In this study, organically
modified montmorillonite
(OMMT) was prepared by modifying MMT with a cationic surfactant cetyltrimethylammonium
bromide (CTAB). The obtained OMMT of different loading contents (1,
2, 4, 6, and 8 wt %) was melt-blended with poly(acrylonitrile-
co
-butadiene-
co
-styrene) (ABS) to prepare
a series of ABS/OMMT composites, which were laser marked using a neodymium-doped
yttrium aluminum garnet (Nd:YAG) laser beam of 1064 nm under different
laser current processes. X-ray diffraction (XRD), color difference
spectrometer, optical microscope, water contact angle tests, scanning
electron microscope (SEM), and Raman spectroscopy were carried out
to characterize the morphology, structure, and properties of the laser-patterned
ABS composites. The effects of the addition of OMMT and the laser
marking process on the mechanical properties of ABS/OMMT composites
were investigated through mechanical property tests. The results show
that the obtained ABS/OMMT composites have enhanced laser marking
performance, compared to the ABS. When the OMMT content is 2 wt %
and the laser current intensity is 9 A, the marking on ABS composites
has the highest contrast (Δ
E
= 36.38) and sharpness,
and the quick response (QR) code fabricated can be scanned and identified
with a mobile app. SEM and water contact angle tests showed that the
holes, narrow cracks, and irregular protrusion are formed on the composite
surface after laser marking, resulting in a more hydrophobic surface
and an increased water contact angle. Raman spectroscopy and XRD indicate
that OMMT can absorb the near-infrared laser energy, undergo photo
thermal conversion, and cause the pyrolysis and carbonization of ABS
to form black marking, and the crystal structure itself does not change
significantly. When the 2 wt % of OMMT is loaded, the tensile strength,
elongation at break, and impact strength of ABS/OMMT are increased
by 15, 20, and 14%, respectively, compared to ABS. Compared with the
unmarked ABS/OMMT, the defects including holes and cracks generated
on the surface of the marked one lead to the decreased mechanical
property. The desirable combination of high contrast laser marking
performance and mechanical properties can be achieved at an OMMT loading
content of 2 wt % and a laser current intensity of 9 A. This research
work provides a simple, economical, and environmentally friendly method
for laser marking of engineering materials such as ABS.