Effects of the chain‐extender content on the structure and performance of poly(lactic acid)–poly(butylene succinate)–microcrystalline cellulose composites
Abstract:Composites of poly(lactic acid) (PLA) with poly(butylene succinate) (PBS) and microcrystalline cellulose (MCC) as reinforcements of the polymer matrix were prepared by melt blending to improve the brittleness of PLA. As a reactive compatibilizer, a chain extender was used in an attempt to solve the composites’ interfacial problems and to improve their mechanical properties; Fourier transform infrared spectroscopy indicated that the chain extender functionally reacted with PLA, PBS, and MCC mainly through end c… Show more
“…As a result, consistent filaments were successfully extruded and the processing window for 3D printing was widened such that the blends could be printed at higher temperatures. Based on preliminary evaluation and existing research 16,17,24,25 , as well as taking the biocompatibility into consideration, a low amount of CE (0.25 parts per hundred-phr) was selected for this study.…”
Section: Resultsmentioning
confidence: 99%
“…As a result, consistent filaments were successfully extruded and the processing window for 3D printing was widened such that the blends could be printed at higher temperatures. Based on preliminary evaluation and existing research 16 , 17 , 24 , 25 , as well as taking the biocompatibility into consideration, a low amount of CE (0.25 parts per hundred—phr) was selected for this study. Figure 1 The optimization of 3D printing parameter and 3D printed samples: ( A ) the effect of chain extender on the melt-extrusion filament performance (PHBV:PLA (40:60) blend); ( B ) the effect of temperature on the complex viscosity of PHBV:PLA:CE (40:60:0.25) blend; ( C ) the effect of printing speed on the complex viscosity of PHBV:PLA:CE blends; ( D ) the 3D printed PHBV:PLA:CE (40:60:0.25) tensile and flexural bar at optimized temperature and printing speed.…”
In this study, the 3D printability of a series of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/poly(lactic acid) (PLA) blends were investigated using fused filament fabrication (FFF). The studied blends suffered from poor 3D printability due to differences in compatibility and low thermal resistance. These shortcomings were addressed by incorporating a functionalized styrene-acrylate copolymer with oxirane moieties as a chain extender (CE). To enhance mechanical properties, the synergistic effect of 3D printing parameters such as printing temperature and speed, layer thickness and bed temperature were explored. Rheological analysis showed improvement in the 3D printability of PHBV:PLA:CE blend by allowing a higher printing temperature (220 °C) and sufficient printing speed (45 mm s −1). The surface morphology of fractured tensile specimens showed good bonding between layers when a bed temperature of 60 °C was used and a layer thickness of 0.25 mm was designed. The optimized printing samples shown higher storage modulus and strength, resulting in stiffer and stronger parts. The crystallinity, morphology and performance of the 3D printed products were correlated to share key methods to improve the 3D printability of PHBV:PLA based blends which may be implemented in other biopolymer blends, and further highlight how process parameters enhance the mechanical performance of 3D printed products. Conventional sources of energy such as fossil fuels are becoming less sustainable and reliable due to our limited natural resources 1. The development of greener materials with at least similar mechanical properties to conventional feedstock is of importance for their successful implementation in manufacturing sectors such as additive manufacturing (AM) 2. Fused filament fabrication (FFF) is an AM technology in which thermoplastic materials are melted and deposited layer by layer onto a free surface platform 3. FFF allows freedom of design, which facilitates prototyping and customization of products in a timely and cost-effective manner. Due to the nature of FFF processing, material properties are highly anisotropic and research on materials, as well as printing parameters such as layer width, thickness, raster angle and air gap between layers, is vital for the optimization of fabricated products 3-6. Consequently, previous researchers have determined that layer orientation of 0° raster angle in the axial load direction results in higher tensile properties, while products with build orientation angles of ± 45° have improved impact strength and less warping 7-9. Polyhydroxyalkanoates (PHAs) are gaining immense attention in the field of biopolymers due to their inherent nature such as biodegradability, biocompatibility and promise for use in a range of applications, especially in the biomedical industry 10,11. In addition, PHAs are reducing the high dependency on petroleum-based materials. Among PHAs, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is currently one of the most widely produced and commercialized bioplas...
