Kinetic parameters estimation of ring-opening poly(lactic acid) polymerization by modeling and simulation

2011 ◽  
Vol 31 (2-3) ◽  
Author(s):  
Rajeev Mehta ◽  
Vineet Kumar ◽  
Sidh Nath Upadhyay
Keyword(s):  
Molecular Weight ◽  
Lactic Acid ◽  
Rate Constants ◽  
Ring Opening ◽  
Numerical Technique ◽  
Kinetic Scheme ◽  
Degree Of Polymerization ◽  
Parameters Estimation ◽  
Polymerization Reaction ◽  
Poly Lactic Acid

Abstract The modeling of ring-opening polymerization of lactide to poly(lactic acid) (PLA) has been carried out. Carothers first synthesized PLA in 1932. Since then, hundreds of research papers and patents have appeared in the literature. However, there is a lack of data concerning the rate constants for initiation, propagation and termination steps of PLA polymerization, except some data about the apparent rate constant. This work investigates, theoretically, the individual rate constants using a simple numerical technique. The progress of lactide polymerization can be modeled by assuming a ring opening reaction mechanism comprising chain initiation, chain propagation, and chain termination. The simulator developed, based on the solutionof differential equations corresponding to the above-mentioned kinetic scheme, Generates a detailed molecular weight distribution that can be used to estimate average molecular weights (or average degree of polymerization) vs. polymerization time curves. These simulated curves, on matching with the reported experimental data (for different catalysts), yield the absolute values of rate constants. The values have been determined for zinc lactate. Rate constants could be determined by using the molecular weight and the polydispersity vs. polymerization data. This methodology offers greater opportunity for capturing high, non-equilibrium polymer yield through appropriately timed termination of the polymerization reaction.

scholarly journals Biodegradable polymer dari asam laktat

2018 ◽  
Vol 6 (2) ◽  
pp. 626
Author(s):  
Irwan Noezar ◽  
V.S. Praptowidodo ◽  
R. Nugraheni ◽  
M.H. Nasution
Keyword(s):  
Molecular Weight ◽  
Lactic Acid ◽  
Biodegradable Polymer ◽  
Gel Permeation Chromatography ◽  
Polymerization Reaction ◽  
Poly Lactic Acid ◽  
Condensation Polymerization ◽  
Purity Analysis ◽  
Gel Permeation ◽  
Degradation Time

The objective of this research is to learn and to make the biodegradable polymer, Poly(lactic acid), from lactic acid by condensation polymerization without catalyst. Poly(lactic acid) that will be produced in this research should have the molecular weight between 3000-5000 grams/mole. The scopes of this research are the_purification of lactic acid, purity analysis, polymerization reaction, and polymer's characteristic analysis. The method of lactic acid purification is distillation in nitrogen atmosphere. Polymerization reaction which is used in this research is the condensation polymerization without catalyst. The polymer's characteristics that will be analyzed are molecular weight and  degradation time Molecular weight is analyzed by viscosimetry method and Gel Permeation Chromatography. Degradation time is analyzed by landfill method Based on this research, purification of D,L-lactic acid (91%-weight) reaches 98%-weight and for L-lactic acid (93%-weight) reaches 96%-berat. Molecular weight of D,L-lactic acid between 450-3600 grams/mole and L-lactic acid between 4200-8500 grams/mole.  The degradation time of polymer is 5 weeks.Keywords: Poly(lactic acid), polymer,  biodegradable AbstrakPenelitian ini bertujuan untuk mempelajari dan mensintesis biodegradable polymer, Poly(lactic acid) dari asam laktat melalui reaksi polimerisasi kondensasi tanpa katalis. Poly(lactic acid) yang dihasilkan dalam penelitian ini diharapkan memiliki berat molekul antara 3000-5000 gram/mol. Ruang lingkup penelitian meliputi pemurnian asam laktat, analisa kemurnian asam laktat, reaksi polimerisasi kondensasi dan karakterisasi polimer. Pemurnian asam laktat dilakukan melalui distilasi pada atmosfer nitrogen dan tekanan 1 atmosfer. Reaksi polimerisasi dilakukan melalui polimerisasi kondensasi tanpa katalis dengan variasi waktu reaksi pengadukan mekanik dan laju pemanasan. Karakteristik polimer yang dianalisis adalah berat molekul dan waktu degradasi. Berat molekul dianalisis dengan metode GPC (Gel Permeation Chromatography) dan viskosimetri. Degradasi polimer dilakukan secara landfill. Berdasarkan hasil percobaan, pemurnian asam laktat untuk monomer D,L-Lacticacid (91%-berat) mencapai 98%-berat sedangkan untuk monomer L-Lactic acid (93%-berat) mencapai 96%-berat. Berat molekul yang dihasilkan untuk monomer D,L-Lactic acid adalah 450 - 3600 gram/mol sedangkan untuk monomer L-Lactic acid adalah 4200- 8500 gram/mol. Waktu degradasi polimer secara landfill adalah 5 minggu.Kata kunci : Poly(lactic acid), polimer, biodegradable

Synthesis and Characterization of Poly(Lactic Acid)-Grafted Natural Rubber by Reactive Melt-Blending Technique

