SiO2气凝胶增强碳泡沫复合材料的制备工艺及性能

碳泡沫复合材料因其特有的多孔结构,在隔热、储能、吸附等领域具有广阔的应用前景.为进一步改善其力学、隔热性能,本工作以锆改性酚醛树脂、酚醛空心微球为原料,SiO2气凝胶为增强相,通过模压成型-碳化工艺制得SiO2气凝胶改性碳泡沫复合材料.采用扫描电子显微镜、万能试验机、比表面积及孔径分布测试仪等研究了SiO2气凝胶含量对...     

EP/纳米SiO2/空心微珠复合材的性能研究

选用微米级空心微珠和纳米SiO2作为填料,制备环氧树脂(EP)／纳米SiO2／空心微珠复合材料,研究空心微珠用量对复合材料的拉伸性能和冲击性能的影响,采用扫描电镜(SEM)研究复合材料的断裂模式,初步讨论了复合材料的隔热性能。结果表明,纳米SiO2和空心微珠的加入可以提高复合材料的拉伸强度和冲击强度,并且当空心微珠用量为10％、纳米SiO2用量为3％时,复合材料的各项力学性能最佳。随着空心微珠含量的继续增加,复合材料的拉伸强度和冲击强度均有不同程度的降低,拉伸弹性模量却有提高趋势。此外,空心微珠的加入使复合材料的脆性提高、韧性降低,隔热性能却有所改善。     

无机改性颗粒对水性氟碳涂料性能的影响

将空心玻璃微球、陶瓷微球、α-氧化铝和γ-氧化铝添加至水性氟碳涂料中,研究其对水性氟碳涂料的反射隔热性能、白度、黏度、耐酸性、耐热性和涂料外观形貌的影响。结果表明：多聚磷酸钠对无机填料具有良好的分散效果;空心玻璃微球提高了涂料隔热性能,降低了涂料用量,改善了涂料其他性能,但加入量过多会增加涂料黏度,影响施工性能。陶瓷微球、α-氧化铝和γ-氧化铝等无机粒子会提高涂料的热反射性能。混掺空心玻璃微球、陶瓷微球和γ-氧化铝加入水中,提高了涂料的反射隔热、耐酸性和耐热性性能。     

空心玻璃微球填充改性PVC的研究

采用共混法合成了空心玻璃微球／聚氯乙烯（PVC）复合材料,空心玻璃微球使用前先用硅烷偶联剂KH-550进行了表面改性。通过高倍光学显微镜、红外分析仪、电子拉力机、邵氏硬度检测仪等手段研究了空心玻璃微球的含量对PVC抗拉强度,冲击强度和硬度等性能影响。结果表明：随着玻璃微球含量的逐渐增加,PVC复合材料的拉伸强度先增加后...     

空心微球填充聚氨酯弹性体的合成与性能研究

以PEA/TDI-100/MOCA作为聚合体系,采用预聚物法合成聚氨酯弹性体,考察了空心微球填充份数与粒径、偶联剂种类与用量等对聚氨酯弹性体性能的影响。结果表明,加入未经改性空心微球的聚氨酯弹性体性能下降,经偶联剂改性空心微球填充聚氨酯能明显提高试样的硬度、撕裂强度力学性能,合成工艺对改性空心微球填充聚氨酯弹性体力学性能影响较大。     

空心玻璃微球导热系数数值模拟与实验研究北大核心

根据超景深三维显微镜所观察到的环氧树脂/空心玻璃微球的实际微观结构,基于Ansys软件和简化的实际模型,使用随机序列吸附算法,建立代表性体积单元,设置相应实际模型。通过简化模型拟合填料与复合材料导热系数之间的关系,结合实际模型的复合材料导热系数求解结果,对空心玻璃微球隔热性能进行求解。结果表明:由不同牌号填料制备的环氧树脂/空心玻璃微球复合材料,数值模拟结果与实验结果误差保持在3.00%以内,在此基础上对空心玻璃微球导热系数进行求解,并与不同理论结果对比,验证了空心玻璃微球导热系数求解方法的正确性。     

