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Abdulbasit, A. O.
Mechanical Engineering Department, Ladoke Akintola University of Technology, Ogbomoso, Nigeria
Durowoju, M. O.
Mechanical Engineering Department, Ladoke Akintola University of Technology, Ogbomoso, Nigeria
Asafa, T. B.
Mechanical Engineering Department, Ladoke Akintola University of Technology, Ogbomoso, Nigeria
Olatunji, G. O.
Mechanical Engineering Department, Ladoke Akintola University of Technology, Ogbomoso, Nigeria
ABSTRACT
The increasing volume
of plastic waste from additive manufacturing and the demand for sustainable
engineering materials have intensified efforts to repurpose post-consumer
polylactic acid (PLA). However, recycled PLA (rPLA) remains underutilised due
to diminished functional efficiency in high-performance uses. This study reinforces
rPLA with graphene, graphite, and corn silk ash (CSA) nanoparticles to enhance
its mechanical, thermal, and shape-memory behaviour for sustainable
applications. PLA waste was obtained from failed 3D-printed parts, graphite was
recovered from spent lithium-ion battery electrodes, and graphene nanoparticles
(99.9% purity, 1.5 nm) were sourced from Nanografi Nano Technology, USA. Corn
silk fibres were calcined at 400 °C to produce CSA. The shredded rPLA was
melted at 196 °C, and each filler was incorporated at 1.0, 1.5, and 2.0 wt%
using melt blending. Composite samples were examined using scanning electron
microscope, energy-dispersive x-ray spectroscopy, and x-ray diffraction;
tensile strength, micro-hardness, and thermomechanical shape-memory performance
were evaluated. SEM showed homogeneous dispersion of graphene and CSA in PLA.
EDX confirmed characteristic carbon-rich spectra for graphite composites and
silicon and calcium peaks indicating CSA incorporation. XRD revealed increased
crystallinity at 1.5 wt% for all fillers, with graphene composites exhibiting
the sharpest diffraction peaks. Tensile strength increased from 0.068 MPa for
rPLA to 1.541 MPa, 0.657 MPa, and 0.486 MPa for 1.5 wt% graphene, 1.5 wt%
graphite, and 2.0 wt% CSA, respectively. Graphite improved hardness to 28.30,
28.70, and 26.90 HRB at 1.0, 1.5, and 2.0 wt%, while graphene and CSA did not.
Shape-recovery time improved from 120 s (rPLA) to 25 s, 27 s, and 53 s at 2.0
wt% graphene, graphite, and CSA, respectively. Graphene, graphite, and CSA
nanofillers markedly enhanced rPLA structural and shape-memory performance,
with 1.5 wt% graphene providing the most balanced improvement. It
is recommended to investigate hybrid reinforcement systems.
Keywords: Recycled PLA, Graphene, Graphite, Corn silk ash, Shape memory polymer, Nanocomposites, Sustainability
https://doi.org/10.33922/j.ujet_v12i1_1
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Published
Saturday, February 21, 2026
Issue
Vol. 12, No. 1, March 2026
Article Section
GENERAL
The contents of the articles are the sole opinion of the author(s) and not of UJET.
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