COST-FP1105: Properties of PLA films reinforced with unmodified and acetylated freeze dried nanofibrillated cellulose

Holzforschung ◽  
2016 ◽  
Vol 70 (12) ◽  
pp. 1125-1134 ◽  
Author(s):  
Vesna Žepič ◽  
Ida Poljanšek ◽  
Primož Oven ◽  
Matjaž Čop
Keyword(s):  
Heterogeneous System ◽  
Cellulose Nanofibrils ◽  
Composite Films ◽  
Hydrophobic Surface ◽  
Nanofibrillated Cellulose ◽  
Nanocomposite Films ◽  
Poly Lactic Acid ◽  
Scanning Calorimetry ◽  
Elongation At Break ◽  
Freeze Dried

Abstract Freeze dried nanofibrils were acetylated in a heterogeneous system with acetic anhydride, pyridine, and dimethylformamide and the obtained acetylated cellulose nanofibrils (CNFac) were combined with poly(lactic acid) (PLA) to a composite. CNFac with its partially hydrophobic surface showed a good compatibility with PLA resulting in composite films with improved properties. Tensile strength (TS), modulus of elasticity (MOE), and elongation at break (EB) of PLA/CNF increased significantly when 2–5% of CNFac was added to the PLA matrix, while the addition of 10% and higher amounts CNFac decreased the EB at a higher TS and MOE. Mechanical parameters did not improve in the case of unmodified CNF addition. The addition of CNFac maintained transparency and had absorbance values between those of pure PLA film and PLA film with 2% CNF, while films formed with the addition of 5 and 10% of CNF were less transparent. The addition of CNF did not essentially affect the thermal properties of nanocomposite films. The addition of 2–10% of CNFac increased the enthalpy and maximal temperature of cold crystallization as opposed to higher loading of CNFac. The results of differential scanning calorimetry (DSC) coincide with those of the mechanical properties. Tailoring properties of PLA/CNF are only reproducible in case of homogenously distributed CNF within the PLA matrix and by an improved interphase adhesion between PLA and CNFac.

scholarly journals Influence of the Lignin Content on the Properties of Poly(Lactic Acid)/lignin-Containing Cellulose Nanofibrils Composite Films

Polymers ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1013 ◽  
Author(s):  
Xuan Wang ◽  
Yuan Jia ◽  
Zhen Liu ◽  
Jiaojiao Miao
Keyword(s):  
Lactic Acid ◽  
Lignin Content ◽  
Cellulose Nanofibrils ◽  
Composite Films ◽  
Tensile Tests ◽  
Nucleating Agent ◽  
Mechanical Analysis ◽  
Degree Of Crystallinity ◽  
Poly Lactic Acid ◽  
Scanning Calorimetry

Poly(lactic acid) (PLA)/lignin-containing cellulose nanofibrils (L-CNFs) composite films with different lignin contents were produced bythe solution casting method. The effect of the lignin content on the mechanical, thermal, and crystallinity properties, and PLA/LCNFs interfacial adhesion wereinvestigated by tensile tests, thermogravimetric analysis, differential scanning calorimetry (DSC), dynamic mechanical analysis, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The tensile strength and modulus of the PLA/9-LCNFs (9 wt % lignin LCNFs) composites are 37% and 61% higher than those of pure PLA, respectively. The glass transition temperature (Tg) decreases from 61.2 for pure PLA to 52.6 °C for the PLA/14-LCNFs (14 wt % lignin LCNFs) composite, and the composites have higher thermal stability below 380 °C than pure PLA. The DSC results indicate that the LCNFs, containing different lignin contents, act as a nucleating agent to increase the degree of crystallinity of PLA. The effect of the LCNFs lignin content on the PLA/LCNFs compatibility/adhesion was confirmed by the FTIR, SEM, and Tg results. Increasing the LCNFs lignin content increases the storage modulus of the PLA/LCNFs composites to a maximum for the PLA/9-LCNFs composite. This study shows that the lignin content has a considerable effect on the strength and flexibility of PLA/LCNFs composites.

