Boosting PLA melt strength by controlling the chirality of co-monomer incorporation

Abstract

Bio-based and degradable polymers such as poly(lactic acid) (PLA), have become prominent. In spite of encouraging features, PLA has a low melt strength and melt elasticity, resulting in processing and...

Liquid PEG4‐PLLA copolymers: Effect of chirality and molecular weight on mechanical properties

“…PEG 4 -PDLLA-4k demonstrated Newtonian behavior at low shear rates, with a viscosity of 44 Pa s, but as shear rates increased, minor shear thinning was observed, with a final value of 38 Pa s. PEG 4 -PLLA-4k presented pronounced viscosity throughout the entire shear rate range, from 1250 to around 50 Pa s. The positive effect of Mw on viscosity has been established in polymer melts [19][20][21]. However, unlike previous works in which the L:D ratio in the PLA segment showed minor differences,[21][22][23] PEG 4 -PDLLA-4k…”

Development and Characterization of PLA Composites with High Contents of a Brazilian Refractory Clay and Improved Fire Performance

“…The polymer matrix used was PLA (Ingeo TM Biopolymer 7001D) from NatureWorks LLC, USA, with specific density of 1.24 g/cm 3 , melt flow index (MFI) of 6.0 g/10min (210 °C/2.16 kg), M w of 83,300 g/mol and 1.5% of D-isomer 30 .…”

“…In Brazil, deposits of RC are spread over the states of Minas Gerais, São Paulo and Santa Catarina; in Poços de Caldas region (Minas Gerais), it is found a highly refractory non-plastic clay, with high alumina content (about 52%), surface area of 37.32 m 2 /g, but without a proper use due to its lack of moldability 30 . Thus, the aim of this research is to produce PLA/refractory clay biocomposites to face the PLA limitations in terms of flammability and also to make the final material cheaper than neat PLA, without degrading the mechanical and thermal properties of the polymeric matrix; for this purpose, clay contents higher than those commonly seen in literature (up to 5 wt%) should be used; also, it is believed that the highly refractory clay can have an interesting effect on the composite flame retardance; it is worth mentioning that no surface treatment was employed in order to understand the real role of the clay refractoriness on flammability, thermal and mechanical results and to prevent any costs increase.…”

Progress of 3D Bioprinting in Organ Manufacturing

“…The final metabolic products are carbon dioxide and water, which can be eliminated from the bodys [ 122 , 123 , 124 ]. PLA has many advantages in organ 3D pringing, such as good thermal stability, water/solvent/bacteria resistance, excellent gloss, transparency, and flame retardancy [ 125 ].…”