Palygorskite (Pal) is a natural clay mineral with fibrous morphology and high surface area. Depending on the geological origin, it presents impurities, such as quartz and carbonates, which can harm some of its properties. Therefore, this work seeks to define a viable methodology for the purification of a Brazilian Pal. Two types of mixing processes (sonication and milling) and two types of dispersing agents (sodium silicate and sodium polyacrylate) were investigated. In addition, a subsequent acid activation with hydrogen peroxide and sulfuric acid was performed for complete purification. The viability of the purification of Pal was confirmed by X-ray diffraction, X-ray fluorescence, and thermogravimetric analyses. The sonication mixture process and the use of sodium polyacrylate as a dispersing agent were more effective. In addition, BET analysis showed an increase in the surface area of Pal, and scanning electron microscopy confirmed the permanence of its fibrous morphology after the purification steps.

Antistatic packages are used to protect and storage sensitive electronic compounds, plates, and integrated circuit. To produce antistatic packages, polymers must have good mechanical properties and low electrical resistivity to prevent the accumulation of static electricity and damage the stored product. Many polymers can be used to produce packages, especially polyolefins. In the field of sustainable packaging, green low‐density polyethylene (green LDPE) has been highlighting in recent years due to its origin: sugar cane. Thus, it is a green polymer that has the same properties as LDPE obtained from petroleum. Due to its insulating character, it is necessary the addition of conductive fillers, thus in this work, glassy carbon (GC) was used as a conductive filler. GC is a carbon material made from furfuryl alcohol resin obtained from rice husk or sugar cane, it is a conductive material and can decrease the electrical resistivity of the green LDPE/GC composite, making it possible to use as an antistatic packaging. Eco‐friendly green composites based on green LDPE/GC with different contents of GC (0.1, 0.3, and 0.5 wt%) were prepared using a thermokinetic homogenizer. The green composites were characterized by mechanical and thermal properties, structural characteristics, water vapor permeability, optical properties, and impedance spectroscopy. The results indicate that the use of green LDPE/GC composites with low concentrations of GC (0.1 wt%) is feasible for the preparation of antistatic packaging since the green composites showed low electrical resistivity and improvement in elastic modulus.

In the aerospace industry, many composite parts are manufactured by processes using plastic vacuum bags made of polyamide 6 (PA6) as a consumable material. This implies that after demolding the part, this plastic material should be discarded, generating a considerable amount of waste. Tons of vacuum bags are discarded and incinerated per month by several companies in this sector, which highlights the need to recycle and/or reuse this material. PA6/linear low-density polyethylene (LLDPE) blends are of great technological interest because they can combine the excellent thermo-mechanical and oxygen barrier properties of the PA6 with high impact strength, good processability, and low cost of LLDPE. The replacement of neat PA6 by the post-processing vacuum bags residue PA6 may be a new strategy for the recycling of this material. In this work, PA6/LLDPE/maleic anhydride-grafted LLDPE (LLDPE-g-MA) (90/5/5) blends were prepared using a co-rotational twin-screw extruder and the neat PA6 was replaced by different contents of post-processing PA6 (5, 10, 15 and 20 wt.%). The mechanical, thermal, and morphological characterization was evaluated. The increase in the content of post-processing PA6 caused an increase in the crystallinity degree of the LLDPE phase, acting as a nucleating agent to the LLDPE phase, reducing the toughening effect of this phase in the blends and, therefore, providing this phase to act as a reinforcing agent.

No abstract

Polypropylene (PP)/ethylene-vinyl acetate (EVA) (60/40) blends-based glassy carbon (GC) composites with different contents of GC (0.1 to 5 wt%) were melting processed in a twin-screw extruder and the thermal, mechanical, electrical and morphological properties were evaluated to verify the effectiveness of the addition of GC as filler. Moreover, the effect of the addition of maleic anhydride grafted polypropylene (PP-g-MA) as a compatibilizer agent was also verified. The composites presented dispersed phase morphology with preferential localization of GC on interfacial regions and into the EVA phase. The mechanical properties were improved with the addition of PP-g-MA as a compatibilizer agent for the blend and the addition of GC had little influence on these properties. The results obtained from thermal properties revealed that the GC contributes to the increase in the degree of crystallinity and thermal stability of the composites. The addition of 0.1 wt% of GC increased the elastic modulus and the ultimate tensile strength without loss in the impact strength when compared to the compatibilized blend. The addition of GC increases a decade of magnitude in the electrical conductivity of the PP/EVA blends.