Explore the vast range of titles available.

Cellulose-derived materials are an emergent opportunity for reducing the environmental impact of polymers. Microcrystalline cellulose (MCC) has increasing relevance in many sectors, including pharmacy, food, and reinforcement of polymers, but its application is limited by the low coupling between it and nonpolar polymers and the polar behavior of cellulose derivates. There is not a well-defined model for the isolation of MCC and the factors involved in the length and width, which are elements of high influence on the reinforcement effect of MCC. This study proposes a mechanism for the size reduction of cellulose fibrils isolated through acid hydrolysis and a post-plasma surface modification (PSM) to enhance coupling of the MCC with hydrophobic polymer matrixes. MCC was characterized by FTIR, XRD, and SEM before and after the plasma surface treatment with caprolactone, a biodegradable polymer. There were no changes in the FTIR spectra; however, in XRD the sample exhibited a decrease in intensity. These results suggest that PSM did not change the structure of MCC or chemical composition. However, an increase in the peak temperature of degradation confirmed the surface modification of MCC.

This article proposes a process to prepare fully bio-based elastomer nanocomposites based on polyfarnesene and cellulose nanocrystals (CNC). To improve the compatibility of cellulose with the hydrophobic matrix of polyfarnesene, the surface of CNC was modified via plasma-induced polymerization, at different powers of the plasma generator, using a trans-β-farnesene monomer in the plasma reactor. The characteristic features of plasma surface-modified CNC have been corroborated by spectroscopic (XPS) and microscopic (AFM) analyses. Moreover, the cellulose nanocrystals modified at 150 W have been selected to reinforce polyfarnesene-based nanocomposites, synthesized via an in-situ coordination polymerization using a neodymium-based catalytic system. The effect of the different loading content of nanocrystals on the polymerization behavior, as well as on the rheological aspects, was evaluated. The increase in the storage modulus with the incorporation of superficially modified nanocrystals was demonstrated by rheological measurements and these materials exhibited better properties than those containing pristine cellulose nanocrystals. Moreover, we elucidate that the viscoelastic moduli of the elastomer nanocomposites are aligned with power–law model systems with characteristic relaxation time scales similar to commercial nanocomposites, also implying tunable mechanical properties. In this foreground, our findings have important implications in the development of fully bio-based nanocomposites in close competition with the commercial stock, thereby producing alternatives in favor of sustainable materials.

Sodium montmorillonite nanoclay (Na+-MMT) was modified by plasma polymerization with methyl methacrylate (MMA) and styrene (St) as monomers and was denominated as Na+-MMT/MMA and Na+-MMT/St, respectively. This plasma modified nanoclay was used as reinforcement for polystyrene (PS) nanocomposites that were prepared by melt mixing. Pristine and modified Na+-MMT nanoclay were analyzed by the dispersion in various solvents, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The results confirmed a change in hydrophilicity of the modified Na+-MMT, as well as the presence of a polymeric material over its surface. The pristine PS/Na+-MMT and modified PS/Na+-MMT/MMA and PS/Na+-MMT/St nanocomposites were studied with X-ray diffraction (XRD), differential scanning calorimetry (DSC), and TGA, as well as mechanical properties. It was found that the PS/Na+-MMT/St nanocomposites presented better thermal properties and an improvement in Young’s modulus (YM) in compared to PS/Na+-MMT/MMA nanocomposites.

Composites based on low-density polyethylene (LDPE) were prepared with Agave fiber powder (AFP) that was coated by plasma polymerization process using ethylene gas. Treated and pristine AFP were analyzed by infrared spectroscopy, scanning electron microscopy, and contact water angle for the assessment of surface properties. The polymer composites were prepared by melt mixing using 0, 5, 10, and 20 wt% of AFP and their mechanical and thermal properties were measured. Dispersion evaluation in water confirmed that the AFP treated changed from hydrophilic to hydrophobic behavior and it was also corroborated with water contact angle tests. The addition of treated and untreated AFP (200 mesh) at 20 wt% promotes an increase of Young’s modulus of the composites of up to 60% and 32%, respectively, in relation to the neat matrix. Also, an increase of crystallinity of LDPE was observed by the addition of treated and untreated AFP; however no significant effect on the crystallization temperature was observed in LDPE containing AFP.

Carbon nanofibers (CNFs), graphene platelets (GPs), and their mixtures were treated by plasma polymerization of propylene. The carbon nanoparticles (CNPs) were previously sonicated in order to deagglomerate and increase the surface area. Untreated and plasma treated CNPs were analyzed by dynamic light scattering (DLS), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and thermogravimetric analysis (TGA). DLS analysis showed a significant reduction of average particle size, due to the sonication pretreatment. Plasma polymerized propylene was deposited on the CNPs surface; the total amount of polymerized propylene was from 4.68 to 6.58 wt-%. Raman spectroscopy indicates an increase in the sp3 hybridization of the treated samples, which suggest that the polymerized propylene is grafted onto the CNPs.

