高分子复合材料中键合剂在不同纳米填料表面的吸附能计算

由高分子、填料、键合剂及各种功能助剂组成的高分子复合材料广泛应用于轮胎、含能材料、医疗、环保、建筑、交通等行业。键合剂在填料表面的吸附特性对高分子复合材料的性能有重要影响。分别以未改性的高氯酸铵、炭黑和二氧化硅填料为对象,利用第一性原理计算评估了五种键合剂分子,即三乙醇胺(TEA)、三氟化硼三乙醇胺络合物(T313)、N,N'-二邻甲苯胍(DOTG)、N,N'-二苯基硫脲(DPTU)和二苯胍(DPG),在填料表面的吸附能。计算结果表明,随着填料基底层数的增加,吸附能逐渐增加,最后趋于一个稳定值。其中TEA和T313键合剂在高氯酸铵表面的吸附能为-0.84~-1.37 eV;DOTG、DPTU和DPG在炭黑表面的吸附能为-1.01~-1.29 eV;在二氧化硅表面的吸附能为-0.87~-0.94 eV;在接枝羟基的二氧化硅上的吸附能为-1.16~-1.36 eV。依次考察了单层炭黑点缺陷(单空位缺陷、双空位缺陷、Stone-Wales缺陷)和二氧化硅表面接枝羟基对吸附能的影响,发现单空位和双空位缺陷对吸附能影响不大,而Stone-Wales缺陷和二氧化硅接枝羟基显著增加吸附能。     

功能纳米填料在橡胶中的作用及橡胶纳米复合材料的制备

综述了功能纳米填料在橡胶中的作用,如可提高橡胶力学性能,改善橡胶硫化性能、抗老化性能、阻隔及隐身等性能;介绍了橡胶纳米复合材料的制备方法,主要有共混法、原位聚合法、溶胶-凝胶法及层间插入法;展望了功能纳米填料在橡胶中的作用及橡胶纳米复合材料制备的发展前景。     

疏水性非微珠型建筑反射隔热涂料性能研究

建筑外墙和屋面用疏水性非微珠型建筑反射隔热涂料采用纳米隔热粉和纳米辐射粉作为主要功能性填料,可用普通建筑涂料生产工艺生产,产品具有良好的隔热、疏水性,且能减少雨水的渗透,提高建筑节能的效果.     

高分子复合材料中键合剂在不同纳米填料表面的吸附能计算

由高分子、填料、键合剂及各种功能助剂组成的高分子复合材料广泛应用于轮胎、含能材料、医疗、环保、建筑、交通等行业。键合剂在填料表面的吸附特性对高分子复合材料的性能有重要影响。分别以未改性的高氯酸铵、炭黑和二氧化硅填料为对象,利用第一性原理计算评估了五种键合剂分子,即三乙醇胺(TEA)、三氟化硼三乙醇胺络合物(T313)、N,N'-二邻甲苯胍(DOTG)、N,N'-二苯基硫脲(DPTU)和二苯胍(DPG),在填料表面的吸附能。计算结果表明,随着填料基底层数的增加,吸附能逐渐增加,最后趋于一个稳定值。其中TEA和T313键合剂在高氯酸铵表面的吸附能为-0.84~-1.37 eV;DOTG、DPTU和DPG在炭黑表面的吸附能为-1.01~-1.29 eV;在二氧化硅表面的吸附能为-0.87~-0.94 eV;在接枝羟基的二氧化硅上的吸附能为-1.16~-1.36 eV。依次考察了单层炭黑点缺陷(单空位缺陷、双空位缺陷、Stone-Wales缺陷)和二氧化硅表面接枝羟基对吸附能的影响,发现单空位和双空位缺陷对吸附能影响不大,而Stone-Wales缺陷和二氧化硅接枝羟基显著增加吸附能。     

聚3, 4-乙烯二氧噻吩: 聚苯乙烯磺酸盐基柔性复合热电材料研究进展

热电材料可以实现热能与电能的直接转化,是一种安全环保的新型能源材料。近年来,随着可穿戴电子设备的发展,柔性热电材料成为研究人员关注的焦点。传统无机热电材料具有优异的热电性能,但由于自身固有的脆性,限制了在柔性领域的发展。聚3, 4-乙烯二氧噻吩: 聚苯乙烯磺酸盐(PEDOT: PSS)具有高电导率、低热导率和良好的柔性,在柔性热电领域具有巨大的潜力。当选择合适的无机填料与PEDOT: PSS进行复合,可以得到优异的热电性能和良好的力学性能。本文综述了PEDOT: PSS基纳米复合薄膜的最新进展,并详细介绍了提高PEDOT: PSS基纳米复合薄膜热电性能的有效方法。最后,本文总结了实现高性能PEDOT: PSS基柔性热电材料的途径及面对的挑战。      

Rheological characterization of filled polyamide 11 and polyamide 12 solutions in polyols

