Controlling the properties of parts 3D printed from recycled thermoplastics: A review of current practices

Gomes, Tiago E. P.; Cadete, Mylene S.; Dias-de-Oliveira, João; Neto, Victor

doi:10.1016/j.polymdegradstab.2022.109850

Cited by 35 publications

(11 citation statements)

References 59 publications

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“…Among various modalities of PET recycling, the production of filament for 3D printing—also valorized in the case of other thermoplastics [ 10 , 11 ]—has gained increasing interest, especially after the start of its commercialization in 2015 [ 12 ]. Thus, comprehensive studies were performed to ascertain the suitability of recycled PET (R-PET) for the production of powders [ 13 ] and filaments for 3D printing [ 14 ].…”

Section: Introductionmentioning

confidence: 99%

DMA Investigation of the Factors Influencing the Glass Transition in 3D Printed Specimens of Shape Memory Recycled PET

Pricop

Sava²,

Lohan

et al. 2022

Polymers

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Polyethylene terephthalate (PET) is used worldwide for packing, and for this reason, it is the main material in plastic waste. The paper uses granules of recycled PET (R-PET) as raw material for producing filaments for 3D printing, subsequently used for printing the test specimens in different ways: longitudinally and at angles between 10° and 40° in this direction. Both the filaments and the printed specimens experience thermally driven shape memory effect (SME) since they have been able to recover their straight shape during heating, after being bent to a certain angle, at room temperature (RT). SME could be reproduced three times, in the case of printed specimens, and was investigated by cinematographic analysis. Then, differential scanning calorimetry (DSC) was used, in R-PET granules, filaments and 3D printed specimens, to emphasize the existence of glass transition, which represents the governing mechanism of SME occurrence in thermoplastic polymers, as well as a recrystallization reaction. Subsequently, the paper investigated the 3D printed specimens by dynamic mechanical analysis (DMA) using a dual cantilever specimen holder. Temperature (DMA-TS) and isothermal scans (DMA-Izo) were performed, with the aim to discuss the variations of storage modulus and loss modulus with temperature and time, respectively.

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Section: Introductionmentioning

confidence: 99%

DMA Investigation of the Factors Influencing the Glass Transition in 3D Printed Specimens of Shape Memory Recycled PET

Pricop

Sava²,

Lohan

et al. 2022

Polymers

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show abstract

“…Other studies have focused on adding materials such as metals, carbon, and fibers to PLA to maintain and improve its mechanical properties [ 52 , 53 ]. Furthermore, some studies involve reusing PLA with other materials [ 54 , 55 ]. Thus, research on reusing PLA and adding additives to maintain or improve its mechanical properties is progressing worldwide.…”

Section: Discussionmentioning

confidence: 99%

Accuracy of Dental Models Fabricated Using Recycled Poly-Lactic Acid

et al. 2023

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Based on the hypothesis that the fabrication of dental models using fused deposition modeling and poly-lactic acid (PLA), followed by recycling and reusing, would reduce industrial waste, we aimed to compare the accuracies of virgin and recycled PLA models. The PLA models were recycled using a crusher and a filament-manufacturing machine. Virgin PLA was labeled R, and the first, second, and third recycles were labeled R1, R2, and R3, respectively. To determine the accuracies of the virgin and reused PLA models, identical provisional crowns were fitted, and marginal fits were obtained using micro-computed tomography. A marginal fit of 120 µm was deemed acceptable based on previous literature. The mesial, distal, buccal, and palatal centers were set at M, D, B, and P, respectively. The mean value of each measurement point was considered as the result. When comparing the accuracies of R and R1, R2, and R3, significant differences were noted between R and R3 at B, R and R2, R3 at P, and R and R3 at D (p < 0.05). No significant difference was observed at M. This study demonstrates that PLA can be recycled only once owing to accuracy limitations.

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“…In previous filament development efforts on some recycled thermoplastic wastes, it has been emphasized that proper additive selection at an optimized proportion applied to a thermoplastic polymer was critical during the double-screw modification process to fabricate its composite material. 44,45 In addition, more efforts and investigations in 3D printing parameter optimization and post-processing are also recommended to improve the relevant mechanical performance, as well as the geometrical accuracy for a 3D printed object from recycled polymer composites. 46 Currently, COVID-19 seems to have no end in the world due to the virus variants being updating and, accordingly, the daily generated waste masks in a large quantity will remain as environmental and health threat for a long time.…”

Section: Discussionmentioning

confidence: 99%

Recycling polypropylene from non-woven disposable masks in developing a three-dimensional printing filament

Zhang

Sun

Liu

et al. 2023

Textile Research Journal

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Non-woven disposable masks play a unique role in reducing the COVID-19 pandemic threat in transmission between people, but the huge amount of disposable non-woven masks generated every day are currently posing a serious challenge to our environment on a global-wide scale. In line with this emerging problem, a series of recycling processes were designed and conducted to evaluate the performance of material recovered from those waste masks for potential use in three-dimensional (3D) printing. A composite filament from recycled polypropylene (rPP) and an additive material, glass fiber (GF), was fabricated by melt-blending processing followed by single-screw extrusion. A variety of material properties, including the chemical/mechanical/microstructure property, thermal stability, printability, rheology performance, and geometrical accuracy toward GF/rPP composite filaments, were comprehensively analyzed. Our results demonstrated that two important mechanical properties, the compression strength and the tensile strength, to a 3D printed object by fused deposition modeling (FDM) from the GF/rPP composite were significantly higher than that of a FDM 3D printed object from GF/polypropylene composites. The specific warpage parameter ( Wsp) and the surface roughness ( Sa) for a 3D printed object from the GF/rPP composite at 30 wt% GF additive would have printing accuracy of 0.54% ± 0.0014 and 21.1 ± 0.76 µm, respectively, and no clogging phenomenon was observed in the printer nozzle channel during the printing processing, suggested that this recycling method for a large number of non-woven waste masks was potentially applicable in serving as a FDM 3D printing material.

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Controlling the properties of parts 3D printed from recycled thermoplastics: A review of current practices

Cited by 35 publications

References 59 publications

DMA Investigation of the Factors Influencing the Glass Transition in 3D Printed Specimens of Shape Memory Recycled PET

DMA Investigation of the Factors Influencing the Glass Transition in 3D Printed Specimens of Shape Memory Recycled PET

Accuracy of Dental Models Fabricated Using Recycled Poly-Lactic Acid

Recycling polypropylene from non-woven disposable masks in developing a three-dimensional printing filament

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