Highly compatible PLA plasticizers were prepared using lactide, which demonstrated “double green” based on renewability and biodegradation, and “dual performances” including flexible and elastomeric behaviors.

A series of [poly­(l-lactide)–poly­(dimer acid methyl ester-alt-poly­(propylene glycol))–poly­(l-lactide)] n (PLLA–PDP–PLLA) n multiblock copolymers was synthesized in a three-step procedure: PLLA–PDP–PLLA (LDPL) triblock copolymers were synthesized using ring-opening polymerization of l-lactide with PDP macroinitiators, which was prepared via step-growth melt polycondensation based on biodiesel and macro-diol, followed by chain extension of the LDPL triblock with 4,4′-methylenebis­(phenyl isocyanate). Molecular characterization revealed that the synthetic procedures yielded the desired triblock and multiblock copolymers (f PLLA = 0.22–0.27). The relationship between thermal behavior and morphology indicated microphase separation into two domains in both the triblocks and multiblocks. Compared to previously reported triblocks with a high molar mass and PLLA hard blocks with inaccessible order–disorder transition temperature (T ODT) values, the multiblock architectures in this study were found to become disordered at much lower temperatures (T ODT = 82–128 °C). To prepare (LDPL) n multiblocks, coupling low-molar-mass LDPL triblocks without free-standing thin films led to dramatically enhanced tensile properties. The self-adhesive performance of the pressure-sensitive adhesive (PSA) system including the multiblocks was evaluated, showing a peel strength of 3.1 N cm–1, a probe tack of 1.9 N, and static shear strength of >50 000 min, which are values comparable to those of current PSAs. These biodiesel-based thermoplastic elastomers hold promise for sustainability and high value-added economy.

Sustainable, mechanically reinforced, and hydrolytically degradable thermoset elastomers were synthesized by one-pot, three-step synthesis & crosslinking.

A sustainable nanofabrication approach is developed for isolating hybrid nanocelluloses (Hy-NCs) comprised of both long flexible fibers (CNFs) and needle-like crystals (CNCs) from a hardwood wet pulp (WP) using electron-beam irradiation (EBI). The method was applied to prepare spray-dried powders that could be transparently redispersed. As a result, the disassociated wet pulps had increased carboxylate contents of 0.04−0.12 mmol g −1 compared to the initial wet pulps and the corresponding dried pulps. The irradiated pulp was subsequently disintegrated by alkaline high-pressure homogenization to form stable Hy-NC dispersions which retained background transparency due to the considerable negative surface charges of −34 to −38 mV. The resulting NC-WP-E0500 and NC-WP-E1000 dispersions were prepared in two mixtures with CNF/CNC ratios of 68/32 and 33/67, based on a 700 nm length to determine CNF and CNC, with the average lengths of 927 ± 512 and 653 ± 382 nm, respectively. NC-WP-E1000 was neutralized with CO 2 , spray-dried to prepare dehydrated products, and was clearly redispersible. We also studied oilin-water (O/W) Pickering emulsions formed by the Hy-NC particles, observed by merged confocal and SEM images. NC-WP-E1000 promoted monodispersed oil droplets of around 2.6 μm where bimodal distribution converged, which remained stable even when creaming force was applied for highly concentrated (dense) emulsion applications. This could be attributed both to the degree of viscoelastic thickening and depletion stabilization by the still repulsive and nonabsorptive CNFs in the continuous phase and the absorption caused by CNC layer at the O/W interfaces in the emulsions.

A series of semicrystalline-glassy (poly(amide11)–poly(lactide)) n (PA11–PLA) n multiblock copolymers with >97% renewable carbon content were developed for tough PLA. The resulting copolymers exhibited superior mechanical performance, comparable to those of commercial PA11 and PLA. Amine-terminated PA11 with a M n,NMR of 12 kg mol–1 was prepared by bulk self-condensation and subsequently capped with only one LA molecule through mechanochemical ball milling, to produce HO–LA–PA11–LA–OH. After adding Sn(Oct)2, unreacted LA was propagated in one-pot by ring-opening polymerization to make PLA–PA11–PLA with a f PLA of 0.5–0.8. The hydroxyl-telechelic triblocks were also coupled with diisocyanate by ball milling to manufacture (PA11–PLA) n multiblocks. The well-defined molecular structures demonstrated controlled PA11 and PLA lengths. Thermal analysis determined the phase separation of PA11 and PLA based on T g,PLA (48–56 °C) and T m,PA11 (183–186 °C) and confirmed the two transitions of thermal degradation (T d). SAXS profiles of the multiblocks also verified their microphase-separated morphologies. The temperature dependence of χ for the PA11–PLA system, χPA11–PLA = (426.00 ± 4.81)/T – (0.90 ± 0.01), simply represented as 0.24 and 0.13 at 100 and 140 °C, was estimated using the T ODT values obtained from the DMA of three symmetric PLA–PA11–PLA triblocks with a f PLA of 0.5. The resulting semicrystalline-glassy multiblocks showed superior tensile characteristics, merging PLA-originated initial modulus and yield stress (E = 758–903 MPa and σyield = 57–63 MPa), and a PA11-derived toughening even with strain hardening (εb = 380–500%, σb = 40–51 MPa, and γ = 124–171 MJ m–3). These results show promising potential for polymeric materials with sustainability and strength-toughness balance.