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Pyrolysis volatiles and the environmental impact of printing paper, newspaper, and silk were investigated to identify suitable materials for heat-induced eco-printing (HIEP) using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Furthermore, the printing effects of simulated HIEP and the material microstructures were studied using scanning electron microscopy (SEM). The results indicated that the toxicity of pyrolysis volatiles is highest for newspaper, followed by silk and then printing paper, whereas environmental friendliness follows the opposite trend. A high concentration of lignin, the basic structural element of which is phenyl propane, and the presence of halogens in the newspaper led to the generation of more toxic substances during the pyrolysis process. The benzene compounds and heterocyclic compounds in silk also produced high levels of toxic substances. Based on these findings and the higher color permeability of newspaper, printing paper was the most suitable material for HIEP and newspaper was the least suitable. Additionally, silk may still be used in HIEP in small amounts for the production of art, name cards, and clothing tags. [ABSTRACT FROM PUBLISHER]

Microstructural changes in paper after heat-induced inkless eco-printing (HIEP) and pyrolysis productions of paper were investigated by scanning electron microscopy and pyrolysis-gas chromatography/mass spectrometry (Py-G/MS). The results were as follows: (1) When the heat-induced temperature is between 350°C and 600°C, slight scratches are left on the paper surface after scan printing, but click printing leaves obvious concave indentations. Both of these printing methods can create a clear and clean boundary with no significant carbonized microstructure. (2) Experimental studies show that paper undergoes true pyrolysis at 500°C. The simulated printing test shows that the fibers on the paper surface exhibit a yellow discoloration that meets printing requirements. (3) Compared with current laser printing techniques and laser inkless eco-printing (LIEP), HIEP has the advantages of avoiding the de-inking process during paper recycling and preserving paper strength better than LIEP. [ABSTRACT FROM AUTHOR]