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Yan M, Pang Y, Shao W, Ma C, Zheng W. Utilization of spent coffee grounds as charring agent to prepare flame retardant poly(lactic acid) composites with improved toughness. Int J Biol Macromol 2024; 264:130534. [PMID: 38432276 DOI: 10.1016/j.ijbiomac.2024.130534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 02/20/2024] [Accepted: 02/27/2024] [Indexed: 03/05/2024]
Abstract
The objective was to utilize spent coffee grounds (SCG) as charring agent to combine with ammonium polyphosphate (APP) to prepare flame retardant poly(lactic acid) (PLA) composites with improved toughness. PLA/APP-SCG and PLA/APP-SCG/KH560 composites were prepared, and silane coupling agent KH560 was applied to improve particle-matrix interfacial compatibility. The particle-matrix interface, char formation, flame retardancy, mechanical properties and fracture morphology of PLA composites were studied. Results showed that PLA/APP-SCG5% and PLA/APP-SCG20% passed UL-94 V-0 rating, and increase in charred residues was favorable for improving flame retardancy. Improved toughness was also obtained compared to PLA, attributed to debonding of APP from matrix under external force as well as plasticization effect of coffee oil contained in SCG. PLA/APP-SCG5%/KH560 and PLA/APP-SCG20%/KH560 showed smaller elongation at break and impact strength compared to PLA/APP-SCG5% and PLA/APP-SCG20%, respectively. The improved interfacial compatibility was unfavorable for debonding of APP from matrix, and both APP and SCG played the role of enhancing strength, thus decreasing toughness. PLA/APP-SCG/KH560 counterparts were actually set as parallel samples to prove that PLA/APP-SCG composites showed improved toughness with weak interfacial compatibility. This study has provided a practical approach to utilize bio-derived wastes as charring agent to prepare flame retardant PLA composites with enhanced toughness.
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Affiliation(s)
- Ming Yan
- School of Materials Science and Engineering, Shenyang University of Chemical Technology, Shenyang 110142, Liaoning Province, China; Key Laboratory of Bio-based Polymeric Materials Technology and Application of Zhejiang Province, Laboratory of Polymers and Composites, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, Zhejiang Province, China
| | - Yongyan Pang
- Key Laboratory of Bio-based Polymeric Materials Technology and Application of Zhejiang Province, Laboratory of Polymers and Composites, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, Zhejiang Province, China.
| | - Weiwei Shao
- School of Materials Science and Engineering, Shenyang University of Chemical Technology, Shenyang 110142, Liaoning Province, China; Key Laboratory of Bio-based Polymeric Materials Technology and Application of Zhejiang Province, Laboratory of Polymers and Composites, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, Zhejiang Province, China
| | - Chi Ma
- School of Materials Science and Engineering, Shenyang University of Chemical Technology, Shenyang 110142, Liaoning Province, China
| | - Wenge Zheng
- Key Laboratory of Bio-based Polymeric Materials Technology and Application of Zhejiang Province, Laboratory of Polymers and Composites, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, Zhejiang Province, China
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Paramatti M, Romani A, Pugliese G, Levi M. PLA Feedstock Filled with Spent Coffee Grounds for New Product Applications with Large-Format Material Extrusion Additive Manufacturing. ACS OMEGA 2024; 9:6423-6431. [PMID: 38371822 PMCID: PMC10870276 DOI: 10.1021/acsomega.3c05669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 12/01/2023] [Accepted: 12/07/2023] [Indexed: 02/20/2024]
Abstract
Food waste and loss generate significant waste such as spent coffee grounds (SCGs) from coffee consumption. These byproducts can be valorized by following circular economy and bioeconomy principles, e.g., using SCGs in polymer-based composites for 3D printing. Although desktop-size material extrusion additive manufacturing is increasingly adopted for biomass-polymer-based composites, the potential of large-format direct extrusion 3D printing systems remains unexplored. This work investigated the thermal, rheological, and mechanical properties of PLA/SCG composites for applications with a large-format pellet extrusion 3D printer. The formulations exhibit minimal degradation at typical 3D printing temperatures of PLA, i.e., ∼190 °C, and limited effects on crystallinity by increasing the SCG weight percentage. The decrease in viscosity due to SCGs improves the printability and layer adhesion, as confirmed by the tensile test results, such as higher ultimate tensile strength and elongation at break values compared to those of the state-of-the-art values. Using pellet feedstocks contributes to limiting the effects of thermomechanical degradation by reducing raw material processing, i.e., avoiding filament extrusion. Using PLA/SCGs formulations was demonstrated through 3D printed complex parts with nonplanar slicing techniques, including a large-scale furniture product, validating large-format pellet extrusion 3D printers for scaling up the use of biomass-filled polymers.
