氧化铝/环氧树脂/聚氨酯导热复合材料的制备及表征

采用硅烷偶联剂KH550对氧化铝表面进行改性,并以改性氧化铝为导热填料,以环氧树脂为基体树脂,自制的聚氨酯预聚体为柔性改性剂,制备了氧化铝/环氧树脂/聚氨酯导热复合材料。采用红外光谱对KH550改性氧化铝的结构进行了表征,探讨了影响复合材料热导率的主要因素,研究了改性氧化铝用量对复合材料力学性能的影响,并利用扫描电镜对复合材料的微观结构进行了观察。结果表明,KH550已通过化学键接枝在氧化铝表面。随着KH550改性氧化铝用量的增加,复合材料的拉伸强度逐渐增大,而导热率和断裂伸长率呈现先上升后下降的趋势。当改性氧化铝的用量为150 phr时,复合材料的导热率达到最大值0.66 W/(m·K),拉伸强度和断裂伸长率分别为37.2 MPa和1.62%。随着m(PUA)/m(EP)的增大,复合材料的导热率相应下降,适宜的m(PUA)/m(EP)为15/85。     

球形氧化铝填充聚氨酯制备导热塑料

以聚氨酯为基材,球形氧化铝为导热填料,制备了填充型热固性塑料,研究了氧化铝填充量、表面处理对复合材料导热性能的影响,比较了不同粒径氧化铝填充的导热塑料的导热性能,并进行了两者复配研究。结果表明:聚氨酯复合材料的导热系数是导热通道的形成与界面层阻碍效应相互作用的结果;当氧化铝填充总量为600质量份且m(BAK–0100):m(BAK–0300)为1:2,并经过占总填料质量1.5%的KH560改性后,所得材料的导热系数高达2.51 W/(m·K)。     

改性石墨对天然橡胶复合材料导热性能的影响

研究表面活性剂或不同偶联剂对石墨改性效果以及石墨用量对天然橡胶(NR)复合材料物理性能、导热性能及微观结构的影响。结果表明:偶联剂Si69对石墨的改性效果最好,石墨呈现亲油性;与未改性石墨填充NR复合材料相比,偶联剂Si69改性石墨填充NR复合材料中石墨与NR间的界面相容性得到改善,物理性能和导热性能提高;随着偶联剂Si69改性石墨用量的增大,复合材料导热性能提高,物理性能先提高后下降。当改性石墨用量为30份时,复合材料的综合性能较好。     

聚合物/Al_2O_3导热绝缘复合材料研究进展

Al_2O_3以其优越电绝缘性及良好导热能力、价格低廉等综合性能成为目前制备导热绝缘复合材料的一类重要填料。综述了聚合物/Al_2O_3导热绝缘复合材料的研究进展,重点阐述了氧化铝的用量、形状、粒径、表面改性、混杂填充及加工方法等对聚合物/Al_2O_3复合材料热导率及其他性能的影响,为制备综合性能优良的聚合物/Al_2O_3复合材料提供有益参考。     

LED用低热阻硅脂的制备

选用合适粒径的氮化铝和氧化铝为混杂导热填料、使用自制的硅烷低聚物为表面处理剂,以溶液插层法对混杂导热填料进行表面改性;然后与甲基苯基硅油混合制备了LED用低热阻导热硅脂。研究了导热填料的种类、粒径、表面处理剂种类及用量对导热硅脂的热导率和黏度的影响。采用LED灯作为实际测试平台表征了导热硅脂的导热性能。结果表明,当填料总质量分数为90.9%,粒径为5μm的氮化铝与粒径为1μm的氧化铝作混合填料且质量比为2.8∶1时,导热硅脂的热导率和黏度有较好的平衡;使用填料质量0.5%的硅烷低聚物对氮化铝和氧化铝混合填料进行表面处理有较好的处理效果;自制10号硅脂样品的黏度（25℃）为174 Pa·s,热阻为1.94℃/W,热导率为4.31 W/m·K。     

氧化铝和碳化硅填充硅橡胶的导热性能研究

研究氧化铝和碳化硅填充硅橡胶的导热性能。结果表明:采用不同粒径碳化硅填充硅橡胶时,随着碳化硅用量的增大,硅橡胶的热导率逐渐增大;在相同填料用量下,粒径小的碳化硅填充硅橡胶热导率高于粒径大的碳化硅填充胶;氧化铝/碳化硅并用填充硅橡胶的导热性能优于单用氧化铝填充胶;当氧化铝/碳化硅质量比为8:2、填充量为600份时,硅橡胶的导热性能最佳。     

