scholarly journals The impact of thermal reprocessing of 3D printable polymers on their mechanical performance and airborne pollutant profiles

2021 ◽  
Vol 28 (11) ◽  
Author(s):  
Antti Juho Kalevi Väisänen ◽  
Lauri Alonen ◽  
Sampsa Ylönen ◽  
Isa Lyijynen ◽  
Marko Hyttinen
Keyword(s):  
3D Printing ◽  
Mechanical Performance ◽  
Plastic Material ◽  
Ultrafine Particle ◽  
Poly Lactic Acid ◽  
Testing System ◽  
Multiple Materials ◽  
Airborne Pollutant ◽  
Mechanical Performances ◽  
The Impact

AbstractThe alterations in volatile organic compound (VOC) and ultrafine particulate (UFP) matter emission profiles following thermal reprocessing of multiple materials were examined. Additionally, mechanical performance of the materials was studied. The VOCs were identified by collecting air samples with Tenax® TA tubes and analyzing them with a GC–MS system. UFP concentrations were monitored with a portable ultrafine particle counter. Total VOC emissions of all materials were reduced by 28–68% after 5 thermal cycles (TCs). However, slight accumulation of 1,4-dioxane was observed with poly(lactic acid) materials. UFP emissions were reduced by 45–88% for 3D printing grade materials over 5 TCs but increased by 62% in the case of a waste plastic material over 3 TCs. The mechanical performance of the materials was investigated by measuring their tensile strengths (TSs) and elastic moduli (EM) with an axial-torsion testing system. The reprocessed materials expressed fluctuations in their 3D printing qualities and mechanical performances. The mechanical performances were observed to reduce only slightly after 5 TCs, and the trend was observable only after the data was mass-normalized. The TSs of the samples were reduced by 10–24%, while the EM were reduced by 1–9% after 5 TCs. The TS and EM of one material were increased by 14 and 33%, respectively. In conclusion, recycled polymers are plausible 3D printing feedstock alternatives as they possess acceptable mechanical performance and low emittance according to this study. Furthermore, non-3D printing grade polymers may be applied in a 3D printer with caution.

scholarly journals Cellulose Nanofibrils Filled Poly(Lactic Acid) Biocomposite Filament for FDM 3D Printing

Molecules ◽  
2020 ◽  
Vol 25 (10) ◽  
pp. 2319 ◽  
Author(s):  
Qianqian Wang ◽  
Chencheng Ji ◽  
Lushan Sun ◽  
Jianzhong Sun ◽  
Jun Liu
Keyword(s):  
Thermal Stability ◽  
3D Printing ◽  
Fused Deposition Modeling ◽  
Mechanical Performance ◽  
Cellulose Nanofibrils ◽  
Poly Lactic Acid ◽  
Fused Deposition ◽  
Wide Range ◽  
The Matrix ◽  
Direct Digital Manufacturing

As direct digital manufacturing, 3D printing (3DP) technology provides new development directions and opportunities for the high-value utilization of a wide range of biological materials. Cellulose nanofibrils (CNF) and polylactic acid (PLA) biocomposite filaments for fused deposition modeling (FDM) 3DP were developed in this study. Firstly, CNF was isolated by enzymatic hydrolysis combined with high-pressure homogenization. CNF/PLA filaments were then prepared by melt-extrusion of PLA as the matrix and CNF as the filler. Thermal stability, mechanical performance, and water absorption property of biocomposite filaments and 3D-printed objects were analyzed. Findings showed that CNF increased the thermal stability of the PLA/PEG600/CNF composite. Compared to unfilled PLA FDM filaments, the CNF filled PLA biocomposite filament showed an increase of 33% in tensile strength and 19% in elongation at break, suggesting better compatibility for desktop FDM 3DP. This study provided a new potential for the high-value utilization of CNF in 3DP in consumer product applications.

Effect of various enzymatic treatments on the mechanical properties of coir fiber/poly(lactic acid) biocomposites

2019 ◽  
pp. 089270571986461
Author(s):  
Kubra Coskun ◽  
Aysenur Mutlu ◽  
Mehmet Dogan ◽  
Ebru Bozacı
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Mechanical Performance ◽  
Mechanical Analysis ◽  
Poly Lactic Acid ◽  
Coir Fiber ◽  
Test Results ◽  
Fiber Reinforced ◽  
Remarkable Effect ◽  
The Impact

