Inclusion of additives in polymers is necessary to impart desirable properties which improve ease of processing and performance. Bio-based additives can provide sustainable alternatives to their synthetic counterparts but due to their polar nature are incompatible with widely used polymer systems which typically exhibit low polarity. This issue results in non-uniform dispersion of the fillers which prevents their full potential from being fulfilled. The aim of this study was to develop a new, one-pot synthesis method for effectively dispersing bio-based fillers in a weakly polar matrix. One such matrix is poly(butylene succinate) (PBS), a bio-based polyester whose properties are comparable to that of widely used polyethylene. The fillers chosen for this experiment included cellulose nanofibers (CNF) and lignin nanoparticles (LNP) as mechanical property enhancers.
The synthesis method involved the suspension of CNF and LNP in a solution of PBS in N’N-dimethylformamide followed by coagulation of the PBS via the addition water. This was followed by drying and hot-pressing to obtain composite films. The composites obtained were then evaluated using tensile and rheological testing to quantify the effects of the fillers on thermal and mechanical properties. Additional testing was conducted to determine the light transmission and glass transition temperature of the composites. The spatial variation of these properties will be discussed in the context of filler dispersibility which will provide insight regarding the experimental and formulation variables. The devised protocol could be adapted for other polymers with similar polarity.
