scholarly journals Poly(lactic Acid)–Biochar Biocomposites: Effect of Processing and Filler Content on Rheological, Thermal, and Mechanical Properties

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 892 ◽  
Author(s):  
Rossella Arrigo ◽  
Mattia Bartoli ◽  
Giulio Malucelli
Keyword(s):  
Lactic Acid ◽  
Filler Content ◽  
Processing Method ◽  
Poly Lactic Acid ◽  
Rheological Characterization ◽  
Scanning Calorimetry ◽  
Melt Mixing ◽  
Dsc Measurements ◽  
The Matrix ◽  
Filler Dispersion

Biocomposites based on poly(lactic acid) (PLA) and biochar (BC) particles derived from spent ground coffee were prepared using two different processing routes, namely melt mixing and solvent casting. The formulated biocomposites were characterized through rheological, thermal, and mechanical analyses, aiming at evaluating the effects of the filler content and of the processing method on their final properties. The rheological characterization demonstrated the effectiveness of both exploited strategies in achieving a good level of filler dispersion within the matrix, notwithstanding the occurrence of a remarkable decrease of the PLA molar mass during the processing at high temperature. Nevertheless, significant alterations of the PLA rheological behavior were observed in the composites obtained by melt mixing. Differential scanning calorimetry (DSC) measurements indicated a remarkable influence of the processing method on the thermal behavior of biocomposites. More specifically, melt mixing caused the appearance of two melting peaks, though the structure of the materials remained almost amorphous; conversely, a significant increase of the crystalline phase content was observed for solvent cast biocomposites containing low amounts of filler that acted as nucleating agents. Finally, thermogravimetric analyses suggested a catalytic effect of BC particles on the degradation of PLA; its biocomposites showed decreased thermal stability as compared with the neat PLA matrix.

scholarly journals Barrier Properties and Hydrophobicity of Biodegradable Poly(lactic acid) Composites Reinforced with Recycled Chinese Spirits Distiller’s Grains

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2861
Author(s):  
Zhi-Jun Chen ◽  
Chi-Hui Tsou ◽  
Meng-Lin Tsai ◽  
Jipeng Guo ◽  
Manuel Reyes De Guzman ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Barrier Properties ◽  
Poly Lactic Acid ◽  
Control Group ◽  
Scanning Calorimetry ◽  
Melt Mixing ◽  
Distiller's Grains ◽  
The Matrix ◽  
Section Structure

Adding natural biomass to poly(lactic acid) (PLA) as a reinforcing filler is a way to change the properties of PLA. This paper is about preparing PLA/biomass composites by physically melting and blending Chinese Spirits distiller’s grains (CSDG) biomass and PLA to optimize the composite performance. Composites of modified PLA (MPLA) with varying amounts of CSDG were also prepared by the melt-mixing method, and unmodified PLA/CSDG composites were used as a control group for comparative analysis. The functional groups of MPLA enhanced the compatibility between the polymer substrate and CSDG. The composite water vapor/oxygen barrier and mechanical properties were studied. It was found that the barrier and mechanical properties of MPLA/CSDG composites were significantly improved. SEM was adopted to examine the tensile section structure of the composites, and the compatibility between the filler and the matrix was analyzed. An appropriate amount of CSDG had a better dispersibility in the matrix, and it further improved the interfacial bonding force, which in turn improved the composite mechanical properties. X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry were conducted to determine the crystalline properties and to analyze the stability of the composites. It was found that the CSDG content had a significant effect on the crystallinity. Barrier and biodegradation mechanisms were also discussed.

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

Nanomaterials ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 22 ◽  
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.

Poly(lactic acid)/polypropylene and compatibilized poly(lactic acid)/polypropylene blends prepared by a vane extruder: analysis of the mechanical properties, morphology and thermal behavior

2015 ◽  
Vol 35 (8) ◽  
pp. 753-764 ◽  
Author(s):  
Rong-yuan Chen ◽  
Wei Zou ◽  
Hai-chen Zhang ◽  
Gui-zhen Zhang ◽  
Zhi-tao Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Thermal Resistance ◽  
Flexural Modulus ◽  
Weight Fraction ◽  
Poly Lactic Acid ◽  
Scanning Calorimetry ◽  
Crystallization Property ◽  
The Matrix ◽  
Pp Blends

