Abstract Plasticulture improves crop quality and yield through polymeric films, but their improper disposal harms the environment due to humidity and contamination. This study aimed to develop biodegradable mulch films using soybean and peanut hulls and poly (butylene-adipate-co-terephthalate) (PBAT). The residues were characterized by thermogravimetric analysis and mulch films were evaluated by water absorption, contact angle and mechanical properties. The thermal behavior of the residues indicated stability below 200ºC. The agro-waste improved hydrophobicity but increased the water absorption values of the films by up to 18.5x (PBAT/SH5 after 14 days). Micrographs obtained by scanning electron microscopy indicated an important distribution of residue particles and formation of agglomerates, leading to lower mechanical performance. The study found that agro-industrial residues in powder form can be added to the polymeric matrix to produce biodegradable mulch films through traditional processing techniques. This approach has the potential to contribute to a more sustainable production system.

Abstract Polymeric composite materials, presenting a practical solution for sealing non-metallic expansion joints under extreme conditions such as high temperatures and harsh chemical and physical abrasion, were investigated in this scientific study to discern the impact of welding parameters on their degradation and properties. The study entailed the bonding of polymeric composite blankets through hot plate pressing with a PTFE film, encompassing variations in temperature, duration, and load application. The findings elucidated that lower temperatures and shorter processing times failed to achieve optimal blanket adhesion, while higher temperatures led to material degradation, subsequently diminishing the mechanical strength of the welded joint. In contrast, extended processing times and the application of load during welding demonstrated a positive correlation, enhancing the mechanical strength of the joint by ameliorating interfacial adhesion. This research underscores the critical significance of carefully selecting welding parameters to ensure the peak performance and durability of polymeric composite structures.

Abstract The objective of this work was to produce Pebax®/polydopamine (PDA) blends and apply these blends to produce membranes for gas separation. Flat sheet membranes were tested for gas permeation, differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), wide angle x-ray diffraction (WAXD), scanning electron microscopy (SEM) and fourier transformed infrared spectroscopy (FTIR). The results show an optimal concentration of dopamine hydrochloride that produces the best results (��=100, P=114 Barrer). DSC and WAXD results indicate that polydopamine influences the crystallization of Pebax®, reducing the melting and crystallization temperatures of PA blocks and increasing the melting temperature of PEO blocks. The incorporation of PDA decreases gas permeability and increases gas selectivity. The decrease in permeability indicates that the presence of polydopamine reduces the diffusion coefficient of Pebax® by reducing the segmental mobility of PEO blocks and possibly the fraction free volume. Compared to the trade-off, Pebax®/PDA membranes surpasses the upperbound for CO2/N2 separation.

Abstract Most of the discarded plastics originate mainly from food and beverage packaging, thus the consumer's perception of biodegradable packaging must be understood. This study aimed to investigate the consumer perception of biodegradable packaging films made of pectin and whey protein isolate. An online questionnaire was conducted to assess the consumer responses. Results showed that the majority of consumers (77.3%) did not observe the biodegradability of the packaging during purchase, although biodegradable packaging can positively affect the purchase decision (71.9%). The acceptance, purchase intention, and preference are influenced by visual aspects, and the consumers preferred lighter and more transparent films, with less saturated colors. Consumers established correlations between color and transparency with film thickness and resistance, these correlations were not observed in the physical analysis of the film. In addition, a variety of applications were highlighted for the films produced, demonstrating the effectiveness of these materials for food and beverage packaging.

Abstract Bacterial cellulose (BC) is promising as a wound dressing because it is non- toxic and maintains moisture in the wound. Although BC does not have antimicrobial activity, its structure allows the incorporation of antimicrobial compounds such as essential oils (EOs). This study aims to associate BC with rosemary, clove, eucalyptus, ginger, lavender and lemongrass EOs to obtain wound dressings. The Gas Chromatography-Mass Spectrometry and Fourier Transform Infrared Spectroscopy analyses showed characteristic compounds of EOs in the incorporated membranes. These compounds reduced the thermal stability of most samples due to their different degrees of volatility. The Scanning Electron Microscopy indicated that the EOs filled the membrane pores and coated the cellulose fibers. Samples incorporated with clove, ginger and lemongrass EOs inhibited Escherichia coli, Staphylococcus aureus and Candida albicans due to the presence of eugenol and citral. The results confirmed the incorporation method's effectiveness, maintaining the composition and antimicrobial characteristics of the EOs.

