Polypropylene/Ethylene—And Polar—Monomer-Based Copolymers/Montmorillonite Nanocomposites: Morphology, Mechanical Properties, and Oxygen Permeability

Abstract

This research reports the influence of polar monomer contents in ethylene vinyl acetate copolymer (EVA) and ethylene vinyl alcohol copolymer (EVOH) on the morphology, mechanical and barrier properties of polypropylene/ethylene copolymer (PP) reinforced with organically modified montmorillonite (MMT). PP/EVA and PP/EVOH (75/25 wt %) blends were reinforced with 3 wt % MMT in an internal mixer system. Samples were compression-molded into films of 300μ μm. The structural characterization was made using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), the mechanical properties were obtained by tension tests and the barrier properties by oxygen transmission rate (OTR). XRD patterns showed a combination of intercalated/exfoliated morphologies for the MMT, with higher d-001 interplanar distance increments for the blends with higher content of polar functional groups. SEM and TEM micrographs complement the results of the XRD analysis and show differences in the morphologies depending on the miscibility of the polyolefin and the polar monomer copolymer. Mechanical properties and oxygen permeability of composites exhibited a higher improvement, by the addition of MMT, for higher intermolecular interactions and most miscible polymeric system of the EVA. These results show that the higher the number of interactions, given by the VA or OH polar functional groups, the morphology and the miscibility between polyolefin and copolymer imply dispersion improvements of the nanocomposites and, in consequence, a higher improvement on the mechanical and barrier properties of the composite material.

Hybridization of MMT/Lignocellulosic Fiber Reinforced Polymer Nanocomposites for Structural Applications: A Review

“…Table 3 shows the Young's modulus, elongation at break and tensile strength of various polymeric blends and nanocomposites samples studied by Castro-Landinez et al [136]. A 21% increase in stiffness was seen for blends with EVA28 while it was 15% with EVA12 as compared with EVOH systems.…”

“…The results demonstrated that the MMT showed better interactions with PP/EVA blends because they operate as a reinforcing agent than the effect on the PP/EVOH blends. Interestingly, with the introduction of clay into polymeric blends for both PP/EVA and PP/EVOH, the elongation at break and the tensile strength showed no significant change [136]. Shikaleska et al [137] reported that poly(ethylmethacrylate) (PEMA) and MMT clay particles have a considerable effect on the mechanical properties of poly(vinylchloride) (PVC)/PEMA 90/10 blend composite.…”

Permeabilidad al Oxígeno en Envases para Alimentos Fabricados con Polipropileno Mediante Moldeo por Inyección

“…Es importante mencionar que, existen empaques que presentan una serie de defectos, como bajas propiedades antimicrobianas, alta permeabilidad al oxígeno y/o a la humedad, que pueden solucionarse añadiendo un componente de refuerzo (Hsissou et al, 2021;Nejatian et al, 2023), y que según Kim et al (2021) pueden modificar las propiedades de permeabilidad en los envases en función de la temperatura, reduciendo así los efectos perjudiciales del gas en el interior de los productos envasados, como la aceleración de la maduración y la reducción de la vida útil de los productos frescos. Por ejemplo, Castro-Landinez et al (2021) indican que el EVOH es muy conocido como material polimérico de baja permeabilidad al oxígeno; entre 0,4 a 3 cm 3 ꞏmm/m 2 ꞏdayꞏatm que, agregándole al PP mejora la barrera al oxígeno, a diferencia del etileno acetato de vinilo (EVA) tiene una permeabilidad al oxígeno mayor, que oscila entre 800 a 1000 cm 3 ꞏmm/m 2 ꞏdayꞏatm, los cuales son superiores a los reportados en el presente trabajo.…”

Recent Advances in Halogen-Free Flame Retardants for Polyolefin Cable Sheath Materials

“…In general, inorganic silicones are mainly used as adjuvants in combination with other FRs for PO polymers. Among them, SiO 2 [ 54 , 55 ] and MMT are the most commonly used inorganic silicone adjuvants [ 56 , 57 ]. Thus, this section mainly discusses these two types of FRs.…”