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Affiliation(s)
- Martina Paramatti
- Department
of Chemistry, Materials, and Chemical Engineering “Giulio Natta”, Piazza Leonardo Da Vinci 32, 20133 Milano, Italy
| | - Alessia Romani
- Department
of Chemistry, Materials, and Chemical Engineering “Giulio Natta”, Piazza Leonardo Da Vinci 32, 20133 Milano, Italy
- Design
Department, Via Durando, 20158 Milano, Italy
| | | | - Marinella Levi
- Department
of Chemistry, Materials, and Chemical Engineering “Giulio Natta”, Piazza Leonardo Da Vinci 32, 20133 Milano, Italy
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Zheng NC, Chien HW. UV-crosslinking of chitosan/spent coffee ground composites for enhanced durability and multifunctionality. Int J Biol Macromol 2024; 255:128215. [PMID: 37992943 DOI: 10.1016/j.ijbiomac.2023.128215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 11/05/2023] [Accepted: 11/15/2023] [Indexed: 11/24/2023]
Abstract
Spent coffee grounds (SCGs) have numerous applications and are often blended with polymers to create composites. However, SCGs are physically trapped within the polymer matrix, lacking strong chemical bonding. Therefore, this study has developed a new method for UV crosslinking composites using phenyl azide to address the issue of SCG leakage and limited durability of the composites. The main approach involves grafting phenyl azide onto chitosan, which is then combined with SCGs. When exposed to UV light, the SCGs become covalently linked to the chitosan chains. This method not only resolves the problem of chitosan's porous material fragility but also prevents SCG detachment, surpassing the performance of glutaraldehyde-crosslinked composites. Regarding applications, CS/SCG composites exhibit rapid heating and photothermal stability, making them suitable for use as thermal pads in evaporative water purification, enabling for the collection of pure water from contaminated sources. Furthermore, SCGs have the ability to adsorb metal ions, significantly enhancing the Cu2+ adsorption capacity of CS/SCG composites compared to pure CS, with an increase of more than twofold. This research not only presents a practical solution for stabilizing fillers within polymer matrices but also demonstrates the reusability of SCGs.
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Affiliation(s)
- Nai-Ci Zheng
- Department of Chemical and Materials Engineering, National Kaohsiung University of Science and Technology, Kaohsiung 80778, Taiwan
| | - Hsiu-Wen Chien
- Department of Chemical and Materials Engineering, National Kaohsiung University of Science and Technology, Kaohsiung 80778, Taiwan; Photo-Sensitive Material Advanced Research and Technology Center (Photo-SMART Center), National Kaohsiung University of Science and Technology, Kaohsiung 80778, Taiwan.
