Water-soluble polyelectrolytes based on polyacrylonitrile for wastewater treatment

The possibility of modifying oxidized asphalt by performing polycondensation of maleic anhydride with aliphatic amines of various chemical structures in the dispersion medium was considered. The influence of the reactant structures and reaction conditions on the physicomechanical and structural-rheological properties of the polymer-modified asphalt was examined.     

A novel cationic emulsifier used for preparing slow-cracking and rapid-setting asphalt: Synthesis,surface activity,and emulsification ability

A novel cationic emulsifier including nonionic fatty alcohol polyoxyethylene ether was synthesized in two steps from epichlorohydrin, octadecyl dimethyl amine, and fatty alcohol polyoxyethylene ether, and the intermediate product could also be used as an emulsifier. Their structures were characterized by FTIR, and the surface activities were investigated by surface tension, electrical conductivity, and HLB. The obtained results indicated that the critical micelle concentration (CMC) of the final product was low, 0.442 mmol/L, and the surface tension at the CMC was 41.02 mN/m. The hydrophile-lipophile balance (HLB) value was 12, which meet the requirements of asphalt emulsifiers. A series of experiments of the emulsified asphalt prepared by the emulsifiers were performed. The results showed that the emulsified asphalt could be stably stored for more than 5 days when the emulsifier was 2 wt% and the pH value was between 3 and 4. The result of demulsification experiments showed that the emulsifier is a slow-cracking and rapid-setting asphalt emulsifier.     

SBS改性沥青机理研究进展

介绍了沥青的特性、苯乙烯-丁二烯-苯乙烯三嵌段共聚物(SBS)的性能,分析了SBS与基质沥青之间的溶胀性和相容性问题,着重论述了SBS改性沥青机理的研究进展,指出机理主要分为物理共混和化学改性两类:物理共混——SBS微粒受到沥青组分中油分的作用发生溶胀而均匀分散在沥青中,SBS与沥青之间没有发生化学作用,只是一种分子间作用力;化学改性——加入添加剂使沥青和SBS之间发生加成、交联或接枝等化学反应,形成较强的共价键或离子键,改善沥青的化学性质。提出化学改性是提高SBS改性沥青路用性能的重要手段。     

Aging properties and mechanism of the modified asphalt by packaging waste polyethylene and waste rubber powder

For the consideration of the environmental and economic issues, retrieved packaging waste polyethylene and waste rubber powder were selected as modifiers to modify the ordinary oil asphalt, and the rotating film oven test was adopted to study the aging process of the modified asphalt. The results showed that the performance of the modified asphalt deteriorated, as indicated by the increase in the softening point and the reduced ductility and penetration. However, compared with nonmodified asphalt, the rangeability of the performance indicators of the modified asphalt before and after aging became narrow, indicating that the aging properties of the modified asphalt were improved. In the modified asphalt system, the swelling of the polymer modifiers was caused by the absorption of the light components of the asphalt, thereby reducing the formation of asphaltenes in the aging process. The polymer modifiers absorb the light oil of the asphalt, which can reduce the content of free radicals and improve the aging properties of the asphalt. In addition, the waste rubber power containing antioxidants and anti‐ozone agents effectively improves the antiaging properties of the asphalt. Copyright © 2012 John Wiley & Sons, Ltd.     

Synthesis of a novel betaine-type asphalt emulsifier and its investigation by online FTIR spectrophotometry

