scholarly journals Effect of Nano-Clay and Surfactant on the Biodegradation of Poly(Lactic Acid) Films

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 311 ◽  
Author(s):  
Pooja C. Mayekar ◽  
Edgar Castro-Aguirre ◽  
Rafael Auras ◽  
Susan Selke ◽  
Ramani Narayan
Keyword(s):  
Molecular Weight ◽  
Lactic Acid ◽  
Direct Measurement ◽  
Significant Variation ◽  
Hydrolytic Degradation ◽  
Poly Lactic Acid ◽  
Nano Clay ◽  
Biodegradation Process ◽  
Organomodified Montmorillonite

This study examined the effect of nanoclays and surfactant on the hydrolytic degradation and biodegradation of poly(lactic acid) (PLA) and PLA nanocomposites. Organomodified montmorillonite (OMMT), unmodified montmorillonite (MMT) and an organomodifier (surfactant) for MMT (QAC) were extruded with PLA to produce PLA nanocomposites. The films were produced with the same initial molecular weight, thickness and crystallinity since these properties have a significant effect on the biodegradation process. The biodegradation experiments were carried out in an in-house built direct measurement respirometric system and were evaluated in inoculated vermiculite and vermiculite media for extended periods of time. Hydrolysis experiments were also conducted separately to decouple the abiotic/hydrolysis phase. The results showed no significant variation in the mineralization of PLA nanocomposites as compared to pristine PLA. The addition of nanoclays did not enhance the biodegradability of PLA when the initial parameters were strictly controlled. The hydrolysis test indicated that the nanoclays and surfactant did not aid in the degradation of PLA.

scholarly journals Hydrolytic Degradation of 3D-Printed Poly (Lactic Acid) Structures

2021 ◽  
Vol 3 (3) ◽  
pp. p17
Author(s):  
Logan Mulderrig ◽  
Franchino Chambers ◽  
Taylor A. Isais ◽  
Richard Jeske ◽  
Yan Li ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Lactic Acid ◽  
Hydrolytic Degradation ◽  
Time Frame ◽  
Deionized Water ◽  
Poly Lactic Acid ◽  
Rapid Decay ◽  
Linear Viscoelastic ◽  
3D Printed ◽  
Broad Molecular Weight Distribution

Hydrolytic degradation of commercially available 3D printing filament, i.e. poly (lactic acid) with broad molecular weight distribution was induced by incubating 3D-printed parts in deionized water at 3 temperatures. Small changes in orthogonal dimensions occurred due to relaxation of printing stresses, but no mass or volume loss were detected over the time-frame of the experiments. Molecular weight decreased while polydispersity remained constant. The most sensitive measure of degradation was found to be nondestructive, small-amplitude oscillatory tensile measurements. A rapid decay of tensile storage modulus was found with an exponential decay time constant of about an hour. This work demonstrates that practical monitoring of commercially available PLA degradation can be achieve with linear viscoelastic measurements of modulus.

scholarly journals A Slow-Release Fertilizer of Urea Prepared via Melt Blending with Degradable Poly(lactic acid): Formulation and Release Mechanisms

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1856
Author(s):  
Mujtahid Kaavessina ◽  
Sperisa Distantina ◽  
Esa Nur Shohih
Keyword(s):  
Molecular Weight ◽  
Lactic Acid ◽  
Slow Release ◽  
Release Kinetics ◽  
Nutrient Balance ◽  
Hydrolytic Degradation ◽  
Poly Lactic Acid ◽  
Release Process ◽  
Slow Release Fertilizer ◽  
Micro Holes

In this research, a low molecular weight poly(lactic acid) (or PLA) synthesized from direct polycondensation was melt compounded with urea to formulate slow-release fertilizer (SRF). We studied the influence of the molecular weight (MW) of PLA as a matrix and the urea composition of SRF towards release kinetics in water at 30 °C. The physical appearance of solid samples, the change in urea concentration, and acidity (pH) of water were monitored periodically during the release test. Three studied empirical models exhibited that diffusion within the matrix dominated the urea release process, especially when the release level was less than 60%. Thus, a lower MW of PLA and a higher urea content of SRF showed a faster release rate. For the entire length of the release experiment, a combination of diffusion and degradation mechanisms exhibited the best agreement with the experimental data. The hydrolytic degradation of PLA may begin after 96 h of immersion (around 60% release level), followed by the appearance of some micro-holes and cracks on the surface of the SRF samples. Generally, this research revealed the good release performance of urea without residues that damage the soil structure and nutrient balance.

Non-toxic polyester urethanes based on poly(lactic acid), poly(ethylene glycol) and lysine diisocyanate

2016 ◽  
Vol 32 (3) ◽  
pp. 225-241 ◽  
Author(s):  
Alena Pavelková ◽  
Pavel Kucharczyk ◽  
Zdenka Kuceková ◽  
Jiří Zedník ◽  
Vladimír Sedlařík
Keyword(s):  
Molecular Weight ◽  
Lactic Acid ◽  
Ethylene Glycol ◽  
Biomedical Applications ◽  
Hydrolytic Degradation ◽  
Chain Extension ◽  
Poly Lactic Acid ◽  
Side Reactions ◽  
Poly Ethylene Glycol ◽  
Poly Ethylene

Poly(lactic acid)-based polymers are highly suitable for temporary biomedical applications, such as tissue support or drug delivery systems. Copolymers of different molecular weight based on poly(lactic acid) and poly(ethylene glycol) were prepared by polycondensation, catalysed by hydrochloric acid. A chain-extension reaction with l-lysine ethyl ester diisocyanate was employed afterwards to obtain polyester urethanes with enhanced properties. The GPC results showed that the molecular weights of the products reached about 50,000 g·mol−1 and the hydrolytic progress was rapid in the first 2 weeks; the drop in Mn equalled approximately 70%. Additionally, elemental analysis of the buffer medium proved that hydrolytic degradation was more rapid in the first stage. Tensile-strength testing revealed that ductility increased alongside reduced molecular weight of poly(ethylene glycol), also suggesting that polymer branching occurred due to side reactions of isocyanate. Based on the envisaged biomedical applications for these polymers, cytotoxicity tests were carried out and the cytotoxic effect was only moderate in the case of 100% polymer extract prepared according to ISO standard 10993-12. In their research, the authors focused on preparing metal-free, catalysed synthesis of polyester urethanes, which could prove useful to numerous biomedical applications.

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.

Morphological behaviour of poly(lactic acid) during hydrolytic degradation

2008 ◽  
Vol 93 (10) ◽  
pp. 1964-1970 ◽  
Author(s):  
Xiaoqing Zhang ◽  
Maria Espiritu ◽  
Alex Bilyk ◽  
Lusiana Kurniawan
Keyword(s):  
Lactic Acid ◽  
Hydrolytic Degradation ◽  
Poly Lactic Acid

Synthesis and hydrolytic degradation of graft copolymers containing poly(lactic acid) side chains

2002 ◽  
Vol 76 (3) ◽  
pp. 411-417 ◽  
Author(s):  
Valérie Langlois ◽  
Karine Vallee-Rehel ◽  
Jean Jacques Peron ◽  
Alain le Borgne ◽  
Michael Walls ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Graft Copolymers ◽  
Hydrolytic Degradation ◽  
Poly Lactic Acid ◽  
Side Chains
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