Abstract Poly(lactic acid) (PLA)/polypropylene (PP) blends with different weight fractions were prepared by a novel vane extruder. The mechanical properties, morphology, crystallization behavior and thermal stability of the blends were investigated. The tensile strength, flexural strength and elongation at break decreased nonlinearly when the PP content was not more than 50 wt% and then increased with an increase in the PP content. The flexural modulus decreased with increasing PP weight fraction. The PLA/PP 90:10 blend exhibited the optimum impact strength. Scanning electron microscopy measurements revealed that the PLA/PP blends were immiscible. Phase separation occurred significantly at a blend ratio of 50:50. Regarding the PLA/PP 90:10 blend, the mean diameter of the disperse-phase PP particles was the smallest at 1.11 μm. Differential scanning calorimetry measurements showed that low content of PP enhanced the crystallization of PLA. The PLA component in the blends impeded the crystallization of PP when PP was used as the matrix. The thermogravimetric analysis measurement involved a two-step decomposition process of the blends. The thermal resistance of the blends was improved by compounding with PP. As compatibilizers, both the maleic anhydride-grafted PP and the ethylene/n-butyl acrylate/glycidyl methacrylate terpolymer helped improve the mechanical properties, crystallization property and thermal resistance of the PLA/PP blends.

scholarly journals Nonisothermal Crystallization Kinetics of Polylactic Acid under the Influence of Polyolefin Elastomers

2020 ◽  
Vol 4 (2) ◽  
pp. 65
Author(s):  
Azadeh Khosravi ◽  
Abdolhossein Fereidoon ◽  
Mohammad Mehdi Khorasani ◽  
Vincent Berthe ◽  
Henri Vahabi ◽  
...  
Keyword(s):  
Crystallization Kinetics ◽  
Crystallization Kinetic ◽  
Ethylene Vinyl Acetate ◽  
Poly Lactic Acid ◽  
Experimental Investigations ◽  
Melt Mixing ◽  
Dsc Measurements ◽  
Theoretical Approaches ◽  
The Matrix ◽  
Kinetics Of

Crystallization kinetics of various blends of poly(lactic acid) (PLA)/polyolefin elastomer (POE) was studied through nonisothermal experimental investigations and theoretical approaches. The PLA/POE blends were prepared in a melt mixing process by using two types of POEs and compatibilizers. The rubber phases used were adopted on the basis of polyethylene (PE) and polypropylene (PP) type olefin elastomers. The effects of two kinds of compatibilizers containing ethylene vinyl acetate copolymer (EVA) and ethylene acrylic ester-glycidyl methacrylate terpolymer (EGMA) on the morphology and various parameters of crystallization of PLA were investigated using scanning electron microscopy (SEM) and differential scanning calorimeter (DSC) measurements, respectively. The morphology investigations on PLA blends containing PP based olefin elastomers showed that the introduction of EGMA compatibilizer into the matrix led to a more than 100% reduction in the size of the rubber droplets. The experimental measurements of crystallization behavior of various PLA/POE blends showed that the POEs and compatibilizers could cause a fall in the initial crystallization temperature more than 13 °C. The theoretical approaches used for studying the kinetics of crystallization of PLA in the presence of various POEs and compatibilizers indicated a decrease in the crystallinity of PLA and a 64% reduction in the activation energy compared to the neat PLA. The results suggest that the largest variation in the crystallization kinetic parameters of PLA was resulted from the PP based olefin elastomer and EGMA compatibilizer.

scholarly journals Poly(Lactic Acid)/Graphite Nanoplatelet Nanocomposite Filaments for Ligament Scaffolds

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2796
Author(s):  
Magda Silva ◽  
Carina Gomes ◽  
Isabel Pinho ◽  
Hugo Gonçalves ◽  
Ana C. Vale ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Cruciate Ligament ◽  
Poly Lactic Acid ◽  
Graphite Nanoplatelets ◽  
Melt Mixing ◽  
Regenerative Capacity ◽  
Additive Fabrication ◽  
3D Printed ◽  
Filler Dispersion ◽  
Anterior Cruciate

The anterior cruciate ligament (ACL) is one of the most prone to injury in the human body. Due to its insufficient vascularization and low regenerative capacity, surgery is often required when it is ruptured. Most of the current tissue engineering (TE) strategies are based on scaffolds produced with fibers due to the natural ligament’s fibrous structure. In the present work, composite filaments based on poly(L-lactic acid) (PLA) reinforced with graphite nanoplatelets (PLA+EG) as received, chemically functionalized (PLA+f-EG), or functionalized and decorated with silver nanoparticles [PLA+((f-EG)+Ag)] were produced by melt mixing, ensuring good filler dispersion. These filaments were produced with diameters of 0.25 mm and 1.75 mm for textile-engineered and 3D-printed ligament scaffolds, respectively. The resulting composite filaments are thermally stable, and the incorporation of graphite increases the stiffness of the composites and decreases the electrical resistivity, as compared to PLA. None of the filaments suffered significant degradation after 27 days. The composite filaments were processed into 3D scaffolds with finely controlled dimensions and porosity by textile-engineered and additive fabrication techniques, demonstrating their potential for ligament TE applications.

