PA6／CNT复合材料的动态机械性能和增强机理分析

采用三种处理方法得到了不同表面性质的碳纳米管，与尼龙6共混制备了PA6／CNTs复合材料。考察了复合材料的动态机械性能。研究发现，碳纳米管的加入提高了尼龙6的储能模量和损耗模量，碳纳米管表面的性质决定了对复合材料动态机械性能的改变程度。经过高温高压剧烈反应的CNTs3#会断裂为尺寸较小的碳管，小尺寸碳管的成核作用使得复合材料结晶度提高，以及CNTs3#表面接枝的一NH2和未反应的-COOH，会造成尼龙6大分子链段的交错缠绕，因而PA6／CNTs3#的储能模量和损耗模量最大。混酸和加热搅拌条件下氧化CNTs1#含有比单纯浓硝酸氧化的CNTs2#更多的-COOH，所以PA6／CNTs 1#的储存模量和损耗模量大于PA6／CNTs2#。     

PLA/CNTs复合材料研究进展

介绍了近年来国内外用碳纳米(管CNTs)改性聚乳(酸PLA)的研究进展,重点介绍了PLA/CNTs复合材料的制备方法以,及CNTs对PLA复合材料的力学性能导、电性热、稳定性结、晶性能和生物相容性等的影响。     

铝炭复合材料的机械性能

对影响铝炭复合材料机械性能的诸因素，如气孔率、结合剂种类及用量、焙烧温度、石墨用量等进行了实验研究。     

PEEK/GF/CNTs复合材料的制备及性能研究

采用模压法制备了PEEK/GF/CNTs复合材料,研究了复合材料的力学、电性能、导热、耐摩擦等性能。结果表明:当CNTs含量为8%时,PEEK/GF/CNTs复合材料的拉伸强度最大为80.63 MPa;其导热系数随着CNTs含量的增加而增加,当CNTs含量为10%时,导热系数最大,为0.354 8 W/(m·K);体积电阻率随着CNTs含量的增加而逐渐减小;当CNTs含量为8%时,PEEK/GF/CNTs复合材料摩擦系数最佳值为0.113;CNTs能有效阻止PEEK基体从PEEK/GF/CNTs复合材料表面翘起、剥落;CNTs的加入降低了PEEK的结晶性能。     

早龄期CNTs增强水泥基复合材料的性能研究

研究了碳纳米管增强水泥基复合材料的力学及电学性能.水泥基体中掺入碳纳米管后,水泥基复合材料的抗折、抗压强度出现了显著地增强,并且复合材料的平均电阻率出现了明显地降低.当掺入0.08wt％的CNTs时,CNTs-008水泥基复合材料的抗折、抗压强度最优,分别增强到11.0 MPa、58.8 MPa,比空白水泥基的抗折、抗压强度分别增强近41.0％和36.7％.XRD和TGA的结果证明,CNTs掺入水泥基体后可以提高早龄期下复合材料水泥基体的水化速度,从而对水泥基体有明显的增强、增韧效果.当掺入0.1wt％的CNTs后,CNTs-010试样中的平均电阻率下降至32.3Ω·m,相比空白样品CNTs-000的63.3Ω·m,降幅达到了48.9％.根据试样的压敏性能测试发现,CNTs-008具有良好的压敏性能,样品的平均电阻率随着压应力的增加,出现了线性降低的趋势.     

PA/CNTs复合材料的电性能研究

采用共沉淀法制备了尼龙6(PA6)/碳纳米管(CNTs)复合材料,研究了该复合材料的电性能。结果表明,CNTs的质量分数为5%时,复合材料的电导率由纯PA6的1×10-15S/cm提高到2.1×10-5S/cm,比纯PA6提高了10个数量级;CNTs的质量分数为15%时,复合材料的电导率为0.13S/cm,比纯PA6提高了14个数量级。在所研究的温度范围内,该复合材料表现出负电阻温度系数效应。当CNTs的质量分数为15%时,复合材料的伏安特性曲线非线性明显,符合半导体特性。     

碳纳米管/聚脲纳米复合材料的制备和性能

提出了一种聚脲/碳纳米管纳米复合材料的分子设计以及制备方法。首先,采用混酸氧化处理得到羟基改性的碳纳米管。随后,利用原位聚合的方法合成了含有碳纳米管的端异氰酸根预聚物,其中碳纳米管通过表面羟基和异氰酸根的反应,以共价键形式连接到预聚物分子链中。最后,使用端氨基聚醚固化端异氰酸根预聚物,得到碳纳米管/聚脲纳米复合材料。结果发现随着碳纳米管含量的增加,碳纳米管/聚脲纳米复合材料的凝胶含量和拉伸强度均有显著提高。     

碳纳米管-水泥基复合材料的力学性能和微观结构

研究了掺碳纳米管水泥砂浆的力学性能和微观结构,并与掺碳纤维水泥砂浆的性能进行了对比。低含量的碳纳米管-水泥复合材料具有良好的抗压强度和抗折强度。用扫描电镜对碳纳米管-水泥复合材料以及碳纤维-改性水泥复合材料的微观结构进行了分析。结果表明：复合材料中碳纳米管表面被水泥水化产物包裹,同时碳纳米管水泥砂浆的结构密实。碳纤维表面光滑,在碳纤维与水泥石之间存在明显裂缝。孔隙率测试结果表明碳纳米管的掺入改善了材料的孔结构。     

