Abstract This study investigated how lignin—used as a
natural adhesion promoter in biodegradable, thermoplastic
cotton fibre-reinforced composites—influences the composites’
mechanical properties. Composites with fibre mass
proportions of 40% were produced by compression moulding.
Poly(lactic acid) (PLA), a biopolymer, served as matrix.
Cotton/PLA composites with and without lignin content
were manufactured. As reference samples of bast fibrereinforced
composites, kenaf/PLA composites were produced
under the same conditions. The composites were
tested for stiffness, tensile strength, elongation at break and
impact strength. Fractured surfaces were analysed using
scanning electron microscopy (SEM). The results of the
composite investigations showed that the addition of lignin
has an influence on the cotton/PLA composite characteristics.
SEM investigations showed that the adhesion between
fibre and matrix could be improved by the addition of lignin.
Tensile characteristics like tensile strength and Young’s
modulus could be improved clearly, while the impact properties
were decreased