聚羧酸原位改性氧化石墨烯减水剂的制备及对混凝土性能的影响

Preparation of polycarboxylic modified graphene oxide superplasticizer by in situ polymerization and its effects on concrete properties

摘要:

通过异戊烯醇聚氧乙烯醚（IPEG）对氧化石墨烯（GO）进行原位酯化改性，合成了氧化石墨烯-异戊烯醇聚氧乙烯醚中间体（GO-IPEG），与丙烯酸通过自由基共聚合反应制备了聚羧酸原位改性氧化石墨烯减水剂GO-PCE。利用FTIR、Raman、UV-Vis及Zeta电位分别对GO-IPEG和GO-PCE结构进行了表征。红外结果表明，IPEG接枝到GO表面，而后GO-IPEG与丙烯酸发生原位接枝聚合反应。UV-Vis及Zeta电位结果表明，GO-PCE依靠IPEG的空间位阻作用使GO在基体中具有较优的分散效果。水泥及混凝土性能结果显示，当GO-PCE折固掺量为0.15%（以水泥质量为基准）时，即可达到饱和吸附，水泥净浆流动度高达280 mm，混凝土28 d抗压强度为57 MPa、28 d收缩率为190×10-6、28 d电通量为1950 C。

Abstract:

Isopentenol polyoxyethylene ether modified graphene oxide (GO-IPEG) was prepared by in situ esterification reaction, and then polycarboxylic modified graphene oxide superplasticizer (GO-PCE) was prepared by GO-IPEG and acrylic acid (AA) using the method of in situ free radical copolymerization. The molecular structure and the dispersion stability of GO-IPEG and GO-PCE were characterized by FTIR, Raman spectra, UV-vis and zeta potential. FTIR results indicate that IPEG was successfully grafted onto the surface of GO by the esterification of carboxyl groups and hydroxyl groups, and then GO-IPEG fabricated with acrylic acid by in situ free radical polymerization. The results of UV-vis and zeta potential show that the the better dispersion properties of GO in polycarboxylic matrix depending on the steric resistance effect of IPEG. The results of cement and concrete show that saturated adsorption can be achieved when the solid content of GO-PCE is 0.15% (by mass of cement), and the fluidity of cement paste can reach 280 mm, the 28 d compressive strength of concrete is 57 MPa, and the 28 d shrinkage rate is 190 × 10-6, and the 28 d electric flux is 1950 C.