Preparation of a Poly(Lactic Acid)/Montmorillonite Nanocomposite

2014 ◽  
Vol 631 ◽  
pp. 151-155
Author(s):  
Ko Nakanishi ◽  
Shuichi Yamagata ◽  
Tsukasa Akasaka ◽  
Shigeaki Abe ◽  
Yasuhiro Yoshida ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Flexural Modulus ◽  
Weight Fraction ◽  
Silicate Layer ◽  
Poly Lactic Acid ◽  
Differential Scanning Calorimetry Measurement ◽  
Scanning Calorimetry ◽  
Solution Intercalation ◽  
The Matrix ◽  
Diffraction Patterns

Poly (L-lactic acid)/organically modified montmorillonite (PLLA/OMMT) nanocomposites were fabricated by a solution intercalation method. OMMT, modified with quaternary alkylammonium ion, was prepared by alkyltrialkoxysilane. The differential scanning calorimetry measurement revealed that the crystallization temperatures of PLLA/OMMT nanocomposites were at around 110 °C regardless of the existence of OMMT or the weight fraction of them. X-ray diffraction patterns suggested that the (001) diffraction was around 2θ = 2.5°. The TEM image showed variously expanded interlayer galleries of OMMT and partially exfoliated silicate layer unit in the matrix. Board-shaped specimens for mechanical property tests were fabricated by compression-molding at 190 °C (including 30 min annealing at 110 °C). The flexural modulus of the nanocomposites increased with increasing content of OMMT. Vickers hardness of the nanocomposites were almost same independent on weight fraction of OMMT.

Preparation and characterization of poly(lactic acid)/sisal fiber bio-composites under continuous elongation flow

2018 ◽  
Vol 39 (1) ◽  
pp. 76-84 ◽  
Author(s):  
Yongbin Tan ◽  
Xiaoqiu Zhang ◽  
Jin-ping Qu
Keyword(s):  
Lactic Acid ◽  
Extrusion Direction ◽  
Tensile Modulus ◽  
Mechanical Tests ◽  
Sisal Fiber ◽  
Poly Lactic Acid ◽  
Scanning Calorimetry ◽  
Electron Microscopic ◽  
The Matrix ◽  
Elongation Flow

AbstractIn this study, poly(lactic acid) (PLA) matrix bio-composites reinforced with various quantities of sisal fibers (SFs) (from 10% to 50% in weight) were fabricated by using a self-made vane mixer, which can generate continuous elongation flow. The morphology, crystallization, and mechanical properties of PLA/SF bio-composites under continuous elongation flow were investigated. Scanning electron microscopic images showed that SFs were uniformly dispersed in the matrix and oriented along the extrusion direction. Meanwhile, it was found that the diameter of SFs decreased from 250 to 20 μm, which certified that continuous elongation flow remarkably affected the separation of elementary fibers from fiber bundles. Wide-angle X-ray diffraction and differential scanning calorimetry measurements indicated that the addition of SFs promoted the crystallization of PLA as well as increased the crystallinity of PLA. The mechanical tests exhibited that both impact strength and tensile modulus were significantly enhanced (about 64% and 94.63%, respectively) with SFs loading at 40%, which was due to the well dispersion and separation of elementary fibers.

