Synthesis And Properties Of Amphiphilic 1-octene-styrene Copolymer

Amphiphilic polymers' structure has the characteristic of incompatibility between hydrophilic segment and hydrophobic segment, which shows it unique properties in selective solvents, surfaces and bulk structure. So it has long been of scientific interest. Long chain α-olefin homopolymers have a good solvability in oil and the monomers of long chain α-olefin are economically availble, but few report about amphiphilic copolymers containing long chain α-olefin was published.Synthesis of poly(l-octene-co-styrene) polymerized with high yield spherical TiCl₄/MgCl₂ Ziegler-Natta catalyst in n- heptane solution and the sulphonation of copolymers were investigated.The reactivity ratio of 1-octene and styrene was calculated by Mayo-Lewis theory based on ¹H-NMR spectra of copolymers. The reactivity ratio of 1-octene and styrene are 6.66 and 2.32, respectively. Influences of polymerization temperature, the ratio of two monomers and the comsuption of hydrogen were studied by GPC, NMR and DSC. It showed styrene segments in copolymers mainly exited in a random distribution. The molecular weight of copolymers decreased with the increase of polymerization temperature, the content of styrene in the monomer or the comsuption of hydrogen. As polymerization temperature or the content of styrene in monomer increased the content of styrene in copolymers increased. But the comsuption of hydrogen had no influence on the structure of copolymers.After being sulphonated by dense sulfuric acid (50wt%), amphiphilic poly(l-octene-co-styrene) was prepared. Various factors such as copolymers' molecular weight, the content of styrene in copolymers and reaction time impacted sulphonation degree. Sulphonated copolymers were coated onto the surface of LDPE film. And the water droplet contact angel of LDPE film sharply decreased. Afterbeing treated by vapor, the sulphonated copolymer was well sticked to the surface of LDPE film. And further the hydrophilicity of LDPE film was improved. Because hydrophilic segments transported to the surface induced by water.Sulphonated copolymers formed spherical micelles by dissolving them in toluene/ethanol mixed solvent. The hydrophilic segments formed the cores, and hydrophobic segments formed the shells. The diameters of micelles were 50-400nm which was influenced by copolymers' molecular weight, sulphonation degree and properties of solvents. The micelles was stable at room temperature.