支链羟基官能化SBS的制备及在改性沥青中的应用研究

以市售聚苯乙烯-聚丁二烯-聚苯乙烯嵌段共聚物(SBS)为原料，巯基乙醇(MCH)为改性剂，偶氮二异丁腈(AIBN)为引发剂，利用巯基-烯加成接枝反应制备出支链官能化羟基SBS(SBS-g-OH)。通过傅里叶红外光谱(FT-IR)、核磁共振氢谱(1H NMR)、热重分析仪(TGA)的表征验证了接枝反应的可靠性，考察了反应时间、温度和改性剂用量对接枝官能度的影响，以及官能度对SBS-g-OH分子量及PB段1,2-和1,4-结构C=C双键结构的影响。最终考察了不同官能度的SBS-g-OH在沥青中的分散性及对改性沥青热存储稳定性的影响，当官能度为24.07 mol%时，羟基主要接枝在SBS的PB段1,2-C=C双键上，将改性沥青离析实验中的上、下段试样软化点差异由25.1 oC降低至14.7 oC，使离析程度最小，改性沥青的热储存稳定得到明显提高。

Preparation of Hydroxyl Branched-Functionalized SBS and Application in Modified Asphalt

The hydroxyl branched-functionalized styrene-butadiene-styrene triblock copolymer (SBS-g-OH) was prepared using thiol-ene radical addition reaction with commercial SBS(raw material), 2-mercaptoethanol(MCH, modifying agent), azodiisobutyronitrile(AIBN, initiator), 1,4-dioxane(DOA, solvent). The reliability of this reaction was proved by the characterization of fourier transform-infrared spectroscopy (FT-IR), 1H-nuclear magnetic resonance(1H NMR) spectroscopy, and thermogravimetric analyzer(TGA). The effects of reaction time, temperature, MCH amount on grafting functionality degree were investigated, furthermore, the effects of grafting functionality degree on the C=C units of PB chains and molecule weight of SBS-g-OH were also investigated. Hydroxyl was mainly grafted onto the 1,2-C=C units of PB chains in SBS at the scale of functionality degree below 33.27 mol%, based on a certain amount of materials(SBS: MCH: AIBN: DOA = 10: 2: 0.02: 200 (g)), functionality degree was increased with increasing reaction time and temperature at the temperature ranged from 60 to 80 oC and time ranged from 1 to 15 h. A little number of hydroxyl was grafted onto the 1,4-C=C units of PB chains at the functionality degree of 38.57 mol%, and the 1,4-C=C units began to scissor, which made the molecular weight of SBS reduced, at the functionality degree of 41.27 mol%. The phenomenon of gel occurred at the SBS(g)/MCH(g) ranged from 0.05/1 to 0.2/1. Finally, the dispersivity of SBS-g-OH with different functionality degree in modified asphalt, and the storage stability of modified asphalt were investigated. The dispersivity was improved with increasing functionality degree at the scale of functionality degree below 33.27 mol%, especially, at the functionality degree of 24.07 mol%, segregation degree and storage stability of modified asphalt was most improved by SBS-g-OH.