Degradation of Polylactic Acid Using Sub-Critical Water for Compost

Polylactic acid (PLA) is expected to replace many general-purpose plastics, especially those used for food packaging and agricultural mulch. In composting, the degradation speed of PLA is affected by the molecular weight, crystallinity, and microbial activity. PLA with a molecular weight of less than 10,000 has been reported to have higher decomposition rates than those with higher molecular weight. However, PLA degradation generates water-soluble products, including lactic acid, that decrease the pH of soil or compost. As acidification of soil or compost affects farm products, their pH should be controlled. Therefore, a method for determining suitable reaction conditions to achieve ideal decomposition products is necessary. This study aimed to determine suitable reaction conditions for generating preprocessed PLA with a molecular weight lower than 10,000 without producing water-soluble contents. To this end, we investigated the degradation of PLA using sub-critical water. The molecular weight and ratio of water-soluble contents (WSCs) affecting the pH of preprocessed products were evaluated through kinetic analysis, and crystallinity was analyzed through differential scanning calorimetry. Preprocessed PLA was prepared under the determined ideal conditions, and its characteristics in soil were observed. The results showed that the crystallization rate increased with PLA decomposition but remained lower than 30%. In addition, the pH of compost mixed with 40% of preprocessed PLA could be controlled within pH 5.4–5.5 over 90 days. Overall, soil mixed with the preprocessed PLA prepared under the determined ideal conditions remains suitable for plant growth.

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Effect of DMPA and Molecular Weight of Polyethylene Glycol on Water-Soluble Polyurethane

Polymers ◽

10.3390/polym11121915 ◽

2019 ◽

Vol 11 (12) ◽

pp. 1915 ◽

Cited By ~ 2

Author(s):

Eyob Wondu ◽

Hyun Woo Oh ◽

Jooheon Kim

Keyword(s):

Molecular Weight ◽

Contact Angle ◽

Polyethylene Glycol ◽

Photoelectron Spectroscopy ◽

Water Solubility ◽

Soft Segment ◽

Water Soluble ◽

Size Exclusion ◽

Resonance Spectroscopy ◽

Scanning Calorimetry

In this study water-soluble polyurethane (WSPU) was synthesized from isophorone diisocyanate (IPDI), and polyethylene glycol (PEG), 2-bis(hydroxymethyl) propionic acid or dimethylolpropionic acid (DMPA), butane-1,4-diol (BD), and triethylamine (TEA) using an acetone process. The water solubility was investigated by solubilizing the polymer in water and measuring the contact angle and the results indicated that water solubility and contact angle tendency were increased as the molecular weight of the soft segment decreased, the amount of emulsifier was increased, and soft segment to hard segment ratio was lower. The contact angle of samples without emulsifier was greater than 87°, while that of with emulsifier was less than 67°, indicating a shift from highly hydrophobic to hydrophilic. The WSPU was also analyzed using Fourier transform infrared spectroscopy (FT-IR) to identify the absorption of functional groups and further checked by X-ray photoelectron spectroscopy (XPS). The molecular weight of WSPU was measured using size-exclusion chromatography (SEC). The structure of the WSPU was confirmed by nuclear magnetic resonance spectroscopy (NMR). The thermal properties of WSPU were analyzed using thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC).

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Multifunctional PLA Blends Containing Chitosan Mediated Silver Nanoparticles: Thermal, Mechanical, Antibacterial, and Degradation Properties

Nanomaterials ◽

10.3390/nano10010022 ◽

2019 ◽

Vol 10 (1) ◽

pp. 22 ◽

Cited By ~ 8

Author(s):

Agueda Sonseca ◽

Salim Madani ◽

Gema Rodríguez ◽

Víctor Hevilla ◽

Coro Echeverría ◽

...