A novel betaine-type asphalt emulsifier, 3-(dodecyloxy)-2-hydroxypropan-N-carboxymethyl-N,N-dimethylammonium chloride, has been synthesized in a three-step reaction from lauryl alcohol, epichlorohydrin, dimethylamine, and chloroacetic acid. The optimum reaction conditions were obtained for synthesis of 2-(dodecyloxymethyl)oxirane in the first step. The yield reaches 75.7 % under the optimum conditions of reaction temperature 50 °C, reaction time 5 h, feedstock mole ratio of epichlorohydrin to lauryl alcohol 1.4, basicity 33.3 %. The structures of the three products were identified by FTIR. Synthesis of 2-(dodecyloxymethyl)oxirane in the first step was monitored by online FTIR, and an intermediate was detected. On the basis of the experimental data, a plausible reaction mechanism was proposed for the reaction. The critical micelle concentration (CMC) of the final product is low, 8.8 × 10^?5 mol/L. The surface tension at the CMC is 21.2 mN/m. This product is an excellent emulsifier for asphalt. The prepared bituminous emulsion had high storage stability. The emulsifier is a rapid-set asphalt emulsifier.     

Combined modification of asphalt with polyethylene packaging waste and organophilic montmorillonite

Organophilic montmorillonite (OMMT) was prepared via ion exchange of Ca-montmorillonite (Ca-MMT) using dioctadecyl dimethyl ammonium chloride (DDAC). The OMMT and polyethylene packaging waste (WPE) were used as a combined modifier for asphalt, and the microstructure and performance of the modified asphalt were studied. Results show that the organophilic modification with DDAC results in an obvious increase of interlayer spacing of Ca-MMT, and the OMMT nano-lamellas can be completely exfoliated during the preparation of modified asphalt. The WPE, dispersed in asphalt, exhibits relatively small particles with homogeneous distribution, indicating that the OMMT addition is beneficial for the dispersion of WPE in asphalt. Compared with ordinary polymer modified asphalt, the penetration, softening point and ductility of the modified asphalt are all markedly improved. The modified asphalt obtained possesses excellent high-temperature stability, low-temperature anti-cracking performance and deformation resistance.     

Identification and quantification of urinary benzo[a]pyrene and its metabolites from asphalt fume exposed mice by microflow LC coupled to hybrid quadrupole time-of-flight mass spectrometry

Prolonged, extensive exposure to asphalt fume has been associated with several adverse health effects. Inhaled polycyclic aromatic hydrocarbons (PAHs) from asphalt fume exposure have been suspected of inducing such effects. In this study, a bioanalytical method was proposed and evaluated to identify and quantify benzo[a]pyrene and its hydroxy-metabolites. This method is based on coupling a microflow liquid chromatography (LC) to a hybrid quadrupole orthogonal acceleration time-of-flight mass spectrometry (Q-TOFMS). In the experiment, thirty-two B6C3FI mice were exposed to asphalt fume in a whole body inhalation chamber for 10 days (4 h day(-1)) and twelve other mice were used as controls. The asphalt fume was generated at 180 degrees C and the concentrations in the animal exposure chamber ranged 175-182 mg m(-3). Benzo[a]pyrene and its metabolites of 3-hydroxybenzo[a]pyrene, benzo[a]pyrene-7,8-dihydrodiol(+/-), benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide(+/-), and benzo[a]pyrene-7,8,9,10-tetrahydrotetrol(+/-) in the urine of asphalt fume exposed mice were identified and found at 3.18 ng 100 mL(-1), 31.36 ng 100 mL(-1), 11.56 ng 100 mL(-1), 54.92 ng 100 mL(-1), and 45.23 ng 100 mL(-1) respectively. The results revealed that the urinary benzo[a]pyrene and its hydroxy-metabolites from exposed mice were at significantly higher levels (p < 0.001) than those from the control groups. Compared with several other technologies such as HPLC-UV and HPLC-fluorescence, the new method is more sensitive and selective, and it can also provide additional useful information on the structures of the metabolites. Hence, this method can be used to perform the assessment and to study the mechanisms of the adverse health effects. The fragmentation patterns established in this study can also be used to identify and quantify PAH metabolites in other biological fluids.     

Asphalt adsorption in relation to the surface area of the mineral filler and content of aromatic oils

The composition and properties of asphalts were examined in relation to the time of keeping at 160°C of asphalt-granite and asphalt-gabbro-diorite blends. The time of filling of the filler surface with the adsorbed asphalt components was established. A criterion was suggested for estimating the properties of asphalt during preparation and pouring of asphalt concrete.     

