The environment faces a serious threat from plastic waste, especially smaller plastic items, which are frequently challenging to recycle or properly collect. This study explores the creation of a fully biodegradable composite material, sourced from pineapple field waste, designed for use in small-sized plastic products, particularly difficult to recycle, such as bread clips. As the matrix, starch with a high amylose content, sourced from discarded pineapple stems, was used. Glycerol and calcium carbonate were, respectively, employed as plasticizer and filler, improving the moldability and hardness characteristics of the material. A variety of mechanical properties were observed in composite samples by systematically changing the amounts of glycerol (20 to 50% by weight) and calcium carbonate (0 to 30 wt.%). Tensile moduli were found to lie within a range of 45 MPa to 1100 MPa, tensile strengths varied from 2 to 17 MPa, and the elongation at failure was observed to be between 10% and 50%. The resulting materials, featuring a good degree of water resistance, displayed a noticeably lower water absorption rate ranging from ~30% to ~60%, outperforming other comparable starch-based materials. Experiments involving burying the material in soil showed that it completely broke down into particles having a size smaller than 1mm in 14 days. A bread clip prototype was produced to gauge the material's proficiency in tightly holding a filled bag. Results demonstrate the possibility of pineapple stem starch's use as a sustainable alternative for petroleum- and bio-based synthetic materials in smaller plastic products, contributing to a circular bioeconomy.
Denture base materials' mechanical properties are improved by the strategic addition of cross-linking agents. Various crosslinking agents, exhibiting differing chain lengths and flexibilities, were scrutinized in this investigation of their effect on the flexural strength, impact resilience, and surface hardness of polymethyl methacrylate (PMMA). Ethylene glycol dimethacrylate (EGDMA), tetraethylene glycol dimethacrylate (TEGDMA), tetraethylene glycol diacrylate (TEGDA), and polyethylene glycol dimethacrylate (PEGDMA) were the chosen cross-linking agents. Various concentrations of these agents, 5%, 10%, 15%, and 20% by volume, as well as 10% by molecular weight, were incorporated into the methyl methacrylate (MMA) monomer component. Bioavailable concentration In total, 21 groups of specimens were fabricated, totaling 630. A 3-point bending test served to assess flexural strength and elastic modulus; meanwhile, impact strength was measured using the Charpy test, and surface Vickers hardness was determined. Employing the Kolmogorov-Smirnov, Kruskal-Wallis, Mann-Whitney U, and ANOVA tests with a subsequent Tamhane post-hoc comparison, statistical analysis of the data was undertaken, setting a significance level at p < 0.05. Evaluations of flexural strength, elastic modulus, and impact strength demonstrated no statistically significant improvement in the cross-linking groups in contrast to the conventional PMMA material. With the inclusion of PEGDMA, from 5% to 20%, there was a noticeable reduction in surface hardness. Cross-linking agents, present in concentrations varying from 5% to 15%, enhanced the mechanical performance of PMMA.
The combination of excellent flame retardancy and high toughness in epoxy resins (EPs) proves remarkably difficult to achieve. Medical pluralism Our work proposes a simple strategy for combining rigid-flexible groups, promoting groups, and polar phosphorus groups with vanillin, creating a dual functional modification in EPs. Modified EPs, featuring a phosphorus loading as low as 0.22%, demonstrated a limiting oxygen index (LOI) of 315% and secured a V-0 grade in UL-94 vertical burning tests. The introduction of P/N/Si-containing vanillin-based flame retardants (DPBSi) significantly boosts the mechanical properties of epoxy polymers (EPs), especially their strength and resilience. EP composites demonstrate a substantial increase in both storage modulus (611%) and impact strength (240%) in contrast to EPs. This work therefore introduces a new molecular design paradigm for creating epoxy systems, simultaneously achieving high fire safety and outstanding mechanical resilience, thereby having vast potential to broaden the applicability of epoxy polymers.