A thorough understanding of the rheological properties of real-world, formulated polymer melts and solutions is important to fabricate articles via typical melt processing techniques. Polyamides have been studied extensively in the area of water purification applications. In this work, the viscosity of these homogeneous polyamide 11 and polyamide 12 solutions in specific polyols was measured in the single phase region as a function of shear rate and temperature via capillary rheometry. In addition, the viscosity of the same polyamide solutions containing various levels of dispersed, nanoscale calcium carbonate particles was characterized in order to understand the rheology of the filled systems. Viscosity-reduced shear rate master curves were constructed by applying the principle of time–temperature superposition, and the activation energies were measured for the polyamide-polyol solutions. The observed increase in viscosity caused by the addition of nanofiller could not be explained by simply applying a vertical shift to the master curve, and a density exponent was required to account for the stiffening mechanism. Also, the dependence of the relative viscosity on the filler loading was shown to be consistent with the hypothesis that the filler particles were organized in the form of small fractal aggregates. The filled polyamide 11 systems exhibited higher relative viscosities than the filled polyamide 12 systems, indicating a higher level of particle aggregation and larger mean cluster size for the filled polyamide 11 systems. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48244.     

β晶型聚丙烯混杂复合体系的结构和性能

为了了解β晶型聚丙烯混杂复合体系的结构和性能,研究了β晶型聚丙烯在化学交联、添加纳米填料和热处理后的力学性能变化规律。结果表明5％～10％(wt)纳米CaCO3填料或2％(wt)交联剂与0．5％(wt)β晶型成核剂TMB共用时对聚丙烯有优良的增强、增韧效果;在80～150℃热处理温度范围内,加有05％(wt)TMB的聚丙烯在130℃时有最小的抗拉强度。经X衍射分析、差热分析证明在0.4％～0.8％(wt)TMB的用量范围内,对聚丙烯的β晶体的有序性和结晶效率影响不大,在0．5％(wt)成核剂TMB用量时,聚丙烯有最大的结晶度,130℃热处理可进一步提高聚丙烯β晶的结晶效率和总结晶度,结晶温度和熔融温度;加入纳米填料对β晶型聚丙烯的总结晶度和结晶效率影响不大,对有序性有较大的影响：而加入2％(wt)交联剂大大增加了总结晶度,同时大幅降低了β晶的有序度。偏光显微测试发现,纳米填料加入可降低球晶的尺寸和诱导纤维状的β晶形成。     

Preparation and characterization of an epoxy nanocomposite toughened by a combination of thermoplastic,layered and particulate nano-fillers

This paper reports the development of an epoxy-based nanocomposite toughened by the combination of thermoplastic, layered and particulate nano-fillers. The main objective of this work is to incorporate poly(acrylonitrile-co-butadiene-co-styrene) (ABS), clay (layered nano-filler) and nano-TiO₂ (particulate nano-filler) into epoxy matrix with the aim of obtaining the quaternary nanocomposite with higher impact strength and lower cost without attenuating the other desired mechanical properties such as tensile strength. Taguchi methodology was applied for the optimization and statistical determination of the significant factors influencing the mechanical properties of the quaternary nanocomposite. Impact and tensile strengths of the quaternary nanocomposite with optimum composition increased by 168% and 64% compared to neat epoxy, respectively. Furthermore, synergistic effect was observed with the addition of three type modifiers. It was found that ABS content has the most significant effect on mechanical properties of the obtained quaternary nanocomposite. Also correlation between morphological and mechanical properties of the nanocomposite was investigated. A dispersion of nano-size ABS and TiO₂ particles along with exfoliated clay nano-platelets in epoxy matrix was achieved as main morphological property of the quaternary nanocomposite. A new morphology was obtained for ABS phase in epoxy rich matrix.     

纳米填料在不饱和聚酯(UP)包覆层改性中的应用前景

不饱和聚酯（UP）作为固体推进剂包覆层存在固化物脆性大、低温延伸率低、阻燃耐烧蚀性差的缺点,为了克服这些缺点,文献中提出了一些用纳米填料改性UP包覆层的方法,文章索集了用纳米填料改性UP韧性和阻燃性的最新进展和应用前景,附参考文献21篇.     

材料特性对50Hz交流介质阻挡放电均匀性影响的实验研究

通过采用预埋电极,向介质阻挡材料中添加纳米材料的方法,研究了介质阻挡材料对50Hz工频放电均匀性的影响。将根据电压电流波形获得的均匀放电、丝状放电和混合放电(均匀放电与丝状放电共存)3种放电模式作为判断放电均匀与否的依据,对实验结果进行了分析。结果表明,利用未改性硅橡胶预埋金属丝网电极难以提高介质阻挡均匀放电的气压范围,采用纳米Al2O3改性的硅橡胶材料作为介质阻挡层可以有效提高均匀放电气压范围,此外实验发现介质阻挡材料的厚度对放电均匀性影响显著。