Synthesis and Characterization of Chemically‐Modified Cassava Starch Grafted with Poly(2‐Ethylhexyl Acrylate) for Blending with Poly(Lactic Acid)

Abstract

Native cassava starch (CS) is chemically modified by grafting with 2-ethylhexyl acrylate (EHA) monomer to make it more hydrophobic for improved blending with poly(lactic acid) (PLA). Grafting is carried out using CS:EHA weight ratios of 2:1, 1:1, 1:2, and 1:3 in a methanol-water solvent mixture at 45 C for 48 h. L-Ascorbic acid and hydrogen peroxide are used as the redox initiating system. Following purification, the poly(2-ethylhexyl acrylate)-grafted starch, starch-g-PEHA, is obtained either as a finely divided powder or as a slightly tacky solid with % grafting values in the range of 13-26% by weight. The main objective of this chemical modification is to improve the interfacial adhesion between the starch particles and the PLA matrix through the hydrophobic PLA-PEHA interactions. PLA/starch-g-PEHA blends are prepared in the form of solution-cast films with weight ratios ranging from 100/0 to 60/40. Tensile testing of the films shows a marked increase in extensibility and toughness up to a loading of 10% starch-g-PEHA above which the properties deteriorated rapidly due to starch particle aggregation. Thus, for potential use as biodegradable film packaging, the best properties are obtained for the PLA/starch-g-PEHA 90/10 blend.

Effects of wood flour and MA-EPDM on the properties of fused deposition modeling 3D-printed poly lactic acid composites

“…Figure 1(d) shows the typical wave pattern when brittle fracture occurred. This can confirm the brittleness of PLA as a morphological characteristic (Martínez-Vázquez et al 2014;Bunkerd et al 2018). Figure 2 shows the 3D-printed PLA composite in which only 5 phr of MA-EPDM was added to PLA.…”

Toughening polylactic acid by melt blending with polybutylene adipate‐co‐terephthalate and natural rubber, and the performance of the resulting ternary blends

“…Morphological characteristics at the tensile fractured surfaces of samples were observed by SEM; the images are shown in Figure 6. Both the PLA and the extruded PLA exhibited smooth fractured surfaces (Figure 6a,b), indicating their rigidity and brittleness 46 . By blending with different variations of PBAT/NR blend, the obtained PLA/PBAT/NR ternary blends showed rougher surfaces with stretched fibrils, which might relate to one or more elastic components, that is, PBAT and/or NR, as clearly seen in Figure 6c,d.…”

“…The higher tensile strength and Young's modulus of PLA/-PBAT/NR ternary blends were explained by the presence of the strong and stiff PLA. 46 By blending with different variations of PBAT/NR blend, the obtained PLA/PBAT/NR ternary blends showed rougher surfaces with stretched fibrils, which might relate to one or more elastic components, that is, PBAT and/or NR, as clearly seen in Figure 6c,d. Previous articles also reported that PBAT formed fibrils in the matrix of PLA/PBAT blends.…”

Chemical modification of rice (Oryza sativa) and potato (Solanum tuberosum) starches by silanization with trimethoxy(methyl)silane

“…According to standard D7334, when the contact angle is higher than 90º, the silanized starches are hydrophobic and the wetting of these polysaccharides is reduced (Bergel et al, 2020). Bunkerd et al (2018) obtained cassava starch modified with 2-ethylhexyl acrylate, and it presented a contact angle higher than 80º. This allowed the researchers to adhere the starch to the hydrophobic PLA matrix.…”