The effects of enzymatic treatments on the properties of coir fiber-reinforced poly(lactic acid) (PLA) were not found in the literature. Accordingly, the effects of various enzymatic treatments on the mechanical performance of the coir fiber-reinforced PLA composites were investigated in the current study. Four different enzymes, namely lipase, lactase, pectinase, and cellulase, were used. The mechanical properties of the composites were determined by the tensile, flexural, impact tests, and dynamic mechanical analysis. According to the test results, the use of enzyme treated coir fibers affected the mechanical properties except for the flexural properties with different extents depending upon their type. The tensile strength increased with the treatments of lipase and lactase, while the treatments with pectinase and cellulase had no remarkable effect. The impact strength was improved with enzymatic treatments except for pectinase. All enzymatic treatments improved the elastic modulus below the glass transition temperature. In brief, enzymatic treatments improved the interfacial adhesion between coir fiber and PLA via the waxes and fatty acids removal and/or the increment in surface roughness.

scholarly journals Casein/Apricot Filler in the Production of Flame-Retardant Polyurethane Composites

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3620
Author(s):  
Sylwia Członka ◽  
Agnė Kairytė ◽  
Karolina Miedzińska ◽  
Anna Strąkowska
Keyword(s):  
Mechanical Properties ◽  
Mechanical Performance ◽  
Dynamic Mechanical Properties ◽  
Uniform Structure ◽  
Thermal And Mechanical Properties ◽  
Mechanical Performances ◽  
Polyurethane Composites ◽  
Natural Combination ◽  
The Impact ◽  
And Storage

Polyurethane (PUR) composites reinforced with 1, 2, and 5 wt.% of apricot filler modified with casein were synthesized in the following study. The impact of 1, 2, and 5 wt.% of casein/apricot filler on the cellular structure and physico-mechanical performances of reinforced PUR composites were determined. It was found that the incorporation of 1 and 2 wt.% of casein/apricot filler resulted in the production of PUR composites with improved selected physical, thermal, and mechanical properties, while the addition of 5 wt.% of casein/apricot filler led to some deterioration of their physico-mechanical performance. The best results were obtained for PUR composites reinforced with 2 wt.% of casein/apricot filler. Those composites were characterized by a uniform structure and a high content of closed cells. Compared with the reference foam, the incorporation of 2 wt.% of casein/apricot filler resulted in improvement in compressive strength, flexural strength, impact strength, and dynamic mechanical properties—such as glass transition temperature and storage modulus. Most importantly, PUR composites showed better fire resistance and thermal stability due to the good thermal performance of casein. The main aim of this article is to determine the influence of the natural combination of the apricot filler and casein on the mechanical properties and flammability of the obtained composites.

Effect of low nanoclay content on the physico-mechanical properties of poly(lactic acid) nanocomposites

2018 ◽  
Vol 27 (2) ◽  
pp. 43-54 ◽  
Author(s):  
JR Robledo-Ortíz ◽  
AS Martín del Campo ◽  
EJ López-Naranjo ◽  
M Arellano ◽  
CF Jasso-Gastinel ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Impact Strength ◽  
Flexural Strength ◽  
Mechanical Performance ◽  
Flexural Modulus ◽  
Poly Lactic Acid ◽  
Scanning Calorimetry ◽  
Degradation Temperature ◽  
Nanoclay Content ◽  
The Impact

In this work, three different nanoclays (1.44P, 1.34MN, and Cloisite 15A) were used to reinforce an injection grade poly(lactic acid) (PLA). The nanocomposites (NCs) were prepared using three different nanoclay concentration levels (1, 3, and 5 wt%) in a twin-screw extruder. To evaluate their mechanical performance (static and dynamic tests) and thermal properties, the respective samples were obtained by injection molding. Results showed that the three nanoclays significantly increased the tensile and flexural modulus of the injection grade PLA. The 1.34MN NCs also showed improvement in the tensile strength. An increment in flexural strength was obtained with 1.34MN and 1.44P nanoclays, while with nanoclay 15A, the flexural strength decreased. Additionally, the use of 5 wt% of 1.44P nanoclay allowed an increase in impact strength while using 1.34MN and 15A nanoclays, the impact strength was similar to the one observed for pure PLA. In general, mechanodynamic analysis results showed that storage modulus increased with nanoclay content; while thermogravimetric analysis indicated that none of the nanoclays has a significant effect over the degradation temperature of pure PLA. Differential scanning calorimetry results showed that the crystallinity of PLA is enhanced with nanoclay inclusion. For 1.34MN NCs, X-ray diffraction observations exposed that the mineral clay relative intensity peaks disappeared indicating nanoclay exfoliation, which contributes to the increase in tensile and flexural strength in the NCs. Nevertheless for 1.44P and 15A nanoclays, an increase in the interlayer distance (intercalation) was detected.

scholarly journals Binary Green Blends of Poly(lactic acid) with Poly(butylene adipate-co-butylene terephthalate) and Poly(butylene succinate-co-butylene adipate) and Their Nanocomposites

