Tailoring polyamide 6 to exhibit super‐tough behavior and high thermomechanical stability: The role of <scp>AES</scp> and <scp>EPDM‐MA</scp> hybridization

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Low‐density biopolyethylene (BioLDPE) ecocomposites added with particles of eggshell (ES) residue were produced using linear low‐density polyethylene grafted with maleic anhydride (LDPE‐g‐MA) as a compatibilizing agent. BioLDPE/ES and BioLDPE/ES/LDPE‐g‐MA compounds were processed in a twin‐screw extruder, and the specimens were injection molded. Torque rheometry increased and melt flow index reduced more prominently for the BioLDPE/LDPE‐g‐MA biocomposite with 20 phr ES, suggesting higher viscosity. Consequently, there was a higher level of ES particles breakdown, generating greater distribution and dispersion, as verified in optical microscopy and scanning electron microscopy images. This finding was supported by Fourier transform infrared spectroscopy, considering the intense absorption band at 871 cm−1 for BioLDPE/ES (20 phr)/LDPE‐g‐MA biocomposite, indicating a higher level of ES particles dispersion in BioLDPE matrix. Therefore, BioLDPE/ES (20 phr)/LDPE‐g‐MA biocomposite increased the elastic modulus, tensile strength, Shore D hardness, and heat deflection temperature by 51.4%, 16.9%, 16.4%, and 14, 6%, respectively, related to BioLDPE. Additionally, the flexibility was kept as seen in the elongation at break and impact strength, including not fractured during the impact test. Reported results for the biocomposites are valuable mainly for the polymer additive sector, since the ES has the potential to improve BioLDPE properties, expanding the range of applications.

Toward the production of biopolyethylene‐based ecocomposites with improved performance: The potential of eggshell particles as an ecological additive

Bezerra,

Wellen,

Barreto Luna

et al. 2024

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Tuning the mechanical and thermomechanical properties through the combined effect of crosslinking and annealing in poly(lactic acid)/acrylonitrile‐EPDM‐styrene blends

Luna,

Da Silva Barbosa Ferreira,

Do Nascimento

et al. 2024

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Acrylonitrile‐EPDM‐styrene (AES) was applied as an impact modifier for poly(lactic acid) (PLA), and the combined effect of dicumyl peroxide (DCP) crosslinking and annealing heat treatment was investigated. Torque rheometry, melt flow index (MFI), mechanical properties (impact, tensile, and Shore D hardness), X‐ray diffraction (XRD), infrared spectroscopy (FTIR), heat deflection temperature (HDT), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) were investigated. There was a considerable torque increment and fluidity drop in the PLA/AES/DCP blends caused by the crosslinking process and the formation of PLA‐g‐AES. Consequently, the impact strength and elongation at break properties improved. As an engineering terpolymer, AES was decisive in maintaining high elastic modulus, Shore D hardness, and HDT values. The PLA/AES/DCP (0.8 phr) composition leaned towards a synergism of mechanical properties, gaining 505.6% and 264.8% in impact strength and elongation at break, respectively, compared to neat PLA. FTIR and XRD analysis revealed high crystallinity, with samples presenting large crystals. The higher crystallinity had a deleterious effect on the mechanical properties of the PLA/AES/DCP blends. However, there was a marked improvement in HDT and higher toughness compared to PLA. The results before and after annealing the PLA/AES/DCP (0.8 phr) blend are promising for constructing new semi‐biodegradable materials for additive manufacturing.

Tuning multifunctional behavior of PLA/POE‐g‐GMA/MWCNT nanocomposites: Mechanical, rheological, thermal, thermomechanical, and electromagnetic properties

Luna,

da Silva,

dos Santos Filho

et al. 2024

Nanocomposites of polylactic acid (PLA) and poly(ethylene‐octene) grafted with glycidyl methacrylate (POE‐g‐GMA) were prepared using multi‐walled carbon nanotubes (MWCNT) as conductive nanofillers. The PLA/POE‐g‐GMA/MWCNT nanocomposites were processed through extrusion and injection molding for rheological, mechanical, electromagnetic, thermal, thermomechanical, and morphological characterization. The carbon nanotubes were dispersed in the PLA/POE‐g‐GMA chain, as seen by Raman spectroscopy. With higher MWCNT content, the complex viscosity (η*) and storage modulus (G') significantly increased in the nanocomposites, suggesting percolation formation. The nanocomposites melt flow index (MFI) results indicated lower fluidity, confirming the trend in η*. Electrical conductivity was optimal for PLA/POE‐g‐GMA/MWCNT (5 phr), reaching a value of 2.21°×°10−6 S/cm and providing electromagnetic shielding of 8 dB across the entire Ku band (12.2–18 GHz). The impact strength of the nanocomposites was higher than that of pure PLA and the PLA/POE‐g‐GMA blend, while the heat deflection temperature (HDT) remained stable at around 56°C. Increased MWCNT content in the nanocomposites promoted recovery of the elastic modulus, tensile strength, and Shore D hardness compared to PLA/POE‐g‐GMA blend. Overall, the results indicate that the PLA/POE‐g‐GMA/MWCNT (5 phr) nanocomposite has potential antistatic applications.