Structure And Properties Of Polycarboxylic Acid Dispersants Synthesized By Raft Method

Polycarboxylic acid dispersants (PCs) with comb-like molecular structure have become the focus of dispersants. However, there are many contradictions in the study of molecular structure of polycarboxylic acids. In this article, a series of PCs with different molecular structures were prepared from acrylic acid (AA) and methyl allyl alcohol polyoxyethylene ether (TPEG) by reversible addition fragmentation chain transfer (RAFT) polymerization. The structural characteristics of PCs were characterized by flourier transform infrared spectrometer (FT-IR), H-1 nuclear magnetic resonance (NMR) spectroscopy and gel permeation chromatography (GPC). The dispersion performance of PCs to cement was measured by the fluidity and adsorbing capacity. The results show that the dispersion performance and adsorbing capacity of PCs are significantly related to its structure. The adsorption and dispersion properties increase with the increase of carboxyl content and molecular weight. However, this phenomenon is limited to a certain range that the acid ether ratio in this range is no greater than 5:1, and the molecular weight is no greater than PC-4 (Mw = 82 125, Mn = 63 889).