Potential uses of N-methylmorpholine N-oxide for the treatment of agricultural waste biomass

Lignocellulosic fibers have been used in polymer composites for a long time but their treatment process is still challenging due to insufficient efficiency and environmental impact. This research analyses the influence of N-methylmorpholine N-oxide (NMMO) on the structure and properties of three types of lignocellulosic fibers â sweet clover (SCS), buckwheat (BS) and rapeseed straws (RS). The fibers were treated with an NMMO solution at 90 °C for different periods of time (80 min, 180 min, 300 min and 30 h). It was detected that after treatment in a dilute NMMO solution, non-cellulosic substances were removed, the morphology and aspect ratio were affected and the fibers were characterized by higher thermal stability. However, the results show that before using NMMO for the production of microfibers, additional research on the pretreatment process will be necessary because an insufficient aspect ratio value and surface morphology were obtained. The current research shows that it is not economically feasible to process fibers using NMMO for the production of reinforcement for polymer composites

Effect of Agricultural Biomass Residues on the Properties of Recycled Polypropylene/Polyethylene Composites

The aim of the study was to assess the usefulness of agricultural biomass residues as reinforcement in recycled polymer matrices. In this study, recycled polypropylene and high-density polyethylene composites (rPPPE) filled with three types of biomass residues, sweet clover straws (SCS), buckwheat straws (BS) and rapeseed straws (RS), are presented. The effects of the fiber type and the fibers content on the rheological behavior, mechanical properties (including tensile, flexural and impact strength), thermal stability and moisture absorbance were determined, in addition to morphological analysis. It was revealed that the addition of SCS, BS or RS increased the materials’ stiffness and strength. The reinforcement effect increased as the loading of the fibers was increased, especially for BS composites in the flexural test. After the moisture absorbance test, it was found that the reinforcement effect slightly increased for the composites with 10% fibers but decreases with 40% fibers. The results highlight that the selected fibers are a feasible reinforcement for recycled polyolefin blend matrices

Characterisation of Nanoclay and Spelt Husk Microfiller-Modified Polypropylene Composites

Current research is devoted to the investigation of spelt husk (SH) and nanoclay-modified compatibilised polypropylene (PP) binary and ternary composites for injection-moulding applications. PP composites were obtained using twin-screw extrusion. The content of mechanically milled SH microfiller with aspect ratio within 2 and 6 was fixed at 40 wt.%, whereas the amount of nanoclay functional filler in the polypropylene matrix was changed in the range from 0.5 to 5 wt.%. Nanoclay filler was introduced in the polypropylene matrix either in the form of nanoclay powder (C) or as a masterbatch (M). Regular distribution of the clay nanofiller within the polymer matrix has been observed, disregarding its form and concentration. The effects of the individual or combined addition of SH microreinforcement and nanoclay fillers on the rheological, mechanical, calorimetric, and thermal properties of the developed PP composites were investigated. It is revealed that the addition of the nanoclay fillers insignificantly influences the viscosity of both PP nanocomposites and hybrid composites with SH. Additionally, for PP nanocomposites, remarkable increases in tensile and flexural modules and strength are observed by maintaining considerable ultimate deformations, mainly in the case of M-containing systems. Concomitantly, because of the addition of the nanoclay filler, the improvement in thermal stability of PP nanocomposites and PP hybrid composites with SH is observed. As a result of SH addition, considerable increases in tensile and flexural modules are also observed. Results of the research demonstrate the potential of the use of natural materials (agricultural residues and clay minerals) for the development of PP composites with increased stiffness and thermal properties