Investigation Of The Synthesis And The Dispersing Properties Of Comb POE-b-PAA

In this article,novel comb POE-b-PAA polymers have been successfully synthetized through aqueous RAFT polymerization.Firstly,oligo(ethylene glycol)methyl ether acrylate(OEGA)and oligo(ethylene glycol)methyl ether methacrylate(OEGMA)were used to synthesize comb macro-RAFT agents(POE-RAFT).Then,POE-RAFT reacted with acrylic acid to form POE-b-PAA.FT-IR,'H-NMR and GPC are applied to analyze the structure and reaction condition of POE-RAFT and POE-b-PAA.When POE-RAFT were synthesized,the buffer with pH=5.2 was suitable for polymerization.The molecular weight and polydispersity improved with the increase of reaction time and the mole ratio of monomer to RAFT agent.The POE-b-PAA with different PA A chains could be synthesized by modulating the mole ratio of POE-RAFT to AA.The dispersing properties of POE-b-PAA in CaCO3 suspension were studied by Zeta potential,granularity,TEM,viscosity and FT-IR.Compared with raw CaCO3 suspension,the granularity and viscosity of CaCO3/POE-b-PAA decrease significantly.With the increase of POE-b-PAA content,the granularity and viscosity are further decline.In order to investigate effect of the molecular weight of POE-b-PAA on dispersing CaCO3,the POE-b-PAA with same PAA content and different Mw are used to disperse CaCO3.The POE-b-PAA with Mw near 30000 show the best dispersibility in CaCO3 suspension.The length of PAA chains also will affect the dispersibility.The experimental results indicate that the POE-b-PAA with a too long PAA chain show worse dispersibility.Different side chains will affect the dispersibility of POE-b-PAA.By comparison,the absolute value of Zeta potential of CaCO3/POEGMA500-b-PAA suspension is higher than CaCO3/POEGMA950-b-PAA suspension.But POEGMA950-b-PAA with long side chains show better dispersibility,due to the important contribution of steric hindrance.