Reduction of molar mass loss and enhancement of thermal and rheological properties of recycled poly(lactic acid) by using chain extenders obtained from RAFT chemistry

2020 ◽  
Vol 153 ◽  
pp. 104628
Author(s):  
Juan José Benvenuta-Tapia ◽  
Eduardo Vivaldo-Lima
Keyword(s):  
Lactic Acid ◽  
Mass Loss ◽  
Rheological Properties ◽  
Molar Mass ◽  
Poly Lactic Acid ◽  
Chain Extenders

scholarly journals Improving Recycled Poly(lactic Acid) Biopolymer Properties by Chain Extension Using Block Copolymers Synthesized by Nitroxide-Mediated Polymerization (NMP)

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2791
Author(s):  
Juan José Benvenuta-Tapia ◽  
Pascale Champagne ◽  
José Alfredo Tenorio-López ◽  
Eduardo Vivaldo-Lima ◽  
Ramiro Guerrero-Santos
Keyword(s):  
Lactic Acid ◽  
Block Copolymers ◽  
Molar Mass ◽  
Average Molecular Weight ◽  
Melt Processing ◽  
Cold Crystallization ◽  
Chain Extension ◽  
Poly Lactic Acid ◽  
Chain Extenders ◽  
Nitroxide Mediated Polymerization

The aim of this contribution is to assess the use poly(styrene-co-glycidyl methacrylate-b-styrene) copolymers synthesized by nitroxide mediated polymerization (NMP) as chain extenders in the recycling of poly(lactic acid) biopolyester. Concisely, the addition of such block copolymers during the melt processing of recycled poly(lactic acid) (rPLA) leads to important increases in the viscosity average molecular weight of modified polymeric materials. Molar masses increase from 31,000 g/mol for rPLA to 48,000 g mol−1 for the resulting rPLA/copolymer blends (bPLA). Fortuitously, this last value is nearly the same as the one for pristine PLA, which constitutes a first piece of evidence of the molar mass increase of the recycled biopolymer. Thermograms of chain extended rPLA show significant decreases in cold crystallization temperature and higher crystallinity degrees due to the chain extension process using NMP-synthesized copolymers. It was found that increasing epoxide content in the NMP-synthesized copolymers leads to increased degrees of crystallinity and lower cold crystallization temperatures. The rheological appraisal has shown that the addition of NMP synthesized copolymers markedly increases complex viscosity and elastic modulus of rPLA. Our results indicate that P(S-co-GMA)-b-S) copolymers act as efficient chain extenders of rPLA, likely due to the reaction between the epoxy groups present in P(S-co-GMA)-b-PS and the carboxyl acid groups present in rPLA. This reaction positively affects viscometric molar mass of PLA and its performance.

Microcellular foaming of poly(lactic acid) branched with food‐grade chain extenders

2021 ◽  
Vol 138 (29) ◽  
pp. 50686
Author(s):  
Krishnaa B. Venkatesan ◽  
Sonal S. Karkhanis ◽  
Laurent M. Matuana
Keyword(s):  
Lactic Acid ◽  
Poly Lactic Acid ◽  
Food Grade ◽  
Microcellular Foaming ◽  
Chain Extenders

Rheological Properties of Starch-Based Materials and Starch/Poly(lactic acid) Blends

2007 ◽  
Vol 249-250 (1) ◽  
pp. 529-534 ◽  
Author(s):  
Fengwei Xie ◽  
Tao Xue ◽  
Long Yu ◽  
Ling Chen ◽  
Xiaoxi Li ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Rheological Properties ◽  
Poly Lactic Acid

Thermal, mechanical and rheological properties of poly (lactic acid)/epoxidized soybean oil blends

2008 ◽  
Vol 62 (1) ◽  
pp. 91-98 ◽  
Author(s):  
Fathilah Ali ◽  
Young-Wook Chang ◽  
Shin Choon Kang ◽  
Joon Yong Yoon
Keyword(s):  
Lactic Acid ◽  
Soybean Oil ◽  
Rheological Properties ◽  
Epoxidized Soybean Oil ◽  
Poly Lactic Acid ◽  
Oil Blends