Keyword(s):

Thermal Stability ◽

Silver Nanoparticles ◽

Lactic Acid ◽

Food Packaging ◽

Synthesis Method ◽

Crystallization Rate ◽

Poly Lactic Acid ◽

Scanning Calorimetry ◽

The Matrix ◽

Degradation Properties

Poly(lactic acid) (PLA) is one of the most commonly employed synthetic biopolymers for facing plastic waste problems. Despite its numerous strengths, its inherent brittleness, low toughness, and thermal stability, as well as a relatively slow crystallization rate represent some limiting properties when packaging is its final intended application. In the present work, silver nanoparticles obtained from a facile and green synthesis method, mediated with chitosan as a reducing and stabilizing agent, have been introduced in the oligomeric lactic acid (OLA) plasticized PLA in order to obtain nanocomposites with enhanced properties to find potential application as antibacterial food packaging materials. In this way, the green character of the matrix and plasticizer was preserved by using an eco-friendly synthesis protocol of the nanofiller. The X-ray diffraction (XRD) and differential scanning calorimetry (DSC) results proved the modification of the crystalline structure as well as the crystallinity of the pristine matrix when chitosan mediated silver nanoparticles (AgCH-NPs) were present. The final effect over the thermal stability, mechanical properties, degradation under composting conditions, and antimicrobial behavior when AgCH-NPs were added to the neat plasticized PLA matrix was also investigated. The obtained results revealed interesting properties of the final nanocomposites to be applied as materials for the targeted application.

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Thermal characterization of novel aliphatic polyesters with ether and thioether linkages

e-Polymers ◽

10.1515/epoly.2010.10.1.934 ◽

2010 ◽

Vol 10 (1) ◽

Cited By ~ 1

Author(s):

M. Soccio ◽

N. Lotti ◽

L. Finelli ◽

A. Munari

Keyword(s):

Thermal Stability ◽

Molecular Weight ◽

Chemical Structure ◽

Room Temperature ◽

Crystallization Rate ◽

Thermal Characterization ◽

Scanning Calorimetry ◽

Aliphatic Polyesters ◽

Good Thermal Stability

AbstractSeveral novel ether or thioether linkage containing aliphatic polyesters and poly(alkylene dicarboxylate)s were synthesized for comparison and characterized in terms of chemical structure and molecular weight. The thermal behavior was examined by thermogravimetric analysis and differential scanning calorimetry. All the polymers showed a good thermal stability, even though lower for the ether or thioether linkage-containing polyesters. The decrement of the thermal stability appears to be more relevant in the case of the presence of sulphur atoms. At room temperature the samples appeared semicrystalline, except PTTDG and PDEDG, which were viscous oils; the effect of the introduction of ether or thioether group was an increment of the Tgvalue, a decrement of the melting temperature and a significant decrease of the crystallization rate. The entity of the variations was found to be affected by the kind of group introduced, and the trend observed can be explained on the basis of atom electronegativity and dimensions

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Novel Templated Polyphenol for Ionic Conductivity

MRS Proceedings ◽

10.1557/proc-702-u6.6.1 ◽

2001 ◽

Vol 702 ◽

Author(s):

Ferdinando F. Bruno ◽

Ramaswamy Nagarajan ◽

Jayant Kumar ◽

Lynne A. Samuelson

Keyword(s):

Molecular Weight ◽

Ionic Conductivity ◽

High Molecular Weight ◽

Polyethylene Oxide ◽

Phenol Formaldehyde ◽

Industrial Applications ◽

Water Soluble ◽

Reaction Conditions ◽

Water Solvent ◽

Potential Use

ABSTRACTPhenolic polymers and phenol formaldehyde resins are of great interest for a number of electronic and industrial applications. Unfortunately, the toxic nature of the starting materials (formaldehyde) and harsh reaction conditions required for the synthesis of these polymers have severely limited their use in today’s markets. We present here an alternative, biocatalytic approach where the enzyme horseradish peroxidase is used to polymerize phenol in the presence of a template such as polyethylene oxide. Here the template serves as a surfactant that can both emulsify the phenol and polyphenol chains during polymerization and maintain water/solvent solubility of the final polyphenol/template complex. The reactants and the reaction conditions of this approach are mild and result in high molecular weight, electrically and optically active, water-soluble complexes of polyphenol and the template used. High molecular weight water-soluble polyphenol/polyethylene oxide complexes were formed. The ionic conductivity and potential use of these polymers as polyelectrolytes for battery and solution cell applications will be discussed.

