基于动态力学的纳米碳粉-橡胶粉-SBS改性沥青相态结构分析

为了分析纳米碳粉、橡胶粉、苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)在沥青中的相态结构,首先对基质沥青和改性沥青进行物理性能试验、动态剪切流变试验(DSR),其次借助Han曲线理论和van Gurp-Palmen(vGP)图分析三种改性剂与基质沥青的相容性及相态结构。结果表明:在相同的试验条件下,2%纳米碳粉-18%橡胶粉-1.0%SBS改性沥青(以上均为质量分数)物理性能最佳,高低温性能较优;与基质沥青相比,添加改性剂后沥青材料出现微观相分离现象。在高温条件下,纳米碳粉-橡胶粉-SBS改性沥青相态结构较好,结合SEM照片阐释了改性机理,得出改性剂SBS可以有效改善纳米碳粉和橡胶粉在沥青中的骨架结构,形成三维连续稳定体系。     

表面活化处理胶粉改性沥青的性能

用液体不饱和聚合物增容剂对废旧轮胎胶粉进行表面活化处理,制备了废旧轮胎胶粉改性沥青(CRMA),考察了其储存稳定性,并与苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)改性沥青的流变性能进行比较.结果表明,经表面活化处理的胶粉在基质沥青中的分散性得到明显改善;与胶粉直接改性沥青相比,活化胶粉改性沥青的储存稳定性好;基质沥青、SBS改性沥青、活化胶粉改性沥青三者相比,以最后者的高温抗车辙性能、抗疲劳开裂性能和抗低温开裂性能最好,基质沥青最差.     

SBS改性脱油沥青宏观性能与微观形态的关系研究

以脱油沥青(DOA)制备针入度30号和50号的调和硬质沥青,并掺量2%到6%的星型SBS在170℃下经剪切、搅拌工艺制备SBS改性硬质沥青,对产物进行常规指标分析及荧光显微检测。常规指标分析表明SBS可以提高沥青的高温稳定性、低温抗裂性能和感温性能;存储稳定性分析表明稳定剂的加入可以明显的改善沥青的稳定性和抗老化性能;荧光显微镜图像表明改性沥青宏观性能与微观结构之间存在相关性,改性沥青要达到较好的宏观性能需要其微观结构中改性剂和沥青呈现均匀连续分散的状态。利用SBS和稳定剂制备优质改性硬质沥青合适配方为:SBS添加量为3.0%,稳定剂添加量为0.2%。     

基于储存稳定性的橡胶改性沥青制备工艺

为了制备储存稳定性良好的橡胶改性沥青,基于高温混炼工艺,使用聚苯乙烯-聚丁二烯-聚苯乙烯嵌段聚合物(SBS)、芳烃油、辛烯聚合物橡胶反应剂(TOR)、稳定剂与橡胶粉对基质沥青进行复合改性。提出了橡胶改性沥青的制备方法,分析了改性剂对沥青常规性能和流变特性的影响,并通过荧光试验观察改性剂在沥青中的分散效果。研究结果表明:添加质量分数为25%的40目(380 μm)胶粉可以明显提高沥青的高温性能;180 ℃下剪切60~90 min后溶胀发育60 min可以得到稳定性良好的橡胶改性沥青;加入相容剂和稳定剂可以提高胶粉的溶胀与分散程度,改性剂之间对沥青性能的影响存在协同作用;复合改性沥青具有良好的弹性恢复能力和高温抗变形性能;橡胶粉、SBS在沥青中的溶胀程度和分散均匀性是影响沥青常规性能和储存稳定性的直接因素。     

动态硫化乙烯-乙酸乙烯酯共聚物/苯乙烯-丁二烯-苯乙烯嵌段共聚物复合改性沥青的性能

用乙烯-乙酸乙烯酯共聚物(EVA)和苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)复合改性沥青,研究了EVA/SBS复合改性沥青动态硫化前后的软化点、针入度(25 ℃)、延度(5 ℃)及贮存稳定性,并用应变控制流变仪与光学显微镜分析了复合改性沥青的动态力学性能和相态结构.结果表明,动态硫化处理后,EVA/SBS复合改性沥青的延度和针入度下降,而软化点提高;随着硫黄用量的增加,EVA/SBS复合改性沥青的高温贮存稳定性提高,温度敏感性降低;随着EVA用量的增加,EVA/SBS复合改性沥青的高温贮存稳定性先提高后降低;当EVA质量分数为3%、硫黄质量分数为3%时,其对沥青的改性效果最佳;改性剂微粒与沥青的相容性和稳定性明显改善.     

