【作者】 张宝昌；

【导师】 张宝砚； 张会轩；

【作者基本信息】 东北大学 ， 材料学， 2008， 博士

【摘要】 随着现代交通事业的发展,高等级公路建设步伐加快,对高性能、低成本改性沥青的需求越来越大。聚合物改性剂由于其可改善沥青的高温刚性、低温柔性以及温度敏感性,一直是人们研究的热点,但改性沥青高温贮存不稳定、改性成本高等缺点限制了其推广应用。本文采用熔融共混法与种子乳液聚合法,分别制备了丁苯橡胶/蒙脱土(SBR/MMT)、丁苯嵌段共聚物/蒙脱土(SBS/MMT)复合材料改性剂和核壳结构聚丁二烯粒子接枝苯乙烯(PB-g-PS)、聚丁二烯粒子接枝苯乙烯及沥青组分(PB-g-PS/Asphalt)的接枝聚合物改性剂,利用高速剪切法研制出力学性能好、高温贮存稳定的SBR/MMT改性沥青、SBS/MMT改性沥青、PB-g-PS改性沥青及PB-g-PS/Asphalt与SBR协同改性沥青,系统地研究了各种改性沥青的物理机械性能、相态结构、贮存稳定性及流变学性质,探讨了它们的改性机理,揭示了其贮存稳定性和力学性能改善的内在原因。第一,采用熔融插层法制备了SBR/MMT复合材料改性剂,利用高速剪切法获得了力学性能好、稳定化、低成本的SBR/MMT改性沥青。XRD、TEM研究表明,弹性体SBR与无机蒙脱土形成了插层型或剥离型结构的复合材料。考察了不同质量比SBR/MMT改性沥青的结构与性能,发现当SBR与MMT的质量比为3/5时,改性沥青的性能最好,剥离型结构复合材料对改性沥青性能的改进贡献较大。荧光显微镜的形貌观察显示,SBR/MMT复合材料以微球形结构、呈点阵状分布在基质沥青中,形成了以改性剂为分散相,以基质沥青为连续相的单相连续结构。高温贮存稳定性实验表明,在一定SBR/MMT质量比和掺量范围内,SBR/MMT改性沥青高温贮存稳定,离析差均小于2.5℃。尤其是,SBR/MMT改性沥青具有较高的复数模量(G*)和较低的损耗因子(Tanδ),说明SBR/MMT复合材料改性剂改善了基质沥青的黏弹性,可使其在高温下的弹性明显增加,温度敏感性减弱,高温抗车辙能力提高。第二,研制了高性能、稳定化的SBS/MMT复合材料改性沥青。XRD、TEM研究分析发现,当SBS与MMT质量比为5/1时,形成剥离型结构复合材料,其它比例为插层型复合材料。系统考察了不同质量比的SBS/MMT复合材料对改性沥青性能的影响,比较了SBS改性沥青、SBS/MMT复合材料改性沥青,SBS、MMT简单混合改性沥青的结构与性能,发现SBS与MMT形成复合材料以后能更显著地提高改性沥青的物理性能和改善贮存稳定性。质量比为5/5的SBS/MMT复合材料改性沥青的各项物理性能最佳,高温贮存稳定性最好,上下段软化点的离析差仅为0.4℃。荧光显微镜分析发现,SBS/MMT复合材料改性剂在基质沥青中分散效果良好,即在高温贮存以后也没有沉降和聚集现象发生。动态力学性能分析发现,SBR/MMT改性沥青具有较高的复数模量(G*)和较低的损耗因子(Tanδ),同时复数模量(G*)随温度升高而下降、损耗因子(Tanδ)随温度的升高而上升的趋势都趋缓,表明SBS/MMT复合改性剂改善了基质沥青的黏弹性。第三,采用种子乳液聚合法制备了核壳结构PB-g-PS接枝聚合物沥青改性剂,并首次在PB-g-PS的聚合过程中引入沥青成分合成了PB-g-PS/Asphalt聚合物粒子。对比考察了S/B不同质量比的PB-g-PS、PB-g-PS/Asphalt改性沥青的物理性能及贮存稳定性,利用SEM进行了改性沥青的形貌观察,并应用示差扫描量热法(DSC)对沥青的改性效果进行了定性分析。结果表明：核壳结构接枝聚合物对沥青的高温性能改善效果显著,对低温性能的改善效果不明显；当S/B的质量比为30/70时,核壳接枝聚合物对沥青的改善效果最佳；PB-g-PS/Asphalt改性沥青的高温稳定性要明显好于PB-g-PS改性沥青,说明沥青成分的引入提高了核壳接枝聚合物与基质沥青的相容性。第四,以PB-g-PS/Asphalt聚合物粒子为增容剂,制备了高低温性能均较好的PB-g-PS/Asphalt、SBR协同改性沥青。通过对改性沥青的物理性能、高温贮存稳定性和橡胶相分散状态等的分析,发现PB-g-PS/Asphalt的增容效果明显,它使SBR改性沥青的相态结构发生了变化,增加了SBR吸收沥青中饱合小分子的能力,提高了SBR与沥青中的胶质和沥青质作用的几率,进而改善了基质沥青的各项性能。更多还原

