Poly(butyl methacrylate-g-methoxypoly(ethylene glycol)) and poly(methyl methacrylate-g-methoxypoly(ethylene glycol)) graft copolymers: preparation and aqueous solution properties.
A series of water-soluble, amphiphilic graft copolymers has been prepared by free-radical copolymerization of methoxypoly(ethylene glycol) macromonomers, with either methyl methacrylate or butyl methacrylate as the comonomers, in water/ethanol solvent mixtures. Lower molecular weight copolymers were obtained by increasing the concentration of the initiator, azobisisobutyronitrile (AIBN), used in the polymerization reaction. However, the route used also led to the formation of significant quantities of tetramethylsuccinodinitrile, a toxic byproduct resulting from the cage reaction of AIBN. Static fluorescence measurements using pyrene as a probe, along with 1H NMR experiments, showed that the graft copolymers form aggregates in water at very low concentrations (approximately 0.01 g l(-1)) with the pendant hydrophilic graft chains forming a stabilizing shell around the hydrophobic backbone. An increase in the hydrophile-lipophile balance of the graft copolymers was found to lead to smaller aggregates with lower aggregation numbers and highly swollen hydrophilic shells, as revealed by small angle neutron scattering (SANS).
Horgan
Adrian
A
School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
Saunders
Brian
B
Vincent
Brian
B
Heenan
Richard K
RK
D008689:Methacrylates / Q000737:chemistry; D008823:Micelles; D011092:Polyethylene Glycols / Q000737:chemistry*; D011109:Polymethacrylic Acids / Q000737:chemistry*; D019904:Polymethyl Methacrylate / Q000737:chemistry; D012996:Solutions; D014867:Water
D008689:Methacrylates; D008823:Micelles; D011109:Polymethacrylic Acids; D012996:Solutions; C456562:methoxy polyethylene glycol methacrylate; D014867:Water; D011092:Polyethylene Glycols; C068872:polybutyl methacrylate; D019904:Polymethyl Methacrylate