高耐热低介电常数的聚酰胺复合材料的制备与分子动力学模拟研究

同时具有高模量和低介电常数的聚酰胺复合材料在电子电器领域具有重要的潜在应用。本文将玻璃纤维和空心玻璃微球引入到聚酰胺体系中制备聚合物复合材料,利用万能材料试验机和宽频介电谱阻抗分析仪等手段对复合材料的性能进行测试发现,玻璃纤维能改显著地改善聚酰胺复合材料的拉伸性能,空心玻璃微球能够有效地降低聚酰胺复合材料的介电性能。当玻璃纤维的含量为45%,空心玻璃微球的质量分数为10%,复合材料的性能最佳。分子动力学模拟结果表明分子链越长,聚酰胺的介电常数越小。这些实验结果和理论模拟为进一步提升聚酰胺复合材料的综合性能提供了参考。     

轻质环氧基复合材料隔热性能的实验与数值研究

通过实验和数值模拟方法研究了空心玻璃微球/环氧树脂复合材料隔热性能。首先使用ANSYS/APDL建立代表性体积单元,探讨了模拟过程中模型尺寸、填料体积分数、填料平均粒径及基体与填料导热系数之比(λ_m/λ_p,λ_m保持不变)对复合材料导热系数的影响。数值研究结果表明:当代表性体积单元尺寸大于500μm时,模型尺寸对复合材料导热系数的计算结果影响较小;复合材料导热系数随填料体积分数和λ_m/λ_p的增大而减小,且基本不受填料粒径影响。其次,将复合材料导热系数实验值和计算结果进行对比,比较发现导热系数计算结果和实验值及Agari模型理论值吻合较好,证明了计算方法的可靠性。同时,空心玻璃微球的掺入有效地降低了树脂的密度。轻质隔热的空心玻璃微球/环氧树脂复合材料有潜力成为一种具有广泛应用前景的节能环保材料。     

热电池隔热涂层的制备与性能

采用水热法制备ZrO2空心微球作为隔热填料,以萘改性的耐热酚醛环氧树脂为基体,制备了4种不同ZrO2含量的热电池隔热涂层,表征了其性能. 结果表明,所制ZrO2为直径约500 nm的空心球,表面粗糙;酚醛环氧树脂的热分解温度约为370℃,适宜的ZrO2空心球添加量为50%~60%(w). ZrO2含量为50%(w)时,室温下隔热涂层结合强度为21.6 MPa,剪切强度为11.4 MPa,热导率为0.05 W/(m×K);300℃下隔热涂层剪切强度为3.1 MPa,热导率为0.04 W/(m×K).     

空心玻璃微珠／聚四氟乙烯复合材料的性能研究

采用共混方法制备了空心玻璃微珠/聚四氟乙烯复合材料.研究了复合材料的密度、吸水性、压缩强度、冲击强度、邵氏硬度、隔热性能,并借助SEM探讨了冲击断面的微观形态结构,对各影响因素进行了分析.结果表明:加入适量的玻璃微珠可以提高复合材料的隔热性能,降低复合材料的密度;由于空心玻璃微珠强度低及界面缺陷的存在,复合材料的机械性能下降,但在加入少量空心玻璃微珠时,模压过程中产生的玻璃碎片提高了复合材料的压缩强度.     

Mechanical, thermal and ablative properties of interply continuous/spun hybrid carbon composites

The mechanical and thermal properties of interply hybrid carbon fiber (continuous and spun fabric)/phenolic composite materials have been studied. Hybrid carbon/phenolic composites (hybrid CP) with continuous carbon fabric of high tensile, flexural strength and spun carbon fabric of better interlaminar shear strength and lower thermal conductivity are investigated in terms of mechanical properties as well as thermal properties.Through hybridization, tensile strength and modulus of spun type carbon fabric reinforced phenolic composites (spun CP) increased by approximately 28% and 20%, respectively. Hybrid CP also exhibits better interlaminar shear strength than continuous carbon fabric/phenolic composites (continuous CP).The in-plane thermal conductivity of hybrid CP is 4-8% lower than that of continuous CP. As continuous filament type carbon fiber volume fraction increases, the transversal thermal conductivity of hybrid CP decreases.The erosion rate and insulation index were examined using torch test. Spun CP has a higher insulation index than continuous CP and hybrid CP over the entire temperature range. Hybrid CP with higher content of spun fabric exhibits higher insulation index as well as lower erosion rate.     