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2489
Author(s):  
Serena Coiai ◽  
Maria Laura Di Lorenzo ◽  
Patrizia Cinelli ◽  
Maria Cristina Righetti ◽  
Elisa Passaglia
Keyword(s):  
Lactic Acid ◽  
Mechanical Performance ◽  
Impact Resistance ◽  
Barrier Properties ◽  
Morphological Properties ◽  
Poly Lactic Acid ◽  
Butylene Succinate ◽  
Butylene Terephthalate ◽  
Green Materials ◽  
The Impact

Poly(lactic acid) (PLA) is the most widely produced biobased, biodegradable and biocompatible polyester. Despite many of its properties are similar to those of common petroleum-based polymers, some drawbacks limit its utilization, especially high brittleness and low toughness. To overcome these problems and improve the ductility and the impact resistance, PLA is often blended with other biobased and biodegradable polymers. For this purpose, poly(butylene adipate-co-butylene terephthalate) (PBAT) and poly(butylene succinate-co-butylene adipate) (PBSA) are very advantageous copolymers, because their toughness and elongation at break are complementary to those of PLA. Similar to PLA, both these copolymers are biodegradable and can be produced from annual renewable resources. This literature review aims to collect results on the mechanical, thermal and morphological properties of PLA/PBAT and PLA/PBSA blends, as binary blends with and without addition of coupling agents. The effect of different compatibilizers on the PLA/PBAT and PLA/PBSA blends properties is here elucidated, to highlight how the PLA toughness and ductility can be improved and tuned by using appropriate additives. In addition, the incorporation of solid nanoparticles to the PLA/PBAT and PLA/PBSA blends is discussed in detail, to demonstrate how the nanofillers can act as morphology stabilizers, and so improve the properties of these PLA-based formulations, especially mechanical performance, thermal stability and gas/vapor barrier properties. Key points about the biodegradation of the blends and the nanocomposites are presented, together with current applications of these novel green materials.

scholarly journals Improvement of Interlayer Adhesion and Heat Resistance of Biodegradable Ternary Blend Composite 3D Printing

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 740
Author(s):  
Wattanachai Prasong ◽  
Akira Ishigami ◽  
Supaphorn Thumsorn ◽  
Takashi Kurose ◽  
Hiroshi Ito
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Heat Resistance ◽  
Fused Deposition Modeling ◽  
Mechanical Performance ◽  
Dimensional Accuracy ◽  
Shell Morphology ◽  
Poly Lactic Acid ◽  
Ternary Blend ◽  
Fused Deposition

Poly(lactic acid) (PLA) filaments have been the most used in fused deposition modeling (FDM) 3D printing. The filaments, based on PLA, are continuing to be developed to overcome brittleness, low heat resistance, and obtain superior mechanical performance in 3D printing. From our previous study, the binary blend composites from PLA and poly(butylene adipate-co-terephthalate) (PBAT) with nano talc (PLA/PBAT/nano talc) at 70/30/10 showed an improvement in toughness and printability in FDM 3D printing. Nevertheless, interlayer adhesion, anisotropic characteristics, and heat resistance have been promoted for further application in FDM 3D printing. In this study, binary and ternary blend composites from PLA/PBAT and poly(butylene succinate) (PBS) with nano talc were prepared at a ratio of PLA 70 wt. % and blending with PBAT or PBS at 30 wt. % and nano talc at 10 wt. %. The materials were compounded via a twin-screw extruder and applied to the filament using a capillary rheometer. PLA/PBAT/PBS/nano talc blend composites were printed using FDM 3D printing. Thermal analysis, viscosity, interlayer adhesion, mechanical properties, and dimensional accuracy of binary and ternary blend composite 3D prints were investigated. The incorporation of of PBS-enhanced crystallinity of the blend composite 3D prints resulted in an improvement to mechanical properties, heat resistance, and anisotropic characteristics. Flexibility of the blend composites was obtained by presentation of PBAT. It should be noted that the core–shell morphology of the ternary blend influenced the reduction of volume shrinkage, which obtained good surface roughness and dimensional accuracy in the ternary blend composite 3D printing.

scholarly journals Improving the Toughness and Thermal Resistance of Polyoxymethylene/Poly(lactic acid) Blends: Evaluation of Structure–Properties Correlation for Reactive Processing

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 307 ◽  
Author(s):  
Jacek Andrzejewski ◽  
Katarzyna Skórczewska ◽  
Arkadiusz Kloziński
Keyword(s):  
Lactic Acid ◽  
Thermal Resistance ◽  
High Efficiency ◽  
Mechanical Performance ◽  
Softening Temperature ◽  
Thermomechanical Properties ◽  
Poly Lactic Acid ◽  
Reactive Processing ◽  
Scanning Calorimetry ◽  
The Impact

