Rheological properties of graphene/tourmaline composite modified asphalt

Abstract

The purpose is to improve performance of asphalt by synergistic enhancement of graphene and tourmaline. Graphene/tourmaline composite modified asphalt was prepared. The basic properties and rheological properties of graphene/tourmaline composite modified asphalt were analyzed systematically. The results indicate that the basic viscoelastic properties of asphalt were not destroyed after graphene/tourmaline composites added into asphalt. The rutting resistance of graphene/tourmaline composite modified asphalt was superior than tourmaline. And the larger the composite material content, the superior the rutting resistance of modified asphalt. The rutting resistance was increased by 10.12%.     

改性高岭土结构特性研究

考察了不同焙烧温度的高岭土分别经酸、碱改性后的结构特性.结果表明,焙烧温度为700～900℃时,强酸改性后偏高岭土的SiO2/Al2O3值(质量比)、比表面积和比孔容均显著增大,表面酸值增大且出现强酸中心;强碱改性后偏高岭土的SiO2/Al2O3值变化不明显,比表面积和比孔容均有所降低;强碱改性偏高岭土的表面酸值小于强酸改性偏高岭土的表面酸值.     

改性炭黑制备工艺与性能研究

采用机械研磨的方法探讨了研磨时间、研磨介质、研磨介质类型对炭黑物理性能的研究,利用红外光谱仪、ASAP表面吸附仪对改性炭黑的显微组织形貌、表面结构、基团种类、孔道大小、孔容等进行了分析测试。结果表明:在相同工艺条件下,研磨时间是影响炭黑粒子结构改变的重要因素,研磨时间越长,炭黑粒子结构被改变的越多。研磨使炭黑粒聚结体结构被破坏,使表面基团的种类和数量发生改变,表面活性和极性增加,降低炭黑再附聚趋势,改善了炭黑的性能白炭黑复合改性炭黑性能实验结果表明:白炭黑添加量为10%的复相炭黑较白炭黑添加量为5%的复相炭黑性能优异     

Tuning the thermal,mechanical, and combustion properties of NC-TEGDN-RDX propellants via incorporation of graphene nanoplates

ABSTRACT

Graphene nanoplates (GNPs) were incorporated into a solid composite propellant (NC-TEGDN-RDX) to tune the thermal, mechanical, and combustion properties of the material. Physical, thermal, and combustion properties of NC-TEGDN-RDX with <2 wt% addition of GNPs were characterized using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), tensile/compressive/impact strength testing, and constant volume combustion experiments. Microstructure of the composite propellants examined using SEM demonstrated uniform dispersion of the GNPs at low-weight percent additives (<1 wt%), but began to show large agglomerations of the additives at higher additive content. Decomposition enthalpy of the propellant with 1 wt% GNPs increased by ~130 J/g compared to neat propellants. Moreover, the maximum burning rate was observed for samples containing 1 wt% GNPs, with values of 19 cm/s at 20°C and 17 cm/s at ?40°C. Dynamic vivacity of the propellant achieved a maximum upon addition of 1 wt% GNPs. The pressure exponent of the propellant decreased with the addition of GNPs, as well. The mechanical properties including tensile, compressive, and impact strength were improved at 20°C and ?40°C. These results demonstrate that the addition of GNPs may offer new methods by which to tune and improve thermal decomposition, thermal conductivity, combustion performance, and mechanical properties of the NC-TEGDN-RDX propellants.     

NH_4HCO_3水热改性对氧化铝载体结构与性质的影响

以NH_4HCO_3为原料,对含有微米级孔道γ-Al_2O_3载体进行水热改性处理,并应用XRD、IR、SEM、N_2吸附-脱附、Py-FTIR等方法表征NH_4HCO_3水热改性对γ-Al_2O_3载体结构与性质的影响。实验结果表明,水热改性过程中,部分氧化铝发生晶相转变,形成微米级棒状NH_4Al(OH)_2CO_3,并交织生长在氧化铝载体表面及微米级孔道中,焙烧时生成的NH_4Al(OH)_2CO_3再次转变为γ-Al_2O_3。经NH_4HCO_3水热改性后γ-Al_2O_3载体的比表面积、孔体积略有降低,而1～2μm左右的孔道含量明显增加,载体表面总酸量、弱酸及中强酸含量降低,(111)晶面六配位铝离子表面羟基(HO-μ_2-Al_Ⅵ)相对含量降低,(100)晶面六配位铝离子表面羟基(HO-μ_3-Al_Ⅵ)相对含量增加。     

工艺条件对SBS改性沥青性质的影响

通过稳定剂加入次数、加入方式、星型SBS加入方式,研究了工艺条件对改性沥青性质的影响。研究发现,稳定剂加入次数越多,改性沥青的软化点越高,薄膜烘箱老化后延度越好。通过剪切方式加入稳定剂和加入SBS得到的改性沥青延度性质更稳定,薄膜烘箱老化前和薄膜烘箱老化后延度变化幅度减小。     