PA6／CNTs复合材料的电性能研究

采用共沉淀法制备了尼龙6（PA6）／碳纳米管（CNTs）复合材料．研究了该复合材料的电性能。结果表明,CNTs的质量分数为5％时,复合材料的电导率由纯PA6的1×10^-15S／cm提高到2．1×10^-5S／cm,比纯PA6提高了10个数量级;CNTs的质量分数为15％时,复合材料的电导率为0．13S／cm,比纯PA6提高了14个数量级。在所研究的温度范围内,该复合材料表现出负电阻温度系数效应。当CNTs的质量分数为15％时,复合材料的伏安特性曲线非线性明显,符合半导体特性。     

氨基酸同时剥离和功能化二硫化钼对环氧树脂机械性能增强的研究

通过液相剥离法用氨基酸(Gly)成功地剥离和改性了二硫化钼(MoS2),并将改性后MoS2采用物理共混法加入到环氧树脂中,表征了其结构、热力学性能、力学性能等.研究结果表明:Gly已经成功地连接到MoS2纳米片表面;改性后复合材料的热学性能、力学性能显著优于纯环氧树脂,其中拉伸剪切强度在室温下和150℃下分别增加约55...     

木粉/UPR复合材料的制备及力学性质研究

使用硅烷偶联剂表面处理的木粉(MW)和未改性木粉(UW)填充不饱和聚酯树脂(UPR)制备了复合材料.研究了表面改性处理和木粉粒径对复合材料力学强度的影响.结果表明,相对于未改性的木粉,用硅烷偶联剂处理的木粉对不饱和聚酯树脂有更强的增强作用,添加量为20(wt)％的MW/UPR复合材料的拉伸强度比纯UPR提高74.4％,...     

PVC/高岭土复合材料的制备及其力学性能研究

针对PVC加工过程中韧性差、冲击强度低、热不稳定等问题,制备了PVC/N-十六烷基马来酰胺酸镧(Ⅲ)-高岭土复合材料。通过刚果红实验、傅里叶红外光谱(FTIR)、X-射线衍射(XRD)、热重分析(TGA)等表征了其结构与热性能;通过扫描电镜(SEM)观察复合材料表观形貌;研究了插层后的高岭土对PVC材料抗冲击强度的影响。结果表明,插层改性后的高岭土层间距增大;PVC复合材料圆形度得到了提高,外形变得更加规整;获得的复合材料断裂伸长率和冲击强度都有所增强,复合材料的热稳定性能也得到了提高。     

Preparation and mechanical properties of machinable alumina/mica composites

Using a mica-crystallizing glass powder in which a large amount of mica crystal was precipitated and a larger amount of MgF₂ component was contained as the raw materials of mica, machinable alumina/mica composites were obtained at 1400 °C. In the firing process, magnesia component in the mica crystals reacted with alumina to form spinel at 1150–1200 °C. The reaction made the mica crystals melt. However, the mica crystals were precipitated again during the cooling. Because a larger amount of MgF₂ component was contained in the mica-crystallizing glass powder, the nucleation of the mica crystals was caused during the cooling by the residual magnesium and fluorine in the liquid phase and succeedingly the mica crystals were precipitated. The precipitated mica crystals grew to anisotropicaly larger size than alumina grains, which lowered the bending strength and Vickers hardness and little heightened the fracture toughness.     

Preparation and mechanical properties of waterborne polyurethane/carbon nanotube composites

Waterborne polyurethane (WBPU) and multiwalled carbon nanotubes (CNTs) composite films with 0–4.0 wt% CNTs were prepared by ultrasonic dispersion of carboxylic acid‐functionalized CNTs in WBPU followed by emulsion casting process. The elongations at break of the WBPU/CNTs composites increase with the incorporation of CNTs. The tensile strength and crystallinity of the nanocomposite films with lower CNTs contents (<2 wt%) increase obviously; while the tensile strengths of the composites with more CNTs (≥2 wt%) decrease, in contrast to the pure PU film. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations indicated that the CNTs are uniformly dispersed in the composites incorporated with lower CNTs contents (≤1.5 wt%). However, aggregation of CNTs increased with increasing CNTs content in the WBPU/CNTs composites, causing the macrophase separation. The dispersion state of the CNTs affects the crystallinity of the PU matrix and the phase separation of the composites, which are two key factors to influence the mechanical properties of the WBPU/CNTs composites. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

