scholarly journals Influence of Controlled Cooling on Crystallinity of Poly(L-Lactic Acid) Scaffolds after Hydrolytic Degradation

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2943
Author(s):  
Javier Vazquez-Armendariz ◽  
Raquel Tejeda-Alejandre ◽  
Aida Rodriguez-Garcia ◽  
Yadira I. Vega-Cantu ◽  
Christian Mendoza-Buenrostro ◽  
...  
Keyword(s):  
Fused Deposition Modeling ◽  
Cooling System ◽  
Thermo Gravimetric Analysis ◽  
Hydrolytic Degradation ◽  
Degree Of Crystallinity ◽  
Gravimetric Analysis ◽  
Controlled Cooling ◽  
Scanning Calorimetry ◽  
Fused Deposition ◽  
Deposition Modeling

The use of hybrid manufacturing to produce bimodal scaffolds has represented a great advancement in tissue engineering. These scaffolds provide a favorable environment in which cells can adhere and produce new tissue. However, there are several areas of opportunity to manufacture structures that provide enough strength and rigidity, while also improving chemical integrity. As an advancement in the manufacturing process of scaffolds, a cooling system was introduced in a fused deposition modeling (FDM) machine to vary the temperature on the printing bed. Two groups of polylactic acid (PLA) scaffolds were then printed at two different bed temperatures. The rate of degradation was evaluated during eight weeks in Hank’s Balanced Salt Solution (HBSS) in a controlled environment (37 °C–120 rpm) to assess crystallinity. Results showed the influence of the cooling system on the degradation rate of printed scaffolds after the immersion period. This phenomenon was attributable to the mechanism associated with alkaline hydrolysis, where a higher degree of crystallinity obtained in one group induced greater rates of mass loss. The overall crystallinity was observed, through differential scanning calorimetry (DSC), thermo gravimetric analysis (TGA), and Fourier transformed infrared spectroscopy (FTIR) analysis, to increase with time because of the erosion of some amorphous parts after immersion.

scholarly journals Fused Deposition Modeling of Polyamides: Crystallization and Weld Formation

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2980
Author(s):  
Andrea Costanzo ◽  
Umberto Croce ◽  
Roberto Spotorno ◽  
Seif Eddine Fenni ◽  
Dario Cavallo
Keyword(s):  
3D Printing ◽  
Crystallization Kinetics ◽  
Fused Deposition Modeling ◽  
Degree Of Crystallinity ◽  
Temperature History ◽  
Weld Strength ◽  
Processing Conditions ◽  
Scanning Calorimetry ◽  
Fused Deposition ◽  
Deposition Modeling

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.

Fabrication of modified-release custom-designed ciprofloxacin tablets via fused deposition modeling 3D printing

2020 ◽  
Vol 4 (1) ◽  
pp. 17-27
Author(s):  
Nasir Abbas ◽  
Nadia Qamar ◽  
Amjad Hussain ◽  
Sumera Latif ◽  
Muhammad Sohail Arshad ◽  
...  
Keyword(s):  
3D Printing ◽  
Drug Release ◽  
Fused Deposition Modeling ◽  
Structural Characteristics ◽  
Thermo Gravimetric Analysis ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Ciprofloxacin Hydrochloride ◽  
Fused Deposition ◽  
Degradation Temperature

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.

Development of three-dimensional printing filaments based on poly(lactic acid)/hydroxyapatite composites with potential for tissue engineering

2021 ◽  
pp. 002199832098856
Author(s):  
Marcela Piassi Bernardo ◽  
Bruna Cristina Rodrigues da Silva ◽  
Luiz Henrique Capparelli Mattoso
Keyword(s):  
Tissue Engineering ◽  
Lactic Acid ◽  
Fused Deposition Modeling ◽  
Three Dimensional ◽  
Poly Lactic Acid ◽  
Scanning Calorimetry ◽  
Three Dimensional Printing ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
3D Printed

Injured bone tissues can be healed with scaffolds, which could be manufactured using the fused deposition modeling (FDM) strategy. Poly(lactic acid) (PLA) is one of the most biocompatible polymers suitable for FDM, while hydroxyapatite (HA) could improve the bioactivity of scaffold due to its chemical composition. Therefore, the combination of PLA/HA can create composite filaments adequate for FDM and with high osteoconductive and osteointegration potentials. In this work, we proposed a different approache to improve the potential bioactivity of 3D printed scaffolds for bone tissue engineering by increasing the HA loading (20-30%) in the PLA composite filaments. Two routes were investigated regarding the use of solvents in the filament production. To assess the suitability of the FDM-3D printing process, and the influence of the HA content on the polymer matrix, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) were performed. The HA phase content of the composite filaments agreed with the initial composite proportions. The wettability of the 3D printed scaffolds was also increased. It was shown a greener route for obtaining composite filaments that generate scaffolds with properties similar to those obtained by the solvent casting, with high HA content and great potential to be used as a bone graft.

