Rapid Biodegradable Ionic Aggregates of Polyesters Constructed with Fertilizer Ingredients

Abstract

Synthetic biodegradable polyesters tend to undergo slow biodegradation under ambient natural conditions and, hence, have been rejected or even banned recently in ecofriendly applications. Here, we demonstrate the preparation of polyesters exhibiting enhanced biodegradability, which were generated through a combination of old controversial macromolecules and aggregate theories. H 3 PO 4 -catalyzed diacid/diol polycondensation afforded polyester chains bearing chain-end −CH 2 OP(O)(OH) 2 and inner-chain (−CH 2 O) 2 P(O)(OH) groups, which were subsequently treated with M(2-ethylhexanoate) 2 (M = Zn, Mg, Mn, and Ca) to form ionic aggregates of polyesters. The prepared ionic aggregates of polyesters, which were constructed with fertilizer ingredients (such as M 2+ and phosphate), exhibit much faster biodegradability than that of the conventional polyesters under controlled soil conditions at 25 °C, while displaying comparable or superior rheological and mechanical properties.

Recyclable and Degradable Ionic-Substituted Long-Chain Polyesters

“…This correlates with Mg being the smallest cation with the highest ionic associations, Ca being similar yet due to the larger ionic radius exhibiting lowered ionic associations, and Zn having a less ionic nature and more covalent character, therefore exhibiting lower Coulombic interaction . This was previously also observed in ionically cross-linked PBAT materials; however, the magnitude of the effect observed herein is much larger …”

“…The presence of sulfonic acid groups in polyesters enables the introduction of other cations via neutralization reactions, as previously demonstrated by Lee et al for PBS- and PBAT-containing phosphate groups . In this study, metal stearates were employed as neutralizing agents.…”

“…33 This was previously also observed in ionically cross-linked PBAT materials; however, the magnitude of the effect observed herein is much larger. 30 Temperature sweep rheology measurements revealed that the strong difference in the melt viscosity prevails throughout the entire temperature range studied (80−180 °C, Figure 3b). No discontinuous changes are observed upon heating in the melt state, showing that the ionic aggregates are present at all temperatures below 180 °C.…”

Dual-Site Polymeric Heterogeneous α-Diimine Ni Catalysts with Tailored Spatial Distribution for Ethylene Polymerization

“…Furthermore, the ABtype spatial distribution resulted in a much higher storage modulus of the melt at a low shear (Figure 6B) compared with the A + B type and the AB homogeneous system, making the former more suitable for manufacturing thin film products than the latter. 64 The influence of mesoscopic spatial distribution on the mechanical properties of polyethylene in-reactor blends was investigated. Compared with A + B, A/B, and B/A types, ABtype spatial distribution leads to better tensile strength, elongation at break, and toughness (Figure 7A−C).…”

“…Among them, the AB -type spatial distribution led to the smallest increase, indicating that the three polyolefin components were well mixed by entanglement at the level of a micro-scale (Figure D). Furthermore, the AB -type spatial distribution resulted in a much higher storage modulus of the melt at a low shear (Figure B) compared with the A + B type and the AB homogeneous system, making the former more suitable for manufacturing thin film products than the latter …”