聚氯乙烯材料表面无钯化学镀镍及活化机理

Preparation and activation mechanism of electroless nickel plating on poly (vinyl chloride) by palladium-free activation

以壳聚糖基水凝胶为聚氯乙烯(PVC)的亲水修饰层,通过表面化学吸附镍核制备催化活性中心,在非金属基材表面引发了化学镀镍,得到均匀致密的非晶态镍磷合金。利用金相显微镜研究水凝胶修饰层厚度对化学镀层表面形貌的影响。通过X光电子能谱(XPS)、全反射红外光谱、扫描电镜和X线衍射等检测手段对水凝胶修饰层的形成及镍活化过程进行表征,并初步讨论了活化机理。研究结果表明:修饰层厚度较薄(7.5 nm)时镀层表面较平整、光亮。PVC基材经水凝胶处理后,表面富含氨基或羟基等亲水性功能基团,XPS分析表明水凝胶修饰层中的氨基与镍相互作用形成了N—Ni配位化学键,通过化学键合作用吸附了活性镍核。

A novel palladium-free and environmentally friendly surface activation process for electroless nickel plating on PVC was developed by applying a chitosan-based hydrogel film to modify the poly（vinyl chloride） （PVC） surface by chemical bonds. The hydrogel layer was used as the chemisorption sites for nickel, and the nickel nuclei could initiate the subsequent electroless nickel plating onto the PVC surface in the absence of Sn. Finally, a compact and continuous Ni-P amorphous alloy was deposited on PVC surface. The effect of thickness of hydrogel film on morphology of the as-obtained layer was investigated by optical microscope. The preparation of hydrogel film on PVC and activation process were monitored by attenuated total reflection fourier transform infrared （ATR FT-IR）, X-ray photoelectron spectroscopy （XPS） and scanning electron microscopy. Moreover, the activation mechanism of nickel was discussed preliminarily. The result shows that a smooth and sheeney electroless plating can be obtained when the thickness of hydrogel film is below 7.5 nm. The PVC surface with abundant hydrophilic groups such as amino groups and hydroxyl is formed after pretreating with hydrogel film. XPS analysis indicates that the activation process is achieved by linking the nickel to the amino groups of hydrogel film via N-Ni chemical bond.