含氟丙烯酸酯嵌段共聚物的迁移行为及表面性能研究

摘要

利用原子转移自由基聚合(ATRP)法合成结构明确且含氟量相同的两种嵌段共聚物：甲基丙烯酸丁酯-b-甲基丙烯酸六氟丁酯(PBMA-b-PHFBMA)和甲基丙烯酸丁酯-b-甲基丙烯酸十二氟庚酯嵌段共聚物(PBMA-b-PDFHMA)。利用表面红外光谱和原子力显微镜研究了两种含氟嵌段聚合物以及它们加入到聚丙烯酸酯树脂中的迁移行为和表面性能。结果表明：对于含氟量相同的嵌段共聚物，具有较长含氟侧基的共聚物 PBMA-b-PDFHMA比PBMA-b-PHFBMA的表面含氟量更高，表面自由能更低，且含氟侧链在薄膜表面呈针状垂直分布。含氟嵌段共聚物加入到聚丙烯酸酯树脂中后，混合树脂表面自由能降低明显，体现出明显的迁移行为；含氟嵌段共聚物的加入量在5%(wt)以上时，混合树脂的表面自由能趋于不变。在相同加入量情况下，具有较长含氟侧基的共聚物 PBMA-b-PDFHMA比PBMA-b-PHFBMA降低表面自由能的作用更明显。%Poly(butyl acrylate-b-hexafluorobutyl methacrylate) (PBMA-b-PHFBMA) and poly(butyl acrylate-b-dodecafluo roheptyl methacrylate)(PBMA-b-PDFHMA) two block copolymers with same fluorine content were synthesized by ATRP. The surface performances and migration behaviors of the two copolymers and the blends of these copolymers with polyacrylates were investigated by Attenuated Total Reflectance FT-IR spectroscopy (ATR-FTIR) and atomic force microscopy (AFM). Results show that with the same fluorine content the block copolymer with a longer fluorine-containing side chain (PBMA-b-PDFHMA) has a higher surface fluorine content and lower surface free energy than those of PBMA-b-PHFBMA, which has a shorter fluorine-containing side chain. And the fluorine-containing side chain shows a needle-like morphology and is vertically spreads on the film surface. When the fluorine-containing block copolymers are blended with polyacrlyate resin, the surface free energy of the blends decreases obviously, which indicates the migration of fluorine-containing side chain of the block copolymer on to the surface of the blend film. When the amount of fluoro-containing block copolymer added is up to 5%(wt), the surface free energy of the blends is leveled off. The block copolymer of PBMA-b-PDFHMA which has a longer fluorine-containing side chain decreases the surface free energy of the blend film more effectively than that of PBMA-b-PHFBMA.