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Combined Effects of Cellulose Nanofiber Nucleation and Maleated Polylactic Acid Compatibilization on the Crystallization Kinetic and Mechanical Properties of Polylactic Acid Nanocomposite

Polymers ◽

10.3390/polym13193226 ◽

2021 ◽

Vol 13 (19) ◽

pp. 3226

Author(s):

Siti Shazra Shazleen ◽

Lawrence Yee Foong Ng ◽

Nor Azowa Ibrahim ◽

Mohd Ali Hassan ◽

Hidayah Ariffin

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Polylactic Acid ◽

Crystallization Kinetics ◽

Crystallization Kinetic ◽

Crystallization Rate ◽

Combined Effects ◽

Dsc Analysis ◽

Scanning Calorimetry ◽

Isothermal Crystallization Kinetics

This work investigated the combined effects of CNF nucleation (3 wt.%) and PLA-g-MA compatibilization at different loadings (1–4 wt.%) on the crystallization kinetics and mechanical properties of polylactic acid (PLA). A crystallization kinetics study was done through isothermal and non-isothermal crystallization kinetics using differential scanning calorimetry (DSC) analysis. It was shown that PLA-g-MA had some effect on nucleation as exhibited by the value of crystallization half time and crystallization rate of the PLA/PLA-g-MA, which were increased by 180% and 172%, respectively, as compared to neat PLA when isothermally melt crystallized at 100 °C. Nevertheless, the presence of PLA-g-MA in PLA/PLA-g-MA/CNF3 nanocomposites did not improve the crystallization rate compared to that of uncompatibilized PLA/CNF3. Tensile strength was reduced with the increased amount of PLA-g-MA. Contrarily, Young’s modulus values showed drastic increment compared to the neat PLA, showing that the addition of the PLA-g-MA contributed to the rigidity of the PLA nanocomposites. Overall, it can be concluded that PLA/CNF nanocomposite has good performance, whereby the addition of PLA-g-MA in PLA/CNF may not be necessary for improving both the crystallization kinetics and tensile strength. The addition of PLA-g-MA may be needed to produce rigid nanocomposites; nevertheless, in this case, the crystallization rate of the material needs to be compromised.

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A Greener Enzymatic Oligoesterification of Biobased Renewable Synthons

Journal of the Brazilian Chemical Society ◽

10.21577/0103-5053.20210024 ◽

2021 ◽

Author(s):

Juan Villavicencio ◽

Ferley Orozco ◽

Ricardo Benitez ◽

Jaime Martin ◽

Giovanni Rojas

Keyword(s):

Molecular Weight ◽

Molar Mass ◽

Gel Permeation Chromatography ◽

Scanning Calorimetry ◽

Reaction Conditions ◽

Step Process ◽

Gel Permeation ◽

One Step ◽

First Time ◽

Temperature Time

Polyesters of xylitol and succinic acid were prepared yielding from 70 to 75% by enzymecatalyzed esterification using a molar mass from 1:1 to 2:5 at 120 and 140 °C employing from 1 to 10% m/m of enzyme. Control over branching degree was achieved by tuning the reaction conditions (temperature, time, comonomer ratio, enzyme content). This one-step process from renewable starting materials avoids protection-deprotection techniques, as well as the use of toxic solvents by introducing limonene as solvent for polyesterification for the first time. All materials were structurally characterized by infrared (IR) and nuclear magnetic resonance (NMR)spectroscopy, their thermal properties were studied by differential scanning calorimetry (DSC)and thermogravimetric analysis (TGA), and the molecular weight of samples were obtained by gel-permeation chromatography (GPC).

