Protective Low-Density Polyethylene Residues from Prepreg for the Development of New Nanocomposites with Montmorillonite: Recycling and Characterization

Knot strength and antimicrobial evaluations of partially absorbable suture

Partially absorbable suture is useful for orthopedic repair as it possesses the capacity to promote a balance between strength, degradation rate and minimal inflammation. Still, the availability of partially absorbable suture is scarce. So far, no study has examined the mechanical strength and anti-microbial properties of partially absorbable monofilament suture made of low-density polyethylene (LDPE)/polylactide (PLA)/chitosan (CHS); hence, the reason for this study with a view to improve knot strength, antimicrobial property and degradation rate. In this study, monofilament suture was extruded using different weight fractions of LDPE, PLA and CHS. In vitro degradation studies were carried out using phosphate buffer solution (PBS). Mechanical and morphological changes were also examined. A standard Fourier transform infrared spectral of 3433, 2909-2840, 1738, 1452, 1174, 1062, 706 cm^-1 were assigned to OH group, C-H stretch, C=O vibration of ester, CH₃ bending, alkyl ester and CH₂ stretch, respectively. Tensile strength of knotted neat LDPE (4.84 MPa) exhibited 48.7% improvement in LDPE/PLA/CHS (60/39.5/0.5). This suggests that a good knot can be achieved to 40% weight fraction of PLA. The monofilament suture also demonstrated better antimicrobial property as the monofilament, LDPE/PLA/CHS (60/39.5/0.5) and LDPE/PLA/CHS (50/49.5/0.5) covered 12.7 mm zone of inhibition which is greater than the standard 1 mm. The suture's morphological phases show dark fibre-like rough surfaces with microstructural irregularities as PLA and CHS were added to the matrix, which is required for enhanced degradation. Thus, the partially absorbable suture produced in this study could serve as a suture for tendon repair.

Wastes from Agricultural Silage Film Recycling Line as a Potential Polymer Materials

The recycling of plastics is currently one of the most significant industrial challenges. Due to the enormous amounts of plastic wastes generated by various industry branches, it is essential to look for potential methods for their utilization. In the presented work, we investigated the recycling potential of wastes originated from the agricultural films recycling line. Their structure and properties were analyzed, and they were modified with 2.5 wt % of commercially available compatibilizers. The mechanical and thermal performance of modified wastes were evaluated by tensile tests, thermogravimetric analysis, and differential scanning calorimetry. It was found that incorporation of such a small amount of modifiers may overcome the drawbacks caused by the presence of impurities. The incorporation of maleic anhydride-grafted compounds enhanced the tensile strength of wastes by 13–25%. The use of more ductile compatibilizers—ethylene-vinyl acetate and paraffin increased the elongation at break by 55–64%. The presence of compatibilizers also reduced the stiffness of materials resulting from the presence of solid particles. It was particularly emphasized for styrene-ethylene-butadiene-styrene and ethylene-vinyl acetate copolymers, which caused up to a 20% drop of Young’s modulus. Such effects may facilitate the further applications of analyzed wastes, e.g., in polymer film production. Thermal performance was only slightly affected by compatibilization. It caused a slight reduction in polyethylene melting temperatures (up to 2.8 °C) and crystallinity degree (up to 16%). For more contaminated materials, the addition of compatibilizers caused a minor reduction in the decomposition onset (up to 6 °C). At the same time, for the waste after three washing cycles, thermal stability was improved. Moreover, depending on the desired properties and application, materials do not have to go through the whole recycling line, simplifying the process, reducing energy and water consumption. The presented results indicate that it is possible to efficiently use the materials, which do not have to undergo the whole recycling process. Despite the presence of impurities, they could be applied in the manufacturing of products which do not require exceptional mechanical performance.