Rotational molding of biocomposites with addition of buckwheat husk filler. Structure-property correlation assessment for materials based on polyethylene (PE) and poly(lactic acid) PLA

• Published in: Composites. Part B, Engineering Vol. 202; p. 108410
• Main Authors: Andrzejewski, Jacek, Krawczak, Anna, Wesoły, Karolina, Szostak, Marek
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2020
• Subjects: Composite structure; Natural fillers; Poly(lactid acid); Polyethylene; Rotational molding; Rotational molding; Poly(lactid acid); Polyethylene; Natural fillers; Composite structure
• ISSN: 1359-8368; 1879-1069
• DOI: 10.1016/j.compositesb.2020.108410

The main subject of the project is to obtain a natural filler polymer composite through the rotational molding process (rotomolding). For the purpose of comparison, two varieties of a matrix polymer were used: linear low-density polyethylene (PE) as a standard material used in this technology and poly(lactid acid) biopolymer (PLA). Ground buckwheat husk (BH) was used as a natural filler. Due to the key aspect of the size and morphology of the processed materials, three different BH particle sizes were used during the study: <50 μm, 50–200 μm and 200–500 μm. The filler content for PE/BH samples varied from 1 to 30 wt%, and for the PLA/BH it was 1–25%, however, the maximum volume content was similar for both materials (≈22%). Technological tests showed difficulties in obtaining composite samples with the addition of the smallest BH fraction (<50 μm). The prepared composites have been subjected to a mechanical properties assessment (tensile tests), thermo-mechanical analysis (DMTA, Vicat tests), and thermal analysis (DSC). The mechanical analysis indicated deterioration in most material characteristics – the significant porosity of the prepared composites was the main reason for that. On the other hand, the thermomechanical properties were not affected by the filler addition, which can be considered a positive feature. The DSC analysis did not reveal any correlation between the filler content and crystallinity of PE/BH materials. For the PLA/BH samples a slight increase was observed, however, it was insignificant as an effective nucleation phenomenon.