The study focuses on the development of polyoxymethylene (POM)/poly(lactic acid) (PLA) blends with increased impact and thermal resistance. The study was conducted in two phases; in the first part, a series of unmodified blends with PLA content of 25, 50, and 75 wt.% was prepared, while the second part focused on the modification of the PLA/POM (50/50) blends. An ethylene/butyl acrylate/glycidyl methacrylate terpolymer (E/BA/GMA) elastomer (EBA) was used to improve the impact strength of the prepared blends, while reactive blending was used to improve interfacial interactions. We used a multifunctional epoxy chain extender (CE) as the compatibilizer. Static tensile tests and notched Izod measurement were used to evaluate the mechanical performance of the prepared samples. The thermomechanical properties were investigated using dynamic mechanical thermal analysis (DMTA) analysis and heat deflection temperature (HDT)/Vicat softening temperature (VST) methods. The crystallinity was measured using differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXS) measurements, while the rheology was evaluated using a rotational rheometer. The paper also includes a structure analysis performed using the SEM method. The structural tests show partial miscibility of the POM/PLA systems, resulting in the perfect compatibility of both phases. The impact properties of the final blends modified by the EBA/CE system were found to be similar to pure POM resin, while the E modulus was visibly improved. Favorable changes were also noticeable in the case of the thermomechanical properties. The results of most of the conducted measurements and microscopic observations confirm the high efficiency of the reaction for PLA as well as for the modified POM/PLA mixtures.

Design, Fabrication and Implementation of a High-Performance Compliant Nanopositioner via 3D Printing with Continuous Fiber-Reinforced Composite

2021 ◽  
Author(s):  
Mengjia Cui ◽  
Erwei Shang ◽  
Shouqian Jiang ◽  
Yu Liu ◽  
Zhen Zhang
Keyword(s):  
3D Printing ◽  
High Performance ◽  
Compliant Mechanisms ◽  
Plastic Material ◽  
Industrial Applications ◽  
Structure Design ◽  
Fiber Reinforced ◽  
Precision Engineering ◽  
Vertical Stiffness ◽  
Mechanical Performances

Abstract Nanopositioning systems have been widely applied in scientific and emerging industrial applications. With simplicity in design and operation, flexure bearings with spatial constraints and voice coil based nano-actuators are considered in designing compliant compact nanopositioning systems. To achieve nano-metric positioning quality, monolithic fabrication of the positioner is preferred, which calls for 3D printing fabrication. However, conventional plastic material-based 3D printing suffers from low mechanical performances, and it is challenging to monolithically fabricate 3D compliant mechanisms with high mechanical performances. Here, we study the fabrication of continuous carbon fiber reinforced composites by 3D printing of the double parallelogram flexure beam structures for spatial constrained nanopositioner with enhanced vertical stiffness. Also, with the consideration of the beam structure design, the process parameters for embedding the carbon fibers are optimized to enhance the beam strengths. Experimental results demonstrate a significant performance improvement with the composite based nanopositioner in both stiffness and natural frequency, and its positioning resolution of 30 nm is achieved. The result of this study will serve as the building block to apply advanced 3D printing of composite structure for precision engineering in the presence of more complex spatial structures.

Rheological properties of micro-nano magneto-rheological fluid

2019 ◽  
Vol 9 (7) ◽  
pp. 827-830
Author(s):  
Hongbo Wang ◽  
Xinyi Liang ◽  
Jifan Guo ◽  
Chungeng Zhu
Keyword(s):  
Mass Fraction ◽  
Mechanical Performance ◽  
Nano Particles ◽  
Testing System ◽  
Mr Fluid ◽  
Mechanical Performances ◽  
Magneto Rheological ◽  
Nonmagnetic Particles ◽  
Magnetic Induction Intensity ◽  
Constant Shear Rate

In this paper, a novel micro-nano Magneto-rheological Fluid (MR) is proposed, and its mechanical performance, mainly including the shear torque and normal stress, is studied. Here, the magnetic particle in this kind of smart fluid is composed by the micro and nano particle, that is, produced by adding some nano magnetic or nonmagnetic particles into the traditional MR fluid (its particle size about 1–10 μm). A set of testing system, mainly including the plate-on-plate shearing test rig, is built to investigate the effect of the added percent of particles on the mechanical performances of MR fluid. In the condition of a constant shear rate, if the mass fraction of the nano particles is a constant, for example 4%, with the increasing of the magnetic induction intensity, the shear torque will also increase. The normal force increases rapidly with the increasing of mass fraction of the nano particles and decrease gradually.

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