In this study, a new plastic film with antiviral and antibacterial properties was developed using modified cassava starch with glycidyltrimethylammonium chloride (GTMAC) and reinforced by crystalline nanocellulose (CNC), called Q-CS/CNC. For comparison, a control film (Q-CS) was produced without the addition of CNC. Elemental analysis revealed a degree of substitution (DS) of 0.552, indicating the replacement of the OH groups of starch by the NR₄⁺ groups of GTMAC during the quaternization reaction. The addition of CNC resulted in significant increases (p < 0.05) of 38.9, 38.2, and 43.1% in thickness, opacity, and water vapor permeability measurements, respectively, compared to Q-CS. Incorporating CNC also contributed to an increase of 43.6% in tensile strength and 109% in stiffness but slightly decreased thermal stability. The Q-CS/CNC film demonstrated efficacy by inactivating 99% of the coronavirus in 1 min and inhibiting the growth of Staphylococcus aureus and Escherichia coli. This action is attributed to the electrostatic interaction of quaternary amino groups, grafted onto starch, with the phospholipid membrane of microorganisms, resulting in the inactivation of these microorganisms. Therefore, these results highlight the potential use of Q-CS/CNC film as antimicrobial packaging, especially against coronavirus.

Biocomposites have recently received more attention because of raising environmental awareness and the drive toward sustainable technologies. The most common biodegradable polymer is poly(lactic acid) (PLA), which has an excellent balance of physical and rheological properties, but there is some limit to its usage. PLA properties can be improved by adding different types of fibers or fillers that come from agricultural waste. In this study, corn cob and lavender stem were used to reinforce PLA without any coupling agent, and the properties of the composites were investigated. The melt flow rate (MFR) values decreased with the corn cob content and increased with the addition of lavender stem. Mechanical tests showed that the tensile and flexural modulus of the composites increased and the strengths decreased with the reinforcement material content. The rigidness of PLA slightly decreased with the addition of fillers. There was no significant effect on the thermal properties. The unremarkable improvement of the reinforcement was due to the lack of appropriate adhesion of the two phases. The structure of the compounds was found to be homogenous on the scanning electron microscopy (SEM) micrographs. The incorporation of corn cob and lavender stem can reduce the production cost of materials.

In this study, we investigated the influence of processing parameters on the cellular structure and density of specimens fabricated using in-situ foam 3D printing. First, we conducted a comprehensive analysis to examine how the combined effects of printing temperature and speed influence the four key stages of the foaming process: gas dissolution, cell nucleation, cell growth, and stabilization. By evaluating the structural characteristics of the printed foams, we identified the dominant mechanisms governing each stage. Next, we explored the effect of nozzle diameter, an aspect previously unexamined in the literature. We found that smaller nozzle diameters promote higher cell density due to enhanced pressure drop and shear-induced nucleation, resulting in a 36.78% reduction in density and a 60.31% increase in cell density when using a 0.4 mm nozzle instead of 0.8 mm (at 240°C, 60 mm/sec). Finally, we fabricated functionally graded four-layer structures by adjusting the printing temperature for each layer to control porosity distribution. To evaluate the mechanical performance of these graded structures, we performed three-point bending and drop-weight impact tests, allowing us to assess how layer order influences mechanical properties. Our results showed that proper layer sequencing can increase flexural strength by up to 69.35% and improve perforation energy by more than 94.82% compared to homogeneous structures.

This study demonstrated, for the first time, the successful formation of porous paramylon esters, which were made from euglenoid polysaccharide known as paramylon and short-chain fatty acids, through supercritical CO₂ processing. By maintaining a constant ester functional group attached to the paramylon and varying its proportion, distinct porous structures were selectively produced. Solubility parameter estimations indicated that changes in esterification had no significant effect on the solubility of the paramylon esters used in the experiment. Thus, these structural differences are likely attributed to variations in the viscoelastic properties of paramylon esters under supercritical CO₂ conditions. Furthermore, thermal conductivity measurements revealed reductions of up to 20%. Intriguingly, substantial decreases in thermal conductivity were observed even at low foaming ratios, achieved through precise control of the porous structure.

Particulate matter (PM) has been always a significant environmental and public health concern due to its adverse effects on air quality and respiratory health. This study evaluates the efficiency of hydrophobic nanostructured bioaerogels as PM filters under both normal and high-humidity conditions. Bioaerogels were prepared using nanocellulose and chitosan and modified with varying concentrations of tetraethyl orthosilicate (TEMS). At normal humidity, the 3% TEMS-modified bioaerogel demonstrated the highest average PM removal efficiency of 91.6%, attributed to its optimized balance of hydrophobicity, porosity, and mechanical strength. Under high-humidity conditions, the unmodified 0% TEMS bioaerogel exhibited a significant decline in performance due to water absorption, reducing its efficiency by over 15% after prolonged exposure. Conversely, the hydrophobic 3% TEMS bioaerogel maintained its efficiency at 91.4%, highlighting its ability to resist water-induced degradation. This study provide valuable insights into the design of bioaerogel-based filters for realworld applications where variable humidity poses a challenge.