Fully Biobased and Supertough Polylactide-Based Thermoplastic Vulcanizates Fabricated by Peroxide-Induced Dynamic Vulcanization and Interfacial Compatibilization

Abstract

A fully biobased and supertough thermoplastic vulcanizate (TPV) consisting of polylactide (PLA) and a biobased vulcanized unsaturated aliphatic polyester elastomer (UPE) was fabricated via peroxide-induced dynamic vulcanization. Interfacial compatibilization between PLA and UPE took place during dynamic vulcanization, which was confirmed by gel measurement and NMR analysis. After vulcanization, the TPV exhibited a quasi cocontinuous morphology with vulcanized UPE compactly dispersed in PLA matrix, which was different from the pristine PLA/UPE blend, exhibiting typically phase-separated morphology with unvulcanized UPE droplets discretely dispersed in matrix. The TPV showed significantly improved tensile and impact toughness with values up to about 99.3 MJ/m(3) and 586.6 J/m, respectively, compared to those of 3.2 MJ/m(3) and 16.8 J/m for neat PLA, respectively. The toughening mechanisms under tensile and impact tests were investigated and deduced as massive shear yielding of the PLA matrix triggered by internal cavitation of VUPE. The fully biobased supertough PLA vulcanizate could serve as a promising alternative to traditional commodity plastics.

Fully bio-based, highly toughened and heat-resistant poly(L-lactide) ternary blends via dynamic vulcanization with poly(D-lactide) and unsaturated bioelastomer

“…7 shows the SEM micrographs of cryo-fractured surfaces of both regular and annealed injection molded samples. Although phase-separated morphology is observed for all the samples, no obvious gaps between dispersed VUB and polylactide matrix could be observed, indicating strong interfacial adhesion between VUB and the matrix due to the interfacial compatibilization [30]. It is hard to discriminate VUB phase from the matrix for regular injection molded PLLA/VUB binary ( Fig.…”

“…Succinic acid (SA), adipic acid (AA), 1,4-butanediol (BDO), tetraisopropyl titanate (TIPT), hydroquinone monomethyl ether (MEHQ) and dicumyl peroxide (DCP) were all obtained from Kelong Chemical Factory (Chengdu, China). UBE with M w and PDI of 1.79×10 5 g mol −1 and 3.24 was prepared from condensation polymerization of SA, AA, IA, and BDO with mole ratio of 0.35/0.55/0.10/1.05 with 0.05 wt.% MEHQ and 0.1 wt.% TIPT as the inhibitor and catalyst, respectively, according to the procedure reported previously [30]. All chemicals were used without purification, and PLLA, PDLA and UBE were vacuum dried at 80°ʠ prior to further processing.…”

“…It is worth noting that the sustainability of PLLA was compromised since most elastic polymers in previous studies were prepared from non-renewable feedstocks [19,25,28,29]. In this sense, some sustainable elastomers such as natural rubber, epoxidized natural rubber, and bioelastomer have gained much attention in fabricating fully sustainable supertough PLLA via dynamic vulcanization [22,24,30,31].…”

“…In our previous study, we prepared an unsaturated bioelastomer (UBE) by condensation polymerization of renewable dicarboxylic acids and diols and fabricated a fully sustainable and supertough PLLA blend by dynamical vulcanization with the UBE [30]. In this study, we report a ternary blend consisting of PLLA, PDLA, and vulcanized unsaturated bioelastomer (VUB) by dynamic vulcanization with the aim of enhancing the crystallization rate and heat resistance of the fully sustainable and supertough blend.…”

Properties and medical applications of polylactic acid: A review

“…In addition, a ternary blend consisting of PLA, PC, and poly(butylene adipate-coterephthalate) (PBAT) was fabricated to obtain a novel material with unique properties including high toughness and good biodegradability [37]. Recently, a bio-based vulcanized unsaturated aliphatic polyester elastomer (UPE) was used to fabricate a super-tough thermoplastic blends containing PLA [30,38]. The results showed that the interfacial compatibilizations between PLA and UPE would lead to improved tensile and impact toughness with values up to ~99 MJ/m 3 and ~586 J/m, respectively, as compared to those of ~3.2 MJ/m 3 and ~16.8 J/m for neat PLA, respectively.…”