Effect of hybrid hollow microspheres on thermal insulation performance and mechanical properties of silicone rubber composites

Hollow microspheres (HM) of ceramic, silica, and glass‐filled silicone rubber (SR) composites were prepared, and the effects of hybrid HM on thermal and mechanical properties of composites were investigated. The results indicate that hybrid HM can effectively improve the thermal insulation property of HM/SR composites. Especially, for sample 15S, the thermal conductivity and thermal degradation temperature reached 0.1273 W/m K and 521 °C (45 °C higher than that of neat SR), respectively. Besides, thermal insulation performance was improved, showing as a temperature of 103.2 °C after 15 min heating, which is 37.8 °C lower than that of SR. The tensile strength of composites was enhanced from 1.92 MPa at 11.56 vol % hollow silica microspheres (HSM) loading to 3.08 MPa at 21.88 vol % HSM loading. Moreover, the compressive strength was improved from 3.33 to 5.68 MPa by introducing more hollow ceramic microspheres into the matrix, in this case, from 7.79 to 15.33 vol %. Furthermore, the failure mechanism was analyzed. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46025.     

轻质环氧复合材料的制备与性能研究

制备了一种以空心玻璃微珠为填充材料的轻质环氧复合材料,确定了材料的固化工艺,并对不同型号的空心玻璃微珠进行了筛选.研究了玻璃微珠填充量对材料密度及力学性能的影响.研究发现,复合材料的密度随空心玻璃微珠填充量的加大呈现先降低后略有升高的趋势;拉伸强度和压缩强度均随填充量的增加而减小;拉伸弹性模量和压缩弹性模量随着填充量提...     

剑麻纤维/玻璃纤维/酚醛树脂复合材料的性能研究

采用剑麻纤维和玻璃纤维与酚醛树脂共混，制备纤维混杂复合材料；测定其弯曲强度、弯曲模量、无缺口冲击强度、电性能以及耐水浸泡性能；借助扫描电子显微镜观察复合材料的形态结构，并进行理论分析。初步探讨了复合材料的界面行为。结果表明，复合材料在力学性能方面出现正的混杂效应，吸水性能大大降低，在电性能方面没有很大影响。     

Structure and properties of UHMWPE fiber/carbon fiber hybrid composites

Ultrahigh molecular weight polyethylene (UHMWPE) fiber/carbon fiber hybrid composites were prepared by inner‐laminar and interlaminar hybrid way. The mechanical properties, dynamic mechanical analysis (DMA), and morphologies of the composites were investigated and compared with each other. The results show that the hybrid way was the major factor to affect mechanical and thermal properties of hybrid composites. The resultant properties of inner‐laminar hybrid composite were better than that of interlaminar hybrid composite. The bending strength, compressive strength, and interlaminar shear strength of hybrid composites increased with an increase in carbon fiber content. The impact strength of inner‐laminar hybrid composite was the largest (423.3 kJ/m²) for the UHMWPE fiber content at 43 wt % to carbon fiber. The results show that the storage modulus (E′), dissipation factor (tan δ), and loss modulus (E″) of the inner‐laminar hybrid composite shift toward high temperature remarkably. The results also indicate that the high‐performance composite with high strength and heat resistance may be prepared by fibers' hybrid. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1880–1884, 2006     