Influence of aging on thermal behavior and characterization of SBR compound-modified asphalt

Sulfur and polyphosphoric acid (PPA) were used to improve the thermal stability and high-temperature property of styrene–butadiene rubber (SBR)-modified asphalt before and after short-term and long-term aging. The physical, rheological properties, and thermal behavior of asphalt binders were studied. The study showed that the addition of PPA improved the thermal stability and high-temperature property of SBR-modified asphalt evidently, and the improved property caused by the gelation effect of PPA was not influenced by aging further. Though sulfur also improved thermal stability and high-temperature property of SBR-modified asphalt before aging, the improved properties declined evidently with further aging, due to the susceptibility of SBR/sulfur-modified asphalt to aging. It is reasonable to assume that the SBR-modified asphalt could be improved further only by the addition of PPA. In the study of polymer-modified asphalts, thermodynamic analysis can reflect the structural characteristics of asphalt binders before and after aging efficiently and confirms the conclusions of physical and rheological testings to some extent.     

基于苯甲醛交联剂的煤直接液化残渣改性石油沥青

以苯甲醛为交联剂,采用煤直接液化残渣的四氢呋喃萃取物(THFS)对石油沥青进行了改性。考察了THFS、交联剂的掺杂量以及掺混温度对改性沥青性能的影响。研究表明,当THFS的掺杂量为4 %,掺混温度为170 ℃时改性效果最佳,而且苯甲醛作为交联剂加入可使沥青改性效果更佳。利用热重-傅里叶红外光谱联用仪(TG-FTIR)、傅里叶变换红外光谱仪(FT-IR)和荧光显微镜对改性沥青进行了表征,结果表明,添加了苯甲醛的改性沥青的失重残余率较其他沥青略有提高;苯甲醛交联的改性沥青在热解过程中释放的CH₄含量减少且释放温度有所提高;改性沥青在2 924 cm^-1和2 854 cm^-1处的脂肪族-CH₂-的伸缩振动和表征苯环位取代872、810和746 cm^-1处吸收峰的透射率均有较大幅度的提高,并在1 060 cm^-1处出现C-O-C伸缩振动峰,以及荧光显微镜图像中出现新的改性粒子,表明交联剂的添加使THFS和基质沥青发生了缩合反应。     

Microwave assisted fabrication of polymethyl methacrylate-graphene composite nanoparticles applied for the preparation of SBS modified asphalt with enhanced high temperature performance

In order to improve the high temperature rutting resistance ability and stability of styrene-butadiene-styrene (SBS) modified asphalt, microwave heating emulsion polymerization strategy was used to prepare polymethyl methacrylate (PMMA) and graphene nanoparticles (GNPs) composite (PMMA-GNPs) which was used to prepare PMMA-GNPs/SBS modified asphalt. Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy and thermogravimetric analysis characterizations showed that PMMA-GNPs particles were successfully prepared having a weight ratio of GNPs: PMMA of 1:9. Microwave heating reduced the reaction time from 5 h to 30 min compared to conventional oil bath heating. Dynamic shear rheological test and multi-stress creep recovery test confirmed that 0.06% PMMA-GNPs/SBS modified asphalt (0.06% PMMA-GNPs of the mass of base asphalt) exhibited an increase of 14.2% in elastic modulus (G′), while rutting resistance was enhanced and sensitivity to stress changes was reduced as compared to those of 5% SBS modified asphalt. Fluorescence microscopy analysis and phase separation test revealed that an appropriate amount of PMMA-GNPs can be uniformly dispersed in SBS modified asphalt and enhance the mutual interaction of SBS with base asphalt. Based on the results of mechanical tests and characterizations, a suitable modification mechanism of PMMA-GNPs particles in the original SBS modified asphalt was described in detail. This study proposes a simple, cost effective and fast strategy for the preparation of PMMA-GNPs incorporated SBS modified asphalt and hence can be envisioned of great promise in construction and highway industries.     