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de Bomfim ASC, de Oliveira DM, Benini KCCDC, Cioffi MOH, Voorwald HJC, Rodrigue D. Effect of Spent Coffee Grounds on the Crystallinity and Viscoelastic Behavior of Polylactic Acid Composites. Polymers (Basel) 2023; 15:2719. [PMID: 37376365 DOI: 10.3390/polym15122719] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 06/02/2023] [Accepted: 06/08/2023] [Indexed: 06/29/2023] Open
Abstract
This work investigated the addition of spent coffee grounds (SCG) as a valuable resource to produce biocomposites based on polylactic acid (PLA). PLA has a positive biodegradation effect but generates poor proprieties, depending on its molecular structure. The PLA and SCG (0, 10, 20 and 30 wt.%) were mixed via twin-screw extrusion and molded by compression to determine the effect of composition on several properties, including mechanical (impact strength), physical (density and porosity), thermal (crystallinity and transition temperature) and rheological (melt and solid state). The PLA crystallinity was found to increase after processing and filler addition (34-70% in the 1st heating) due to a heterogeneous nucleation effect, leading to composites with lower glass transition temperature (1-3 °C) and higher stiffness (~15%). Moreover, the composites had lower density (1.29, 1.24 and 1.16 g/cm3) and toughness (30.2, 26.8 and 19.2 J/m) as the filler content increased, which is associated with the presence of rigid particles and residual extractives from SCG. In the melt state, polymeric chain mobility was enhanced, and composites with a higher filler content became less viscous. Overall, the composite with 20 wt.% SCG provided the most balanced properties being similar to or better than neat PLA but at a lower cost. This composite could be applied not only to replace conventional PLA products, such as packaging and 3D printing, but also to other applications requiring lower density and higher stiffness.
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Affiliation(s)
- Anne Shayene Campos de Bomfim
- Fatigue and Aeronautical Materials Research Group, Department of Materials and Technology, UNESP-São Paulo State University, Guaratinguetá 12516-410, SP, Brazil
| | - Daniel Magalhães de Oliveira
- Fatigue and Aeronautical Materials Research Group, Department of Materials and Technology, UNESP-São Paulo State University, Guaratinguetá 12516-410, SP, Brazil
| | - Kelly Cristina Coelho de Carvalho Benini
- Fatigue and Aeronautical Materials Research Group, Department of Materials and Technology, UNESP-São Paulo State University, Guaratinguetá 12516-410, SP, Brazil
| | - Maria Odila Hilário Cioffi
- Fatigue and Aeronautical Materials Research Group, Department of Materials and Technology, UNESP-São Paulo State University, Guaratinguetá 12516-410, SP, Brazil
| | - Herman Jacobus Cornelis Voorwald
- Fatigue and Aeronautical Materials Research Group, Department of Materials and Technology, UNESP-São Paulo State University, Guaratinguetá 12516-410, SP, Brazil
| | - Denis Rodrigue
- Center for Research on Advanced Materials (CERMA), Department of Chemical Engineering, Université Laval, Quebec, QC G1V 0A6, Canada
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Thermoplastic starch based blends as a highly renewable filament for fused deposition modeling 3D printing. Int J Biol Macromol 2022; 219:175-184. [PMID: 35926678 DOI: 10.1016/j.ijbiomac.2022.07.232] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 07/25/2022] [Accepted: 07/29/2022] [Indexed: 11/20/2022]
Abstract
3D printing technology is considered as a highly flexible method which can achieve a various customized end products. The employment of bio-based materials can significantly decrease the environmental footprint of the end 3D printing products. This study presents the preparation of thermoplastic starch (TPS)/poly(lactic acid) (PLA)/poly(butyleneadipate-co-terephthalate) (PBAT) composite that dedicated for the FDM 3D printing technology, the ratio of TPS:PLA:PBAT was fixed at 50:40:10 wt%. In addition, the chain extender ADR4468 (CE) was added to improve the brittleness of the blends to obtain better 3D printing filament. The mechanical properties of blends were improved by the addition of CE with 113 % increase in elongation at break and the 190 % raise in impact strength. Dynamic rheological analysis showed the maximum degree of complex viscosity and melt strength when the content of CE reached 1 wt%. The successful printability of TPS-based filament was demonstrated by accurate and complex printing samples. This paper provided a method to prepare highly renewable filaments for 3D printing.
