scholarly journals Preparation, Mechanical, and Thermal Properties of Biodegradable Polyesters/Poly(Lactic Acid) Blends

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
Peng Zhao ◽  
Wanqiang Liu ◽  
Qingsheng Wu ◽  
Jie Ren
Keyword(s):  
Lactic Acid ◽  
Gel Permeation Chromatography ◽  
Poly Lactic Acid ◽  
Mechanical And Thermal Properties ◽  
Scanning Calorimetry ◽  
Butylene Succinate ◽  
Biodegradable Polyesters ◽  
H Nmr ◽  
Melt Polycondensation ◽  
Twin Screw

Series of biodegradable polyesters poly(butylene adipate) (PBA), poly(butylene succinate) (PBS), and poly(butylene adipate-co-butylene terephthalate) (PBAT) were synthesized successfully by melt polycondensation. The polyesters were characterized by Fourier transform infrared spectroscopy (FTIR),1H-NMR, differential scanning calorimetry (DSC), and gel permeation chromatography (GPC), respectively. The blends of poly(lactic acid) (PLA) and biodegradable polyester were prepared using a twin screw extruder. PBAT, PBS, or PBA can be homogenously dispersed in PLA matrix at a low content (5–20 wt%), yielding the blends with much higher elongation at break than homo-PLA. DSC analysis shows that the isothermal and nonisothermal crystallizabilities of PLA component are promoted in the presence of a small amount of PBAT.

Wood, silver-substituted zeolite and triclosan as biodegradation controllers and antibacterial agents for poly(lactic acid) (PLA) and PLA composites

2015 ◽  
Vol 30 (5) ◽  
pp. 583-598 ◽  
Author(s):  
Chana Prapruddivongs ◽  
Narongrit Sombatsompop
Keyword(s):  
Lactic Acid ◽  
Antimicrobial Agents ◽  
Wood Flour ◽  
Plate Count ◽  
Poly Lactic Acid ◽  
Mechanical And Thermal Properties ◽  
Scanning Calorimetry ◽  
Elongation At Break ◽  
Plate Count Agar ◽  
Twin Screw

Poly(lactic acid) (PLA) and wood flour/PLA composites were prepared and blended with two antimicrobial agents, triclosan and silver-substituted zeolite (Zeomic), using a twin-screw extruder. The mechanical and thermal properties, antimicrobial activity, and biodegradation performance were investigated. The addition of wood and Zeomic was found to increase the Young’s modulus of the composites, whereas the tensile strength, elongation at break, and impact strength dropped. However, the mechanical properties of PLA and wood/PLA loaded with triclosan did not show any definite trends. Differential scanning calorimetry data indicated that the glass transition temperature value of neat PLA was 63°C, whereas those of wood/PLA composites were lower. When wood and Zeomic were incorporated, PLA exhibited double melting peaks. Triclosan (1.0 and 1.5 wt%) demonstrated antibacterial activity against Staphylococcus aureus, as determined by plate count agar technique, whereas Zeomic did not. Biodegradation tests of neat PLA and wood/PLA composites showed that after a 60-day incubation period, the biodegradation rate of wood/PLA was higher than that of PLA. PLA and wood/PLA-containing Zeomic were found to degrade more quickly, suggesting that wood and Zeomic acted as biodegradation promoters. On the other hand, triclosan could be considered a biodegradation retarder since no biodegradation was observed for any triclosan-loaded samples during the initial 20 days of incubation, while neat PLA and wood/PLA composites began to degrade within the first few days.

scholarly journals Feasibility of Reprocessing Natural Fiber Filled Poly(lactic acid) Composites: An In-Depth Investigation

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Sujal Bhattacharjee ◽  
Dilpreet S. Bajwa
Keyword(s):  
Lactic Acid ◽  
Natural Fiber ◽  
Environmental Concern ◽  
Wood Flour ◽  
Gel Permeation Chromatography ◽  
Thermomechanical Properties ◽  
Poly Lactic Acid ◽  
Filler Concentration ◽  
Scanning Calorimetry ◽  
Abrupt Decrease

Poly(lactic acid) (PLA) based composites are biodegradable; their disposal after single use may be needless and uneconomical. Prodigal disposal of these composites could also create an environmental concern and additional demand for biobased feedstock. Under these circumstances, recycling could be an effective solution, since it will widen the composite service life and prevent the excessive use of natural resources. This research investigates an in-depth impact of recycling on the mechanical and thermomechanical properties of oak wood flour based PLA composites. Two composite formulations (30 and 50 wt% filler), each with 3 wt% coupling agent (PLA-g-MA), were produced and reprocessed six times by extrusion followed by injection molding. Measurements of fiber length and molecular weight of polymer were, respectively, carried out by gel permeation chromatography (GPC). Scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR) tools were used to study morphological and molecular alterations. With consecutive recycling, PLA composites showed a gradual decrease in strength and stiffness properties and an increase in strain properties. The 50% and 30% filler concentration of fibers in the composite showed an abrupt decrease in strength properties after six and two reprocessing cycles, respectively.