纳米氧化铝填充EPDM制备高性能复合材料

采用纳米氧化铝(Al_2O_3)为填料,制备不同配比的EPDM/Al_2O_3复合材料,并分别研究了复合材料的机械性能、导热系数和微观形貌。研究结果表明,随着Al_2O_3用量的增加,复合材料的力学性能表现得更为优异,导热系数也明显增加;纳米Al_2O_3的用量增加至100份,复合材料的导热系数增加至0.53 W/(m·K),压缩疲劳值增加的较少,大大降低了填料与橡胶基体之间的摩擦,因此表现出较小的热量积累。在同一配比下,填充纳米Al_2O_3的复合材料与其他填料的机械性能接近,导热系数明显增加,比炭黑N550填充复合材料的热导率高约32.3%,比聚氯乙烯(PVC)填充复合物的热导率高出57.7%。Al_2O_3填料在橡胶基体中可以均匀地分散,复合材料的交联网络较为完善,对于延长材料的使用寿命具有重要意义。     

氧化铝的表面改性及其在导热有机硅灌封胶中的应用

比较了3种硅烷偶联剂对氧化铝的表面改性效果。相对于未改性氧化铝,十六烷基三甲氧基硅烷、γ-氨丙基三乙氧基硅烷和乙烯基三(β-甲氧基乙氧基)硅烷改性氧化铝的吸油值分别降低了56.8%、32.5%、35%,而对应的硅橡胶胶料的黏度分别降低了74.3%、48.6%和45.4%,分散性提高,颗粒无明显团聚,改性效果突出;十六烷基三甲氧基硅烷的改性效果最优,其最佳用量为氧化铝粉体质量的1.5%。将十六烷基三甲氧基硅烷改性氧化铝填充至有机硅灌封胶中,考察了填充量对硅橡胶导热性能、黏度和力学性能的影响。结果表明,当改性氧化铝的填充量为900份时(相对于100份乙烯基硅油),胶料的黏度仅11 800 mPa.s,硫化硅橡胶的热导率高达2.47 W/m.K,拉伸强度1.6 MPa,拉断伸长率35%。     

酚醛树脂改性淀粉/NR复合材料的性能研究

采用间苯二酚-甲醛(RF)树脂改性淀粉,通过乳液共沉法制备淀粉/NR复合材料,研究改性淀粉用量对复合材料性能的影响,并与相同体积分数的炭黑和偶联剂Si69改性的白炭黑填充的NR复合材料进行对比。试验结果表明,RF树脂的加入增强了淀粉与NR之间的交联作用,提高了淀粉/NR复合材料的物理性能;当淀粉用量为20份、经3.6份RF树脂改性后,复合材料的综合性能最佳;随着改性淀粉用量的增大,复合材料的硬度和300%定伸应力增大。当填料体积分数相同时,改性淀粉对NR的补强效果与炭黑接近,且优于白炭黑。     

填充型高分子导热复合材料的研究进展

介绍填充型高分子导热复合材料的研究进展,综述3种无机非金属材料（氧化物、碳化物和氮化物）、碳系填料以及表面功能化填料、杂化填料对高分子导热复合材料导热性能的影响。指出填料的表面功能化改性和杂化有利于改善填料在聚合物基体中的分散性能和界面相容性,从而构建有效的导热网络以提高复合材料的热导率,提出设计合适的配方和工艺是填充型导热复合材料的研究重点。     

SiC/Al2O3/MVQ导热复合材料的制备与性能研究

分别使用碳化硅(SiC)、氧化铝(Al2O3)和SiC/Al2O3复配物制备了导热甲基乙烯基硅橡胶材料(MVQ),研究了SiC,Al2O3和SiC/Al2O3用量及表面改性对MVQ导热系数和力学性能的影响,结果表明,随导热填料用量的增大,MVQ导热系数增大;同等用量下,SiC/Al2O3/MVQ复合材料的导热性能均优于SiC/MVQ和Al2O3/MVQ;当SiC/Al2O3总用量为50份且SiC/Al2O3质量比为3/1时,复合材料导热系数为0.76 W/mK;随SC/Al2O3用量的增加,拉伸强度与拉断伸长率均降低,邵尔A硬度增大.表面处理后,复合材料导热性能得到进一步改善.     