The role of multiwall carbon nanotubes on physical, mechanical and rheological properties of poly(lactic acid)/natural rubber/CNT hybrid systems

2020 ◽  
pp. 096739112093135
Author(s):  
Mohammad Mahdi Salehi ◽  
Fatemeh Hakkak
Keyword(s):  
Lactic Acid ◽  
Natural Rubber ◽  
Rheological Properties ◽  
Droplet Size ◽  
Multiwall Carbon Nanotubes ◽  
Droplet Size Distribution ◽  
Hybrid Nanocomposites ◽  
Poly Lactic Acid ◽  
Melt Mixing

The main objective of the present work was to study the role of carbon nanotube (CNT) on the microstructure development and physical, mechanical, and rheological properties of poly(lactic acid) (PLA)/natural rubber (NR)/CNT hybrid nanocomposites. The PLA/NR blend samples with constant blend ratio (90/10) were prepared by melt mixing in a laboratory internal mixer at a temperature of 190°C. The behavior of the PLA/NR blend was examined depending on the CNT content (0.5–6 wt%). The droplet size and droplet size distribution of the NR phase decreases with the increase in CNTs content. This could be explained in terms of compatibilizing effect of CNT and the changing of the viscosity ratio of the blend phases. The development of the microstructure and the physical properties of the blend were also investigated according to the CNT contents by measuring the linear viscoelasticity. The elongational behavior and mechanical properties of the blends were strongly dependent on the location of the CNT. The CNT worked as an efficient compatibilizer and also it worked as a reinforcing filler making the matrix more rigid.

Rheological Properties of Poly(Lactic Acid)

2019 ◽  
pp. 203-225
Author(s):  
Lee Tin Sin ◽  
Bee Soo Tueen
Keyword(s):  
Lactic Acid ◽  
Rheological Properties ◽  
Poly Lactic Acid

Effect of Size on Degradation of Porous Poly(Lactic Acid) Scaffold

2011 ◽  
Vol 311-313 ◽  
pp. 1741-1745
Author(s):  
Chao Guo ◽  
Xiao Bo Sheng ◽  
Cheng Lin Chu ◽  
Yin Sheng Dong
Keyword(s):  
Molecular Weight ◽  
Lactic Acid ◽  
Mass Loss ◽  
Porous Scaffold ◽  
Repeat Unit ◽  
Poly Lactic Acid ◽  
Porous Scaffolds ◽  
Degradation Behaviors ◽  
The Difference ◽  
Autocatalytic Effect

Poly (lactic acid) (PLA) scaffolds with different sizes are often fabricated for various requirements. A cellular automaton simulation was used to investigate the effect of the size on the degradation behaviors of porous PLA scaffolds. Four porous PLA scaffolds with 90% initial porosity and different sizes were established by a novel repeat unit method. Mass loss and the change in molecular weight during the degradation were simulated. The results indicate that mass loss is related to the size of the porous scaffold while molecular weight change is independent on the size. With the size of the porous scaffold increasing, the mass loss increases while the difference in mass loss between the scaffolds with different sizes decreases. All these changes can be attributed to the difference in the autocatalytic effect and corresponding oligomer diffusion ability of the porous scaffolds with different sizes.

Rheological Properties of Poly(lactic acid) Modified by Contents of Epoxy Group in Chain Extender

Polymer Korea ◽  
2018 ◽  
Vol 42 (3) ◽  
pp. 394-399
Author(s):  
Jae O Park ◽  
Woo Jin Choi ◽  
Kwang Je Kim ◽  
Jae Heung Lee ◽  
Jae Sup Shin
Keyword(s):  
Lactic Acid ◽  
Rheological Properties ◽  
Epoxy Group ◽  
Chain Extender ◽  
Poly Lactic Acid
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