土壤中钢铁表面防护层缺陷的电化学检测

基于电化学阻抗谱技术建立了实验室检测钢铁表面防护层破损与剥离的电化学方法。提出了在一定频率范围内以电极阻抗幅值比Ｋ的变化关系作为防护层缺陷状态的表征。用此方法测定了土壤中阴极保护的表面涂覆不同状态石油沥青防护层的Ａ３钢模拟度片,得到了较为满意的结果。     

煤直接液化残渣对道路沥青改性作用的初步评价

现代交通具有轴载重、通量大和轮胎内压高的特点，因此，对公路路面提出了更高的要求。沥青是路面材料的重要组分之一，起黏结剂的作用，但由于沥青自身的温度敏感性，直接来自原油的道路沥青或重交通道路沥青自身不能满足要求。随着四季自然条件的变化，沥青变软或变硬，以致老化变脆，使路面发生损坏如车辙、开裂、剥离等。为了改善道路沥青路面的使用性能，使用改性沥青是解决这一问题的重要方法。改性沥青是在常规道路沥青中添加改性剂后的均匀沥青混合物。目前，大部分的高速公路的铺设均使用改性沥青。     

Internal structure and linear viscoelastic properties of EVA/asphalt nanocomposites

The effect of the addition of two different organoclays as a third component in polymer-modified asphalts has been investigated. Ternary mixtures were prepared by adding clay and poly(ethylene-co-vinyl acetate) to the asphalt, either separately, or in the form of a premixed master batch. The performed characterizations allowed the determination of how the two methods of mixing influence the interactions between asphalt and polymer and therefore the final rheological properties. In particular, it was shown that the clay had a compatibilizing effect on asphalt and polymer and that a high compatibility between clay and polymer led to a better dispersion of the polymer in the asphalt, thus influencing the final rheological properties of the studied systems.     

Influence of montmorillonite on ageing resistance of styrene–ethylene/butylene–styrene-modified asphalt

Storage-stable styrene–ethylene/butylene–styrene (SEBS)-modified (SM) asphalt was prepared by the addition of 4 mass/% SEBS and 3 mass/% organic montmorillonite (OMMT). The physical and rheological properties of SM and stable SEBS/OMMT-modified (SOSM) asphalts before and after short- or long-term thermal ageing were tested. The rheological tests showed that SOSM asphalt was more susceptible to ageing and became more flexible after ageing. The addition of OMMT restricted the swelling of SEBS in asphalt and led to an obvious susceptibility of SEBS to ageing. The structural characteristics of modified asphalt and OMMT before and after ageing were investigated by using optical microscope, Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscope, thermal analysis, respectively. The microscopic and thermal analysis confirmed the ageing susceptibility of storage-stable SOSM asphalt.     

增容剂对煤直接液化残渣改性沥青低温性能的影响

为了评价不同增容剂对煤直接液化残渣改性沥青低温性能的影响,首先,通过正交实验确定出三种增容剂（硅烷偶联剂、苯甲醛、二甲苯）各自的最佳掺量及掺入方式;其次,采用双边缺口拉伸（DENT）试验评价加入三种增容剂后沥青的低温抗延性断裂性能;最后,结合SEM照片并利用Image Pro plus图像处理软件计算加入三种增容剂后沥青中煤直接液化残渣的分散面积比,以定量地表征三种增容剂对煤直接液化残渣改性沥青低温性能的改善效果。结果表明,加入适量增容剂在一定程度上有助于煤直接液化残渣在沥青中的分散,提高两者之间的相容性,保持煤直接液化残渣改性沥青体系的长期稳定状态,避免因煤直接液化残渣的沉淀聚集而在相界面产生应力集中,增强煤直接液化残渣改性沥青的低温抗延性断裂性能。三种增容剂对煤直接液化残渣改性沥青低温性能改善效果不同,硅烷偶联剂最优,次之为苯甲醛,最差为二甲苯。     

