Tetrafluoroethylene–perfluoroalkyl vinylether copolymer (PFA) has a broad application ranging from biomedical and aerospace to corroding environments in the chemical industry. Despite a low share in end‐of‐life products, PFA processing can produce up to 30% of waste. Thus, understanding how recycled fluorinated polymers affect product performance is crucial to ensure primary recycling, besides economic and environmental reasons. In this paper, the utilization feasibility of PFA waste materials is investigated, i.e., recycled PFA (PFAr) in closed‐loop recycling. The effect of PFAr loading (5–100 wt.%) on the thermal, mechanical, rheological, and color properties and chemical resistance are studied. Thermal properties and chemical resistance showed no significant changes in all ranges of PFAr content tested. The addition of higher loads of PFAr (≥50 wt.%) leads to a reduction in mechanical properties, particularly stress‐strength analysis and elongation at break. However, elastic modulus and hardness have improved concurrently with an increase in the degree of crystallinity. The decrease in complex viscosity and yellowing of the samples occurred probably induced by a polymer chain degradation. Despite that, the addition of up to 10 wt.% of PFAr proved to be an effective alternative to reusing PFA residues based on mechanical recycling.
To evaluate the hydrophilic capacity, polypropylene and surfactant (polyether siloxane) samples were extruded in the proportions of 0.0, 0.5, 1.0 and 3.0 (wt%) and films were obtained in a heated press. The samples were submitted to measurements of contact angle, surface tension, melt flow index and surface roughness. The results indicated that increasing surfactant content promoted better wettability and consequently higher hydrophilicity. Using water, the increase in the surfactant content reduced the contact angle (92.58° to 68.10°) and increased the surface tension (26.7 to 56.9 mN.m-1). However, with ethylene glycol, increasing the surfactant content promoted a small variation on the contact angle (59.14° to 65.10°) and on the surface tension (5.5 to 5.0 mN.m-1). The surfactant promoted a slight change in the melt flow index but not affected the roughness of the samples.
Abstract. The surface adsorption of inorganic clays with ionic liquids has attracted much attention due to improve the interaction of hydrophilic clay with the hydrophobic polymers. However, successful organic adsorption strongly depends on the characteristics of ionic liquid (anion, chain size and concentration), and the reaction conditions (as polarity of solvent). In this study, such factors were analyzed and correlated with morphology, thermal and mechanical properties of the nanocomposites. The heterophasic ethylene-propylene copolymer nanocomposites were prepared by melt intercalation method in a twin screw co-rotating extruder. The halloysite nanotubes (HNT) was used as filler -natural and modified with different ionic liquids. The results showed that a better distribution and dispersion of the nanoparticles was achieved in the samples with modified HNT (m-HNT) and was more significant when the ionic liquid adsorption was conducted in a less polar solvent. The thermal stability of the nanocomposites with m-HNT was higher compared to the neat CP. Additionally, the better balance in the mechanical properties was obtained by the use of the more hydrophobic ionic liquid and higher concentration with improve of 27% in the Young Modulus without loss in the impact properties at room temperature. These superior behaviors of ionic liquid adsorption products exhibit properties suitable for many industrial applications.
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