scholarly journals Study on Aging and Recover of Poly (Lactic) Acid Composite Films with Graphene and Carbon Nanotubes Produced by Solution Blending and Extrusion

Coatings ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 359 ◽  
Author(s):  
Rumiana Kotsilkova ◽  
Polya Angelova ◽  
Todor Batakliev ◽  
Verislav Angelov ◽  
Rosa Di Maio ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Lactic Acid ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Composite Films ◽  
Processing Condition ◽  
Nanocomposite Films ◽  
Poly Lactic Acid ◽  
Scanning Calorimetry ◽  
Slow Cooling

The aging, annealing, and reprocessing of the biodegradable poly (lactic) acid (PLA) based composite films incorporating graphene and carbon nanotubes were investigated in this work. Various monofiller and bifiller nanocomposite films with 6 wt.% filler content were produced by a solution-phase technique followed by extrusion. The freshly produced films were compared with the aged films after 18 months of shelf life in a room environment. The effects of aging, annealing, and melt reprocessing on the crystalline structure, the thermal stability, the hardness, and Young’s modulus were analyzed by differential scanning calorimetry (DSC), TGA, and nanoindentation methods. The fresh and the aged samples were found to have semi-crystalline materials with 3%–7% crystallinity, while the crystallinity was significantly enhanced to 34%–38% by annealing at 80 °C and subsequent slow cooling. A good dispersion was observed in the bifiller films with filler ratios of 4.5:1.5 and 1.5:4.5 [graphene nanoplatelets (GNP) to carbon nanotubes (CNT)], which affected the crystallization processes. The reprocessing at 200 °C followed by fast cooling resulted in amorphous films, which significantly reduced the hardness and Young’s modulus. The nanoindentation properties were dependent on the dispersion of nanofillers at the surfaces. The efficiency of annealing and reprocessing for the recovery and the reuse of aged nanocomposite films is discussed herein. The paper underlines that properties of the nanocomposites under investigation were influenced not only by the composition, the chemical nature of the added filler, and the processing condition, but also by the aging processes, which in turn depended on the type of nanopartcles added to PLA and the compositions. The paper provides valuable information for selection of material and processing conditions.

Preparation of Cellulose Nanofibrils by High-Pressure Homogenizer and Zein Composite Films

2013 ◽  
Vol 829 ◽  
pp. 534-538 ◽  
Author(s):  
Alireza Shakeri ◽  
Sattar Radmanesh
Keyword(s):  
Atomic Force Microscopy ◽  
High Pressure ◽  
Food Packaging ◽  
Cellulose Nanofibrils ◽  
Composite Films ◽  
Average Diameter ◽  
Nanocomposite Films ◽  
Force Microscopy ◽  
Atomic Force ◽  
High Pressure Homogenizer

Cellulose nanofibrils ( NF ) have several advantages such as biodegradability and safety toward human health. Zein is a biodegradable polymer with potential use in food packaging applications. It appears that polymer nanocomposites are one of the most promising applications of zein films. Cellulose NF were prepared from starting material Microcrystalline cellulose (MCC) by an application of a high-pressure homogenizer at 20,000 psi and treatment consisting of 15 passes. Methods such as atomic force microscopy were used for confirmation of nanoscale size production of cellulose. The average diameter 45 nm were observed. Zeincellulose NF nanocomposite films were prepared by casting ethanol suspensions of Zein with different amounts of cellulose NF in the 0% to 5%wt. The nanocomposites were characterized by using Fourier transform infrared spectroscopy ( FTIR ), Atomic force microscopy ( AFM ) and X-ray diffraction ( XRD ) analysis. From the FTIR spectra the various groups present in the Zein blend were monitored. The homogeneity, morphology and crystallinity of the blends were ascertained from the AFM and XRD data, respectively. The thermal resistant of the zein nanocomposite films improved as the nanocellulose content increased. These obtained materials are transparent, flexible and present significantly better physical properties than the corresponding unfilled Zein films.