“…As a result, consistent filaments were successfully extruded and the processing window for 3D printing was widened such that the blends could be printed at higher temperatures. Based on preliminary evaluation and existing research 16,17,24,25 , as well as taking the biocompatibility into consideration, a low amount of CE (0.25 parts per hundred-phr) was selected for this study.…”
Section: Resultsmentioning
confidence: 99%
“…As a result, consistent filaments were successfully extruded and the processing window for 3D printing was widened such that the blends could be printed at higher temperatures. Based on preliminary evaluation and existing research 16 , 17 , 24 , 25 , as well as taking the biocompatibility into consideration, a low amount of CE (0.25 parts per hundred—phr) was selected for this study. Figure 1 The optimization of 3D printing parameter and 3D printed samples: ( A ) the effect of chain extender on the melt-extrusion filament performance (PHBV:PLA (40:60) blend); ( B ) the effect of temperature on the complex viscosity of PHBV:PLA:CE (40:60:0.25) blend; ( C ) the effect of printing speed on the complex viscosity of PHBV:PLA:CE blends; ( D ) the 3D printed PHBV:PLA:CE (40:60:0.25) tensile and flexural bar at optimized temperature and printing speed.…”
In this study, the 3D printability of a series of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/poly(lactic acid) (PLA) blends were investigated using fused filament fabrication (FFF). The studied blends suffered from poor 3D printability due to differences in compatibility and low thermal resistance. These shortcomings were addressed by incorporating a functionalized styrene-acrylate copolymer with oxirane moieties as a chain extender (CE). To enhance mechanical properties, the synergistic effect of 3D printing parameters such as printing temperature and speed, layer thickness and bed temperature were explored. Rheological analysis showed improvement in the 3D printability of PHBV:PLA:CE blend by allowing a higher printing temperature (220 °C) and sufficient printing speed (45 mm s −1). The surface morphology of fractured tensile specimens showed good bonding between layers when a bed temperature of 60 °C was used and a layer thickness of 0.25 mm was designed. The optimized printing samples shown higher storage modulus and strength, resulting in stiffer and stronger parts. The crystallinity, morphology and performance of the 3D printed products were correlated to share key methods to improve the 3D printability of PHBV:PLA based blends which may be implemented in other biopolymer blends, and further highlight how process parameters enhance the mechanical performance of 3D printed products. Conventional sources of energy such as fossil fuels are becoming less sustainable and reliable due to our limited natural resources 1. The development of greener materials with at least similar mechanical properties to conventional feedstock is of importance for their successful implementation in manufacturing sectors such as additive manufacturing (AM) 2. Fused filament fabrication (FFF) is an AM technology in which thermoplastic materials are melted and deposited layer by layer onto a free surface platform 3. FFF allows freedom of design, which facilitates prototyping and customization of products in a timely and cost-effective manner. Due to the nature of FFF processing, material properties are highly anisotropic and research on materials, as well as printing parameters such as layer width, thickness, raster angle and air gap between layers, is vital for the optimization of fabricated products 3-6. Consequently, previous researchers have determined that layer orientation of 0° raster angle in the axial load direction results in higher tensile properties, while products with build orientation angles of ± 45° have improved impact strength and less warping 7-9. Polyhydroxyalkanoates (PHAs) are gaining immense attention in the field of biopolymers due to their inherent nature such as biodegradability, biocompatibility and promise for use in a range of applications, especially in the biomedical industry 10,11. In addition, PHAs are reducing the high dependency on petroleum-based materials. Among PHAs, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is currently one of the most widely produced and commercialized bioplas...
“…This phenomenon proved the aforementioned reaction of CE and PLA/PPC and had the effect of increasing the chain length and relative molecular weight and even producing long branches to increase the width of the molecular weight distribution. Meanwhile, the increase in storage modulus revealed the improvement in melt strength, and it was beneficial for polymer processing such as blow molding …”
Poly(lactic acid) (PLA)/poly(propylene carbonate) (PPC)/mica composites with different amount of chain extender (CE) were melt compounded and then processed via two routes (compression molding and uniaxial stretching) into sheets and films. The tensile, thermal, and oxygen barrier properties of all the samples were investigated.Tensile test showed that the tensile strength and elongation at break of all films were much higher than that of all sheets, especially for PLA/PPC/mica with 0.9-wt% CE composite (CM 3 (CE) 0.9 ) film. The crystallinity of all films increased significantly after uniaxial stretching of sheet samples. The Fourier transform infrared spectroscopy (FTIR) results proved the chemical reactions occurred between PLA/PPC and CE.Scanning electron microscope (SEM) analysis revealed that compatibility and interfacial adhesion of all samples were improved after adding mica and CE, and they were further enhanced after uniaxial stretching. The addition of CE was not favorable to improve the oxygen barrier performance of PLA/PPC/mica sheet samples. However, the oxygen barrier performance of film samples was significantly improved after uniaxial stretching. In particular, the CM 3 (CE) 0.9 film had the lowest oxygen permeability coefficient (1.4 × 10 −15 cm 3 ·cm/(cm 2 ·s·Pa)), and this was the best oxygen barrier properties reported in the literature for PLA-based composites, which was comparable with PA film. This study demonstrated the high efficiency of uniaxial stretching on improvement of properties of composites, which would promote the application of biodegradable polymers in oxygen sensitive food packaging.
“…28 Recently, many authors have shown the interest on using a chain extender, which is multifunctional additives that bind to the ends of different macromolecular fragments (carboxyl and hydroxyl groups in polyesters), thus extending the chain, increasing the average molar mass of the polymer, and also can be used as a reactive compatibilizer in blends. [29][30][31] The chain extender used in blends promotes the formation of copolymers during compounding in the molten state. It acts as the physical compatibilizer by reducing the size of the dispersed phase.…”
Biodegradable poly(lactic acid) (PLA)/poly(butylene adipate‐co‐terephthalate) (PBAT) blends and films were prepared using melt blending and blowing films technique in the presence of chain extender‐Joncryl ADR 4370F. The ADR contains epoxy functional groups and used as a compatibilizer. The morphological, mechanical, rheological, thermal, and crystalline properties of the PLA/PBAT/ADR blown films were studied. Scanning electron microscopy micrographs of the films revealed more ductile deformation with increasing PBAT content. The addition of PBAT enhanced the toughness of the PLA film. Tensile tests indicated that the elongation at break increased from 20.5% to 334.6% in the machine direction and from 7.1% to 715.9% in the transverse direction. The Young modulus increased from 2690.5 to 395.6 MPa in the machine direction and from 2623.5 to 154.0 MPa in the transverse direction. The sealing strength of 40/60/0.15 PLA/PBAT/ADR film was the highest among all the samples up to 9.4 N 15 mm−1. These findings gave important implications for designing and manufacturing polymer packaging materials.
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