乙烯基共聚物改性沥青结构与性能研究

发布时间：2018-05-14 06:49

本文选题：乙烯基共聚物 + 乙烯辛烯共聚物　；参考：《上海应用技术学院》2015年硕士论文

【摘要】：石油沥青是原油经多级精馏之后的残渣,是由不同分子量的长链烷烃及多种非金属化合物组成的黑色粘稠混合物,由于其优异的粘结性能和防水性,被广泛应用于路面结构胶结材料。但由于石油沥青是一种粘弹性材料,其在高温粘度较低易流淌,低温固化后易脆裂,温度敏感性强,难以满足道路铺设要求,因此未经改性的基质沥青难以应用于道路铺装。对石油沥青的改性研究一直是近年来众多道路科研工作者研究的热门。本文通过总结聚乙烯改性沥青在高温条件下贮存稳定下差的缺点,期望能够探索一种新型聚合物对沥青进行改性处理,使其不仅能够具备聚乙烯改性沥青的优秀的高温性能,还能够在贮存稳定性方面有所提高,提出了采用乙烯基共聚物改性沥青的设想。乙烯基共聚物是指指由乙烯与其他单体共聚所得聚合物的总称,其主链上存在乙烯链结与其他单体链结,因此聚合物本身既存在良好的弹性,又有其他聚合物单体提供的新特性。本文采用了两种乙烯基共聚物——乙烯辛烯共聚物(POE)和乙烯丙烯酸共聚物(EAA)对基质沥青进行改性,通过控制改性剂的不同添加比来探索改性剂的最佳加入比,同时通过改性沥青常规性能测定评价了改性沥青的高温性能和粘度和韧性；通过显微形貌观察分析了改性剂加入后在基质沥青当中的分散状态,确定了改性剂的适合的加入比；使用动态剪切流变仪(DSR)测定了改性沥青的流变特性。由于EAA中的丙烯酸链结含有羧基,可能提高与弱碱性的集料颗粒间的粘附力。通过黏附性实验评价了EAA改性沥青同集料之间的黏附性。研究结果表明：乙烯基共聚物的加入能够有效提高改性沥青的高温性能,针入度和粘度也随之增加；显微形貌观察表明,当改性剂添加量较少(4%)时,改性剂在沥青中能够呈“海-岛”结构均匀分散,当聚合物添加量较高时(6%)聚合物颗粒彼此碰撞结合,最终形成复杂的网络结构,改性沥青呈现相分离状态,导致了高温贮存时的离析的发生。流变性能分析表明,聚合物加入沥青中后能够有效提高基质沥青的粘弹性,原因是基质沥青在高温下逐渐转变为牛顿流体,聚合物以其粘弹性较好的高分子链补足了基质沥青丧失的粘弹性,使得改性沥青在高温下仍能表现出较好的粘弹性。通过EAA改性沥青同集料颗粒之间的黏附性研究表明随着EAA含量的增加,改性沥青同集料之间的黏附性增加。由于单纯以EAA或POE对沥青进行改性,其稳定性和性能仍未达到使用要求,因此在论文的最后,本文还通过采用溶解包覆的工艺制备了EAA-硅藻土包覆体系,并将之添加入基质沥青对沥青进行改性实验。通过向改性体系中加入多孔结构的硅藻土,期望能够以复配的方式发挥两者的改性效果,同时降低改性剂成本。研究结果表明：随着包裹产物中硅藻土含量增加,硅藻土逐渐暴露在EAA基质表面。当添加入基质沥青中后,改性沥青高温性能、粘弹性及韧性都有所增加。显微观察结果表明,随着硅藻土含量增加,包裹产物中的硅藻土逐渐从EAA基质中脱附出来,通过高速剪切分散作用进入到基质沥青当中,导致了改性沥青性能的突变。贮存稳定性实验表明,随着包覆产物中硅藻土含量的增加,改性沥青高温贮存过程中会发生明显的分层,其中EAA上浮于上层,硅藻土在底部沉积,导致上下部软化点差增加。尽管乙烯基共聚物改性沥青在性能方面还不能满足现阶段对改性沥青的使用标准要求,但这类新兴的弹性体在改性沥青方面具有巨大的潜力,新的共混分散方法、对聚合物进行接枝改性或与其他改性剂复配进行改性等新方法和新工艺具有较高的研究价值。
[Abstract]:Petroleum bitumen is a residue after multistage distillation of crude oil. It is a black viscous mixture consisting of long chain alkanes and a variety of nonmetallic compounds with different molecular weights. Due to its excellent adhesive properties and waterproof properties, it is widely used in pavement structure cementation material. But as petroleum asphalt is a kind of viscoelastic material, its viscosity is relatively high at high temperature. It is easy to flow, brittle cracking after low temperature curing and strong temperature sensitivity. It is difficult to meet the requirements of road laying. Therefore, the unmodified matrix asphalt is difficult to apply to road pavement. The research on the modification of petroleum asphalt has been a hot topic for many road researchers in recent years. This paper summarizes polyethylene modified bitumen in high temperature conditions. It is expected to be able to explore a new type of polymer to modify asphalt, so that it can not only have excellent high temperature properties of polyethylene modified bitumen, but also improve the storage stability, and put forward the idea of using vinyl copolymer modified asphalt. The total polymer obtained by copolymerization of alkenes with other monomers has a chain of ethylene chain and other monomers on its main chain, so the polymer itself has both good elasticity and new properties provided by other polymer monomers. In this paper, two vinyl copolymers, ethylene octyl copolymer (POE) and ethylene acrylic acid copolymer (EAA) were used in this paper. The matrix asphalt was modified to explore the optimum addition ratio of the modifier by controlling the different addition ratio of the modifier. At the same time, the high temperature performance, viscosity and toughness of the modified bitumen were evaluated by the conventional performance measurement of the modified asphalt. The dispersion state of the modifier