scholarly journals Lignin: A Biopolymer from Forestry Biomass for Biocomposites and 3D Printing

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3006 ◽  
Author(s):  
Mihaela Tanase-Opedal ◽  
Eduardo Espinosa ◽  
Alejandro Rodríguez ◽  
Gary Chinga-Carrasco
Keyword(s):  
3D Printing ◽  
Radical Scavenging Activity ◽  
Matrix Material ◽  
Thermo Gravimetric Analysis ◽  
Radical Scavenging ◽  
Fused Deposition Modelling ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Biobased Materials ◽  
Fused Deposition

Biopolymers from forestry biomass are promising for the sustainable development of new biobased materials. As such, lignin and fiber-based biocomposites are plausible renewable alternatives to petrochemical-based products. In this study, we have obtained lignin from Spruce biomass through a soda pulping process. The lignin was used for manufacturing biocomposite filaments containing 20% and 40% lignin and using polylactic acid (PLA) as matrix material. Dogbones for mechanical testing were 3D printed by fused deposition modelling. The lignin and the corresponding biocomposites were characterized in detail, including thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction analysis (XRD), antioxidant capacity, mechanical properties, and scanning electron microscopy (SEM). Although lignin led to a reduction of the tensile strength and modulus, the reduction could be counteracted to some extent by adjusting the 3D printing temperature. The results showed that lignin acted as a nucleating agent and thus led to further crystallization of PLA. The radical scavenging activity of the biocomposites increased to roughly 50% antioxidant potential/cm2, for the biocomposite containing 40 wt % lignin. The results demonstrate the potential of lignin as a component in biocomposite materials, which we show are adequate for 3D printing operations.

scholarly journals Mechanical, Thermal and Microstructural Characteristic of 3D Printed Polylactide Composites with Natural Fibers: Wood, Bamboo and Cork

2021 ◽  
Author(s):  
Karolina E. Mazur ◽  
Aleksandra Borucka ◽  
Paulina Kaczor ◽  
Szymon Gądek ◽  
Rafał Bogucki ◽  
...  
Keyword(s):  
Fused Deposition Modeling ◽  
Elevated Temperatures ◽  
Fiber Type ◽  
Mechanical Tests ◽  
Degree Of Crystallinity ◽  
Scanning Calorimetry ◽  
Fused Deposition ◽  
The Impact ◽  
Different Levels ◽  
Natural Fillers

AbstractIn the study, polylactide-based (PLA) composites modified with natural particles (wood, bamboo, and cork) and with different levels of infilling (100%, 80%, and 60%) obtained by fused deposition modeling were tested. The effect of fiber type, infill level and crystallization rate on the mechanical properties were investigated by using tensile, flexural, and impact tests. The materials were subjected to mechanical tests carried out at 23 and 80 °C. Differential scanning calorimetry were employed to analyze crystallization behavior of composite. Furthermore, hydrothermal degradation was performed, and its effect on the properties was analyzed. The addition of natural fillers and different levels of infilling result in a similar level of reduction in the properties. However, the addition of natural fillers resulted in a slightly lower drop than the lowered infilling rate − 40% and 50% for tensile strength, respectively. Moreover, it was found that, composites made of PLA are more sensitive to high temperatures than to water. The decrease in Young's modulus of PLA at 80 °C was 90%, while after 28 days of hydrodegradation ~ 9%. The addition of fibers reduced this decrease at elevated temperatures. Importantly, in the case of a brittle material such as PLA, the impact strength has been improved by 50% for composites with cork particles and other lignocellulosic composites remained at the same level as for resin. Generally, the thermal treatment of composites increased the degree of crystallinity of the materials, as reflected in the higher results of mechanical tests.

Effect of heat treatment on crystallinity and mechanical properties of flexible structures 3D printed with fused deposition modeling

2021 ◽  
pp. 152808372110649
Author(s):  
Ajay Jayswal ◽  
Sabit Adanur
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Fused Deposition Modeling ◽  
Scanning Calorimetry ◽  
Fused Deposition ◽  
Dog Bone ◽  
Heat Treated ◽  
Deposition Modeling ◽  
3D Printed

