Publication detail

High-Pressure Depolymerization of Poly(lactic acid) (PLA) and Poly(3-hydroxybutyrate) (PHB) Using Bio-Based Solvents: A Way to Produce Alkyl Esters Which Can Be Modified to Polymerizable Monomers

JAŠEK, V. FUČÍK, J. IVANOVÁ, L. VESELÝ, D. FIGALLA, S. MRAVCOVÁ, L. SEDLÁČEK, P. KRAJČOVIČ, J. PŘIKRYL, R.

Original Title

High-Pressure Depolymerization of Poly(lactic acid) (PLA) and Poly(3-hydroxybutyrate) (PHB) Using Bio-Based Solvents: A Way to Produce Alkyl Esters Which Can Be Modified to Polymerizable Monomers

Type

journal article in Web of Science

Language

English

Original Abstract

The polyesters poly(lactic acid) (PLA) and poly(3-hydroxybutyrate) (PHB) used in various applications such as food packaging or 3D printing were depolymerized by biobased aliphatic alcohols—methanol and ethanol with the presence of para-toluenesulphonic acid (p-TSA) as a catalyst at a temperature of 151 °C. It was found that the fastest depolymerization is reached using methanol as anucleophile for the reaction with PLA, resulting in the value of reaction rate constant (k) of 0.0425 min−1 and the yield of methyl lactate of 93.8% after 120 min. On the other hand, the value of constant k for the depolymerization of PHB in the presence of ethanol reached 0.0064 min−1 and the yield of ethyl 3-hydroxybutyrate was of 76.0% after 240 min. A kinetics study of depolymerization was performed via LC–MS analysis of alkyl esters of lactic acid and 3-hydroxybutanoic acid. The structure confirmation of the products was performed via FT-IR, MS, 1H NMR, and 13C NMR. Synthesized alkyl lactates and 3-hydroxybutyrates were modified into polymerizable molecules using methacrylic anhydride as a reactant and potassium 2-ethylhexanoate as a catalyst at a temperature of 80 °C. All alkyl esters were methacrylated for 24 h, guaranteeing the quantitative yield (which in all cases reached values equal to or of more than 98%). The methacrylation rate constants (k′) were calculated to compare the reaction kinetics of each alkyl ester. It was found that lactates reach afaster rate of reaction than 3-hydroxybutyrates. The value of k′ for themethacrylated methyl lactate reached 0.0885 dm3/(mol·min). Opposite to this result, methacrylated ethyl 3-hydroxybutyrate’s constant k′ was 0.0075 dm3/(mol·min). The reaction rate study was conducted by the GC-FID method and the structures were confirmed via FT-IR, MS, 1H NMR, and 13C NMR.

Keywords

poly(lactic acid); poly(3-hydroxybutyrate); depolymerization; alcoholysis; methacrylation; polymerizable monomers; kinetics

Authors

JAŠEK, V.; FUČÍK, J.; IVANOVÁ, L.; VESELÝ, D.; FIGALLA, S.; MRAVCOVÁ, L.; SEDLÁČEK, P.; KRAJČOVIČ, J.; PŘIKRYL, R.

Released

1. 12. 2022

Publisher

MDPI

Location

Switzerland

ISBN

2073-4360

Periodical

Polymers

Year of study

14

Number

23

State

Swiss Confederation

Pages from

1

Pages to

18

Pages count

18

URL

https://www.mdpi.com/2073-4360/14/23/5236

Full text in the Digital Library

http://hdl.handle.net/11012/208729

BibTex

@article{BUT180377,
  author="Vojtěch {Jašek} and Jan {Fučík} and Lucia {Ivanová} and Dominik {Veselý} and Silvestr {Figalla} and Ludmila {Mravcová} and Petr {Sedláček} and Jozef {Krajčovič} and Radek {Přikryl}",
  title="High-Pressure Depolymerization of Poly(lactic acid) (PLA) and Poly(3-hydroxybutyrate) (PHB) Using Bio-Based Solvents: A Way to Produce Alkyl Esters Which Can Be Modified to Polymerizable Monomers",
  journal="Polymers",
  year="2022",
  volume="14",
  number="23",
  pages="1--18",
  doi="10.3390/polym14235236",
  issn="2073-4360",
  url="https://www.mdpi.com/2073-4360/14/23/5236"
}