Laser Damage Threshold of Hydrophobic Up-Conversion Carboxylated Nanocellulose/SrF2:Hо Composite Films Functionalized With 3-Aminopropyltriethoxysilane

2021 ◽  
Author(s):  
Anna A. Luginina ◽  
Sergey V. Kuznetsov ◽  
Vladimir K. Ivanov ◽  
Valery V. Voronov ◽  
Alexey D. Yapryntsev ◽  
...  
Keyword(s):  
Cellulose Nanofibrils ◽  
Damage Threshold ◽  
Nanocomposite Films ◽  
Laser Damage Threshold ◽  
Laser Damage ◽  
Homogeneous Distribution ◽  
Scanning Calorimetry ◽  
Long Distance ◽  
Oh Groups ◽  
X Ray

Abstract Luminescent nanocomposite films, containing SrF 2 :Но up-conversion particles, were prepared by two different protocols from aqueous dispersions of TEMPO-oxidized cellulose nanofibrils (TOCNF) functionalized with 3-aminopropyltriethoxysilane (APS) without the use of organic solvents at pH = 4.0-4.5 and 9.0-9.5, respectively. Proposed synthetic protocols included formation of the films by drying the dispersions containing pre-hydrolyzed APS adsorbed onto TOCNF and SrF 2 :Но particles followed by heating at 105 °C. Hydrophobic (water contact angle 101 ± 2°), strong, and translucent TOCNF/SrF 2 :Но-APS films were prepared by casting from a solution at pH = 4.0-4.5. Scanning electron microscopy, energy-dispersive X-ray spectroscopy with element mapping, Fourier-transform infrared spectroscopy, X-ray diffraction methods confirmed homogeneous distribution of up-conversion particles in TOCNF matrices as well as the grafting of linear polysiloxanes via the condensation of silanol groups and OH-groups on the surface of TOCNF. Differential scanning calorimetry and thermogravimetry data confirmed an increase in thermal stability of the APS modified nanocomposite films obtained at pH = 4.0-4.5. Hydrophobic TOCNF/SrF 2 :Но-APS nanocomposite films exhibited an intense red luminescence in the visible spectrum range ( 5 I 7 level excitation of Ho 3+ ions with 1912 nm laser irradiation) as well as two-times higher laser damage threshold compared to unmodified TOCNF/SrF 2 :Но films. TOCNF/SrF 2 :Но films can be used for visualization 2 μm laser radiation in medicine and long-distance atmosphere monitoring.

Effects of walnut shell powders on the morphology and the thermal and mechanical properties of poly(lactic acid)

2019 ◽  
Vol 33 (10) ◽  
pp. 1383-1395
Author(s):  
Hongjuan Zheng ◽  
Zhengqian Sun ◽  
Hongjuan Zhang
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Property Testing ◽  
Walnut Shell ◽  
Poly Lactic Acid ◽  
Thermal And Mechanical Properties ◽  
Scanning Calorimetry ◽  
Elongation At Break ◽  
Heat Distortion Temperature ◽  
Testing Techniques

Poly(lactic acid) (PLA) has good environmental compatibility, however, its high brittleness, slow rate of crystallization, and low heat distortion temperature restrict its widespread use. To overcome these limitations, in this study, PLA was mixed with walnut shell (WS) powders. The effects of WS powders on the morphology and the thermal and mechanical properties of PLA were investigated. The products were characterized by differential scanning calorimetry (DSC), infrared (IR) spectroscopy, polarizing optical microscopy (POM), and various mechanical property testing techniques. The results showed that WS powders had a significant effect on the morphology and the thermal and mechanical properties of PLA. The tensile strength, impact strength, and elongation at break of the PLA/WS composites first increased and then decreased with the increasing addition of WS powders. When the addition of WS powders was about 0.5 wt%, they reached maximum values of 51.2 MPa, 23.3 MPa, and 19.0%, respectively. Compared with neat PLA, the spherulite grain size of the composites could be reduced and many irregular polygons were formed during crystallization. The melting, cold crystallization, and glass-transition temperatures of the composites were lower than those of neat PLA.

scholarly journals Sandwich-Structured, Hydrophobic, Nanocellulose-Reinforced Polyvinyl Alcohol as an Alternative Straw Material