改性浒苔固定化微生物制剂的制备及其对柴油的降解性能研究

为了提高固定化技术在海洋溢油处理中的应用效果,采用十二烷基苯磺酸钠（SDBS）为改性剂,采用浸渍法对浒苔进行改性。SDBS改性的浒苔（SDBS-E）作为固定化的吸附载体材料。同时,以海洋降解菌Sp8（Shewanella属）为研究对象。以海藻酸钠为包埋载体,无水氯化钙为交联剂,采用包埋法制备了SDBS-E固定化微生物制剂。与游离菌的降解率（78.87%）相比,SDBS-E固定化微生物对柴油的去除率提高到90.39%。研究了SDBS-E固定化微生物去除柴油的途径,主要包括表面吸附、内吸附和生物降解。早期依靠表面吸附,后期依靠生物降解。SDBS-E固定化微生物对柴油的降解符合准一级降解动力学模型。     

Molecular investigations on the interactions of graphene,crude oil fractions and mineral aggregates at low,medium and high temperatures

Performance of the nanoparticle-modified asphalt binder is greatly influenced by adhesion properties between asphalt binder and nanoparticle. In this work, the adhesion properties of crude oil fractions (e.g., Saturate, Asphaltene, Resin and Aromatic components of asphalt binder), graphene and mineral aggregates (silicon dioxide) at various temperatures are investigated through molecular dynamic simulation and REAXFF force field. The results from SARA-graphene interface demonstrations that aromatic and asphaltene have 30% higher adhesion properties than saturate and resin. Also, while using graphene is valuable for the adhesion properties of the binder, it has no significant advantage over binder in binder-aggregate interactions.     

聚丙烯酰胺的分子结构对微凝胶体系性能的影响

和聚合物驱技术相比,微凝胶驱技术能够大幅度降低部分水解聚丙稀酰胺(HPAM)的用量,提高HPAM溶液的耐温抗盐能力,解决污水配制HPAM溶液的问题,具有明显的经济效益和社会效益.低水解度、高相对分子质量的HPAM能够提高微凝胶体系的成胶能力,其相对分子质量越高,成胶时间越短,成胶黏度越大,临界成胶浓度越低.HPAM的相对分子质量从5×106提高到20×106时,成胶时间从38d缩短到4d,成胶黏度从23.7mPa·s增加到168mPa·     

制备方法对磷锆复合改性ZSM-5分子筛及其催化裂化性能的影响

在组合使用烘干、焙烧、水热老化处理的不同方法制备了磷改性ZSM-5分子筛的基础上,引入金属组分锆制备了磷锆复合改性ZSM-5分子筛系列试样（标记为PHZ-Z 5,PBZ-Z 5,PLZ-Z 5）,并以复合改性分子筛为活性组分制备了催化裂化助剂,使用XRD,BET,NH3-TPD,XPS等方法对经水热老化处理后的磷锆复合改性后分子筛进行了表征,在先进的催化裂化催化剂评价装置（ACE）上,考察评价了不同改性方法制备所得催化助剂对重油催化裂化生产丙烯的影响。结果表明:在连续依次经烘干、焙烧、水热老化处理所得磷改性ZSM-5分子筛后,接着引入锆制备的磷锆复合改性分子筛水热老化试样PLZ-Z 5 L保留有最多的微孔结构和总酸量;当含PLZ-Z 5试样组分制备的催化助剂应用于重油催化裂化反应时,具有最高的丙烯和液化气收率,分别为8.66%和28.41%。     

表面改性对膨润土润滑脂性能影响的研究

通过对钠基膨润土插层改性,制备不同改性剂含量和不同改性剂成分的有机膨润土,并以此为稠化剂制备润滑脂,考察润滑脂的锥入度和压力分油,研究改性过程的影响因素及其对润滑脂性能的影响规律。文章讨论了膨润土的改性过程和膨润土润滑脂的稠化机理。实验结果表明,随着改性剂添加量的增加,膨润土层间距增大,改性剂分子在膨润土层间区域的排列从双层平卧变化为倾斜双层结构。当改性剂分子在膨润土层间区域的排列方式为倾斜单层结构时,即改性剂添加量为120-140mmol/100g,润滑脂的性能最佳。十八烷基三甲基氯化铵和十六烷基三甲基氯化铵混合改性膨润土,制备得到膨润土润滑脂的稠化性能、胶体安定性、抗磨性能和减磨性能均得到提高,最佳混合摩尔比为1:1。     

废胎胶粉改性沥青改性机理研究

借助荧光显微镜、红外光谱等微观结构试验的分析方法，研究废胎胶粉在沥青中的改性机理。高温条件下，胶粉在沥青中吸收轻组分，并溶胀、脱硫和降解，同时胶粉中的活性物质进入沥青胶体体系中，达到改善沥青温度敏感性、老化性能的效果；常温及低温条件下，废胶粉改性沥青中未溶解的胶粉颗粒起到增强沥青的弹性性能和提高其抗裂性能的作用。弄清废胎胶粉改性沥青的改性机理，为合理应用废胶粉改性沥青提供理论支持和技术保障。     