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Franca AS, Oliveira LS. Potential Uses of Spent Coffee Grounds in the Food Industry. Foods 2022; 11:foods11142064. [PMID: 35885305 PMCID: PMC9316316 DOI: 10.3390/foods11142064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/01/2022] [Accepted: 07/07/2022] [Indexed: 11/23/2022] Open
Abstract
Current estimates place the amount of spent coffee grounds annually generated worldwide in the 6 million ton figure, with the sources of spent coffee grounds being classified as domestic (i.e., household), commercial (i.e., coffee houses, cafeterias and restaurants), and industrial (i.e., soluble and instant coffee industries). The majority of the produced spent coffee grounds are currently being inappropriately destined for landfills or to a form of energy recovery (e.g., incineration) as a refuse-derived fuel. The disposal of spent coffee in landfills allows for its anaerobic degradation with consequent generation and emission of aggressive greenhouse gases such as methane and CO2, and energy recovery processes must be considered an end-of-life stage in the lifecycle of spent coffee grounds, as a way of delaying CO2 emissions and of avoiding emissions of toxic organic volatile compounds generated during combustion of this type of waste. Aside from these environmental issues, an aspect that should be considered is the inappropriate disposal of a product (SCG) that presents unique thermo-mechanical properties and textural characteristics and that is rich in a diversity of classes of compounds, such as polysaccharides, proteins, phenolics, lipids and alkaloids, which could be recovered and used in a diversity of applications, including food-related ones. Therefore, researchers worldwide are invested in studying a variety of possible applications for spent coffee grounds and products thereof, including (but not limited to) biofuels, catalysts, cosmetics, composite materials, feed and food ingredients. Hence, the aim of this essay was to present a comprehensive review of the recent literature on the proposals for utilization of spent coffee grounds in food-related applications, with focus on chemical composition of spent coffee, recovery of bioactive compounds, use as food ingredients and as components in the manufacture of composite materials that can be used in food applications, such as packaging.
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Peixoto J, Carvalho EAS, Gomes MLPM, da Silva Guimarães R, Monteiro SN, de Azevedo ARG, Vieira CMF. Incorporation of Industrial Glass Waste into Polymeric Resin to Develop Artificial Stones for Civil Construction. ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING 2022. [DOI: 10.1007/s13369-021-06071-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Valorization of Spent Coffee Grounds as Precursors for Biopolymers and Composite Production. Polymers (Basel) 2022; 14:polym14030437. [PMID: 35160428 PMCID: PMC8840223 DOI: 10.3390/polym14030437] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/14/2022] [Accepted: 01/19/2022] [Indexed: 01/27/2023] Open
Abstract
Spent coffee grounds (SCG) are a current subject in many works since coffee is the second most consumed beverage worldwide; however, coffee generates a high amount of waste (SCG) and can cause environmental problems if not discarded properly. Therefore, several studies on SCG valorization have been published, highlighting its waste as a valuable resource for different applications, such as biofuel, energy, biopolymer precursors, and composite production. This review provides an overview of the works using SCG as biopolymer precursors and for polymer composite production. SCG are rich in carbohydrates, lipids, proteins, and minerals. In particular, carbohydrates (polysaccharides) can be extracted and fermented to synthesize lactic acid, succinic acid, or polyhydroxyalkanoate (PHA). On the other hand, it is possible to extract the coffee oil and to synthesize PHA from lipids. Moreover, SCG have been successfully used as a filler for composite production using different polymer matrices. The results show the reasonable mechanical, thermal, and rheological properties of SCG to support their applications, from food packaging to the automotive industry.
