scholarly journals Medical-Grade PCL Based Polyurethane System for FDM 3D Printing—Characterization and Fabrication

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 887 ◽  
Author(s):  
Agnieszka Haryńska ◽  
Justyna Kucinska-Lipka ◽  
Agnieszka Sulowska ◽  
Iga Gubanska ◽  
Marcin Kostrzewa ◽  
...  

The widespread use of three-dimensional (3D) printing technologies in medicine has contributed to the increased demand for 3D printing materials. In addition, new printing materials that are appearing in the industry do not provide a detailed material characterization. In this paper, we present the synthesis and characterization of polycaprolactone (PCL) based medical-grade thermoplastic polyurethanes, which are suitable for forming in a filament that is dedicated to Fused Deposition Modeling 3D (FDM 3D)printers. For this purpose, we synthesized polyurethane that is based on PCL and 1,6-hexamethylene diisocyanate (HDI) with a different isocyanate index NCO:OH (0.9:1, 1.1:1). Particular characteristics of synthesized materials included, structural properties (FTIR, Raman), thermal (differential scanning calorimetry (DSC), thermogravimetric analysis (TGA)), mechanical and surfaces (contact angle) properties. Moreover, pre-biological tests in vitro and degradation studies were also performed. On the basis of the conducted tests, a material with more desirable properties S-TPU(PCL)0.9 was selected and the optimization of filament forming via melt-extrusion process was described. The initial biological test showed the biocompatibility of synthesized S-TPU(PCL)0.9 with respect to C2C12 cells. It was noticed that the process of thermoplastic polyurethanes (TPU) filaments forming by extrusion was significantly influenced by the appropriate ratio between the temperature profile, rotation speed, and dosage ratio.

Polymers ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1304 ◽  
Author(s):  
Agnieszka Haryńska ◽  
Iga Gubanska ◽  
Justyna Kucinska-Lipka ◽  
Helena Janik

The possibility of using additive manufacturing (AM) in the medicine area has created new opportunities in health care. This has contributed to a sharp increase in demand for 3D printers, their systems and materials that are adapted to strict medical requirements. We described herein a medical-grade thermoplastic polyurethane (S-TPU) which was developed and then formed into a filament for Fused Deposition Modeling (FDM) 3D printers during a melt-extrusion process. S-TPU consisting of aliphatic hexamethylene 1,6-diisocyanate (HDI), amorphous α,ω-dihydroxy(ethylene-butylene adipate) (PEBA) and 1,4 butandiol (BDO) as a chain extender, was synthesized without the use of a catalyst. The filament (F-TPU) properties were characterized by rheological, mechanical, physico-chemical and in vitro biological properties. The tests showed biocompatibility of the obtained filament as well as revealed no significant effect of the filament formation process on its properties. This study may contribute to expanding the range of medical-grade flexible filaments for standard low-budget FDM printers.


Author(s):  
Agnieszka Haryńska ◽  
Iga Gubańska ◽  
Justyna Kucińska-Lipka ◽  
Helena Janik

The possibility of using additive manufacturing (AM) in the medicine area has created a new opportunities in health care. This has contributed to a sharp increase in demand for 3D printers, their systems and materials that are adapted to strict medical requirements. We described herein a medical-grade thermoplastic polyurethane (S-TPU), which was developed and then formed into a filament for Fused Deposition Modeling (FDM) 3D printers during a melt-extrusion process. S-TPU consisting of aliphatic hexamethylene 1,6-diisocyanate (HDI), amorphous α,ω-dihydroxy(ethylene-butylene adipate) (PEBA) and 1,4 butandiol (BDO) as a chain extender, was synthesized without the use of a catalyst. The filament properties were characterized by rheological, mechanical, physico-chemical and in vitro biological properties. The tests showed biocompatibility of the obtained filament as well as revealed no significant effect of the filament formation process on its properties. This study may contribute to expanding the range of medical-grade flexible filaments for standard low-budget FDM printers.