in the matrix bitumen after adding the modifier was observed and analyzed by the microscopic morphology. The suitable addition ratio of the modifier; the rheological properties of modified bitumen were measured by using dynamic shear rheometer (DSR). As the acrylic chain in EAA contains carboxyl groups, it may increase the adhesion between the aggregate particles and the weakly alkaline. The adhesion between the EAA modified asphalt and the aggregate is evaluated by the adhesion test. The addition of allyl copolymers can effectively improve the high temperature performance of the modified asphalt and increase the penetration and viscosity. The microstructure observation shows that when the modifier is less (4%), the modifier can be distributed uniformly in the "Sea Island" structure in the asphalt. When the polymer addition is higher (6%), the polymer particles are collided with each other. At the end of the complex network structure, the modified asphalt presents a phase separation state, which leads to the segregation of the high temperature storage. The rheological analysis shows that the polymer can effectively improve the viscoelasticity of the matrix bitumen after the polymer is added to the asphalt. The reason is that the matrix bitumen gradually turns into Newton fluid at high temperature, and the polymer has better viscoelasticity. The polymer chain complements the viscoelasticity of the matrix bitumen, which makes the modified asphalt exhibit better viscoelasticity at high temperature. The adhesion between the EAA modified asphalt and the aggregate particles shows that the adhesion between the modified asphalt and the aggregate increases with the increase of the content of the EAA. The modified asphalt is modified solely with EAA or POE, At the end of the paper, the EAA- diatomite cladding system was prepared by using the dissolving coating process and added into the matrix bitumen to modify the asphalt. By adding the porous diatomite to the modified system, it was expected to be able to play a compound method. The results show that with the increase of Diatomite Content in the package products, the diatomite gradually exposed to the surface of EAA matrix. When adding matrix bitumen, the high temperature performance, viscoelasticity and toughness of the modified asphalt increased. The results showed that the content of diatomite increased as the content of diatomite increased. The diatomite in the package product is gradually removed from the EAA matrix and enters into the matrix bitumen by high-speed shearing dispersion, which leads to the mutation of the properties of the modified bitumen. The storage stability experiment shows that with the increase of the content of diatomite in the coating products, there will be obvious stratification during the high temperature storage process of the modified asphalt, of which EAA In the upper layer, the diatomite is deposited at the bottom, which leads to the increase of the softening point in the upper and lower parts. Although the performance of the vinyl copolymer modified bitumen can not meet the current standard requirements for the use of modified bitumen, the new elastomers have great potential in the modified asphalt. Grafting modification or modification with other modifiers has high research value.

【学位授予单位】：上海应用技术学院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U414

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