2018 ◽  
Vol 382 ◽  
pp. 7-11
Author(s):  
Yodsathorn Wongngam ◽  
Cattaleeya Pattamaprom
Keyword(s):  
Lactic Acid ◽  
Natural Rubber ◽  
Ring Opening ◽  
Degree Of Polymerization ◽  
Hydroxyl Group ◽  
Synthesis And Characterization ◽  
Poly Lactic Acid ◽  
Esterification Reaction ◽  
Ring Opening Reaction

This study investigated the synthesis and characterization of poly(lactic acid)-grafted natural rubber (PLA-g-NR) in molten state. The grafting was carried out in an internal mixer without and with the presence of tin octoate catalyst (TO). The grafting of lactide onto NR was carried out by using maleic anhydride (MA) as a linker. The FTIR and 1H-NMR spectra revealed new peaks for the MA-grafted NR (NR-g-MA) and PLA indicating that MA was grafted onto NR and that LA was successfully polymerized into PLA. It was also found that MA grafted onto NR could assist as a linker for connecting PLA with NR via esterification reaction between hydroxyl group (OH) at the end chain of PLA and carboxylic group (COOH) from ring opening reaction of MA. Moreover, the decrease of residual LA peak in FTIR spectra suggested that the presence of TO catalyst in the reactive blend promoted higher degree of polymerization of PLA from ring opening reaction of LA.

scholarly journals Poly(lactic Acid): A Versatile Biobased Polymer for the Future with Multifunctional Properties—From Monomer Synthesis, Polymerization Techniques and Molecular Weight Increase to PLA Applications

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1822
Author(s):  
Evangelia Balla ◽  
Vasileios Daniilidis ◽  
Georgia Karlioti ◽  
Theocharis Kalamas ◽  
Myrika Stefanidou ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Lactic Acid ◽  
Chain Extension ◽  
Poly Lactic Acid ◽  
Plastic Pollution ◽  
Practical Applications ◽  
Decomposition Reactions ◽  
Melt Polycondensation ◽  
Polymerization Conditions ◽  
Molecular Weight Increase

Environmental problems, such as global warming and plastic pollution have forced researchers to investigate alternatives for conventional plastics. Poly(lactic acid) (PLA), one of the well-known eco-friendly biodegradables and biobased polyesters, has been studied extensively and is considered to be a promising substitute to petroleum-based polymers. This review gives an inclusive overview of the current research of lactic acid and lactide dimer techniques along with the production of PLA from its monomers. Melt polycondensation as well as ring opening polymerization techniques are discussed, and the effect of various catalysts and polymerization conditions is thoroughly presented. Reaction mechanisms are also reviewed. However, due to the competitive decomposition reactions, in the most cases low or medium molecular weight (MW) of PLA, not exceeding 20,000–50,000 g/mol, are prepared. For this reason, additional procedures such as solid state polycondensation (SSP) and chain extension (CE) reaching MW ranging from 80,000 up to 250,000 g/mol are extensively investigated here. Lastly, numerous practical applications of PLA in various fields of industry, technical challenges and limitations of PLA use as well as its future perspectives are also reported in this review.

scholarly journals Synthesis and Characterization of Polyphosphazenes Modified with Hydroxyethyl Methacrylate and Lactic Acid

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Evelyn Carolina Martínez Ceballos ◽  
Ricardo Vera Graziano ◽  
Gonzalo Martínez Barrera ◽  
Oscar Olea Mejía
Keyword(s):  
Lactic Acid ◽  
Ring Opening ◽  
Room Temperature ◽  
Block Structure ◽  
Ring Opening Polymerization ◽  
Synthesis And Characterization ◽  
Poly Lactic Acid ◽  
Hydroxyethyl Methacrylate ◽  
H Nmr

Poly(dichlorophosphazene) was prepared by melt ring-opening polymerization of the hexachlorocyclotriphosphazene. Poly[bis(2-hydroxyethyl-methacrylate)-phosphazene] and poly[(2-hydroxyethyl-methacrylate)-graft-poly(lactic-acid)-phosphazene] were obtained by nucleophilic condensation reactions at different concentrations of the substituents. The properties of the synthesized copolymers were assessed by FTIR,1H-NMR and31P-NMR, thermal analysis (DSC-TGA), and electron microscopy (SEM). The copolymers have a block structure and show twoTg's below room temperature. They are stable up to a temperature of 100°C. The type of the substituents attached to the PZ backbone determines the morphology of the polymers.

Superhydrophobic functionalization of cutinase activated poly(lactic acid) surfaces

2017 ◽  
Vol 19 (3) ◽  
pp. 816-822 ◽  
Author(s):  
A. Ortner ◽  
A. Pellis ◽  
C. Gamerith ◽  
A. Orcal Yebra ◽  
D. Scaini ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Enzymatic Hydrolysis ◽  
Ring Opening ◽  
Superhydrophobic Surfaces ◽  
Poly Lactic Acid ◽  
Hydrolysis Of

Controlled enzymatic hydrolysis of PLA surfaces, followed by ring opening of AKD, leads to superhydrophobic surfaces (WCA >150°).

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