EOC-g-MAH共混增韧SGF/PP泡沫复合材料的制备及力学性能

采用型内二次发泡工艺制备了马来酸酐接枝乙烯-1-辛烯共聚物(EOC-g-MAH)共混增韧短玻璃纤维(SGF)/聚丙烯(PP)泡沫复合材料,考察了EOC-g-MAH含量对复合材料的泡孔形貌、微观结构和力学性能的影响。结果表明,EOC-g-MAH的引入改善了泡沫体的发泡效果,平均孔径减小约35%,泡孔密度提高近4倍且分布均匀。SGF与基体间的界面结合得到显著增强,且EOC-g-MAH在SGF表面形成了颗粒黏附结构,大幅提高了SGF/PP泡沫复合材料的冲击韧度,并在质量分数为8%时达到最大值,增幅为77%。随着EOC-g-MAH质量分数的增加,SGF/PP泡沫复合材料的抗弯强度先增加后降低,而压缩强度则呈近似线性下降的变化趋势。     

TPS/EVA泡沫复合材料的制备及其阻燃与力学性能

以热塑性淀粉(TPS)为成炭剂与聚磷酸铵(APP)、可膨胀石墨(EG)复配组成膨胀型阻燃剂,通过熔融密炼、开炼塑化、硫化发泡制备了热塑性淀粉/乙烯-醋酸乙烯酯共聚物(TPS/EVA)泡沫复合材料,探讨了TPS用量对泡沫复合材料阻燃性能、力学性能的影响。结果表明,TPS的加入显著提高了TPS/EVA泡沫复合材料阻燃性能,可起到良好的成炭作用;TPS/EVA泡沫复合材料的拉伸强度、断裂伸长率以及撕裂强度随着TPS用量的增加呈现先增大后减小的趋势,相对密度则是小幅度上升。当TPS用量为6%时,TPS/EVA泡沫复合材料综合性能最好,其LOI可达26.5%且UL-94为V-0级,拉伸强度、断裂伸长率、撕裂强度以及相对密度可达2.395 MPa、177.48%、10.59 N·mm^-1、0.21452。     

Preparation and balanced mechanical properties of solid and foamed isotactic polypropylene/SEBS composites

This study presents a self-designed foaming apparatus and routes to manufacture foamed isotactic polypropylene (iPP) blends with uniform and dense cells, using styrene-ethylene-butadiene-styrene (SEBS) block copolymer as toughening additive. The addition of SEBS can clearly enhance the impact strength of solid iPP, iPP blends with a 20 wt% SEBS has obtained high notched impact strength of 75 kJ/m², which is ca. 16 times larger than that of neat iPP. Relatively fine microcellular iPP-SEBS foams with the average cell size of several micrometers, and the cell density of 10⁹ cells/cm³ were fabricated using a batch foaming procedure. Moreover, using our self-designed mold and compression foaming method, iPP-SEBS foams with balanced mechanical properties were produced. With the increasing of SEBS, tensile strength and flexural strength were slightly decreased, but the impact strength was increased clearly. The balanced mechanical properties between stiffness and toughness were achieved after compression foaming.     

Preparation and mechanical properties of alumina composites reinforced with nickel-coated graphene

This paper discusses the influence of nickel–phosphorus coated graphene (Gn–Ni–P) and uncoated graphene (Gn) addition to an alumina matrix and its impact on the mechanical properties of obtained composites. The composites are prepared via powder processing and consolidated using the Spark Plasma Sintering (SPS) method. The effects of the addition of coated graphene and coating thickness on mechanical properties were evaluated. Physical properties such as relative density, hardness and fracture toughness were analyzed. Significant improvement of the fracture toughness (60%) for the composites with 2 vol% Gn–Ni–P compared to reference sample was observed. Moreover, 35% higher K_IC was noticed for Gn–Ni–P reinforced composites than for Al₂O₃–Gn.     

柚皮环氧树脂/埃洛石复合材料的制备及性能

以柚皮素为原料合成了新型柚皮环氧树脂,以埃洛石纳米管为改性剂、马来酸酐为固化剂采用浇注工艺制备了柚皮环氧树脂/埃洛石复合材料,考察了埃洛石纳米管用量对柚皮环氧树脂/埃洛石复合材料力学性能、动态力学性能、热稳定性的影响。结果表明:纯柚皮环氧树脂的冲击强度及玻璃化转变温度较双酚A型环氧树脂分别提高了3.05 kJ/m²,96℃;埃洛石纳米管能够显著提高柚皮环氧树脂/埃洛石复合材料的冲击强度,当埃洛石纳米管用量为0.8%(w)时,柚皮环氧树脂/埃洛石复合材料的冲击强度为5.50 kJ/m²,较纯柚皮环氧树脂提高了52.8%。     

PLA/MCC复合材料的制备及其性能

以水稻秸秆经碱解、酸解得到的微晶纤维素(MCC)作为聚乳酸(PLA)的改性材料,通过溶液共混、流延成膜制备了PLA/MCC复合膜,采用傅里叶变换红外光谱仪、差示扫描量热仪、扫描电子显微镜等对其性能进行了表征。结果表明:水稻秸秆中木质素、半纤维素等杂质大部分被有效除去,当NaOH质量分数为5%时,去除率最大,MCC成功制备;当MCC质量分数为8.3%时,可以最大程度改善PLA/MCC复合膜的拉伸性能,MCC与PLA结合最好,而MCC的加入会使复合膜的热稳定性有所降低。