In order to take advantage of the sustainability and environmental friendliness of a biobased poly(lactide) (PLA), it was used with natural rubber graft-modified glycidyl methacrylate (NR-GMA), via bulk free radical polymerization, to produce a new thermoplastic vulcanizate (TPV) by in situ dynamical vulcanization. The well-dispersed super-tough PLA-based thermoplastic vulcanizate with 20 wt % NR-GMA exhibited a greatly improved notched impact strength of 73.4 kJ/m2 and elongation yield of 136%, which represented a 26- and 33-fold increase, respectively, compared to neat PLA. Interfacial reactive compatibilization between the PLA matrix and NR-GMA phase was confirmed by Fourier transform infrared spectroscopy (FT-IR) and dynamic mechanical analysis (DMA) and differential scanning (DSC) measurements. This strong interfacial interaction, in combination with a fine microscale and nanoscale dispersed phase structure, were responsible for the high toughness of PLA/NR-GMA TPV. These new PLA-based vulcanizates have the potential for application in electrical devices, packaging, and 3D printing materials.Keywords: Dynamic vulcanization; Interfacial reaction; Modification; PLA/NR; Super-tough;

Surface microencapsulated aluminum hypophosphite (SiAHP) was successfully prepared via the condensation polymerization of N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane. The notched impact strength of the ABS/SiAHP composites was significantly enhanced compared to the corresponding ABS/AHP composites because the microencapsulated SiAHP improved the compatibility of SiAHP and the ABS matrix, and the vertical burning rate of the ABS composite with only 22.0 wt% SiAHP achieved V-0. The cone calorimeter tests demonstrated that the peak heat release rate (PHRR) and peak smoke production rate (PSPR) values of the ABS/22 wt% SiAHP composite were decreased by 81.1% and 49.5%, respectively, compared to those of the ABS/22 wt% AHP composite. Moreover, the total heat release (THR) and the total smoke production (TSR) values of the ABS/SiAHP composites were all lower than those of the ABS/AHP composites. These results clearly indicated that the silicone microencapsulation modification of SiAHP not only enhanced the flame retardancy efficiency of the FR ABS/SiAHP composite but also effectively restrained the smoke production rate of the ABS. A comparison of digital photographs and SEM images of the residues of the ABS/AHP and ABS/SiAHP composites after the cone calorimeter tests revealed that the residue of the ABS/SiAHP composites exhibited a denser and more compact surface char layer structure than that of the ABS/AHP composite. Energy-dispersive X-ray spectroscopy (EDS) measurement indicated that SiAHP more effectively promoted the carbon formation in the FR ABS composite at the surface compared to AHP. The three-dimensional compact char layer network containing C and Si effectively improved the flame retardancy of the ABS/SiAHP composite. Therefore, the flame retardancy of the ABS/SiAHP composite was attributed more to condensed-phase mechanisms than the flame retardancy of the ABS/AHP composite.

The crystallization of poly(l-lactide acid) (PLLA) ultrathin films induced by different solvents was investigated using reflection–absorption infrared (RAIR) spectroscopy and atomic force microscopy (AFM). Irregular PLLA dendrite lamellae grew in the flat-on orientation with dichloromethane solvent before being redissolved after longer induction times owing to the strong interaction between the PLLA segments and solvent molecules. Faster formation of PLLA spherulites was induced with acetone than with dichloromethane, and these remained unchanged with increasing induction time because of the polarity difference between the PLLA segments and acetone molecules. PLLA ultrathin films could not be induced to crystallize using chloroform because of the very strong interactions between the chloroform (CHCl3) molecules and PLLA amorphous chains, which caused the CHCl3 solvent molecules to rapidly permeate the PLLA random coils and dissolve the amorphous chains. These phenomena are attributed to solvent-specific competition between solvent-induced crystallization and dissolution effects in PLLA ultrathin films, which ultimately leads to the higher degree of crystallinity obtained with acetone than with dichloromethane.

•Super-tough PLA/PBAT/EMA-GMA multicomponent blends were achieved.•Core-shell dispersed phase microstructure was found in super-tough PLA/PBAT blend.•Interfacial reaction was responsible for super-tough PLA/PBAT/EMA-GMA blends.Poly(lactide) (PLA)/poly(butylene-adipate-co-terephtalate) (PBAT) blends containing varying amounts of ethylene-methyl acrylate-glycidyl methacrylate copolymer (EMA-GMA) are prepared through reactive melt-blending to improve toughness. A super-tough PLA/PBAT/EMA-GMA multicomponent blend (75 wt%:10 wt%:15 wt%) exhibits a significantly improved notched impact strength of 61.9 ± 2.7 kJ/m2, nearly 13 times higher than those of PLA/10 wt%PBAT binary blend, respectively. A special core-shell like dispersed phase microstructure involving PBAT particles and EMA-GMA phase at the cryofractured surface of the PLA blends is observed by Scanning Electron Microscopy (SEM). The strong interfacial adhesion and enormous shear-yielding deformation of the PLA matrix with the dispersed phases are responsible for the super-toughened effect exhibited by the PLA/PBAT/EMA-GMA blends.