SBS改性沥青的结构与性能

通过动态黏弹性能、结构分析和沥青基本性能测试研究了SBS和沥青之间的相容性,以及SBS用量对改性沥青的结构与性能的影响。结果表明,SBS与沥青有一定的相容性,沥青中的某些组分可进入SBS的聚丁二烯(PB)链段区域。使PB的玻璃化转变温度升高,在高剪切力作用下也可进入聚苯乙烯(PS)链段,降低了PS的玻璃化转变温度,但不会使PS物理交联点发生严重解体。当SBS质量分数为5％时,SBS在沥青中呈彼此分离的球状颗粒;当SBS质量分数达到7％或以上时,则形成连续相。随着SBS质量分数的增加。改性沥青的软化点和低温延度升高,针入度和高温贮存稳定性下降。     

POE弹性体改性沥青的结构与性能

研究了聚烯烃弹性体（POE）改性沥青的结构和性能,考察了POE用量对两种基质沥青常规性能的影响,并用光学显微镜观察了POE在沥青中的分布状态。结果表明,随着POE用量增加,沥青的软化点增加,25℃针入度减小,高温性能变好。通过储存稳定性实验发现,POE改性沥青后稳定性较差。POE改性沥青相结构研究发现,随着POE用量的增加,POE由分散相变为连续相,POE质量分数为6%时,基质沥青发生相转变。     

多种类沥青及复合改性材料常规-流变性能相关性分析

通过试验研究胶粉改性沥青、SBS改性沥青及混合改性沥青微观组织结构、高温环境与低温环境对其流变性能影响。测试结果表明:胶粉改性沥青、SBS改性剂与沥青相容性较好,但橡胶粉改性沥青与石材之间界面附着力高于SBS改性沥青。DSR试验表明:橡胶粉改性沥青温度具备低温耐裂性及高温耐变形性。综上对混合改性沥青流变性能研究,旨在为我国研发新型高性能沥青提供有效技术支持。     

碳纳米管/SBS复合改性沥青路用性能与相容性研究

为改善SBS改性沥青的路用性能及相容性,采用高速剪切法,将碳纳米管掺入SBS改性沥青中,制备复合改性沥青。采用三大指标、布氏粘度、离析实验、荧光显微镜等对其性能进行评价。结果表明,碳纳米管可以有效改善SBS改性沥青的高温稳定性、粘滞性,并且随着掺入碳纳米管量的增加,性能效果提升越好,但超过0.9%时改善效果趋于饱和;对改性沥青的温度敏感性和低温性能存在不利影响;碳纳米管的掺入限制了SBS颗粒与沥青分子之间的相对运动,使得SBS在沥青中的分散更均匀,改善了相容性与储存稳定性;综合考量碳纳米管/SBS复合改性沥青的各项性能,当其掺量为0.9%时,改性效果达到最佳。     

贮存稳定的SBS/PE共混物改性沥青

研究了用SBS／PE熔融共混物改性的沥青和直接添加SBS及PE所得改性沥青的高温贮存稳定性,结果表明,前者的高温贮存稳定性明显优于后者,可能是由于熔融共混过程中生成了SBS－g-PE,改善了SBS与PE的相容性,从而提高了改性沥青的高温贮存稳定性。     

丁苯弹性体/蒙脱土复合材料改性老化沥青

将粉末丁苯橡胶(PSBR)或苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)与蒙脱土(MMT)制成复合材料,用于改性老化沥青(PSBR质量分数3%,SBS质量分数5%),研究了复合材料及其改性老化沥青的结构,考察了MMT用量对复合材料改性老化沥青物理性能与高温贮存稳定性的影响.结果表明,在PSBR/MMT复合材料中,MMT与PSBR形成了插层结构;在PSBR/MMT和SBS/MMT复合材料改性老化沥青中,复合材料呈球状分布;当MMT用量过大时,部分MMT滞留在聚合物中,出现颗粒MMT;复合材料对老化沥青的物理性能改性优于单独加入MMT;PSBR/MMT复合材料可改善老化沥青的高低温性能;SBS/MMT复合材料可显著改善老化沥青的高温性能;MMT用量不同时,PSBR/MMT复合材料改性老化沥青的贮存稳定性相当;当SBS/MMT(质量比)为5/3时,复合材料改性老化沥青的贮存稳定性较佳.     

