Talc filled polylactic-acid biobased polymer composites: tensile, thermal and morphological properties

Abstract

Global warming due to human activities (i.e., burning fossil fuels) has led to many issues, such as extreme weather (storm or drought) and rise in sea level making low land uninhabitable. One of the solutions to mitigate the global warming is to promote the use of biobased material. In this work, various dosage of talc powder ranged from 5, 10, 30 and 40 wt% were added into polylactic acid (PLA) to form biobased polymer composites. The biobased polymer composite has the potential to replace fossil-based polymer for sustainable packaging application. The PLA/talc composites were prepared by using melt blending method and compressed into thin sheet for characterisation test. The effect of talc content on the thermal properties and tensile performance of the PLA composites were investigated. Scanning electron microscope was used to study the fracture surface of the composites and the dispersion of talc powder in the matrix. Results showed that the addition of talc ranged from 5 to 30 wt% can enhance the Young's modulus and thermal stability of the composites but there is no improvement in tensile strength and elongation at break due to poor interfacial adhesion. The addition of talc beyond 30 wt% (i.e., 40 wt%) did not show improvement in thermal stability because at high talc content, the formation of agglomerate and voids allows the oxygen to diffuse into the matrix which lead to decomposition process.

Thermal and Mechanical Properties of the Biocomposites of Miscanthus Biocarbon and Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate) (PHBV)

“…However, the increase of thermal stability with the addition of organically modified clay in PHB started to reverse when the particle content was increased from 5 wt % to 10 wt % [ 53 ]. In a recent study of talc-reinforced PLA composites, although the composites with 5, 10, and 30 wt % talc showed slightly higher on-set degradation temperatures than PLA, the addition of 40 wt % talc decreased the on-set degradation temperature by 24 degrees [ 54 ]. Mechanical and morphological analysis in that study showed the agglomeration of the particles and the presence of voids in and around the particle clusters.…”

Talc reinforcement of polylactide and biodegradable polyester blends via injection‐molding and pilot‐scale film extrusion

“…The measurements were conducted with polymer granules (PLA1/0, PLA2/0), injection molded specimens (sample points with 1-5 wt% of talc), and masterbatches (PLA1/30, PLA2/30) expected due to the reported effect of talc, which weakens the permeability and therefore prevents the outdiffusion of the volatile compounds that evolve during decomposition. 21 The miscibility of the composites changed at 2-4 wt% talc loadings, which likely explains the dip observed in the TGA profile at 2-3 wt% talc loading.…”

“…Increased elastic modulus has been explained by the stress transfer from the polymer matrix to the talc particle. 21…”

“…Such effects have been explained to be the result of a decreased permeability, causing blockage of the volatile decomposition compounds. 21 For example, an immiscible blend, PLA/poly(e-caprolactone) (PCL), was effectively compatibilized considering PLA domains in the surrounding PLC polymer matrix. The enhanced miscibility was explained by the reduced size of the PLA domains and voids in the matrix and by the improved inter-polymer adhesion.…”

“…As an evolution of extrusion coating of PLA, [24][25][26][27] talc has been incorporated in PLA to produce composite PLA/talc films. So far, this has been achieved by using compression molding, 21,23 solvent casting, 11,17 extrusion film-blowing 6,12,15 and extrusion casting. 28 Differentiating from this earlier work, we produced PLA/talc films by using a pilot-scale extrusion coating unit which endowed films with significantly smaller thicknesses (18-26 μm).…”