum strength around 1800 MPa and low Young’s modulus around 48 GPa.The plasticity of the alloys is strongly influenced by the volume fraction and morphology of the dendritic β-Ti phase,and the compressive plastic strain was enlarged from 5.9%for the 4 at%Nb alloy to 9.2%for the 8 at%Nb alloy.The preliminary cell culture experiment indicated good biocompatibility of the composite alloys free from highly toxic elements Ni and Be.These Ti-based composite alloys are promising to have potential structural and biomedical applications due to the combination of good mechanical properties and biocompatibility.     

不同粒径的甲基环己基次膦酸盐/环氧树脂阻燃材料的性能比较

采用4种不同粒径的Al(MHP)作为环氧树脂(EP)的阻燃剂,着重讨论了Al(MHP)的粒径对EP复合材料的阻燃性能、热性能以及EP胶粘剂的粘接强度的影响。结果表明,减小Al(MHP)的粒径能显著提高EP复合材料的热性能、分解过程中的残炭率以及EP胶粘剂的粘结强度。当Al(MHP)的粒径从36.50μm减小到4.11μm,Al(MHP)含量为17 wt%的EP复合材料的氧指数(LOI)从34%增加到39%,聚合物空气中热分解到700℃时残炭率由23%增加到31%,剪切强度由4.77 MPa增加到8.44 MPa。