Preparation of nano‐reinforced thermal conductive natural rubber composites

Natural rubber (NR) composites highly filled with nano‐α‐alumina (nano‐α‐Al₂O₃) modified in situ by the silane coupling agent bis‐(3‐triethoxysilylpropyl)‐tetrasulfide (Si69) were prepared. The effects of various modification conditions and filler loading on the properties of the nano‐α‐Al₂O₃/NR composites were investigated. The results indicated that the preparation conditions for optimum mechanical (both static and dynamic) properties and thermal conductivity were as follows: 100 phr of nano‐α‐Al₂O₃, 6 phr of Si69, heat‐treatment time of 5 min at 150°C. Furthermore, two other types of fillers were also investigated as thermally conductive reinforcing fillers for the NR systems: (1) hybrid fillers composed of 100 phr of nano‐α‐Al₂O₃ and various amounts of the carbon black (CB) N330 and (2) nano‐γ‐Al₂O₃, the particles of which are smaller than those of nano‐α‐Al₂O₃. The hybrid fillers had better mechanical properties and dynamic performance with higher thermal conductivity, which means that it can be expected to endow the rubber products serving under dynamic conditions with much longer service life. The smaller sized nano‐γ‐Al₂O₃ particles performed better than the larger‐sized nano‐α‐Al₂O₃ particles in reinforcing NR. However, the composites filled with nano‐γ‐Al₂O₃ had lower thermal conductivity than those filled with nano‐α‐Al₂O₃ and badly deteriorated dynamic properties at loadings higher than 50 phr, both indicating that nano‐γ‐Al₂O₃ is not a good candidate for novel thermally conductive reinforcing filler. POLYM. COMPOS., 37:771–781, 2016. © 2014 Society of Plastics Engineers     

高填充改性复合材料导热预测模型的建立及应用

在对高填充改性复合材料导热过程进行研究的基础上,建立了基于串并联/并串联模型并考虑了界面热阻作用的高填充改性复合材料导热预测模型。借助于双转子连续混炼机制备两种氧化铝粒径不同填充量的聚丙烯/氧化铝（PP/Al₂O₃）复合材料,运用激光导热仪对其导热性能进行了表征,并与模型预测结果进行了对比。结果表明,所建立的模型对高填充复合材料的导热性能的预测具有较高的准确性;当氧化铝填充量较低时,模型中的界面热阻因子最高;随着氧化铝填充量增加,界面热阻因子显著降低;当氧化铝填充量继续增加时,界面热阻因子逐渐降低并趋于稳定;高填充量下相同制备工艺下同种填充改性复合材料的界面热阻近似相同。     

氧化铝及碳纤维对EPDM/MVQ共混胶性能的影响

选用EPDM/MVQ共混胶为基体,研究了氧化铝、碳纤维/氧化铝对EPDM/MVQ共混胶力学性能、导热性能及导电性能的影响。结果表明,随着氧化铝用量的增加,共混胶的力学性能下降,导热性能增加,电阻变化不大;当氧化铝用量为200份时,复合材料的拉伸强度达到4.5MPa,导热系数达到1.1W/(m·k),选用氧化铝/碳纤维混合填料体系,当氧化铝和碳纤维的用量分别为100份和15份时,复合材料的拉伸强度达到4.8MPa,导热系数达到0.66 W/(m·k)。     

Effective thermal conductivity of three‐phase styrene butadiene composites

Transient plane source technique was used for the simultaneous measurement of thermal conductivity and thermal diffisivity of three‐phase styrene butadiene rubber composites. Two series of styrene butadiene rubber composites were studied, having natural rubber as a variable filler in both the composites along with 10 phr of silica and clay, respectively. The measurements were done at room temperature and normal pressure. The experimental results show that there is a small variation in the thermal conductivity of both the composites with the filler (NR) fraction. It is interesting to note that the thermal conductivity shows a sharp decrease at 10 phr filler loading and then increases. The comparative study of these composites shows that the conductivity as well as the diffusivity of the silica reinforced composites is larger than that of the clay composites. The thermal conductivity of the filler NR has been evaluated using the Agari model. It has also been found that the composite with 40 phr of NR has the maximum thermal conductivity. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1799–1803, 2000     