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Effectiveness assessment of TiO2-Al2O3 nano-mixture as a filler material for improvement of packaging performance of PLA nanocomposite films

Journal of Polymer Engineering ◽

10.1515/polyeng-2020-0105 ◽

2020 ◽

Vol 40 (10) ◽

pp. 848-858

Author(s):

Fatima Zohra Yakdoumi ◽

Assia Siham Hadj-Hamou

Keyword(s):

Polylactic Acid ◽

Nanocomposite Film ◽

Food Packaging ◽

Antimicrobial Properties ◽

Young Modulus ◽

Nanocomposite Films ◽

Vapor Permeability ◽

Scanning Calorimetry ◽

Melt Mixing ◽

Vis Spectroscopy

AbstractThe main objective of this study was to assess the effectiveness of TiO2-Al2O3 nano-mixture used as filler in improving packaging films performance. Polylactic acid/titanium dioxide (PLA/TiO2), polylactic acid/alumina (PLA/Al2O3) and polylactic acid/TiO2-Al2O3 (PLA/TiO2-Al2O3) nanocomposite films were successfully prepared via melt mixing process and thoroughly characterized by FTIR spectroscopy, X-ray diffraction (XRD), UV–vis spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The properties such as heat resistant, barrier, mechanical and antimicrobial properties, required for food packaging have also been investigated. As compared to the neat PLA film, the developed PLA nanocomposites have displayed superior properties particularly the PLA/ TiO2-Al2O3 nanocomposite film. This resulted material has showed a 22 °C increase in its thermal stability versus 14 and 2 °C in the cases of PLA/TiO2 and PLA/Al2O3 respectively, and a 54% reduction of its water vapor permeability in comparison with 47% for PLA/TiO2 and 39% for PLA/Al2O3. In addition, the PLA/TiO2-Al2O3 had a significant enhancement of its mechanical properties. Its Young modulus increased by 102% unlike 23.60% for the PLA/TiO2 and 44.66% for the PLA/Al2O3. It was also noticed that this nanocomposite film demonstrated stronger antibacterial activity than the two others. The bacterial growth inhibition effect of TiO2-Al2O3 nano-mixture against Pseudomonas aeruginosa and Escherichia coli bacteria was more effective than that of its two constituents.

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Molecular Interaction, Chain Conformation, and Rheological Modification during Electrospinning of Hyaluronic Acid Aqueous Solution

Membranes ◽

10.3390/membranes10090217 ◽

2020 ◽

Vol 10 (9) ◽

pp. 217

Author(s):

Hao Chen ◽

Xuhong Chen ◽

Huiying Chen ◽

Xin Liu ◽

Junxing Li ◽

...

Keyword(s):

Aqueous Solution ◽

Molecular Weight ◽

Hyaluronic Acid ◽

Aqueous Solutions ◽

Molecular Model ◽

Chain Conformation ◽

Water Soluble ◽

Crystal Formation ◽

Scanning Calorimetry ◽

Chain Entanglement

Most of natural water-soluble polymers are difficult to electrospin due to their specific chain conformation in aqueous solution, which limits their applications. This study investigated the effects of polyethylene oxide (PEO) on the electrospinning of hyaluronic acid (HA) in HA/PEO aqueous solutions. The rheological properties of HA/PEO aqueous solutions showed polymer chain entanglement in HA was the essential factor affecting its electrospinnability. Wide-angle X-ray scattering and differential scanning calorimetry analyses of a PEO crystal showed different crystallization behavior of the PEO chain with different molecular weight, which indicates different interaction with HA. A schematic molecular model has been proposed to explain the effect of PEO on the chain conformation of HA along with the relationship between electrospinnability and chain entanglement. PEO with a relatively high molecular weight with limited crystal formation formed extensive chain entanglements with HA, while PEO with relatively low molecular weight weakened the interactions among HA chains. The findings of this study provide a wide perspective to better understand the electrospinning mechanisms of natural polyelectrolytes and usage in tissue engineering.

