作　　者： ; ; ; ; ; ; ; ;

机构地区： 华南理工大学化学与化工学院

出　　处： 《高分子学报》 2011年第12期1454-1460,共7页

摘　　要： 以甲基丙烯酸2-全氟辛基乙酯(FOEMA)分别和不同烷烃链长丙烯酸酯(RA,CH2CHCOOCn H2n+1,n=4,8,12,16,18)为单体,用自由基聚合法合成了一系列的含氟丙烯酸酯共聚物,通过X射线衍射(XRD)和示差扫描量热法(DSC)对共聚物进行了表征,发现结晶性与丙烯酸酯的烷烃链长度密切相关,当n=4,8,12时,在常温下不具有结晶性,当n=16,18时在常温下结晶,以碳氢侧链结晶为主.由DSC谱图测出了各共聚物的结晶焓.通过热力学计算,发现n=16时,恒压熵变值最小,说明该共聚物有序性最好.用多功能光电子能谱仪(XPS)测定了共聚物表面氟碳比(F/C)和官能团组成,并用接触角测试仪测定了与正十六烷和水的静态接触角.氟碳比随着烷烃侧链的增长而增大,从0.39增加到0.71.当n=16和18,表面非极性基团(—CF3和—CF2)明显增加,极性基团(—C O和—C—O—C O)明显减少导致了与正十六烷的静态接触角明显增大.结果表明共聚物中的碳氢侧链由于结晶导致全氟链段在成膜时更易于向涂膜-空气界面迁移,从而提高共聚合物表面疏水疏油性. A series of fluorinated acrylate copolymers were synthesized via free radical copolymerization by using monomers of 2-（perflurooctyl）ethyl methacrylate（FOEMA） and n-alkyl acrylates（RAs）（n=4,8,12,16,18） with various lengths of side chains.The crystalline behavior of the copolymers was characterized by X-ray diffraction（XRD） and differential scanning calorimetry（DSC）.It is found that the crystallization of acrylate copolymers is in close connection with the side-chain length of acrylates.The copolymers crystallized at room temperature when the side-chain length number n was 16 or 18,however,no crystallization was observed for the copolymers with n less than 16 under the same condition.The crystallization enthalpy changes of RA-co-FOEMA copolymers were determined from the DSC thermograms.The copolymer with n=16 has the minimum entropy change at constant pressure compared with other three crystallized copolymers through thermodynamic calculation,which indicated this copolymer was the most ordered one.The F/C atomic ratios and composition of functional groups on the surfaces of RA/FOEMA copolymer films were determined by multifunctional photoelectron spectroscopy（XPS）,and the static contact angles of n-hexadecane and water on films were measured.The F/C ratios increased from 0.39 to 0.71 with increase in the side-chain length of RA/FOEMA copolymers.When n was 16 or 18,the copolymers demonstrated much more composition of non-polar groups（—CF3 and —CF2） and fewer polar groups（—C-O and —C—O—C-O） on the film surfaces,leading to the rapid increase in the n-hexadecane static contact angles on the films of copolymers.It may suggest that crystallization of hydrocarbon side-chain of copolymers can promote fluorinated component to migrate to the polymer-air interface during the process of film forming and hence improve the hydrophobicity and oleophobicity of the films.

关 键 词： 含氟丙烯酸酯共聚物 结晶性 表面润湿性 疏水疏油

领　　域： [化学工程]