2 research outputs found
Microwave-Assisted Recycling of Waste Paper to Green Platform Chemicals and Carbon Nanospheres
Effective
high-yield recycling of waste paper to well-defined future
platform chemicals and carbon nanospheres was demonstrated. The developed
process utilized the exceptional combined effect of microwave irradiation
and dilute acid catalyst to hydrothermally degrade cellulose in waste
paper. The process was evaluated for three different waste papers,
brown and white paper tissues and white printing paper. Different
pretreatment processes were investigated to further increase the cellulose
liquefaction efficiency. By utilizing soda pretreatment, liquefaction
efficiencies as high as 88% were achieved. The obtained liquefaction
products were fingerprinted by NMR and LDI-MS, while the solid residues
were analyzed by XRD, SEM, TGA, and FTIR. As industrial-scale microwave
reactors are currently under development, the developed method displays
significant potential for recycling waste paper to green platform
chemicals at the industrial scale
Zero-Dimensional and Highly Oxygenated Graphene Oxide for Multifunctional Poly(lactic acid) Bionanocomposites
The unique strengths of 2D graphene
oxide nanosheets (GONSs) in
polymer composites are thwarted by nanosheet agglomeration due to
strong intersheet attractions. Here, we reveal that shrinking the
planar size to 0D graphene oxide quantum dots (GOQDs), together with
the intercalation of rich oxygen functional groups, reduces filler
aggregation and enhances interfacial interactions with the host polymer.
With poly(lactic acid) (PLA) as a model matrix, atomic force microscopy
colloidal probe measurements illustrated that a triple increase in
adhesion force to PLA was achieved for GOQDs (234.8 nN) compared to
GONSs (80.4 nN), accounting for the excellent exfoliation and dispersion
of GOQDs in PLA, in contrast to the notable agglomeration of GONSs.
Although present at trace amount (0.05 wt %), GOQDs made a significant
contribution to nucleation activity, mechanical strength and ductility,
and gas barrier properties of PLA, which contrasted the inferior efficacy
of GONSs, accompanied by clear distinction in film transparency (91%
and 50%, respectively). Moreover, the GOQDs with higher hydrophilicity
accelerated the degradation of PLA by enhancing water erosion, while
the GONSs with large sheet surfaces gave a higher hydrolytic resistance.
Our findings provide conceptual insights into the importance of the
dimensionality and surface chemistry of GO nanostructures in the promising
field of bionanocomposites integrating high strength and multifunction
(e.g., enhanced transparency, degradation and gas barrier)