在氯氧化铋(BiOCl)存在下,以丙烯酰胺(AM)为单体,以过硫酸钾为引发剂,N,N′-亚甲基双丙烯酰胺为交联剂,通过自由基聚合制备复合水凝胶并测试其压缩和溶胀性能。利用掺钕钇铝石榴石激光器对复合水凝胶表面进行激光标记,考察电流强度和BiOCl含量对激光标记效果的影响,利用X射线衍射(XRD)和热重(TGA)分析对标记表面表征分析。结果表明:相比纯水凝胶,复合水凝胶压缩强度提高且BiOCl质量分数为1.0%时,压缩强度最大,溶胀时间有所延长,完全溶胀时两种水凝胶溶胀比接近;BiOCl的添加使水凝胶具有激光响应性能,产生黑色文字和图案清晰度随激光电流强度的增加而变化,当电流强度为17A时,标记区域最清晰;TGA分析结果表明激光的辐照没有引起水凝胶表面高分子链的热解;XRD谱图结果显示复合水凝胶激光标记后产生新的黑色Bi金属;复合水凝胶表面黑色图案的产生是由于BiOCl吸收激光能量分解生成黑色Bi单质的结果。

In the presence of bismuth oxychloride (BiOCl),using acrylamide (AM) as monomer,potassium persulfate as initiator,and N,N′-Methylene-bis-acrylamide as crosslinker,the laser responsive PAM/BiOCl composite hydrogel was prepared by free radical polymerization and tested for the compression and swelling property.The composite hydrogels were marked in air by scanning with a Nd∶YAG pulsed laser beam and their laser marking performance was investigated.XRD and TGA were used for the analysis and characterization of the laser marked surface.The results showed that compared to pure hydrogel,the hydrogel had higher compressive strength and longer swelling time,and the swelling ratio of hydrogel was not changed.The highest compressive strength for the hydrogel can be obtained at 1.0% BiOCl.The addition of BiOCl can lead to the laser responsive property of hydrogel and the formation of black text and pattern on the surface after laser marking,and the marking contrast changed with the increase of laser current intensity.The highest contrast of marked area was obtained at the current intensity of 17 A.TGA data showed that the laser irradiation did not cause the pyrolysis of polymer chains in the hydrogel.X-ray diffraction patterns revealed that the new black Bi metal was produced for the composite hydrogel after laser marking.The black markings on the hydrogel surface were due to the generation of black Bi metal from the decomposition of BiOCl after absorbing the laser light energy.