2021 ◽  
Vol 11 (6) ◽  
pp. 2563
Author(s):  
Ivan Grgić ◽  
Vjekoslav Wertheimer ◽  
Mirko Karakašić ◽  
Željko Ivandić

Recent soft tissue studies have reported issues that occur during experimentation, such as the tissue slipping and rupturing during tensile loads, the lack of standard testing procedure and equipment, the necessity for existing laboratory equipment adaptation, etc. To overcome such issues and fulfil the need for the determination of the biomechanical properties of the human gracilis and the superficial third of the quadriceps tendons, 3D printed clamps with metric thread profile-based geometry were developed. The clamps’ geometry consists of a truncated pyramid pattern, which prevents the tendons from slipping and rupturing. The use of the thread application in the design of the clamp could be used in standard clamping development procedures, unlike in previously custom-made clamps. Fused deposition modeling (FDM) was used as a 3D printing technique, together with polylactic acid (PLA), which was used as a material for clamp printing. The design was confirmed and the experiments were conducted by using porcine and human tendons. The findings justify the usage of 3D printing technology for parts manufacturing in the case of tissue testing and establish independence from the existing machine clamp system, since it was possible to print clamps for each prepared specimen and thus reduce the time for experiment setup.


Author(s):  
Robert I. Ponder ◽  
Mohsen Safaei ◽  
Steven R. Anton

Total Knee Replacement (TKR) is a very common procedure in the United States, especially with the aging population. However, despite high numbers of procedures and advancing technology, about 20% of patients with TKR are unsatisfied with the level of discomfort they experience with their replacement. Prevailing theories suggest that this is due to gradual misalignment of the knee. Multiple methods have been attempted to detect the cause of mechanical failure in replacements. One possible method for performing state detection in knees is the embedding of piezoelectric transducers (PZTs) into the bearing component. Preliminary testing of PZT’s embedded in simplified plastic components has shown that this method contains promise. With this said, further testing on realistic knee implant components is still needed to solidify the method’s validity. Commercial knee implant bearings utilize medical grade Ultra-High Molecular Weight Polyethylene (UHMW) and manufacturers utilize proprietary processing technology to develop the final components. This work focuses on the development of surrogate knee implant prototypes that replicate the material and geometric properties of actual knee implants to provide a convenient and economical solution to evaluate the performance of embedded PZTs. In this work, scans of an original knee bearing are taken and used to create a 3D model. From there, a variety of processes including 3D printing and Computer Numerical Controlled (CNC) machining are used to develop surrogate prototypes that are compared for accuracy to a benchmark. This benchmark is taken as a polished CNC machined non-medical grade UHMW prototype. Standards that the prototypes must meet include cost and time effectiveness as well as similarity in geometry and material property to the benchmark. The performance of the prototypes is experimentally compared through mechanical load testing by using pressure sensitive films placed between the femoral and bearing components of the implant as well as measuring piezoelectric output. In addition, the measured voltage output is compared to predictions from an analytical model for validation of the piezoelectric performance. These two experiments help to derive information about the applied load distribution and location, allowing comparisons to be made to the benchmark. This study shows that, while some types of 3D printing, such as fused deposition modeling, provide fast and cheap prototypes, other options such as stereolithography printing produce higher quality and more replicative components. Results of this study can be used in the development of useful surrogates for the advancement of biomedical sensors.


Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2980
Author(s):  
Andrea Costanzo ◽  
Umberto Croce ◽  
Roberto Spotorno ◽  
Seif Eddine Fenni ◽  
Dario Cavallo

International newspapers and experts have called 3D printing the industrial revolution of this century. Among all its available variants, the fused deposition modeling (FDM) technique is of greater interest since its application is possible using simple desktop printers. FDM is a complex process, characterized by a large number of parameters that influence the quality and final properties of the product. In particular, in the case of semicrystalline polymers, which afford better mechanical properties than amorphous ones, it is necessary to understand the crystallization kinetics as the processing conditions vary, in order to be able to develop models that allow having a better control over the process and consequently on the final properties of the material. In this work it was proposed to study the crystallization kinetics of two different polyamides used for FDM 3D printing and to link it to the microstructure and properties obtained during FDM. The kinetics are studied both in isothermal and fast cooling conditions, thanks to a home-built device which allows mimicking the quenching experienced during filament deposition. The temperature history of a single filament is then determined by mean of a micro-thermocouple and the final crystallinity of the sample printed in a variety of conditions is assessed by differential scanning calorimetry. It is found that the applied processing conditions always allowed for the achievement of the maximum crystallinity, although in one condition the polyamide mesomorphic phase possibly develops. Despite the degree of crystallinity is not a strong function of printing variables, the weld strength of adjacent layers shows remarkable variations. In particular, a decrease of its value with printing speed is observed, linked to the probable development of molecular anisotropy under the more extreme printing conditions.


Pharmaceutics ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 277 ◽  
Author(s):  
Petra Arany ◽  
Eszter Róka ◽  
Laurent Mollet ◽  
Anthony W. Coleman ◽  
Florent Perret ◽  
...  