Abstract Oil spills into water have been an environmental concern since the beginning of large-scale oil extraction. In this study, flexible open-cell polyurethane (PU) foams with added microcrystalline cellulose (MCC) were formulated and chemically modified with organosilane for use as an absorbent system for oil spill cleanup in water. The influence of cellulose concentration on mechanical properties and chemical treatment with organosilane was evaluated. The primary findings indicate that the surface treatment of the solid fraction of the foams was effective, as indicated by the contact angle, increasing the hydrophobicity of the samples. Because of the increased roughness of the PU solid fraction and the cellulose reactivity, the mechanical compressive strength and thickness of the organosilane layer increased with increasing MCC content. However, the higher the MCC content in the composition, the higher was the density, which reduced the sorption capacity of the samples.

Abstract The objective of this research was to develop a more sustainable composite and still keep its characteristics. Fibers treated with NaOH at 5% w/w for 2 hours were incorporated into natural rubber in different proportions (0 phr, 24 phr, 36 phr, 48 phr and 60 phr). The mechanical properties of the composites suffered changes, increasing the hardness, young’s modulus and decreasing its tensile strength. All the physical properties were not statistically different. The coloration became less dark in the WF60/CB0 treatment, and the electrical properties presented better resistivity with the increase in the concentration of fibers in the composite. This presents a possibility of using WF for the production of wood-rubber composites for the production of rubber artifacts which do not require high rolling resistance. Based on the results from this research, we recommended the WF24/CB36 mix to produce antistatic floors.

Abstract High-intensity ultrasound irradiation proved to be an effective method for modifying tara gum by generating low molecular weight products and better water solubility. The objectives of this research were to optimize the parameters for the high-intensity ultrasonic treatment with response surface methodology and improve the tara gum solubility. The results demonstrated that after the ultrasound treatment, the solubility of the tara gum had increased (17.7%) as a result of the reduced intrinsic viscosity (70%). The molecular weight of the untreated tara gum was 1.89 x 106 Da, and after ultrasound treatment, it was reduced to 0.47 x 106 Da. Rheological analyses confirmed the reduction in molecular weight for the modified and optimized tara gum and the resulting increase in solubility. This knowledge provides a better understanding of ultrasound treatment technology and increases the scope for use of tara gum in the food industry.

Abstract Aiming to produce an antimicrobial dressing for wound healing applications, in this work Tea Tree oil (TTO) was incorporated into PHBV nanofibers by absorption. It was observed increase in the nanofiber diameter due to 5% TTO absorption efficiency, which also led to a 54% decrease in the contact angle. The releasing assay indicates a 6.8% oil release in the first 24 h – being probably the oil deposited at the polymer surface – followed by a minimal release at 48 h. The set of antimicrobial assays performed suggests the incorporation of TTO optimized the antimicrobial activity of the polymer for E. coli and C. albicans, while against S. aureus no significant difference was observed. The MTT assay showed no cytotoxicity of PHBV, but the incubation of L929 fibroblast cells with PHBV-TTO reduced cell viability. Overall, the PHBV nanofibers containing TTO present great potential as an antimicrobial dressing.

Abstract While numerous phenoxazine-based small molecules developed for organic electronic devices, very limited attention has been received on synthesized conjugated polymers containing this phenoxazine. Herein, we designed and synthesized two new low-bandgap donor−acceptor conjugated copolymers based on phenoxazine with different side chains and diketopyrrolopyrrole by Pd-catalyzed direct (hetero)arylation polycondensation using a Pd(OAc)2 catalyst and PCy3.HBF4 ligand. The effects of side chain branched alkyl and benzoyl of phenoxazine on the thermal, and optical properties of the polymers have been investigated. Both the polymers have a good yield 85%, high molecular weight up to 41500 g/mol, low dispersity index 1.91, excellent solubility in common organic solvents, and a broad absorption spectrum in the range of 500-900 nm with optical bandgaps as low as 1.40 eV. All these polymers possess good thermal stability with decomposition temperatures over 350 oC and no obvious thermal transitions.

