Abstract:
Polymers produced in living cells have attracted exceptional attention due to their ecofriendliness and biodegradability. These polymers possess similar properties to
conventional plastics, making them suitable potential plastic substitutes for
sustainable development and conservation of finite oil resources. Polylactic acid (PLA)
is comparable to commonly used plastics but is inferior due to poor impact resistance,
hydrophobicity, a lack of reactive side chain groups, a slow degradation rate, and a
relatively high cost. However, PLA can benefit from the incorporation of various
polymer components with complementary properties to yield improved physical
properties. Developing fully bio-based composites of PLA and cellulose is particularly
interesting. They have mechanical and physiological properties that make them more
suitable for a wider range of applications. Herbaceous plant cell walls comprise
semicrystalline cellulose fibres embedded in a soft matrix. The crystalline part of the
inherently stiff chains extracted from plants such as E. autumnalis is subject to
research for potential roles as fillers. In this study, to fabricate a novel composite
consisting of PLA/Cellulose (stem) (PLA/Cs), three characteristically different
celluloses were extracted from various parts of E. autumnalis (bulbs, leaves, and
stem). Based on a distinguished cellulose spectrum (showing all the relevant
functional groups), increased crystallinity and thermal stability compared cellulose
from the leaves, varying contents (99.5/0.5 and 97/3.0 PLA/Cs) of a mixture of fibre
bundles and coarse aggregates of cellulose from the stems were incorporated in a
PLA matrix. The surface morphology and structural properties of the novel composites
were investigated using FTIR and SEM. In addition, the thermal and mechanical
properties of the composites were investigated using standard techniques (i.e., TGA
and Tensile). Generally, there was better distribution of Cs in PLA and improved
interfacial adhesion at high filler content (97/3.0), resulting in a high Young's modulus.
However, no significant improvement in thermal properties was observed.
