Synthesis And Properties Of Amphiphilic Block Copolymer P (BA-b-AM)

Amphiphilic block copolymer is a class of polymer with hydrophilic and hydrophobic chains. And it has viscoelasticity of macromolecules and surfactivity of amphiphilic molecules. It can enrich in the oil - water interface and change the nature of interface. Also it can adsorb on hydrophobic and hydrophilic materials.In this paper, butyl acrylate polymer latex was prepared by reverse atom transfer radical emulsion polymerization of NaHCO₃/NaHCO₃ as alkali, CuBr₂ as catalyst, Pentamethyldiethylenetriamine as ligand, Potassium persulfate as initiator and sodium dodecyl sulfate/triton X-100 as emulsifier, then initiated acrylamide to form block copolymer. The polymerization systems of addition of alkali, emulsifier dosage, initiator dosage, catalyst/ligand ratio and reaction temperature, time and other conditions were discussed. the best synthesis of block copolymer P(BA-b-AM) was: butyl acrylate polymerization, the temperature was 80℃, adding NaHCO3/NaHCO3=0.01/0.01(g/g), SDS/Triton X-100= 1-2%(wt), [I]:[M]=1:100(mol), CuBr2:PMDETA=1:2(mol), [M]:[S]=1:1-1:2(vol), reacted of 4 hours, the monomer conversion was 78%; Amphiphilic block copolymer polymerization, the temperature was 40℃, reaction time was 100min, the conversion of acrylamide was 72%. Monomer conversion was well controlled with reaction time increasing linearly, both polymerizations were well controlled with Mn values increasing linearly with conversion and polydispersity index remained very low, block copolymer polymerization was consistent with linear kinetic plots.Structure and property of block copolymer were characterized by IR, NMR, GPC, viscosity and particle size: the final PBA molecular weight was 5.78×104, polydispersity index was 1.34; P(BA-b-AM) molecular weight was 6.79×104, polydispersity index was 1.61, and the molecular weight distribution of P(BA-b-AM) was uniformity. The final block copolymer emulsion particle size was 282nm, and viscosity was 2.53 mpa?s.Block copolymer adsorption on the surface of fabric and the stability of pigment system were tested, the conclusion was as following: The equilibrium adsorption time of fabric to polymer emulsion was 5min. Compare 40℃, 60℃with 80℃, it was found that emulsion absorbance changed maximum at 60℃, the adsorption capacity of fabric was up to 0.90g. SEM spectra of emulsion characterization found that some block copolymer absorbed on the fiber; adding pigment in emulsion system, it couldn't be dispersed if the emulsion wasn't ultrasonic treatment, but it could be dispersed in the emulsion after ultrasonic treatment. The pigment particle size was uniform distribution, and centrifugal stability was good.