Comparative study of the effect of sulfur on the morphology and rheological properties of SB‐ and SBS‐modified asphalt

The modification of asphalt with styrene‐ butadiene block copolymers and sulfur was studied to elucidate the effect of the molecular characteristics of the polymer, polymer content, and sulfur/polymer ratio on the physical properties of modified asphalts. Two types of styrene‐butadiene copolymers were used (SB and SBS), which differed considerably in terms of their chain architecture, average molecular weights, and size and distribution of their polybutadiene and polystyrene blocks, as shown by gel permeation chromatography, infrared spectroscopy, nuclear magnetic resonance, and differential scanning calorimetry. Sulfur/polymer/asphalt blends were prepared by a hot mixing process and characterized by conventional tests, fluorescence microscopy, and rheology. The results revealed that the morphology of the blends is strongly dependent on polymer concentration and sulfur/polymer ratio. In‐depth rheological characterization showed that the thermomechanical properties changed considerably upon addition of small amounts of sulfur. Collectively, these results suggest that sulfur increases the compatibility between polymer and asphalt by crosslinking polymer chains. Interestingly, the rheological behavior of blends prepared with a combination of SB and sulfur was similar to that exhibited by blends prepared with SBS either in the presence or absence of sulfur. This is explained by assuming that the addition of small amounts of sulfur to SB‐modified asphalt facilitates the formation of an elastomeric network that resembles the one found in SBS‐modified asphalt, effectively contributing to asphalt reinforcement. Nonetheless, the exact dosage of sulfur must be carefully controlled to prevent gel formation. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Optimization of the modification technologies of asphalt by using waste EVA from packaging

Packaging wastes not only pollute the environment, but also waste resources. In this study, bags of suits made mainly from ethylene(vinyl acetate) copolymer (EVA), as the modifier, were used to improve the properties of raw asphalt. On the basis of the common physical modification, crosslinking agents and catalysts were added to the raw oil asphalt. The modification technologies were studied carefully. The results showed that crosslinking agents and catalysts could make the polymer react with raw asphalt, thus providing chemical connections between them and forming three‐dimensional network structures. As a result, the asphalt performance was improved. In addition, the dosages of the crosslinking agent, modification temperature, and time also had effects on the performance of the modified asphalt. When the ratio of divinylbenzene to asphalt was 0.0125, the ratio of catalyst to asphalt was 0.025, the temperature was 140°C, and the modification time was 2.5 h, the softening point of the asphalt rose from 49.5°C to 63.5°C, and the penetration degree dropped from 68.5 to 39.1 (0.1 mm). The results showed that after the modification with waste EVA, the performance of the asphalt had been significantly improved and stabilized. J. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers     

Influence of ageing on rheology of SBR/sulfur‐modified asphalts

The effect of short‐term and long‐term oxidative ageing on the rheological, physical properties, the morphology, and thermodynamic behavior of the styrene‐butadiene rubber (SBR)‐ and SBR/sulfur‐modified asphalts is studied respectively. The dynamic rheological tests show the two major effects of ageing on the rheological behavior of the asphalt binders. Ageing prompts the degradation of polymer and increases the viscous behavior of the binders, on the other, ageing improves the elastic behavior of the binders due to the changed asphalt components, the final rheological behavior of the aged binders depends on the combined effect. The SBR/sulfur‐modified asphalt is more susceptible to ageing and dynamic shear due to the structural instability and show a viscous behavior with increasing the sulfur level after ageing. Under the influence of repeated shear force, the high‐temperature property of the SBR/sulfur‐modified asphalts declines. The morphology observation shows the compatibility between polymer and asphalt is improved with further ageing especially for the SBR/sulfur‐modified asphalt. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

