SBS-g-CaCO3的制备及改性沥青性能

Preparation of SBS-g-CaCO3 and properties of modified asphalt

摘要:

为改善纳米CaCO3与有机基体的相容性及分散性，增强苯乙烯-丁二烯-苯乙烯嵌段共聚物（SBS）和纳米CaCO3在改性沥青中的应用，对纳米CaCO3进行氨基化改性制备了CaCO3-NH2，对SBS进行环氧化处理制备了ESBS，然后采用表面接枝法，将CaCO3-NH2与ESBS进行共价接枝，制备了有机-无机杂化交联结构的SBS接枝纳米CaCO3（SBS-g-CaCO3）。以接枝率、接触角和溶胀指数为关键指标，采用正交实验优化了SBS-g-CaCO3的制备条件，并通过FTIR、XPS、SEM、TGA、荧光显微镜对SBS-g-CaCO3的表面形貌、结构、发光性能进行表征和测试。将SBS-g-CaCO3用于改性沥青，测试其性能并与CaCO3-NH2与ESBS机械共混改性沥青进行对比。得到的最优反应条件为：n(环氧基)∶n(氨基)＝1∶1，反应温度70 ℃，反应时间210 min，0.25mol/L的NaOH水溶液 掺量为1 mL，其中n(环氧基)∶n(氨基)对关键指标的影响最大。与ESBS相比，SBS-g-CaCO3具有更好的热稳定性，接枝率最高可达49.5%；纳米CaCO3颗粒在SBS中呈均匀分散状态并与SBS形成交联互穿网状结构；SBS-g-CaCO3改性沥青的存储稳定性 明显提升，48 h软化点差为0.5 ℃。

Abstract:

In order to improve the compatibility and dispersion of nano-CaCO3 with organic matrix, and enhance the application of styrene-butadiene-styrene block copolymer (SBS) and nano-CaCO3 in modified asphalt, CaCO3-NH2 was prepared by amination modification of nano-CaCO3, ESBS was prepared by epoxidation treatment, and then CaCO3-NH2 and ESBS were covalently grafted by surface grafting method, SBS grafted nano-CaCO3 (SBS-g-CaCO3) with organic-inorganic hybrid cross-linked structure was prepared. Taking grafting ratio, contact angle and swelling index as key indicators, the preparation conditions of SBS-g-CaCO3 were optimized by orthogonal experiments, and the surface morphology, structure and luminescence properties of SBS-g-CaCO3 were characterized and tested by FTIR, XPS, SEM, TGA and fluorescence microscopy. SBS-g-CaCO3 was used in modified asphalt, and its performance was tested and compared with that of CaCO3-NH2 and ESBS mechanically blended modified asphalt. The optimal reaction conditions were as follows: n (epoxy): n (amino) = 1: 1, reaction temperature 70 ℃, reaction time 210 min, 0.25 mol/L NaOH aqueous solution content 1 mL, in which n (epoxy): n (amino) had the greatest influence on the key indexes. Compared with ESBS, SBS-g-CaCO3 has better thermal stability, and the grafting rate can reach up to 49.5%; Nano-CaCO3 particles are uniformly dispersed in SBS and form cross-linked interpenetrating network structure with SBS; The storage stability of SBS-g-CaCO3 modified asphalt is obviously improved, and the softening point difference at 48 h is 0.5 ℃.