Synthesis and Characterization of Poly (L-Lactic acid) Containing the Azobenzene Mesogens

2011 ◽  
Vol 181-182 ◽  
pp. 185-188
Author(s):  
Run Tao Dong ◽  
Qing Bin Xue ◽  
Ling Min Sun ◽  
Quan Xuan Zhang
Keyword(s):  
Lactic Acid ◽  
Optical Rotation ◽  
Gel Permeation Chromatography ◽  
Helical Structure ◽  
Feed Ratio ◽  
Scanning Calorimetry ◽  
Molecular Weights ◽  
H Nmr ◽  
Azobenzene Mesogens

A series of azobenzene containing group Poly (L-lactic acid) (PLLA) were synthesized by Ring-Opening Polymerization of L-lactide (L-LA) catalysted by Sn (Oct)2initiated by alcohol-OH containing the azobenzene chromophores. Their molecular weights were well controlled by the feed ratio as characterized by Gel Permeation Chromatography (GPC) and1H NMR Spectrometry and agreed well with theoretical values. The thermal properties and liquid crystal phases were investigated by Differential Scanning Calorimetry (DSC), polarized optical microscopy (POM) and X-ray Diffraction (XRS) measurements. Cis-trans photoisomerization behavior of the polymers in the solutions and the films were studied with UV irradiation. By the Circular Dichroism Spectroscopy (CD) characterization of the solutions and films of the polymer, the PLLA segments show huge optical rotation power in helical structure.

Crystallization and Thermal Degradation of Green Nanocomposites Based on Lignin Coated Cellulose Nanocrystals and Poly(Lactic Acid)

2017 ◽  
Vol 737 ◽  
pp. 256-261 ◽  
Author(s):  
Martin Boruvka ◽  
Luboš Bĕhálek
Keyword(s):  
Lactic Acid ◽  
Cellulose Nanocrystals ◽  
Raw Material ◽  
Degree Of Crystallinity ◽  
Poly Lactic Acid ◽  
Crystalline Cellulose ◽  
Melt Crystallization ◽  
Scanning Calorimetry ◽  
Wide Range ◽  
Twin Screw

Cellulose is almost inexhaustible source of raw material comprising at least one-third of all biomass matter. Through deconstruction of cellulose hierarchical structure can be extracted highly crystalline cellulose nanocrystals (CNC) with impressive properties. However, the main barrier in the processing of the nanocomposites based on CNC is their inhomogeneous dispersion and distribution in the non-polar polymer matrix. In this paper is this problem addressed by use of novel hydrophobic lignin coated CNC as a biobased nucleation agents in poly (lactic acid) (PLA) nanocomposites. These green nanocomposites based on natural plant derived substances have enormous potential to replace materials originated from non-renewable resources and show promise of providing degradation back into the environment when they are no longer needed. Resulted composites prepared by twin screw extrusion and injection moulding were characterized by means of scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The addition of L-CNC (1, 2 and 3 wt. %) into PLA increased melt crystallization enthalpy and decreases the cold crystallization enthalpy. The degree of crystallinity (cc) increased from 5.6 % (virgin PLA) to 8.5 % (PLA/1-L-CNC), 10.3 % (PLA/2-L-CNC) and 10.7 % (PLA/3-L-CNC). The wide range of degradation temperatures of lignin coating has been observed starting at 100 °C.

scholarly journals Synthesis, Characterization andIn VitroAnticancer Evaluation of Itaconic Acid Based Random Copolyester

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
J. Gowsika ◽  
R. Nanthini
Keyword(s):  
Itaconic Acid ◽  
Hydrolytic Degradation ◽  
Gel Permeation Chromatography ◽  
Xrd Analysis ◽  
Titanium Tetraisopropoxide ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
H Nmr ◽  
Melt Polycondensation

The present study deals with the synthesis and characterization of an aliphatic copolyester, poly [butylene fumarate-co-butylene itaconate] (PIFB) copolymer was obtained from itaconic acid, fumaric acid, and 1,4-butanediol using titanium tetraisopropoxide (TTiPO) through a two step process of transesterification and melt polycondensation. The synthesized aliphatic random copolyester was characterized with the help of FT-IR,1H-NMR,13C-NMR, viscosity measurements, Gel Permeation Chromatography (GPC) and X-ray diffraction (XRD) analysis. Thermal properties have been analyzed using thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC). Hydrolytic degradation studies were carried out in acid and alkaline regions of various pH values. The synthesized copolymer was subjected toin vitroanticancer activity studies against human breast cancer (MCF-7) cell line.