道路用聚氨酯改性沥青的制备工艺探讨

结合不同改性剂掺量单因素试验,确定了采用88mm叶轮、115mm容器、圆盘锯齿式搅拌器(转速1400r/min)、175℃共混温度、改性剂掺量4.27%、单次搅拌300g的制备工艺参数。在此条件下制备的聚氨酯改性沥青具有优异的水稳定性、储存稳定性且耐老化、耐高温,拥有比普通聚合物改性沥青更高的车辙因子G*/sinδ和15℃动态模量,基本满足高模量沥青要求。     

Effect of organic montmorillonite on the hot storage stability of asphalt modified by waste packaging polyethylene

In this paper, waste polyethylene (WPE), a large class of waste plastic packaging, and organic montmorillonite (OMMT) were employed as the polymer modifier and additive to modify base asphalt, and then hot storage stability of modified asphalt was studied. Structure of the modified asphalt was characterized with X‐ray diffraction and fluorescence microscopy. Moreover, the hot storage stability of WPE‐modified asphalt was investigated by Fourier‐transform infrared analysis, differential scanning calorimetry, and thermal gravimetry. Results show that an exfoliated structure is formed in the modified asphalt after adding OMMT. The WPE modifier particles become smaller and are more uniformly dispersed in the modified asphalt system after adding OMMT. Also, the addition of OMMT effectively improves the hot storage stability of the modified asphalt. The OMMT not only increases the compatibility between the WPE modifier and base asphalt but enhances the homogeneity of the modified asphalt at extreme temperatures. Heat capacity and phase behavior of modified asphalt after adding OMMT are changed; in the meantime, the thermal stability of the modified asphalt increases. J. VINYL ADDIT. TECHNOL., 21:89–93, 2015. © 2014 Society of Plastics Engineers     

The viscoelastic properties of polymer‐modified asphalts

The linear viscoelastic properties of one family of base asphalts, unmodified or modified by the simple addition of an elastomer or by further in‐situ crosslinking, have been investigated. The time‐temperature superposition principle was shown to be valid for the base as well as for the modified asphalts. The addition of the elastomer styrene‐butadiene (SB) copolymer increased drastically the storage modulus and the elastic character of the asphalts. The thermal susceptibility of the polymer modified asphalts was considerably reduced and this combined with an increased resistance to deformation (larger complex modulus) suggests much better performances for road applications. The chemically modified asphalt containing 3% SB showed similar viscoelastic properties as the physical blend containing 6% SB.     

具有核壳结构的聚丁二烯接枝聚苯乙烯改性沥青的性能

采用种子乳液聚合法制备了具有核壳结构的聚丁二烯接枝聚苯乙烯(PB-g-PS),并将其与沥青通过高速剪切共混制备了PB-g-PS改性沥青,考察了PB-g-PS改性沥青的物理性能以及热老化性能、感温性、热贮存稳定性和相容性。结果表明,当PB-g-PS的质量分数为5%时,改性沥青的高温热稳定性、抗低温开裂性较好;与基质沥青相比,改性沥青的热老化性能得到改善,感温性下降;在相同条件下,PB-g-PS改性沥青的热贮存稳定性要好于苯乙烯-丁二烯-苯乙烯嵌段共聚物改性沥青;核壳结构的PB-g-PS与基质沥青具有一定的相容性。     

聚乙烯接枝马来酸酐含量对废旧聚乙烯改性沥青性能的影响

首先采用双螺杆挤出造粒技术制备了一种由废旧聚乙烯（RPE）和不同含量（0 %、1 %、3 %、5 %、7 %、9 %,以RPE质量计）马来酸酐接枝聚乙烯（PE?g?MAH）组成的复合改性剂（CM）,然后制备CM（4 %沥青质量）改性沥青,并对常规指标（软化点、25 ℃针入度和25 ℃延度）、旋转黏度、红外光谱、高温存储稳定性（软化点差值、扫描电子显微镜微观形貌）以及流变性能等表征、分析。结果表明,CM改性剂中MAH与沥青中—OH之间发生化学反应,生成酯类物质,且随着PE?g?MAH含量的增加,CM改性沥青软化点、延度、黏度、高温存储稳定性、高温以及低温性能均显著提高,而针入度和相位角则降低;在温度变化较大的地区,可以考虑采用适量的PE?g?MAH制备CM改性沥青进行路面铺筑,并对于高温存储稳定性的改善进行了推理分析。