Radiofrequency (RF) plasma treatment was employed as an alternative method to synthesize sulfur deposits on polyethylene terephthalate (PET) surfaces. In this regard, Optical Emission Spectroscopy (OES) and Energy Dispersive Spectroscopy (EDS) analysis confirmed the obtention of deposits composed of 100% sulfur after the dissociation of hydrogen sulfide (H 2 S) with a carbon dioxide mixture (H 2 S/CO 2 ) in a low-pressure discharge plasma reactor operated at 300 W input power. Furthermore, the structural and antimicrobial features of the obtained sulfur coatings on the PET surface were inspected. The sulfur-coated PET film showed a porous and roughened surface that provided high effectiveness in the inhibition against S. aureus and P. aeruginosa bacteria during the measurement of antimicrobial activity after 180 min of contact. According to the results, RF plasma treatment is an accessible technology to produce functional plastics that include sulfur deposits, which can be helpful in biomedical, food, textile, and other industries.

Concerns on environmental issues are motivating the development of biodegradable materials and the use of sustainable processes. Among the most abundant biodegradable materials are lignocellulosic fibers, which could have widespread use as reinforcing fibers in polymer composites. On the other hand, cold plasma treatment is a sustainable process which is lately gaining great interest for the surface treatment of lignocellulosic fibers aimed at improving the mechanical properties of polymers. Despite such great interest, polymers reinforced with plasma-treated lignocellulosic fibers (PRPLF) remain unknown for most industries manufacturing polymer composites. This review summarizes published studies on PRPLF and discusses the effect of plasma treatment of lignocellulosic fibers on the mechanical properties of PRPLF. The interfacial shear strength, tensile and flexural strength, and stiffness of a variety of PRPLF composites are presented and compared in data tables. Additionally, the tensile strength and stiffness of some plasma-treated lignocellulosic fibers are compared in a data table. Finally, the use of micromechanical models is encouraged to estimate the micromechanical properties of PRPLF. Graphical abstract

The aim of this study was to produce and characterize bioplastics derived from sweet potato peel starch, Aloe vera gel, and eucalyptus essential oil. Starch from sweet potato peels was extracted using a wet method, yielding 3.54%, while eucalyptus oil was obtained via steam distillation, with a yield of 1.4%. In order to assess the influence of Aloe vera and eucalyptus oil concentrations on the properties of bioplastics, a 2^2 factorial design was implemented. Consequently, bioplastic films were produced using the casting technique. As a result, the films appeared brown, translucent, and homogeneous, while also exhibiting a rough surface texture. Mechanical testing revealed that the films possessed a high Young’s modulus of 41.1 ± 11.1 MPa, a maximum tensile strength of 2.1 ± 0.4 MPa, and an elongation at break of 21.6 ± 4.3%. These properties were achieved with a formulation containing 70% w/w Aloe vera, 0.6% w/w eucalyptus oil, and 5% w/w sweet potato peel starch, suggesting a promising eco-friendly alternative to conventional plastics for potential use in packaging applications.

The growing concern for environmental problems has motivated the use of materials obtained from bio-based resources such as cellulose nanocrystals which have a promising application acting as fillers or reinforcements of polymeric materials. In this context, in this article, plasma-induced polymerization is proposed as a strategy to modify nanocrystals at different plasma power intensities using ε-caprolactone and δ-decalactone to improve their compatibility with polymeric matrices. The characterization was carried out using techniques such as FTIR, TGA, XRD, XPS, and AFM, with which a successful functionalization was demonstrated without altering the inherent properties of the nanocrystals. The preparation of ABS nanocomposites was carried out with the modified nanoparticles and the evaluation of the mechanical properties indicates an increase in Young’s modulus and yield stress under certain concentrations of modified cellulose nanocrystals.

Cellulose-derived materials are an emergent opportunity for reducing the environmental impact of polymers. Microcrystalline cellulose (MCC) has increasing relevance in many sectors, including pharmacy, food, and reinforcement of polymers, but its application is limited by the low coupling between it and nonpolar polymers and the polar behavior of cellulose derivates. There is not a well-defined model for the isolation of MCC and the factors involved in the length and width, which are elements of high influence on the reinforcement effect of MCC. This study proposes a mechanism for the size reduction of cellulose fibrils isolated through acid hydrolysis and a post-plasma surface modification (PSM) to enhance coupling of the MCC with hydrophobic polymer matrixes. MCC was characterized by FTIR, XRD, and SEM before and after the plasma surface treatment with caprolactone, a biodegradable polymer. There were no changes in the FTIR spectra; however, in XRD the sample exhibited a decrease in intensity. These results suggest that PSM did not change the structure of MCC or chemical composition. However, an increase in the peak temperature of degradation confirmed the surface modification of MCC.