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4447
Author(s):  
Chun-Tu Chou ◽  
Shih-Chen Shi ◽  
Chih-Kuang Chen
Keyword(s):  
Heat Treatment ◽  
Contact Angle ◽  
Water Vapor ◽  
Polyvinyl Alcohol ◽  
Composite Films ◽  
Nanocomposite Films ◽  
Poly Lactic Acid ◽  
Initial Contact ◽  
Solution Casting ◽  
Water Vapor Barrier

An environmentally friendly, hydrophobic polyvinyl alcohol (PVA) film was developed as an alternative to commercial straws for mitigating the issue of plastic waste. Nontoxic and biodegradable cellulose nanocrystals (CNCs) and nanofibers (CNFs) were used to prepare PVA nanocomposite films by blade coating and solution casting. Double-sided solution casting of polyethylene-glycol–poly(lactic acid) (PEG–PLA) + neat PLA hydrophobic films was performed, which was followed by heat treatment at different temperatures and durations to hydrophobize the PVA composite films. The hydrophobic characteristics of the prepared composite films and a commercial straw were compared. The PVA nanocomposite films exhibited enhanced water vapor barrier and thermal properties owing to the hydrogen bonds and van der Waals forces between the substrate and the fillers. In the sandwich-structured PVA-based hydrophobic composite films, the crystallinity of PLA was increased by adjusting the temperature and duration of heat treatment, which significantly improved their contact angle and water vapor barrier. Finally, the initial contact angle and contact duration (at the contact angle of 20°) increased by 35% and 40%, respectively, which was a significant increase in the service life of the biodegradable material-based straw.

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.

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.

Effect of the talc filler on structural, water vapor barrier and mechanical properties of poly(lactic acid) composites

2016 ◽  
Vol 36 (2) ◽  
pp. 181-188 ◽  
Author(s):  
Aleksandra Buzarovska ◽  
Gordana Bogoeva-Gaceva ◽  
Radek Fajgar
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Water Vapor ◽  
Composite Films ◽  
Water Vapor Permeability ◽  
Barrier Properties ◽  
Poly Lactic Acid ◽  
Vapor Permeability ◽  
Scanning Calorimetry ◽  
Structural Water

Abstract Poly(lactic acid) (PLA) based composite films with different content of talc (5–15 wt%) were prepared by the solvent casting method. The effect of talc on morphological, structural, thermal, barrier and mechanical properties of neat PLA was investigated. The PLA/talc composites revealed a polymorphic crystalline structure, as demonstrated by X-ray diffraction (XRD) study and differential scanning calorimetry (DSC) analysis. The PLA/talc composites also exhibited significantly improved barrier properties (up to 55% compared to neat PLA), as shown by water vapor permeability (WVP) tests. The puncture measurements showed improved mechanical properties at lower content of talc (up to 5 wt%), and increased brittleness of the PLA/talc composite films at higher talc concentrations.

Preparation and characterization of poly(lactic acid) with adipate ester added as a plasticizer

2018 ◽  
Vol 26 (8-9) ◽  
pp. 446-453 ◽  
Author(s):  
Chi-Hui Tsou ◽  
Chen Gao ◽  
Manuel De Guzman ◽  
Dung-Yi Wu ◽  
Wei-Song Hung ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Fourier Transform ◽  
Lactic Acid ◽  
Infrared Spectroscopy ◽  
Poly Lactic Acid ◽  
Biodegradable Materials ◽  
Scanning Calorimetry ◽  
Elongation At Break ◽  
Plasticizer Migration

Poly(lactic acid) (PLA) was thermally blended with adipate ester (AE) to enhance the toughness of PLA. All specimens which were biodegradable materials were prepared using a plasticorder. Differential scanning calorimetry and Fourier-transform infrared spectroscopy indicated that the PLA structure was looser because of the presence of the AE additive. The elongation at break and biodegradable property increased substantially with increasing amounts of AE. The results reveal that excessive amounts of plasticizer would cause the exudation of AE from the PLA/AE composites, which was ascribed to the plasticizer migration phenomenon.

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