3D printing is attracting considerable interest for its capacity to produce prototypes and small production runs rapidly. Fused deposit modeling (FDM) was used to produce polyvalent test plates for investigation of the physical, chemical, and in-vitro biological properties of printed materials. The polyvalent test plates (PVTPs) are poly-lactic acid cylinders, 14 mm in diameter and 3 mm in height. The polymer ester backbone was surface modified by a series of ramified and linear oligoamines to increase its hydrophilicity and introduce a positive charge. The chemical modification was verified by FT-IR spectroscopy, showing the introduction of amide and amine functions, and contact angle measurements confirmed increased hydrophilicity. Morphology studies (SEM, optical microscopy) indicated that the modification of PVTP possessed a planar morphology with small pits. Positron annihilation lifetime spectroscopy demonstrated that the polymeric free volume decreased on modification. An MTT-based prolonged cytotoxicity test using Caco-2 cells showed that the PVTPs are non-toxic at the cellular level. The presence of surface oligoamines on the PVTPs reduced biofilm formation by Candida albicans SC5314 significantly. The results demonstrate that 3D printed objects may be modified at their surface by a simple amidation reaction, resulting in a reduced propensity for biofilm colonization and cellular toxicity.


Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2912 ◽  
Author(s):  
Mateusz Galeja ◽  
Klaudiusz Wypiór ◽  
Jan Wachowicz ◽  
Przemysław Kędzierski ◽  
Aleksander Hejna ◽  
...  

Polyoxymethylene (POM) is one of the most popular thermoplastic polymers used in the industry. Therefore, the interest in its potential applications in rapid prototyping is understandable. Nevertheless, its low dimensional stability causes the warping of 3D prints, limiting its applications. This research aimed to evaluate the effects of POM modification with ethylene-vinyl acetate (EVA) (2.5, 5.0, and 7.5 wt.%) on its processing (by melt flow index), structure (by X-ray microcomputed tomography), and properties (by static tensile tests, surface resistance, contact angle measurements, differential scanning calorimetry, and thermogravimetric analysis), as well as very rarely analyzed emissions of volatile organic compounds (VOCs) (by headspace analysis). Performed modifications decreased stiffness and strength of the material, simultaneously enhancing its ductility, which simultaneously increased the toughness even by more than 50% for 7.5 wt.% EVA loading. Such an effect was related to an improved linear flow rate resulting in a lack of defects inside the samples. The decrease of the melting temperature and the slight increase of thermal stability after the addition of EVA broadened the processing window for 3D printing. The 3D printing trials on two different printers showed that the addition of EVA copolymer increased the possibility of a successful print without defects, giving space for further development.


2020 ◽  
Vol 4 (1) ◽  
pp. 17-27
Author(s):  
Nasir Abbas ◽  
Nadia Qamar ◽  
Amjad Hussain ◽  
Sumera Latif ◽  
Muhammad Sohail Arshad ◽  
...  

Aim: The aim of the present work was to fabricate customized tablets of ciprofloxacin hydrochloride through 3D printing for optimized dosing. Materials & methods: A hot melt extrusion technique was employed to produce polyvinyl alcohol filaments with differing strengths of ciprofloxacin hydrochloride. Drug-loaded filaments were characterized for mechanical strength, thermal behavior and structural characteristics prior to printing of tablets by varying the infill percentage. Final formulations were evaluated for drug release profiles. Results: The prepared formulations contained 15–20% drug. The drug release patterns of different formulations were found to be reliant on infill percentage. Differential scanning calorimetry and thermo-gravimetric analysis confirmed that degradation temperature of drug is way above the printing temperature. Conclusion: This work is potentially significant for optimized antibiotic dosing, which in turn leads to enhanced clinical outcome.


2021 ◽  
pp. 089270572110625
Author(s):  
Ajay Jayswal ◽  
Sabit Adanur

Polylactic acid (PLA) and thermoplastic polyurethane (TPU) were mixed in different proportions and extruded through twin-screw and single-screw extruders to obtain composite filaments to be used for 3D printing with fused deposition modeling (FDM) method. The properties of the filaments were characterized using uniaxial tensile tests, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), rheology, polarized optical microscope (POM), and scanning electron microscope (SEM). 3D printed samples from composite filaments were tested using dynamic mechanical analysis (DMA). It was found that the tensile strength and modulus of the filaments decrease while elongation at break increases with the increasing TPU content in the composite. The analysis also showed a partial miscibility of the polymer constituents in the solution of composite filaments. Finally, a flexible structure, plain weave fabric, was designed and 3D printed using the composite filaments developed which proved that the filaments are well suited for 3D printing.


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