Geraniol and cinnamaldehyde as natural antibacterial additives for poly(lactic acid) and their plasticizing effects

2019 ◽  
Vol 40 (1) ◽  
pp. 38-48
Author(s):  
Mert Akgün ◽  
İhsan Başaran ◽  
Salih C. Suner ◽  
Ayhan Oral
Keyword(s):  
Lactic Acid ◽  
Antibacterial Activities ◽  
Mechanical Tests ◽  
Sem Analysis ◽  
Diffusion Method ◽  
Poly Lactic Acid ◽  
Scanning Calorimetry ◽  
Disk Diffusion Method ◽  
Vis Spectroscopy ◽  
The Matrix

Abstract The main goal of this study is to prepare antibacterial poly(lactic acid) (PLA) containing cinnamaldehyde and geraniol and to evaluate the antibacterial activity and assess the changes of physical properties of the PLA films. Cinnamaldehyde- and geraniol-incorporated (10%, 20%, 30%, and 50% v/w) PLA films were prepared via solution-casting. While preparing these films, plasticizers were not added to the matrix. Antibacterial activities of these films against Escherichia coli and Staphylococcus aureus were investigated by the disk diffusion method. Thermal degradation characteristics were analyzed via thermogravimetric analysis (TGA), glass transition, crystallization, and melting temperatures, and enthalpies of the films were determined from differential scanning calorimetry (DSC) scans. Tensile strength and elongation-at-break values of neat PLA and antibacterial-compound-containing films were evaluated and compared after the mechanical tests. Moreover, the changes in the polymer morphology were observed by SEM analysis, and opacity of the films was determined by UV-vis spectroscopy. Our results showed that both compounds provided antibacterial effect to the PLA, with cinnamaldehyde being more effective than geraniol. Moreover, plasticization effects of the compounds were confirmed by DSC analysis.

Development of three-dimensional printing filaments based on poly(lactic acid)/hydroxyapatite composites with potential for tissue engineering

2021 ◽  
pp. 002199832098856
Author(s):  
Marcela Piassi Bernardo ◽  
Bruna Cristina Rodrigues da Silva ◽  
Luiz Henrique Capparelli Mattoso
Keyword(s):  
Tissue Engineering ◽  
Lactic Acid ◽  
Fused Deposition Modeling ◽  
Three Dimensional ◽  
Poly Lactic Acid ◽  
Scanning Calorimetry ◽  
Three Dimensional Printing ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
3D Printed

Injured bone tissues can be healed with scaffolds, which could be manufactured using the fused deposition modeling (FDM) strategy. Poly(lactic acid) (PLA) is one of the most biocompatible polymers suitable for FDM, while hydroxyapatite (HA) could improve the bioactivity of scaffold due to its chemical composition. Therefore, the combination of PLA/HA can create composite filaments adequate for FDM and with high osteoconductive and osteointegration potentials. In this work, we proposed a different approache to improve the potential bioactivity of 3D printed scaffolds for bone tissue engineering by increasing the HA loading (20-30%) in the PLA composite filaments. Two routes were investigated regarding the use of solvents in the filament production. To assess the suitability of the FDM-3D printing process, and the influence of the HA content on the polymer matrix, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) were performed. The HA phase content of the composite filaments agreed with the initial composite proportions. The wettability of the 3D printed scaffolds was also increased. It was shown a greener route for obtaining composite filaments that generate scaffolds with properties similar to those obtained by the solvent casting, with high HA content and great potential to be used as a bone graft.

Analysis of Coir Fiber Reinforced Poly-Lactic Acid (PLA) and Poly-Propylene (PP) Polymeric Composite

2016 ◽  
Vol 852 ◽  
pp. 10-15
Author(s):  
Sahas Bansal ◽  
M. Ramachandran ◽  
Pramod Raichurkar
Keyword(s):  
Lactic Acid ◽  
Natural Fibers ◽  
Polymeric Composite ◽  
Mechanical Tests ◽  
Composite Resins ◽  
Poly Lactic Acid ◽  
Coir Fiber ◽  
Scanning Calorimetry ◽  
Biodegradable Composite ◽  
Poly Propylene

Green composites shaped by mixture of biodegradable polymers and natural fibers have spellbound massive interest in current years due to their environmentally valuable properties and also to decrease our dependency on the non-renewable resources. Due to the environmental advantages and light weight of natural fibers, an increasing quantity of natural fibers has been used to replace synthetic fibers composites. Coir fiber poly-lactic acid (PLA)/ poly-propylene (PP) resin reinforced polymeric composites have been developed with 90o orientation. The composition of PLA and PP for resin preparation is taken in the ratio 95:05 whereas for the composite, resins and coir fiber in 80:20. The compression molding technique is applied and then the tests are carried out. Mechanical tests (Impact and Hardness), Micro structural analysis (Fourier Transform Infrared Spectroscopy and Optical Imaging) and Differential Scanning Calorimetry are conducted. According to the investigational verification, the new biodegradable composite shows significant results on par with synthetic/ man made composites and the advantages of using bio-composites has been indicated with simplicity.

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