PLA Biocomposites: Evaluation of Resistance to Mold

Abstract

Due to the content of lignocellulosic particles, wood plastic composites (WPC) composites can be attacked by both domestic and mold fungi. Household fungi reduce the mechanical properties of composites, while mold fungi reduce the aesthetics of products by changing their color and surface decomposition of the wood substance. As part of this study, the impact of lignocellulosic fillers in the form of sawdust and bark in poly (lactic acid) (PLA)-based biocomposites on their susceptibility to mold growth was determined. The evaluation of the samples fouled with mold fungi was performed by computer analysis of the image. For comparison, tests were carried out on analogous high-density polyethylene (HDPE) composites. Three levels of composites’ filling were used with two degrees of comminution of lignocellulosic fillers and the addition of bonding aids to selected variants. The composites were produced in two stages employing extrusion and flat pressing. The research revealed that PLA composites were characterized by a higher fouling rate by Aspergillus niger Tiegh fungi compared to HDPE composites. In the case of HDPE composites. The type of filler (bark, sawdust) affected this process much more in the case of HDPE composites than for PLA composites. In addition, the use of filler with smaller particles enhanced the fouling process.

Effective Use of Flax Biomass in Biorefining Processes

“…The conducted microbiological tests showed a greater susceptibility of biocomposites containing flax biomass to the action of mold fungi, in relation to pure PLA. Moreover, in other studies, it was shown that the addition of lignocellulosic fillers, such as conifer bark or coniferous sawdust to PLA composites increased the susceptibility to the mold fungi fouling process [48]. The observed differences are related to the varieties of flax from which the biomass was obtained.…”

A review of research and application of polylactic acid composites

“…The natural fibers themselves are susceptible to fungal and mold infestation, which not only reduces the mechanical properties of the composite, but also affects the aesthetics. Borysiuk et al 103 studied the effect of two different fillers, coniferous wood chips and coniferous bark, on the growth of molds in PLA‐based WPC. The effect of Aspergillus niger on the composites was studied and it was found that the bark blend was more susceptible to corrosion by A. niger .…”

Desarrollo y caracterización de polímeros de alto rendimiento medioambiental derivados de residuos agroindustriales y aditivos de origen renovable

“…[138]. Dentro de estos materiales, el PLA se está combinando por un lado con serrín, paja o madera [139,140]; y por otro lado con residuos de frutas y vegetales como fibra de cáñamo [141], piel de granada [142] o piel de mango [143].…”