scholarly journals Glycerolysis of Poly(lactic acid) as a Way to Extend the “Life Cycle” of This Material

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1963 ◽  
Author(s):  
Marcin Borowicz ◽  
Joanna Paciorek-Sadowska ◽  
Marek Isbrandt ◽  
Łukasz Grzybowski ◽  
Bogusław Czupryński
Keyword(s):  
Lactic Acid ◽  
Life Cycle ◽  
Raw Materials ◽  
Gel Permeation Chromatography ◽  
Acid Value ◽  
Economic Losses ◽  
Poly Lactic Acid ◽  
Scanning Calorimetry ◽  
Economic Point

The article concerns the use of glycerolysis reaction as an alternative method of processing post-production and post-consumer waste from poly(lactic acid) (PLA). Management of waste is a very important issue from an environmental protection and economic point of view. Extending the “life cycle” of PLA is extremely important because it allows to make the most of this material. It also limits economic losses resulting from its disposal in the biodegradation process at the same time. This paper presents a method of glycerolysis of poly(lactic acid) waste using various amounts of anhydrous glycerol (mass ratio from 0.3 to 0.5 parts by weight of glycerol per 1.0 part by weight of PLA). This process was also carried out for pure, unmodified PLA Ingeo® (from NatureWorks) to compare the obtained results. The six liquid oligomeric polyhydric alcohols were obtained as a result of the synthesis. Then, they were subjected to physicochemical tests such as determination of color, smell, density, viscosity, and pH. In addition, the obtained raw materials were subjected to analytical tests such as determination of the hydroxyl value, acid value, water content, and elemental composition. The average molecular weights and dispersity were also tested by gel permeation chromatography (GPC). The assumed chemical structure of the obtained compounds was confirmed by spectroscopic methods such as FTIR, 1H NMR, 13C NMR. Glycerolysis products were also subjected to differential scanning calorimetry (DSC) to determine thermal parameters. The obtained research results have allowed the precise characterization of newly obtained products and determination of their suitability, e.g., for the synthesis of polyurethane (PUR) materials.

Biodegradable Composite Materials Based on Poly(3-Hydroxybutyrate) for 3D Printing Applications

2019 ◽  
Vol 955 ◽  
pp. 56-61
Author(s):  
Premysl Mencik ◽  
Veronika Melcova ◽  
Sona Kontarova ◽  
Radek Prikryl ◽  
Dagmara Perdochova ◽  
...  
Keyword(s):  
Lactic Acid ◽  
3D Printing ◽  
Cross Sections ◽  
Optical Microscope ◽  
Zinc Stearate ◽  
Poly Lactic Acid ◽  
Mechanical And Thermal Properties ◽  
Scanning Calorimetry ◽  
Biodegradable Composite ◽  
Base Polymer

Presented work deals with the development of bio-source and biodegradable composite material for 3D printing. Polymer blend based on poly (3-hydroxybutyrate) (60 wt%) and poly (lactic acid) (25 wt%) plasticized by tributyl citrate (15 wt%) was used as a matrix. This base blend was filled with 10 vol% of kaolin or limestone. Zinc stearate was used for the surface treatment of the limestone samples. The mechanical and thermal properties of the composites, as well as their behavior during 3D printing process, were compared with unfilled blend and commercial poly (lactic acid) based 3D printing filament. Warping behavior, one of the main problems of 3D printing materials, was studied by means of warp coefficient. Cross-sections of specimens 3D printed under the same processing conditions were observed by the optical microscope. In the case of composite samples, individual filaments were separated. Despite the separation, composites filled with kaolin and with surface treated limestone exhibited satisfying mechanical properties. Scanning electron microscopy analysis confirmed good particle distribution of the samples with kaolin and surface treated limestone. No significant particle agglomerates were formed in the composites with limestone proving good dispergation ability of zinc stearate. Thermogravimetric analysis and Differential scanning calorimetry analysis showed no degradable effect of the used fillers on base polymer matrix. Observed results indicate that kaolin and surface treated limestone are suitable fillers for the bio-source composites used for 3D printing.

