【作者】 李军；

【导师】 张玉贞；

【作者基本信息】 中国石油大学 ， 化学工程与技术， 2008， 博士

【摘要】 改性沥青的性质主要受到温度、剪切力、剪切时间等生产工艺参数的影响。本文将溶剂法、双螺杆挤出机(母体法)、高速剪切机法、双螺杆挤出机法(直接)四种制备改性沥青的方法进行分析比较,结果表明溶剂法和双螺杆挤出机(母体法)要高于高速剪切机和双螺杆挤出机(直接)。但通过加入稳定剂,利用双螺杆挤出机法(直接)可以得到的改性沥青性能与溶剂法和母体法制备的改性沥青性能相同。母体法制备改性沥青过程中母体浓度对于改性沥青性质影响不大,随着剪切时间的增加,改性沥青的各方面性能都有所改善,随着加工温度的升高,改性沥青的软化点和延度都有所提高。选取双螺杆挤出机作为加工SBS改性沥青的生产设备,通过改变生产过程中的加工温度、剪切速率、加工时间等工艺条件,测定各条件下生产的改性沥青的性质,研究其变化规律。实验结果表明,通过双螺杆挤出机能够将改性剂较为均匀的分散在基质沥青中,使基质沥青的各方面性质得到改善。在考察的双螺杆挤出机三个操作条件中,对产品性质影响最大的是剪切时间和剪切速率。随剪切时间和剪切速率的增加,软化点上升,延度增加,针入度降低。加工温度在130℃到180℃之间时对产品性能的影响相对较小。本文在聚合物改性沥青多相体系性能研究方面主要研究了两种组分不同的基质沥青和两类聚合物改性剂。两种基质沥青是指四组分含量差别较大。两类聚合物改性剂包括热塑性弹性体,即两种结构的聚苯乙烯-丁二烯-苯乙烯(SBS)和树脂类改性剂如低密度聚乙烯和改性聚乙烯。改性聚乙烯主要是马来酸酐接枝低密度聚乙烯(MAH-g-LDPE)和甲基丙烯酸缩水甘油酯接枝低密度聚乙烯(GMA-g-LDPE)。本文主要通过改变基质沥青种类、SBS的种类、SBS的添加量,制备不同的改性沥青样品,分析和表征改性沥青样品的性质来研究热塑性弹性体SBS改性沥青性能变化规律。实验结果表明两种基质沥青经SBS改性后,软化点升高,针入度下降,延度先升高后降低。R-SBS改性沥青的软化点、延度高于L-SBS改性沥青的软化点、延度。当SBS含量较低时,加入稳定剂可以使SBS改性沥青高温稳定性合格,稳定剂加入量在0.6%-0.8%改性沥青性能比较好。荧光显微镜微观形貌分析发现双螺杆挤出机的强剪切作用使SBS以细小颗粒状均匀分散于改性沥青中,形成以SBS为分散相、沥青为连续相的多相体系。红外光谱显示SBS在稳定剂的存在下,有少量的聚合物大分子发生断裂,产生大分子自由基,从而与沥青发生化学反应。本文以双螺杆挤出机为加工设备分别研究了物理方法和化学方法改性沥青的性能变化。红外光谱显示低密度聚乙烯与沥青属于物理溶涨。而改性低密度聚乙烯(如马来酸酐接枝低密度聚乙烯、甲基丙烯酸缩水甘油酯接枝低密度聚乙烯)改性基质沥青的红外光谱显示GMA所含的906cm-1有环氧基吸收峰消失,说明GMA-g-LDPE的环氧基团与沥青中的官能团发生了反应。MAH-g-LDPE改性沥青体系中羧酸酐的特征吸收峰消失,说明MAH-g-LDPE分子中羧酸酐与沥青中的官能团发生了反应。与LDPE物理方法改性沥青相比,GMA-g-LDPE和MAH-g-LDPE通过官能团与沥青中官能团发生反应,形成化学键,为化学方法改性沥青。与物理方法制备的改性沥青相比,GMA-g-LDPE、MAH-g-LDPE化学法改性沥青能够大幅度提高基质沥青的软化点,降低了基质沥青的温度敏感性。MAH-g-LDPE和LDPE改性沥青的低温延度较低,而GMA-g-LDPE改性沥青的延度有所提高。软化点和动态剪切流变测试中高温抗车辙性能能够证明基质沥青经过化学方法改性后其高温性能得到大幅度提高,同时温度敏感度降低。改性LDPE含量高时沥青质含量高的沥青经改性后软化点升高明显。低温延度和弯曲蠕变试验实验结果表明GMA-g-LDPE改性沥青的低温性能没有降低而且略有提高。LDPE和MAH—LDPE改性沥青的低温性能有所降低。GMA-g-LDPE改性沥青的高温储存稳定性较好。荧光显微镜微观形貌分析发现MAH-g-LDPE改性沥青和LDPE改性沥青的颗粒大小不均匀,聚合物与沥青界面明显,而且MAH-g-LDPE改性沥青体系中出现比较大的颗粒并且形成连续相,表明MAH-g-LDPE改性沥青和LDPE改性沥青高温稳定性能较差,而GMA-g-LDPE改性沥青体系中聚合物颗粒大小均一,界面模糊,说明聚合物与沥青之间有较好的相容性。更多还原