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Abstract
Three-dimensional (3D) printing, or additive manufacturing, is a group of innovative technologies that are increasingly employed for the production of 3D objects in different fields, including pharmaceutics, engineering, agri-food and medicines. The most processed materials by 3D printing techniques (e.g., fused deposition modelling, FDM; selective laser sintering, SLS; stereolithography, SLA) are polymeric materials since they offer chemical resistance, are low cost and have easy processability. However, one main drawback of using these materials alone (e.g., polylactic acid, PLA) in the manufacturing process is related to the poor mechanical and tensile properties of the final product. To overcome these limitations, fillers can be added to the polymeric matrix during the manufacturing to act as reinforcing agents. These include inorganic or organic materials such as glass, carbon fibers, silicon, ceramic or metals. One emerging approach is the employment of natural polymers (polysaccharides and proteins) as reinforcing agents, which are extracted from plants or obtained from biomasses or agricultural/industrial wastes. The advantages of using these natural materials as fillers for 3D printing are related to their availability together with the possibility of producing printed specimens with a smaller environmental impact and higher biodegradability. Therefore, they represent a “green option” for 3D printing processing, and many studies have been published in the last year to evaluate their ability to improve the mechanical properties of 3D printed objects. The present review provides an overview of the recent literature regarding natural polymers as reinforcing agents for 3D printing.
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Biocomposites Developed with Litchi Peel Based on Epoxy Resin: Mechanical Properties and Flame Retardant. J CHEM-NY 2021. [DOI: 10.1155/2021/3287733] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Bio-based composites are reinforced polymeric materials, which include one or two bio-based components. Biocomposites have recently attracted great attention for applications ranging from home appliances to the automotive industry. The outstanding advantages are low cost, biodegradability, lightness, availability, and solving environmental problems. In recent days, biodegradable natural fibers are attracting a great deal of interest from researchers to work on and develop a new type of composite material for diverse applications. The objective of this work is to evaluate fire resistance and mechanical properties of epoxy polymer composites reinforced with lychee peel (Vietnam), at 10 wt%, 20 wt%, and 30 wt% mass%. The study showed that the mechanical properties and flame retardancy tended to increase in the presence of lychee peel reinforcement. In the combined ratios, 20 wt% lychee rind gave a limiting oxygen index of 21.5%, with a burning rate of 23.45 mm/min. In terms of mechanical strength, in which the Izod impact strength increased by 26.46%, the compressive strength increased by 25.20% and the tensile strength increased by 20.62%. The microscopic images (SEM images) show that the particle distribution is quite good and the adhesion and wetting compatibility on the two-phase interface of lychee peel-epoxy resin are strong.
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Hybrid Biocomposites Based on Used Coffee Grounds and Epoxy Resin: Mechanical Properties and Fire Resistance. INTERNATIONAL JOURNAL OF CHEMICAL ENGINEERING 2021. [DOI: 10.1155/2021/1919344] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Studies on using biomaterials hybridized with other materials to produce biomaterials have been paid more attention due to their low cost, abundance, renewability, and degradability. Therefore, these materials are ecofriendly and nontoxic to humans. A large number of used coffee grounds (SCGs) are often discarded and replacements are necessary for dealing with environmental problems. This work developed sustainable materials by reusing SCGs. Used coffee grounds were mixed with epoxy resin at different amounts: 30 wt %, 40 wt %, 50 wt %, and 60 wt %. SCGs were treated with 0.5 N NaOH, at SCGs/NaOH ratio of 1 : 2. SEM images showed that the material with 30 wt % SCGs has good compatibility without phase division on the SCGs-epoxy interface. Results of mechanical properties of epoxy composites with 30 wt % SCGs are as follows: tensile strength of 44.81 ± 10 MPa, flexural strength of 80.07 ± 0.16 MPa, compressive strength of 112.56 ± 0.11 MPa, and Izod strength and impact of 8.21 ± 0.19 kJ/m2. In terms of flame-retardant properties, the oxygen index is limited to 20.8% ± 0.20 and the burning rate according to UL94HB is 27.02 ± 0.29 mm/min. The obtained results indicate that it is possible to produce biohybrid composites from epoxy resin and SCGs. This work offers an ecofriendly alternative method to use the waste of the coffee industry. It contributes to improvements of the general characteristics of composites such as mechanical, thermal, and flame-retardant properties. This work proved that SCGs have a high potential to be used in a wide range of composite materials for civil engineering applications.
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