阳离子型水基疏水涂料的制备及性能

Preparation and Properties of Aqueous Cationic Hydrophobic Coatings

通过可逆加成-断裂链转移聚合(RAFT)合成了聚(丙烯酸二甲氨基乙酯-co-苯乙烯)-b-聚丙烯酸六氟丁酯嵌段共聚物(P(DMAEA-co-St)-b-PHFBA),并以此制备了阳离子型水基疏水涂料。通过凝胶渗透色谱、核磁共振氢谱、接触角等对P(DMAEA-co-St)-b-PHFBA结构及性能进行了研究,探讨了分散介质、烘干温度、纳米二氧化硅粒径及用量对涂料接触角的影响;最后研究了涂料漆膜性能。结果表明,通过RAFT聚合法成功合成了P(DMAEA-co-St)-b-PHFBA,经酸化后,可得阳离子水分散体,薄膜对水接触角为103°。将P(DMAEA-co-St)-b-PHFBA与粒径200 nm的SiO2以质量比1/1混合后,接触角可达153°(8μL)。将上述疏水纳米颗粒与乙烯-醋酸乙烯共聚物乳液(VAE)混合后,可得综合性能优异的阳离子疏水涂料。当P(DMAEA-co-St)-b-PHFBA/SiO2复合物与VAE质量比为1/1时,接触角为133°(8μL),铅笔硬度为HB,附着力为1级,耐冲击性能为50 cm。

Poly(dimethylaminoethyl acrylate-co-styrene)-b-polyhexafluorobutyl acrylate block copolymer(P(DMAEA-co-St)-b-PHFBA) was synthesized by reversible addition-fragmentation chain transfer radical polymerization(RAFT). And an aqueous cationic hydrophobic coating was prepared using this block copolymer. The structure and properties of P(DMAEA-co-St)-b-PHFBA were investigated by gel permeation chromatography(GPC), nuclear magnetic resonance(1H-NMR) and contact angle(WCA). The effects of dispersion medium, dry temperature, particle sizes and amounts of nano-silicon dioxide on contact angles of hydrophobic coatings were studied. Finally, the performances of aqueous cationic hydrophobic coatings were studied. The results show that P(DMAEA-co-St)-b-PHFBA block copolymers were successfully synthesized by RAFT. After acidification, the copolymer could be well-dispersed in water, and the contact angle of the coating to water could reach 103°. When P(DMAEA-co-St)-b-PHFBA was mixed with 200 nm SiO2 at a mass ratio of 1/1, the contact angle of the coating could be increased to 153° measured by 8 μL water droplet, but the performance of the coating is poor. The performance of the coating can be greatly improved by introducing ethylene-vinyl acetate copolymer(VAE) emulsion into the aqueous cationic hydrophobic coating. When the mass ratio of P(DMAEA-co-St)-b-PHFBA/SiO2 to VAE emulsion is 1/1, the contact angle of the coating reaches 133° measured by the water droplet of 8 μL. And the coatings with the pencil hardness of HB, the adhesion level of 1 grade, and the impact strength of 50 cm can be obtained.