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Gum Rosin as A Size Control Agent of Poly(Butylene Adipate-Co-Terephthalate) (PBAT) Domains to Increase the Toughness of Packaging Formulations Based on Polylactic Acid (PLA)

Polymers ◽

10.3390/polym13121913 ◽

2021 ◽

Vol 13 (12) ◽

pp. 1913

Author(s):

Miguel Aldas ◽

José Miguel Ferri ◽

Dana Luca Motoc ◽

Laura Peponi ◽

Marina Patricia Arrieta ◽

...

Keyword(s):

Polylactic Acid ◽

Food Packaging ◽

Impact Resistance ◽

Size Control ◽

Control Agent ◽

Scanning Calorimetry ◽

Transparent Films ◽

Gum Rosin ◽

And Control ◽

The Impact

Gum rosin (GR) was used as a natural additive to improve the compatibility between polylactic acid, PLA, and poly(butylene adipate-co-terephthalate, PBAT, blended with 20 wt.% of PBAT (PLA/PBAT). The PBAT was used as a soft component to increase the ductility of PLA and its fracture toughness. The coalescence of the PBAT domains was possible due to the plasticization effect of the GR component. These domains contributed to increasing the toughness of the final material due to the variation and control of the PBAT domains’ size and consequently, reducing the stress concentration points. The GR was used in contents of 5, 10, 15, and 20 phr. Consequently, the flexural properties were improved and the impact resistance increased up to 80% in PLA/PBAT_15GR with respect to the PLA/PBAT formulation. Field emission scanning electron microscope (FESEM) images allowed observing that the size of PBAT domains of 2–3 µm was optimal to reduce the impact stress. Differential scanning calorimetry (DSC) analysis showed a reduction of up to 8 °C on the PLA melting temperature and up to 5.3 °C of the PLA glass transition temperature in the PLA/PBAT_20GR formulation, which indicates an improvement in the processability of PLA. Finally, transparent films with improved oxygen barrier performance and increased hydrophobicity were obtained suggesting the potential interest of these blends for the food packaging industry.

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Analysis of the rheological property and crystallization behavior of polylactic acid (Ingeo™ Biopolymer 4032D) at different process temperatures

e-Polymers ◽

10.1515/epoly-2021-0071 ◽

2021 ◽

Vol 21 (1) ◽

pp. 702-709

Author(s):

Hyeong Min Yoo ◽

Su-Yeon Jeong ◽

Sung-Woong Choi

Keyword(s):

Rheological Property ◽

Polylactic Acid ◽

Crystallization Kinetics ◽

Crystallization Behavior ◽

Crystallization Rate ◽

Avrami Equation ◽

Scanning Calorimetry ◽

Isothermal Crystallization Kinetics ◽

Shear Rates ◽

Kinetics Of

Abstract The aim of this study was to determine the rheological property and crystallization behavior of polylactic acid (PLA) with improved heat resistance (Ingeo™ Biopolymer 4032D) through investigation of the melt viscosity and crystallization kinetics of PLA at different process temperatures. The viscosity was measured using a rotational rheometer under conditions of shear rates of 0.01, 0.1, and 1/s. The obtained rheological data show that the viscosity tended to decrease slightly as the shear rate increases and decrease sharply as the temperature increases from 180°C to 210°C. To investigate the effect of the process temperature on the crystallization kinetics and final crystallinity of PLA, thermal analysis using isothermal differential scanning calorimetry (DSC) were also performed. The Avrami equation was successfully applied for the isothermal crystallization kinetics model. From crystallization temperature of 85°C to 120°C, we found that the Ingeo™ Biopolymer 4032D PLA had the fastest crystallization rate (t 1/2: 26.0 min) and the largest crystallinity (47.4%) at 100°C.

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