Enhanced laser marking of polypropylene induced by “core-shell” ATO@PI laser-sensitive composite

To achieve an enhanced laser marking for polypropylene , the “core-shell” ATO@PI (antimony-doped tin oxide@polyimide) laser-sensitive composite was successfully designed and prepared. This laser-sensitive composite consisted of an ATO “core” with high photothermal conversion efficiency and a PI “shell” with high laser induced carbonization rate. Compared with pure ATO, the results showed that 0.3 wt% of the ATO@PI composite endowed polypropylene with an enhanced laser marking performance. The results of SEM and TEM revealed that PI was tightly coated around the ATO surface and the laser-sensitive composite particles were approximately spherical. Both Raman and near infrared (NIR) absorption spectrum observed that, after irradiation of 1064 nm laser, the carbonization degree of polypropylene using ATO@PI was much higher than that of only using pure ATO. The photothermal conversion of ATO and the local carbonization of PI in the composite synergistically increase the degree of laser induced carbonization of polypropylene. Importantly, the “core-shell” laser-sensitive composite designed here further broadens the application prospects of inorganic particles in the field of polymer laser marking.