【Abstract】 The performances of the modified asphalt were mainly influenced by temperature, shear stress, shear time and producing technology. In this paper, The four modified asphalt methods such as high-speed shear mixer method, solvent method were studied for comparison. The results showed that The performances of modified asphalts made by solvent method and high polymer content method were better than those of modified asphalts made by high-speed shear mixer method and direct method.The performances of modified asphalt by adding stabilizer agent with twin screw extruder were good compared to those of modified asphalt by solvent method and high contents polymer modified asphalt.The concentration of basic material had little influence on the performances of modified asphalt. The performances of modified asphalt were enhanced with the increase of shear time of twin screw extruder. The softening-point and the ductility were improved slightly with increased temperature. The process method had large influence on the performances of modified asphalt. The The twin screw extruder was used to modify asphalt in this paper. The performances of modified asphalt at various conditions, such as temperature, shear velocity, shear time and the optimum operation technology were investigated. The changing rules were explored as well. The experimental results showed that the SBS could be dispersed evenly by twin-screw extruder and the performances of asphalt could be improved. Shear time, shear velocity and producing temperature were three factors influencing the modified asphalt performances. Shear time and shear velocity were the most important factors. The softening point and ductility were enhanced with the increase of shear time and shear velocity, but the penetration was decreased. The effect of temperature from 130℃to 180℃on the modified asphalt performances was little comparelly.Two kinds asphalt with different components and two kinds polymer modifier were explored in this paper. The asphaltene contents in one kinds asphalt was higher than another asphalt. Two kinds polymers modifier were thermoelastomer such as SBS and thermoresin modifier. The thermoresin included low density polyethylene and maleic anhyride graft polyethylene and glycidyl methyacrylate graft polyethylene. The performances of different modified asphalts were analysised and demonstrated by altering base asphalt and SBS species,the SBS content, respectively.The results showed the modified agent could be evenly dispersed in asphalt by twin-screw extruder and the properties of modified asphalt were developed. Two kinds aspahlts were modified by SBS and the softening points were enhenced and the penetration values were down. The ductility was up and down with the SBS content increasing .The softening points and ductily values of R-SBS modified asphalt were bigger than those of L-SBS modified asphalt. The storage performance in high temperature of SBS modified asphalt was better by using stability agent when the SBS content was low. The performances of modified asphalt were best when stability agent content was 0.6%-0.8%.The morphologies of SBS modified asphalt showed that the SBS particles were fine and the particles were dispersed evenly in asphalt for the strong shear force of twin screw extruder. And the SBS particles were dispersing phase and the asphalt was continuous phase in multiphase system. Little polymer molecular bonds had broken and the macromolecular radical was produced for the stability agents exitence, so the chemical reaction had happened between the SBS and asphalt in FTIR result.The changing performances of modified asphalt by physical methods and chemical methods respectively were studied. The FTIRs results showed no reactions had bappened between the asphalt and LDPE in LDPE modified asphalt system and the polymer had been swollen . The absorbing peak in 906cm-1 which was belonged to epoxy group was disappear in FTIR of GMA-g-LDPE modified asphalt. So the paper deduced the reaction had happened between the GMA-g-LDPE and aspahlt in GMA-g-LDPE modified asphalt system. The absorbing peak of anhydride in MAH-g-LDPE modified asphalt was disappear in FTIRs results which demonstrated the reaction had happened between the MAH-g-LDPE and aspahlt. So the paper thought that the ways of MAH-g-LDPE and GMA-g-LDPE modified asphalt belonged to chemical methods for forming chemical link.The reaction happened between functional group in modified polyethylene and asphalt and the chemical bonds had been formed,which had been thought as chemical methods modified asphalt. And polyethylene modified asphalt were thought as physical methods. Softing points of MAH-g-LDPE and GMA-g-LDPE modified asphalt were improved largely by chemical methods compared to LDPE modified asphalt and the temperature sensitivity was reduced. The high temperature performances of modified asphalt were enhenced largely by chemical modified methods which were demonstrated by softening points values and dynamic shear rheometer test. The temperature sensitivity of modified asphalt was lower. the softening point were promoted obviously for high content asphaltene in asphalt when the modified LDPE content were high. The ductility test in low temperature and bending beam rheometer test showed the performances in low temperature of GMA-g-LDPE modified asphalt were not decreased and promoted while the performances of LDPE modifed asphalt and MAH-g-LDPE modifed asphalt decreased largely. The stability performances in high temperature of GMA-g-LDPE modified asphalt was better. The particles of MAH-g-LDPE and LDPE in modified asphalt systems were not evenly and the boundery between the polymer particles and asphalt was obviously in observing microsurface experiment, which indicted the stability performances were worse. There were many bigger particles in continuouse phase whch showed the crosslink had happened in polymer extruding process. And the particle of GMA-g-LDPE were evenly and the boundery between the polymer and asphalt which showed the better comodified Asphaltbility between the polymer and asphalt.更多还原