【Abstract】 The demands of polymer modified asphalts with high-property and low-cost is increasing with the development of modern traffic and of high-level highway. Polymer modified asphalts possessing high-temperature rigidity and low-temperature flexibility is focused on by many researchers. However, their applications are limited by high-temperature storage unstability and high-cost. In this dissertation, using melted mixing method and seed emulsion grafting technology, the elastomers and their composites modifiers such as SBR/MMT and SBR/MMT composites as well as core-shell PB-g-PS and PB-g-PS/Asphalt particles were prepared, respectively. SBR/MMT modified asphalts, SBR/MMT modified asphalts, PB-g-PS modified asphalts and PB-g-PS/Asphalt cooperated with SBR modified asphalts were prepared using high-speed shearing technology. The properties of these modified asphalts including physical properties, phase structure, high temperature storage stability and rheological properties were systematically studied. The modified mechanisms were also disscussed.Firstly, Styrene-butadiene-rubber/Montmorillonite (SBR/MMT) composite modifiers were prepared by melted mixing method and SBR/MMT modified asphalts were prepared by by high-speed shearing technology. The properties of SBS/MMT modified asphalts such as physical properties, phase structure, high temperature storage stability and rheological properties were investigated. XRD and TEM results show that SBR/MMT composites may form intercalated or exfoliated structures. The structures and properties of modified asphalts with different SBR/MMT mass ratios were investigated. The results indicate that the modified asphalts with 3/5 SBR/MMT mass ratios possess best properties and the exfoliated strcture SBR/MMT is better modifier. The morphologies of the samples have been characterized by fluorescent microscopy. The results indicate that SBR/MMT modifier micro spheres dispersed in continuous phase of asphalt. High-temperature storage stability tests indicated that the modified asphalts are very stable in some SRB/MMT content range and the difference in the softening points between top and bottom sections was lower than 2.5℃.Especially, the modified asphalts exhibited higher complex modulus (G*) and lower damping factor (Tan8). It implies that SBR/MMT displays improved viscoelastic properties, resulting in enhancing its resistance to rutting at high temperature.Secondly, the high-properties SBS/MMT modified asphalts with stability were prepared by melted mixing method. XRD and TEM results show that SBS/MMT composites may form an exfoliated structure at 5/1 SBS/MMT mass ratio and intercalated structure at others mass ratios in SBS/MMT modified asphalts. The different SBS/MMT mass ratios influencing the properties of modified asphalts were investigated. The structures and properties of SBS modified asphalts, composite SBS/MMT modified asphalt and separated SBS,MMT modified asphalt were compared. The results show that SBS/MMT composites have best modified effect in improving physical properties and high temperature storage stability. High-temperature storage stability tests indicated that the modified asphalt is the most stable in 5/5 SRB/MMT mass ratio and the difference in the softening points between top and bottom sections was only 0.4℃.The fluorescent microscopy results show that SBS/MMT composites may form stable structure in SBS/MMT modified asphalts and no sediments particles were found after high temperature storage. The rheological tests indicate that the SBS/MMT modified asphalts exhibited higher complex modulus (G*) and lower damping factor (Tan8).It implied that SBR/MMT modified asphalts displaying improved viscoelastic properties.Thirdly, Core-shell PB-g-PS polymer latex particles and novel sub-micron core-shell rubber PB-g-PS/Asphalt particles were synthesized by the seed emulsion grafting technology. The comparation was taken between PB-g-PS modified asphalts and PB-g-PS/Asphalt modified asphalts in physical properties and high temperature storage stability. The morphologies and thermal properties of the samples have been characterized by SEM and DSC.The results showed that the high-temperature properties were increased obviously but the low-temperature properties were improved unobviously by Core-shell polymer latex particles. At 30/70 S/B mass ratio, Core-shell PB-g-PS polymer latex particles have best modified effect to asphalts. The high temperature storage stability of PB-g-PS/Asphalt modified asphalts is better than one of PB-g-PS modified asphalts.This indicates that the compatibility between PB-g-PS modifier and asphalt was improved by introducing asphalt into PB-g-PS.Finally, in order to obtain a kind of modified asphalt with good high and low temperature properties, the PB-g-PS/Asphalt cooperated with SBR modified asphalts were synthesized. The physical properties, phase structure and high temperature storage stability of the modified asphalts were studied. The results showed that as compatibility agent PB-g-PS/Asphalt has obvious effect. It changed phase structure of modified asphalt and resulted in SBR absorbing small molecule and increasing motive chance to gel and asphaltene in asphalt. This improves all properties of modified asphalts.更多还原