Alberts Erik M, Fernando P U Ashvin Iresh, Thornell Travis L, George Hannah E, Koval Ashlyn M, Shukla Manoj K, Weiss Charles A, Moores Lee C
SIMETRI, 7005 University Blvd., Winter Park, FL 32792, USA.
Bennett Aerospace, 1100 Crescent Green, #250, Cary, NC 27518, USA.
R Soc Open Sci. 2022 Mar 30;9(3):211637. doi: 10.1098/rsos.211637. eCollection 2022 Mar.
The design of bioinspired polymers has long been an area of intense study, however, applications to the design of concrete admixtures for improved materials performance have been relatively unexplored. In this work, we functionalized poly(acrylic acid) (PAA), a simple analogue to polycarboxylate ether admixtures in concrete, with dopamine to form a catechol-bearing polymer (PAA-g-DA). Synthetic routes using hydroxybenzotriazole (HOBt) as an activating agent were examined for their ability in grafting dopamine to the PAA backbone. Previous literature using the traditional coupling reagent 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) to graft dopamine to PAA were found to be inconsistent and the sensitivity of EDC coupling reactions necessitated a search for an alternative. Additionally, HOBt allowed for greater control over per cent functionalization of the backbone, is a simple, robust reaction, and showed potential for scalability. This finding also represents a novel synthetic pathway for amide bond formation between dopamine and PAA. Finally, we performed preliminary adhesion studies of our polymer on rose granite specimens and demonstrated a 56% improvement in the mean adhesion strength over unfunctionalized PAA. These results demonstrate an early study on the potential of PAA-g-DA to be used for improving the bonds within concrete.
长期以来，受生物启发的聚合物设计一直是一个深入研究的领域，然而，将其应用于设计具有改善材料性能的混凝土外加剂方面的研究相对较少。在这项工作中，我们用多巴胺对聚（丙烯酸）（PAA）进行功能化处理，PAA是混凝土中聚羧酸醚外加剂的一种简单类似物，以形成一种含儿茶酚的聚合物（PAA-g-DA）。研究了使用羟基苯并三唑（HOBt）作为活化剂的合成路线将多巴胺接枝到PAA主链上的能力。发现以前使用传统偶联剂1-乙基-3-（3-二甲基氨基丙基）碳二亚胺（EDC）将多巴胺接枝到PAA上的文献结果不一致，并且EDC偶联反应的敏感性使得需要寻找替代方法。此外，HOBt能够更好地控制主链的功能化百分比，是一种简单、稳健的反应，并且显示出可扩展性的潜力。这一发现还代表了多巴胺与PAA之间形成酰胺键的一种新的合成途径。最后，我们对我们的聚合物在玫瑰花岗岩试样上进行了初步的粘附研究，结果表明，与未功能化的PAA相比，平均粘附强度提高了56%。这些结果证明了对PAA-g-DA用于改善混凝土内部粘结力潜力的初步研究。
