Polyurethane-poly(butyl methacrylate) copolymer aqueous dispersions (PUBMA) were synthesized via hydroxyl-terminated poly(butyl methacrylate).The hydroxyl-terminated poly(butyl methacrylate) (PBMA-OH) was synthesized via atom transfer radical polymerization with activators regenerated by electron transfer (ARGET ATRP) using hydroxylbutyl -bromoisobutyrate as an initiator

copper(II) bromide(CuBr2)(0.05% molar fraction of monomer) as a catalyst

pentamethyldiethylene triamine (PMDETA) as a ligand

and stannous octoate (Sn(EH)2) as a reducing agent.Polyurethane-poly(butyl methacrylate) copolymer aqueous dispersions (PUBMA) were then synthesized using polyether diols (N220)

polyether triols (N330)

PBMA-OH

toluene diisocyanate (TDI) and dimethylol propionic acid (DMPA) as the main raw materials.The effects of the amount of PBMA-OH on the properties of PUBMA aqueous dispersions and films were investigated.The results showed that polyurethane-poly(butyl methacrylate) copolymer aqueous dispersions were successfully synthesized.With the increment of the amount of PBMA-OH

the particle sizes of the PUBMA aqueous dispersions increased and the particle size distribution of the PUBMA became broader than that of the pure PU.The results of mechanical properties and water resistance test indicated that the tensile strength of the PUBMA films increased from 6 MPa to 8 MPa

but the elongation at break decreased from 1500% to 800%

and water resistance of the films improved significantly after the PBMA segment was introduced into PU.Atomic force microscope (AFM) and dynamic mechanical analysis (DMA) confirmed that there were obvious two phases in PUBMA

and the PUBMA films had two glass transition temperatures

both the glass transition temperatures increased with the increment of the amount of PBMA.