Synthesis of flexible poly(l-lactide)-b-polyethylene glycol-b-poly(l-lactide) bioplastics by ring-opening polymerization in the presence of chain extender

Abstract

Poly(l-lactide)-b-polyethylene glycol-b-poly(l-lactide) (PLLA-PEG-PLLA) is found to be more flexible than PLLA due to the flexibility of PEG middle blocks. Melt flow and mechanical properties of PLLA-PEG-PLLA were improved through post melt blending with a chain extender (CE). In this work, in situ chain-extended PLLA-PEG-PLLAs were synthesized by ring-opening polymerization in the presence of Joncryl® CE. The influence of CE content (1.0, 2.0, and 4.0 phr) on the gel content, melt flow index (MFI), thermal properties, and mechanical properties of the obtained in situ chain-extended PLLA-PEG-PLLAs was investigated. The gel content of in situ chain-extended PLLA-PEG-PLLA increased while the MFI and degree of crystallinity significantly decreased with increasing CE content. The in situ chain-extended PLLA-PEG-PLLA with 1.0 phr CE showed the best tensile properties. The extensibility of in situ chain-extended PLLA-PEG-PLLA films decreased when the CE contents were higher than 1.0 phr. These in situ chain-extended PLLA-PEG-PLLA films can be used as highly flexible bioplastics.

Phase Morphology, Mechanical, and Thermal Properties of Calcium Carbonate-Reinforced Poly(L-lactide)-b-poly(ethylene glycol)-b-poly(L-lactide) Bioplastics

“…PLLA- b -PEG- b -PLLA block copolymer was synthesized by ring-opening polymerization of L-lactide (LLA) monomer in the presence of a chain extender (2.0 parts per hundred of resin, phr) as described in our previous work [ 21 ]. The block copolymer was synthesized at 165 °C for 6 h under a nitrogen atmosphere using a stannous octoate/PEG mixture as the initiating system.…”

IMPROVEMENT IN MECHANICAL PROPERTIES OF FLEXIBLE POLY(L-LACTIDE)-b-POLYETHYLENE GLYCOL-b-POLY(L-LACTIDE) BIOPLASTIC BY MELT BLENDING WITH BORON NITRIDE

“…Chain-extended PLLA-PEG-PLLA were synthesized through ring-opening polymerization in the bulk of L-lactide monomer under nitrogen atmosphere in the presence of 2 parts per hundred of resin (phr) Joncryl ® ADR4368 as described in our previous work [18]. The Melt flow index of this PLLA-PEG-PLLA at 190˚C under 2.16 kg load was 31 g/10 min.…”

“…The TG curves of pure PLLA-PEG-PLLA are shown in Fig. 4 (black line) indicating that it had two thermal-decomposition steps in ranges 250−350˚C and 350−450˚C assigned to the "unzipping" mechanism at the chain ends of PLLA and thermal decompositions for PEG blocks, respectively [18,27]. The addition of BN did not change thermal-decomposition behaviors of PLLA-PEG-PLLA.…”

The Effect of Mold Conditions on Heat Resistance of Injection-Molded Stereocomplex Polylactide-b-polyethylene Glycol-b-Polylactide Bioplastic

“…It had melt flow index (MFI) of 14 g/10 min (210 o C, 2.16 kg). In situ chain-extended PLLA-PEG-PLLA with MFI of 26 g/10 min (190 o C, 2.16 kg) was synthesized by ring-opening polymerization of L-lactide monomer in the presence of 2.0 phr Joncryl  ADR4368 (chain extender) according to our previous work [30]. PDLA with number-average molecular weight and dispersity index of 90,000 g/mol and 2.8 from GPC respectively, was synthesized as described in our previous work [25].…”