大分子表面活性剂PP-g-PEG对聚丙烯薄膜的表面改性

Surface Modification of PP Films by Macromolecular Surfactant PP-g-PEG

将聚乙二醇接枝聚丙烯(PP-g-PEG)作为大分子表面活性剂用于PP薄膜的表面改性。使用衰减全反射红外光谱、接触角测定仪、电子材料试验机等方法,考察了预处理条件、PEG链段长度及含量对改性薄膜的表面润湿性、表面自由能、表面电阻率等性能的影响。研究表明,随预处理温度的提高,PEG链段向薄膜表面迁移速率加快,聚集程度提高,导致薄膜表面极性和表面自由能迅速增大。经过100℃、6 h的预处理,PEG链段薄膜表面聚集形成的微区基本覆盖薄膜表面。随着薄膜中PEG链段含量增加,薄膜表面聚集的PEG链段增多,表面改性效果增强。当PEG链段含量增加到2%后,薄膜表面PEG相对含量及表面改性效果趋于稳定。PEG链段长度影响其在薄膜中的迁移扩散能力以及在薄膜表面的聚集状态,在相同预处理条件和PEG含量下,薄膜表面PEG聚集程度的高低顺序为:PP/PP-g-PEG-6000薄膜>PP/PP-g-PEG-2000薄膜>PP/PP-g-PEG-1000薄膜。但是由于在PP/PP-g-PEG-6000薄膜表面形成的PEG微区分布密度低于PP/PP-g-PEG-2000薄膜,因而PEG链段长度为6 000的PP-g-PEG-6000对薄膜的表面改性效果不如PEG链段长度为2 000的PP-g-PEG-2000。

Polypropylene grafted polyethylene glycol （PP-g-PEG） was selected as macromolecular surfactant for surface modification of polypropylene films.ATR-FFIR,contact angle （CA）,electronic mechanical tester and other methods were used to investigate the effects of film pretreatment condition,PEG chain length and contents in the film on the surface wettability,surface free energy,surface resistance and other properties of the modified PP films.It was demonstrated by the experiments that the migrating rate of PEG segments to the surface of the films was promoted by raising annealing temperature,giving rise to more PEG congregation on the film surface,which led to a rapid increase of surface polarity and surface free energy of the film.After 6 hour annealing at 100 ℃,the surface of the film could be fully covered by PEG microdomains formed with congregation of migrated PEG segments.With the increase of PEG content in the film,more PEG segments migrated to and congregated on the surface of the film,leading to an enhanced surface modification effects.After PEG content in the film was 2％,PEG concentration on the surface and the surface modification reached a saturation level.The migration capacity of PEG segments in the films and its congregation state on the surface of the film were also influenced by PEG chain length in PP-g-PEG.Among the three modified PP films with different PEG chain lengths,PEG concentration on the surface of films followed this order：PP/PP-g-PEG-6000 film ＞ PP/PP-g-PEG-2000 film ＞ PP/PP-g-PEG-1000 film.However,PP-g-PEG-2000 demonstrated better surface modification effects than PP-g-PEG-6000 did,due to the different PEG congregation state on the surface of the film.