Relaxation time, diffusion, and viscosity analysis of model asphalt systems using molecular simulation

Molecular dynamics simulation was used to calculate rotational relaxation time, diffusion coefficient, and zero-shear viscosity for a pure aromatic compound (naphthalene) and for aromatic and aliphatic components in model asphalt systems over a temperature range of 298-443 K. The model asphalt systems were chosen previously to represent real asphalt. Green-Kubo and Einstein methods were used to estimate viscosity at high temperature (443.15 K). Rotational relaxation times were calculated by nonlinear regression of orientation correlation functions to a modified Kohlrausch-Williams-Watts function. The Vogel-Fulcher-Tammann equation was used to analyze the temperature dependences of relaxation time, viscosity, and diffusion coefficient. The temperature dependences of viscosity and relaxation time were related using the Debye-Stokes-Einstein equation, enabling viscosity at low temperatures of two model asphalt systems to be estimated from high temperature (443.15 K) viscosity and temperature-dependent relaxation time results. Semiquantitative accuracy of such an equivalent temperature dependence was found for naphthalene. Diffusion coefficient showed a much smaller temperature dependence for all components in the model asphalt systems. Dimethylnaphthalene diffused the fastest while asphaltene molecules diffused the slowest. Neat naphthalene diffused faster than any component in model asphalts.     

1-alkyl-1,1-dimethylhydrazinium chlorides as modifiers of oil asphalts for road building applications

Aklylation of 1,1-dimethylhydrazine with higher alkyl chlorides was studied. The resulting 1-alkyl-1,1-dimethylhydrazinium chlorides were tested as modifiers of oil asphalt for preparation of asphalt concrete.     

Kinetic parameters of different asphalt binders by thermal analysis

Each year, 100 millions tons of asphalt are manufactured worldwide and 88% of them are designated to act as binder in mineral aggregate producing asphalt mixtures in the paving industry. The present study investigates the kinetics parameters of thermal degradation through thermal analysis behavior of three different asphalt binders’ samples: an asphalt cement C and two asphalt binders modified by polymers: copolymer styrene–butadiene–styrene S and polyphosphoric acid L. By Thermokinetics software a model-free kinetic analysis could be made using two models: Friedman and Ozawa–Flynn–Wall. Kinetic parameters following both models, through Thermogravimetric curves, showed that for the first step, the binder L presented the highest activation energy followed by binder S. Between all simulations, the FnF1 model was the one which best correspond to the experimental data for all samples.     

The research for low-temperature rheological properties and structural characteristics of high-viscosity modified asphalt

High-viscosity modified (HVM) asphalt was prepared by the addition of styrene–butadiene–styrene, furfural exact oil (FEO, plasticizer), sulphur (crosslinker). The low-temperature rheological properties of HVM asphalt were investigated by using bending beam rheometer, and different analysis ways including Fourier transform infrared (FTIR) analysis, thermal analysis, ¹hydrogen nuclear magnetic resonance (¹NMR) analysis, elemental analysis, optical microscopy were used to investigate the structural characteristics of modified asphalts and FEO. Rheological tests demonstrated the effect of each modifier on low-temperature rheological performances of asphalt and displayed the structural characteristics of each binder to some extent. FTIR analysis indicated the effect of ageing and modifier on the distribution of functional groups of modified asphalt before and after ageing. Morphology observation showed the distribution of polymer in asphalt with different modifications or ageing. The thermal analysis showed the effect of each modifier on thermal behaviour of asphalt before and after ageing and confirmed the result of FTIR analysis and morphology observation further. Besides, the constituents of base asphalt and plasticizer were also investigated and compared further by adopting elemental analysis, and ¹HNMR and FTIR tests.