Possessing outstanding thermal stability, superior mechanical properties, and a flexible molecular design, benzoxazine resins show promise for marine antifouling coatings. Crafting a multifunctional, environmentally sound benzoxazine resin-based antifouling coating that exhibits resistance to biological protein adhesion, a robust antibacterial rate, and reduced algal adhesion continues to pose a considerable design hurdle. This study demonstrates the synthesis of a high-performance coating with reduced environmental impact. The process used urushiol-based benzoxazine containing tertiary amines as a precursor, and a sulfobetaine group was added to the benzoxazine. The urushiol-based polybenzoxazine coating, functionalized with sulfobetaine (poly(U-ea/sb)), displayed a clear capacity for killing marine biofouling bacteria that adhered to its surface, along with substantial resistance against protein attachment. Poly(U-ea/sb) exhibited a 99.99% antibacterial rate against Gram-negative bacteria, such as Escherichia coli and Vibrio alginolyticus, and Gram-positive bacteria, exemplified by Staphylococcus aureus and Bacillus species. It further demonstrated >99% algal inhibition activity and effectively prevented microbial adhesion. A zwitterionic polymer, crosslinkable and dual-functional, which utilized an offensive-defensive tactic, was shown to improve the antifouling properties of the coating. A straightforward, cost-effective, and practical strategy offers innovative concepts for creating high-performing green marine antifouling coatings.
Using two distinct techniques, (a) conventional melt-mixing and (b) in situ ring-opening polymerization (ROP), Poly(lactic acid) (PLA) composites were produced, featuring 0.5 wt% lignin or nanolignin. To track the ROP procedure, torque readings were taken. Composites were quickly synthesized via reactive processing, completing in less than 20 minutes. Doubling the catalyst's presence expedited the reaction, completing it in under 15 minutes. Employing SEM, DSC, nanoindentation, DPPH assay, and DRS spectroscopy, we evaluated the dispersion, thermal transitions, mechanical properties, antioxidant activity, and optical characteristics of the resultant PLA-based composites. To examine the morphology, molecular weight, and free lactide content of the reactive processing-prepared composites, SEM, GPC, and NMR techniques were employed. Superior crystallization, mechanical properties, and antioxidant characteristics were observed in nanolignin-containing composites generated through reactive processing, leveraging in situ ring-opening polymerization (ROP) on reduced-size lignin. The participation of nanolignin as a macroinitiator in the ring-opening polymerization (ROP) of lactide was credited with the observed improvements, yielding PLA-grafted nanolignin particles that enhanced dispersion.
In the demanding space environment, a retainer incorporating polyimide has proven effective. Nevertheless, the structural breakdown of polyimide due to space radiation limits its widespread use in various applications. To further improve the atomic oxygen resistance of polyimide and thoroughly investigate the tribological mechanisms in polyimide composites under simulated space conditions, 3-amino-polyhedral oligomeric silsesquioxane (NH2-POSS) was integrated into the polyimide molecular chain and silica (SiO2) nanoparticles were in situ introduced into the polyimide matrix. The combined effect of vacuum, atomic oxygen (AO), and tribological performance on the polyimide, using bearing steel as a counter body, was evaluated using a ball-on-disk tribometer. AO's application, as evidenced by XPS analysis, resulted in the formation of a protective layer. The wear resistance of polyimide, after being modified, saw an increase when exposed to AO. The inert protective silicon layer, established on the counterpart during the sliding action, was observed using FIB-TEM technology. Worn sample surfaces and the tribofilms formed on the counterbody are systematically characterized to understand the mechanisms.
This paper presents the first instance of using fused-deposition modeling (FDM) 3D-printing to create Astragalus residue powder (ARP)/thermoplastic starch (TPS)/poly(lactic acid) (PLA) biocomposites. The paper further investigates their physical-mechanical characteristics and behaviors under soil burial and biodegradation. Elevating the ARP dosage resulted in a decline in tensile and flexural strengths, elongation at break, and thermal stability, yet an increase in tensile and flexural moduli for the sample; a similar trend of diminished tensile and flexural strengths, elongation at break, and thermal stability was observed when the TPS dosage was increased. Sample C, which included 11 percent by weight, showed unique characteristics compared to all the other samples. In terms of cost and rapid degradation in water, the combination of ARP, 10% TPS, and 79% PLA proved to be the optimal material. Observing sample C's soil-degradation-behavior, the buried samples demonstrated an initial graying of the surfaces, a subsequent deepening of the darkness, and finally roughening, along with detaching components. 180 days of soil burial resulted in a 2140% decrease in weight, with corresponding reductions in flexural strength and modulus, and the storage modulus. The values of MPa and 23953 MPa have been adjusted to 476 MPa, 665392 MPa, and 14765 MPa, respectively. Although buried in soil, the glass transition, cold crystallization, and melting points of the specimens showed little change, but the level of crystallinity reduced. Bioactive Compound Library Soil conditions are conducive to the rapid degradation of FDM 3D-printed ARP/TPS/PLA biocomposites, as concluded. A novel, thoroughly degradable biocomposite for FDM 3D printing was developed in this study.