Composites based on low-density polyethylene (LDPE) were prepared withAgavefiber 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.

Agave fibers (AF) were incorporated either pristine (AF_p) or surface treated by ethylene plasma (AF_m) in low-density polyethylene (LDPE)/ethylene vinyl acetate (EVA) blends at a ratio of 1:1 and foamed by chemical means. The role of the AF content (3, 6, 9, 12, and 15wt.) and its surface modification on the cellular morphology and mechanical properties of LDPE/EVA/AF foams under compression is investigated herein. Fourier transform-infrared spectroscopy, contact angle, and water suspension of AF suggest that plasma treatment using ethylene successfully modifies the surface nature of AF from hydrophilic to hydrophobic. AF and the surface treatment have an important role on the morphological properties of the foams. Composite foams reinforced with 12wt. AF_m exhibited the highest mechanical properties improvements. At this fiber content, the composite foams enhanced 30 of the compressive modulus and 23 of the energy absorption under compression with respect to the neat polymer blend foam, as a result to the formation of more uniform cells with smaller size and the enhancement of compatibility and spatial distribution of the AF_m in the polymer composite foams due to thin clusters of polyethylene-like polymer deposited on the AF surface.