Compatibilization and Characterization of Polylactide and Biopolyethylene Binary Blends by Non-Reactive and Reactive Compatibilization Approaches

Abstract

In this study, different compatibilizing agents were used to analyze their influence on immiscible blends of polylactide (PLA) and biobased high-density polyethylene (bioPE) 80/20 (wt/wt). The compatibilizing agents used were polyethylene vinyl acetate (EVA) with a content of 33% of vinyl acetate, polyvinyl alcohol (PVA), and dicumyl peroxide (DPC). The influence of each compatibilizing agent on the mechanical, thermal, and microstructural properties of the PLA-bioPE blend was studied using different microscopic techniques (i.e., field emission electron microscopy (FESEM), transmission electron microscopy (TEM), and atomic force microscopy with PeakForce quantitative nanomechanical mapping (AFM-QNM)). Compatibilized PLA-bioPE blends showed an improvement in the ductile properties, with EVA being the compatibilizer that provided the highest elongation at break and the highest impact-absorbed energy (Charpy test). In addition, it was observed by means of the different microscopic techniques that the typical droplet-like structure is maintained, but the use of compatibilizers decreases the dimensions of the dispersed droplets, leading to improved interfacial adhesion, being more pronounced in the case of the EVA compatibilizer. Furthermore, the incorporation of the compatibilizers caused a very marked decrease in the crystallinity of the immiscible PLA-bioPE blend.

Structural Features and Properties’ Characterization of Polylactic Acid/Natural Rubber Blends with Epoxidized Soybean Oil

“…However, the unmodified PLA is brittle, with low impact elasticity and break elongation. Its properties are similar to those of another relatively brittle polymer—polystyrene [ 1 , 2 , 3 ]. These properties significantly limit the application of PLA in the polymer packaging manufacture.…”

Manufacturing and compatibilization of binary blends of polyethylene and poly(bulylene succinate) by injection molding

“…Figure 3 shows the FESEM images from the different samples after the impact test. In Figure 3a it is observed the fracture surface of bioPE/PBS blend, which indicates the immiscibility of the two polymers due to the formation of the two well-differentiated phases: the matrix, which corresponds to the bioPE due to it has the highest proportion in the blend, and the small spherical particles being pulled out that present distribution in the range of (1 - 6.5) µm correspond to the PBS (Ferri et al, 2020). Then, in Figure 3b, it can be seen that PE-g-MA causes a slight improve in the compatibilization between the two polymers in some areas of the blend due to some boundaries between bioPE and PBS phases became less discernible, it can also be said that the size of the PBS particles decrease, however, this effect was not enough to contribute with the improvement of mechanical properties when comparing with the uncompatibilized blend as was indicated before.…”

“…However, one of its main drawbacks is that it is not a biodegradable polymer, leading to environmental problems after its life cycle. In order to reduce its final environmental impact, BioPE has been blended with different biodegradable polymers such as PLA (Ferri, Garcia-Garcia, Rayón, Samper, & Balart, 2020;Quiles-Carrillo, Montanes, Jorda-Vilaplana, Balart, & Torres-Giner, 2019), PCL Bezerra, França, Morais, Silva, et al, 2019) or TPS (Samper-Madrigal et al, 2015). One of the most interesting biopolymers to reduce the environmental impact of BioPE is PBS.…”

“…One of the most employed is the use of compatibilizers, mainly prefabricated copolymers (block or grafted). These copolymers are characterized by a dual functionality that allows them to interact with both polymers in the blend, acting as a bridge between them and establishing interactions, thus improving their compatibility and their final mechanical properties (Ferri et al, 2020). Samper-Madrigal et al (2015) studied the effect of incorporating different contents (1, 3, and 5 wt%) of graft copolymer poly(ethylene-g-maleic anhydride) (PE-g-MA) in BioPE/TPS blends (70/30).…”

Rotational Molding of Poly(Lactic Acid)/Polyethylene Blends: Effects of the Mixing Strategy on the Physical and Mechanical Properties

“…The toughness of PLA was improved by incorporation of rubber grade ethylene-co-vinyl acetate (EVM). PLA/Polyolefin blends have been developed [ 19 , 20 ]; for example, Anderson and Hillmyer [ 21 ] studied the influence of Polyethylene on the structure and mechanical properties of PLA/polyethylene blends. A diblock copolymer (PE- b -PLLA) was used as compatibilizer, and toughening was achieved without a copolymer, and the variability of impact resistance decreased with as little as 0.5% of copolymer.…”