Abstract Segmented polyurethanes based on poly(l-lactide)diol - PLLA, poly(ethylene-glycol) - PEG, poly(trimethylene-carbonate)diol - PTMC and hexamethylene diisocyanate were synthesized by a two-step polyaddition. Polyurethanes with variable compositions and molar mass were semi-crystalline and presented PLLA or PLLA + PEG crystalline phases and a heterogeneous amorphous phase. Sequential crystallization of PLLA and PEG resulted in a confined PEG crystallization into the PLLA crystalline phase. The random distribution of the segments in the polymer chains and the partial miscibility of the segments in the amorphous phase strongly influenced the morphology of the crystalline phase, and the kinetics of the crystallization. Morphology changed from not well-defined spherulites with Maltese cross to ring banded spherulites and axialites as the PLLA mass fraction decreased. PLLA nucleation and crystal growth rates varied with crystallization temperature similarly to homopolymers, presenting a bell-shaped curve, and the temperature for the maximum growth rate dependent on the polyurethanes composition.

Abstract Thermally modification of wood is an environment-friendly alternative method for improving several properties of wood without the use of chemicals. The compressive strength (CS) parallel to the grain of reinforced laminated veneer lumber (LVL) manufactured from heat treated beech (Fagus orientalis) veneers and carbon fibre was determined. Thermally modification was performed at 140°C, 160°C, 180°C, and 200 °C according to thermal treatment process. Carbon fibre were added as a reinforcement layer between wood veneers bonded with phenol-formaldehyde (PF), polyvinyl acetate (PVAc) polyurethane adhesives (PU) to improve properties of LVL. Results showed that reinforcing LVL panels with carbon fibre increased both density and CS. The PF adhesive showed better results for reinforced LVL panels with carbon fibre. The anatomical structure and density of the wood material significantly affect its mechanical properties, including compressive strength parallel to the grains. Wood density had a strong significant linear relationship with CS.

Abstract Polyvinylidene fluoride (PVDF) is a polymer material that exhibits piezoelectricity, which is the ability of certain materials to generate an electric charge in response to applied mechanical stress. Electrospun nanofibers were prepared from a solution with 1800 mg PVDF (18 wt.%) powder dissolved in 7.5 ml of dimethylformamide (DMF) and 2.5 ml acetone. The experimental setup used in the electrostatic deposition process was developed in our laboratory. Atomic Force Microscopy (AFM) showed that the fibers vary from 100 nm to 200 nm. Scanning Electron Microscopy (SEM) measurements showed distributed and well-formed nanofibers, but with few incidences of beads. The Energy Dispersive Spectroscopy (EDX) results showed that all points of the formed nanofibers have very similar chemical compositions, based on carbon and fluorine. Raman and Fourier Transform Infrared (FTIR) Spectroscopic analysis revealed the characteristic bands related to β-phase in the sample, which is responsible for the piezoelectricity of PVDF.

Abstract In this paper, the crystallization, fusion, and activation energy (Ea) of PBT/TiO2 were thoroughly evaluated using DSC. Increasing the rates shifted the peaks of melt crystallization to lower temperatures while the fusions were almost unaffected. TiO2 hindered the melt crystallization of PBT and lower crystallization rates, i.e., CMAX and K’ were acquired, in general, the crystallinity degree (Xc) was 4% higher in PBT/TiO2 which is in the marginal error. Pseudo-Avrami and Mo models were applied to evaluate the melt crystallization kinetics; both fitted the melt crystallization quite well; deviations were observed at the beginning and the crystallization end most due to the nucleation and spherulites impingement during the secondary crystallization. Ea was evaluated using the Friedman model, considering the values of Ea less energy has to be removed from PBT/TiO2 when compared to PBT, specifically at 1% of TiO2.

Abstract In this study, walnut shell particles obtained through the grinding of walnut shells were used as a reinforcing material and pumice powder as a filler for developing epoxy-based composites characterized by reduced flammability. Thermogravimetric analysis (TGA), Differential scanning calorimetry (DSC), and Underwriters Laboratories (UL)-94 vertical tests were carried out for evaluating the effectiveness of these pumice powder treatments. Under the UL-94 vertical test, composites (S1, S2, S3, S4, S5 and S6) with 20% pumice powder (i.e., by mass content of walnut particles were not self-extinguished, and could not be classified. S7 and S8 composites (40wt% and 50%) assigned a V-2 rating, which was the least flammable composite However, the mechanical tensile tests showed that the pumice powder treated composites increased their tensile strength. The morphological analysis showed an enhancement of the interfacial adhesion of the composites achieved by pumice powder.