SiO2气凝胶纤维隔热复合材料的常压制备及性能表征

SiO₂气凝胶的力学性能较差,隔热性能较强,为了使其成为良好的隔热材料,本文提出一种SiO₂气凝胶纤维隔热复合材料的制备方法。以正硅酸乙酯(TEOS)为前驱体,玻璃纤维和陶瓷纤维为增强体,硅烷偶联剂KH550和KH570为纤维处理剂,在常压条件下制备SiO₂气凝胶纤维隔热复合材料,并对材料性能进行表征。结果表明:前驱体中十六烷基三甲基溴化铵(CTAB)含量越高,复合材料中SiO₂气凝胶导热系数越低,低至0.028 W/(m·K);使用硅烷偶联剂KH550时,基体和纤维之间结合的紧密程度更高;纤维的加入使SiO₂气凝胶的力学性能达到很高水平;当前驱体中TEOS与CTAB摩尔比为1∶0.022时,经KH550处理的玻璃纤维/SiO₂气凝胶复合材料导热系数为0.054 W/(m·K),力学性能良好,隔热性能最优。     

Synthesis of monolithic alumina-silica hollow microspheres and their heat-shielding performance for adiabatic materials

Al₂O₃ ceramic foams-based composites were firstly synthesized to be used as the thermal insulation material which has excellent mechanical properties of the substrate material and better thermal properties of hollow microspheres. In this research, by doping TEOS, the monolithic hollow microspheres were prepared via a novel and effective synthesis route using propylene oxide as the gelation initiator to induce the gelation of aluminum chloride hexahydrate solution. The influence of TEOS on the morphology and high-temperature stability of the monolithic hollow microspheres was clarified in detail. Based on the optimized additive amount of TEOS, Al₂O₃ ceramic foams were introduced as the substrate material of alumina-silica hollow microspheres to fabricate the final Al₂O₃ ceramic foams-based composites. Benefited from this special structure, the Al₂O₃ ceramic foams-based composites displayed excellent mechanical properties and thermal properties. The samples changed less in appearance and did not show significant shrinkage after heat-treatment at 1200 °C. The density, bending strength and thermal conductivity of the Al₂O₃ ceramic foams-based composite were 0.32 g/cm³, 1.8 MPa and 0.12 W/m K, respectively.     

Carbon-fiber-reinforced phenolics

Carbon-fiber-reinforced (CFR) phenolic composites with equivalent mechanical properties and much superior thermal stability to laboratory-prepared and present commercial epoxy analogs have been achieved by reinforcing 35-50 wt % of an amine-catalyzed resole with either the Hercules' Magnamite carbon fabric or the Great Lakes' Varinit carbon fiber/glass cloth hybrid. Improvement of the interlaminar shear strength (ILSS) of the hybrid-reinforced phenolic laminates was observed with increasing molding pressure and alternate carbon/glass/carbon/glass geometry. Sizings on the carbon fiber do not have any significant effect on the mechanical properties.     

BF/CF层间混杂结构对复合材料性能影响

制备了碳纤维/玄武岩纤维(CF/BF)层间混杂增强酚醛树脂基复合材料,通过力学性能测试研究了混杂结构对复合材料性能的影响,并与层数相同叠合压制成型的BF复合材料的性能进行了对比。结果表明,CF/BF混杂纤维增强酚醛树脂基复合材料较BF复合材料力学性能提高,嵌层结构复合材料综合性能好于夹芯结构。     

Carbon fiber reinforced phenolic Resin/Silica ceramer composites—processing,mechanical and thermal properties

Phenolic/silica ceramers were prepared by the sol‐gel method. Carbon fiber reinforced phenolic/silica ceramer composites with high thermal resistance were fabricated. Tetraethyl orthosilicate (TEOS) was used as a monomer for sol‐gel system. Different ratios of the sol‐gel solutoins and phenolic resins were adopted and the resulting ceramers were used as matrices for carbon fiber reinforced composites. The mechanical and thermal properties of the fabricated composites were studied. The results show that the incorporation of inorganic ingredients into the phenolic resins will increase the thermal resistance of the fabricated composites but not affect the flexural strength of the carbon fiber reinforced phenolic/silica ceramer composites up to 60 wt%. The morphologies of the ceramer matrices were examined by SEM. SiO₂ particles from at the gaps between fibers for higher inorganic contents.