Effect of different rejuvenators on the properties of aged SBS modified asphalt

The styrene-butadiene-styrene copolymer (SBS)–modified asphalt was aged by pressure aging vessel test. The effect of different content of rejuvenators on the physical and rheological properties of aged SBS-modified asphalt was investigated. The results showed that with the increase of the content, the physical and rheological properties of the aged SBS-modified asphalt are restored more significantly. Three kinds of rejuvenators were used to rejuvenate the properties of aged SBS-modified asphalt. It can be concluded that the improvement of rejuvenator-III on the properties of aged SBS-modified asphalt is the most obvious. The results also indicate that the rheological behavior of the aged SBS-modified asphalt is improved obviously by the rejuvenator.     

Effects of carboxymethylcellulose sodium on the morphology and properties of TKX-50, an insensitive high-energy explosive

Dihydroxylammonium 5,5?-bistetrazole-1,1?-diolate (TKX-50) is an energetic ionic salt with excellent properties of low mechanical sensitivity, environment-friendliness, and low toxicity. It meets the requirement of high insensitivity for military high-energy explosives. However, the poor crystal habit of TKX-50 in most solvents, as well as its poor adhesive ability with conventional binders, has limited its application. In the present work, we report a novel strategy to improve the morphology and surface property of TKX-50 using an environmentally friendly anionic polyelectrolyte, carboxymethylcellulose sodium (CMC), by the anti-solvent method. The scanning electron microscope analysis indicates that the morphology of TKX-50 was greatly altered in the presence of CMC, resulting in TKX-50 granules with low aspect ratios. Molecular dynamics simulation was conducted to explore the mechanism of such morphological change. It was found that the combined action of ethanol and CMC promoted the growth of (110) and (011), while the (020) still dominated the crystal growth, resulting in the low aspect ratio of TKX-50. The effects of CMC coating on the particle size of TKX-50 and the interaction between CMC and TKX-50 were investigated with the focused beam reflectance measurement and particle video microscope. Further characterization suggested that the highest coating efficiency (R) could be obtained at the CMC content of 4% with which granular TKX-50 crystals were produced. The non-isothermal kinetic study revealed that the CMC coating also improved the thermal stability of TKX-50. Our work has provided a novel method to improve the properties of TKX-50 for its practical application.     

A statistical analysis on the mechanical properties of nanocomposite modified asphalt mixtures

This study aimed to characterize the rate of change that takes place in the mechanical properties of polymer-nanocomposite asphalt (PNMA) mixtures due to altering asphalt binder grade and styrene-butadiene-styrene (SBS) type. Laboratory testing program included Marshall stability, resilient modulus, and wheel-tracking tests. Test results were compared and analyzed statistically by means of two-way analysis of variance and Tukey test. Variance analysis indicated the significant effect of both binder type and SBS grade on mechanical properties of asphalt mixtures. Interaction between binder type and SBS grade is also meaningful in all the experiments. The results also show that the binder type is the primary affecting factor, followed by the SBS grade.     

合成及改性条件对β分子筛孔结构的影响

考察了合成及改性条件对β分子筛孔结构的影响,发现所有的试样均未出现滞后环,这表明所得β分子筛具有均一孔径,其中的孔可解释为晶粒之间的堆积空隙。随着焙烧温度的提高,分子筛的孔径分布变宽,产生了较大的孔;低温(300℃)与高温组合脱胺有利于结晶度的保持。在碱性处理条件下,二次中孔的体积和孔径较小;而酸性条件处理时,二次中孔的体积和孔径都明显增加。     

镍基镧钡改性氧化铝催化剂性能研究

制备了以La、Ba改性的氧化铝为载体的Ni基催化剂。采用BET ,XRD ,H2 - TPR等表征手段考察了不同载体的催化剂性能 ,并比较了各催化剂对甲烷部分氧化制合成气的反应活性和选择性。结果表明 ,添加La制得的改性氧化铝有较大的比表面积和较大的孔容孔径 ,以它为载体制得的催化剂对甲烷部分氧化制合成气反应在较高反应温度下有很好的活性和选择性     

The effect of dynamic cooling on the flow properties of PPD-treated crude oil

Abstract

By means of DSC, test of flow parameters, and microscopic observation, this paper studied the relation between the influence on the low temperature flow properties and that on the waxy crystal of the PPD-treated crude oil due to different final temperature of dynamic cooling. It has been experimental confirmed that the influence caused by the final temperature of dynamic cooling on low temperature flow properties and waxy crystal vary from the different final temperature of dynamic cooling. With this temperature increases, the depressive effects first get worse, then improved and finally kept nearly unchanged at higher temperature.