Structure and properties of poly(lactic acid)/poly(lactic acid)-α-cyclodextrin inclusion compound composites

2017 ◽  
Vol 37 (9) ◽  
pp. 897-909
Author(s):  
Li Zhang ◽  
Weijun Zhen ◽  
Yufang Zhou
Keyword(s):  
Lactic Acid ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Mechanical Analysis ◽  
Poly Lactic Acid ◽  
Polymerization Temperature ◽  
Scanning Calorimetry ◽  
Synthesis Conditions ◽  
Cyclodextrin Inclusion ◽  
Comprehensive Performance

Abstract Poly(lactic acid) (PLA) was synthesized using a green catalyst, nano-zinc oxide (ZnO). The optimum synthesis conditions of PLA were as follows: a stoichiometric amount of 0.5 wt% of nano-ZnO, polymerization time of 14 h, and polymerization temperature of 170°C. Gel permeation chromatography results showed that the weight-average molecular weight (Mw) of PLA was 13,072 g/mol with a polydispersity index (PDI) of 1.7. Furthermore, PLA-α-cyclodextrin inclusion compounds (PLA-CD-ICs) were prepared by ultrasonic co-precipitation techniques. X-ray diffraction analysis and Fourier transform infrared spectroscopy demonstrated the change in lattice of α-CD from a cage configuration to a tunnel structure and the existence of some physical interactions between α-CD and PLA in the PLA-CD-ICs. To enhance the crystallization properties of PLA, PLA/PLA-CD-IC composites were blended with different contents of PLA-CD-ICs as nucleating agents. The crystallization behavior and comprehensive performance were investigated by differential scanning calorimetry, polarized optical microscopy, tensile testing, dynamic mechanical analysis, and scanning electron microscopy. Compared to PLA, the crystallinities of PLA/PLA-CD-IC composites were increased by 24.0%, 26.3%, 27.3%, and 31.8%. The results of all the analyses proved that PLA-CD-ICs were useful as green organic nucleators and improved the comprehensive performance of PLA materials.

scholarly journals Plasticized Biodegradable Poly(lactic acid) Based Composites Containing Cellulose in Micro- and Nanosize

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Katalin Halász ◽  
Levente Csóka
Keyword(s):  
Lactic Acid ◽  
Microcrystalline Cellulose ◽  
Composite Films ◽  
Poly Lactic Acid ◽  
Twin Screw Extrusion ◽  
Scanning Calorimetry ◽  
Screw Extrusion ◽  
Twin Screw ◽  
Biodegradable Poly ◽  
Poly Ethylene

The aim of this work was to study the characteristics of thermal processed poly(lactic acid) composites. Poly(ethylene glycol) (PEG400), microcrystalline cellulose (MCC), and ultrasound-treated microcrystalline cellulose (USMCC) were used in 1, 3, and 5 weight percents to modify the attributes of PLA matrix. The composite films were produced by twin screw extrusion followed by film extrusion. The manufactured PLA-based films were characterized by tensile testing, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), wide angle X-ray diffraction (WAXD), and degradation test.

scholarly journals Bamboo Fiber Based Cellulose Nanocrystals/Poly(Lactic Acid)/Poly(Butylene Succinate) Nanocomposites: Morphological, Mechanical and Thermal Properties

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1076
Author(s):  
Masrat Rasheed ◽  
Mohammad Jawaid ◽  
Bisma Parveez
Keyword(s):  
Lactic Acid ◽  
Thermal Properties ◽  
Cellulose Nanocrystals ◽  
Natural Fiber ◽  
Testing Machine ◽  
Bamboo Fiber ◽  
Poly Lactic Acid ◽  
Mechanical And Thermal Properties ◽  
Melt Mixing ◽  
Butylene Succinate

The purpose of this work was to investigate the effect of cellulose nanocrystals (CNC) from bamboo fiber on the properties of poly (lactic acid) (PLA)/poly (butylene succinate) (PBS) composites fabricated by melt mixing at 175 °C and then hot pressing at 180 °C. PBS and CNC (0.5, 0.75, 1, 1.5 wt.%) were added to improvise the properties of PLA. The morphological, physiochemical and crystallinity properties of nanocomposites were analysed by field emission scanning electron microscope (FESEM), Fourier-transform infrared spectroscopy (FTIR) and X-ray diffractometry (XRD), respectively. The thermal and tensile properties were analysed by thermogravimetic analysis (TGA), Differential scanning calorimetry (DSC) and Universal testing machine (UTM). PLA-PBS blend shows homogeneous morphology while the composite shows rod-like CNC particles, which are embedded in the polymer matrix. The uniform distribution of CNC particles in the nanocomposites improves their thermal stability, tensile strength and tensile modulus up to 1 wt.%; however, their elongation at break decreases. Thus, CNC addition in PLA-PBS matrix improves structural and thermal properties of the composite. The composite, thus developed, using CNC (a natural fiber) and PLA-PBS (biodegradable polymers) could be of immense importance as they could allow complete degradation in soil, making it a potential alternative material to existing packaging materials in the market that could be environment friendly.

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