聚苯胺改性蒙脱土/天然橡胶纳米复合材料的制备与性能

采用原位聚合法制备了聚苯胺质量分数为20% 的聚苯胺改性蒙脱土,并以此作为增强剂利用机械混炼法制备了聚苯胺改性蒙脱土( PANI － MMT) /天然橡胶( NR) 纳米复合材料。使用X 射线衍射仪、傅里叶变换红外光谱仪及扫描电镜等对PANI － MMT 和PANI － MMT/NR 复合材料的结构进行了表征,并考察了PANI － MMT/NR 复合材料的力学性能。结果表明,PANI － MMT/NR 复合材料形成了插层型纳米结构; 与普通的有机蒙脱土/NR 复合材料相比,PANI － MMT/NR 复合材料的力学性能明显提高,PANI － MMT 添加质量为20 份时其力学性能达到最好,并超过了添加40 份炭黑N 660 的NR 的力学性能。     

Thermal conductivity of natural rubber nanocomposites with hybrid fillers

Natural rubber nanocomposites filled with hybrid fillers of multi-walled carbon nanotubes(CNTs) and carbon black(CB) were prepared. CNTs were ultrasonically modified in mixture of hydrogen peroxide(H_2O_2) and distilled water(H_2O). The functional groups on the surface of CNTs, changes in nanotube structure and morphology were characterized by Fourier transform infrared spectroscopy(FT-IR), Raman Spectroscopy, and transmission electron microscopy(TEM). It shows that hydroxyl(OH·) is successfully introduced. The surface defects of modified CNTs were obviously higher than those of original CNTs, and the degree of agglomeration was greatly reduced. Thermal conductivity of the composites was tested by protection heat flow meter method. Compared with unmodified CNTs/CB filling system, the thermal conductivity of hybrid composites is improved by an average of 5.8% with 1.5 phr(phr is parts per hundred rubber) of hydroxyl CNTs and 40 phr of CB filled. A three-dimensional heat conduction network composed of hydroxyl CNTs and CB, as observed by TEM, contributes to the good properties. Thermal conductivity of the hybrid composites increases as temperature rises. The mechanical properties of hybrid composites are also good with hydroxyl CNTs filled nanocomposites; the tensile strength, 100% and 300% tensile stress are improved by 10.1%, 22.4% and 26.2% respectively.     

Study on thermally conductive ESBR vulcanizates

The thermal conductivities of emulsion polymerized styrene-butadiene rubber (ESBR) vulcanizates filled with alumina (Al₂O₃), zinc oxide (ZnO), carbon nanotubes (CNTs), silicon carbide (SiC), are measured by steady-state method. The effects of types and loadings of the fillers and their mixture on thermal conductivities of the ESBR vulcanizates are investigated. The results show that the thermal conductivity of ESBR vulcanizates filled with alumina or zinc oxide, increases nearly linearly with increasing loading when the filler loading exceeded 20 phr; the ESBR vulcanizates filled with CNTs have the highest thermal conductivity at a given filler loading in comparison with other composite vulcanizates. At a given loading of 100 phr, the ESBR vulcanizate filled with two different particle sizes SiC of 1–3 and 5–11 μm at the mass ratio of 1:1 has the highest thermal conductivity and relatively good mechanical properties. The experimental results are analyzed using Geometric mean model and Agari’s equation to explain the effect of filler types and particle sizes on the formation of thermal conductive networks. The thermal conductivity of the ESBR vulcanizates filled with Al₂O₃ or ZnO or CNTs could be well predicted by optimized parameters using Agari’s equation for a polymer composite filled with mixtures of particles.     

Thermal properties and processability of talc‐ and calcium carbonate‐filled poly(vinyl chloride) hybrid composites

The main objective of this investigation was to study and compare the thermal rigidity, thermal stability, and processability of poly(vinyl chloride) (PVC) composites filled with single fillers of talc and uncoated ground CaCO₃ (SM 90) or a hybrid filler consisting of talc/SM 90. To produce the composites, the PVC resin, fillers, and other additives were dry‐blended in a laboratory mixer before being milled into sheets by using a two‐roll mill. Test specimens were prepared by compression molding, after which the thermal properties and processability of the composites were determined. Single and hybrid filler loadings used were fixed at 30 phr (parts per hundred parts of resin). Talc‐filled PVC composite showed slightly better thermal stability and rigidity than the composite filled with SM 90, and its thermal stability and rigidity slightly decreased with SM 90 content increasing from 5 to 25 phr in order to replace talc filler in the hybrid composites. The fusion time of talc‐filled PVC composite was shorter than that of SM 90‐filled PVC composite; thus, the fusion time of hybrid composites increased with increasing SM 90. The fusion torque showed an opposite behavior. J. VINYL ADDIT. TECHNOL., 2012. © 2012 Society of Plastics Engineers