辐射接枝法制备动态超疏水棉织物及其性能研究

Preparation of Dynamic Superhydrophobic Cotton Fabric via Radiation-induced Graft Polymerization

以棉织物为基材,利用γ-射线辐射引发甲基丙烯酸十二烷基酯(LMA)接枝聚合,使聚苯乙烯(PS)纳米微球通过接枝链以共价键固定到棉织物上,从而在棉织物表面构筑低表面能的纳米尺度粗糙结构,获得低滚动角的动态超疏水棉织物.傅里叶变换红外光谱(FTIR)分析证明通过辐射接枝,在棉织物上存在PLMA接枝链和PS纳米微球.扫描电子显微镜(SEM)表征证明了PS纳米微球的固定使得棉织物表面呈现纳米尺度的粗糙结构.接触角测试结果证明所获棉织物具有超疏水性能,且相对于仅接枝LMA的改性棉织物,PS纳米微球的固定可以显著降低水滴的滚动角,实现动态超疏水的效果.通过抗弯刚度的测量表征了改性前后棉织物的柔软度,结果表明辐射接枝方法对棉织物的柔软度改变不大,不影响穿着性能.

With cotton fabrics as substrates, γ-ray irradiation was used to initiate the graft polymerization of lauryl methacrylate（LMA）, to attach polystyrene（PS） nanospheres to the cotton fabrics in by covalent bonding via the grafted chains, form a nano-scale coarse structure with low surface energy on the surface of cotton fabrics, and obtain dynamic superhydrophobic cotton fabrics with a low water droplet sliding angle. The grafting kinetics was studied and the degree of grafting（DG） increased regularly with the increasing of the concentration of the monomer. Therefore the DG could be controlled by changing the conditions of the graft polymerization. Fourier transform infrared spectroscopy（FTIR） analyses were carried out on the cotton fabrics after the graft and the results confirmed the presence of PS nanospheres and grafted PLMA chains on the modified cotton fabrics. Scanning electron microscopy（SEM） analysis showed that the attachment of the PS nanospheres onto the cotton fabrics led to the formation of a nanoscale coarse structure on the surface of the cotton fibers. The contact angle of water droplet on the modified cotton fabric was higher than 150,, which demonstrated that the modified cotton fabrics were superhydrophobic. Relative to the cotton fabrics solely grafted with LMA, the PS nanospheres-decorated cotton fabrics had a significantly reduced water droplet sliding angle, and possessed dynamic superhydrophobicity. This should be attributed to the ＂lotus effect＂ of the surface of the modified cotton fabrics containing low surface energy and regular nano-scale roughness structure formed by the attachment of PS nanospheres. The softness of the cotton fabrics was characterized through the measurements of their flexural rigidity before and after their modification. The results showed that radiation-induced graft polymerization of LMA and the immobilization of PS nanospheres did not influence the wearability of the cotton fabrics, as it did not have a significant effect on their softness.