Synthesis, Characterization, and Propertis of Amphiphilic Poly(ethyl acrylate) with Uniform Polyoxyethylene Grafts

摘要

Amphiphilic compolymers of ethyo acrylate (EA),with uniform polyoxyethylene (PEO) grafts were synthesIZed by copolymenzatIon with methacrylat~ ter- minated PEO macromer in benzene using azobisisobutYrhJiitt:ile as the initiator. effects of the molecular weight of the macromers, the chtirii~lweight ratio of the macromer to EA, the total monomer concentration, and the grafting efficiency (GE) were reported as was the molecular weight of the copolymers. The highest GE reached to above 90% and the molecular weight of the copolymers varied from (5-15) X 104. The reactivity ratio of EA with the macromer was determined to be 0.83. The graft copolymers were purified with extractions and the purified products were characterized with IR, lH-NMR, gel permeation chromatography, dif- ferential scanning calorimetry , and membrane osmometry. The average grafting num- ber of the copolymer varied from 2 to 11. The glass-transition temperature of the poly(EA) in the copolymer was increased because of the partial compatibility of the two components. The crystalline property, emulsifying property, and dilute solution viscos- ity of the graft copolymers, as well as ionic conductivity of their complexes with alkali metal salts, were studied. The emulsifying volume decreased with the increasing molecular weight of the PEO grafts. The addition ofNaOH to the emulsion affected the emulsifying volume only slightly, whereas the addition of HCl changed the oil in water type emulsion into a water in oil type. The conductivity of the LiC1O4 complex of the copolymer with an oxyethylene/Li ratio of 20 reached 3.7 x 10-5 Slcm at 27°C. The lower the crystallinity of the complex, the higher was the conductivity. The dilute solution viscosity showed the existence of intramolecular microphase separation.