Fused Deposition Modeling (FDM) is a widely used 3D printing technique, which works based on the principle of melted polymer extrusion through nozzle(s) and depositing them on a build plate layer by layer. However, products manufactured with this method lack proper mechanical strength. In this work, 2/1 twill weave fabric structures are 3D printed using poly (lactic) acid (PLA). The ultimate tensile strength in the warp and weft directions and the modulus (stiffnesses) are measured for non-heat-treated (NHT) samples. The printed samples were heat-treated (HT) to improve the strength and stiffness. The variation in ultimate tensile strength is statistically insignificant in warp direction at all temperatures; however, the tensile strength in weft direction decreased after heat treatment. The modulus in warp direction increased by 31% after heat treatment while in the weft direction it decreased after heat treatment. Differential scanning calorimetry (DSC) tests showed the highest crystallinity at 125°C. The properties of the twill fabrics were compared with a standard dog-bone (DB) specimen using uniaxial tensile tests, Differential scanning calorimetry tests, and optical microscope (OM). For dog-bone specimens, the maximum values of crystallinity, ultimate tensile strength, and modulus were found to be at 125°C. The maximum crystallinity percentages are higher than that of the NHT samples. The ultimate tensile strength of NHT DB specimen 3D printed in horizontal orientation improved after heat treatment. The ultimate tensile strength of DB samples in vertical directions increased after heat treatment as well. The stiffness increased in both directions for DB samples.

Silane-Treated Muscovite as Reinforcement for 3D-Printed ABS via Fused Deposition Modeling

2021 ◽  
Vol 877 ◽  
pp. 67-72
Author(s):  
Niño B. Felices ◽  
Bryan B. Pajarito
Keyword(s):  
Thermal Properties ◽  
Fused Deposition Modeling ◽  
Acrylonitrile Butadiene Styrene ◽  
Mechanical And Thermal Properties ◽  
Scanning Calorimetry ◽  
Mechanical Reinforcement ◽  
Fused Deposition ◽  
The Matrix ◽  
Deposition Modeling ◽  
3D Printed

Epoxysilane-treated muscovite (ETM) was used as reinforcing filler to 3D-printed acrylonitrile butadiene styrene (ABS) via fused deposition modeling (FDM). Its effects to the mechanical and thermal properties of ABS were investigated. ETM was loaded at 1, 3, and 5wt%. ABS/ETM composites were characterized via scanning electron microscopy (SEM), tensile test, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Mechanical reinforcement of ABS was observed for ABS/ETM composites loaded at 1 and 3 wt% wherein it was noted that the tensile strength and elastic modulus increased by up to 83.6% and 76.6%, respectively. Reinforcement was brought by interfacial adhesion of ETM with the ABS matrix. There was a sharp decline in mechanical properties for ABS/ETM composites loaded at 5wt% due to agglomeration of ETM in the matrix and discontinuities in the printed layers. The glass transition temperature (Tg) of ABS increased and the onset of its degradation shifted towards higher temperatures with the addition of ETM. It can be concluded that the addition of ETM to ABS for FDM 3D printing improved its mechanical and thermal properties.

scholarly journals Effect of Thermal Processing and Heat Treatment Condition on 3D Printing PPS Properties

Polymers ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 875 ◽  
Author(s):  
Peng Geng ◽  
Ji Zhao ◽  
Wenzheng Wu ◽  
Yulei Wang ◽  
Bofan Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Thermal Processing ◽  
Fused Deposition Modeling ◽  
Polyphenylene Sulfide ◽  
Degree Of Crystallinity ◽  
Fused Deposition ◽  
Treatment Conditions ◽  
Thermal Crosslinking ◽  
Deposition Modeling

Polyphenylene sulfide (PPS) is a high-performance semi-crystalline thermoplastic polymer that is widely used in the automotive, electronics, and aerospace industries, as well as other fields. However, PPS introduces several challenges in fused deposition modeling owing to its inherent properties of crystallization and thermal crosslinking. The present study demonstrates the effects of the thermal processing and heat treatment conditions on the accuracy and mechanical properties of PPS samples three-dimensionally printed through fused deposition modeling. By measuring the degree of crystallinity and thermal crosslinking of three-dimensionally printed PPS samples, we found that the thermal history affects the three-dimensionally printed PPS properties. Results show that the accuracy of three-dimensionally printed PPS samples can be improved by means of air-forced cooling in fused deposition modeling. The balance between mechanical strength and ductility was regulated by altering the heat treatment conditions. This approach is applicable to eliminating the warpage of semi-crystalline polymer in three-dimensional printing (not only for PPS) and provides a method of improving the mechanical properties of three-dimensionally printed PPS samples.

Multifactor optimization of FDM process parameters for development of rapid tooling using SiC/Al2O3-reinforced LDPE filament

2018 ◽  
Vol 33 (5) ◽  
pp. 581-598 ◽  
Author(s):  
Piyush Bedi ◽  
Rupinder Singh ◽  
IPS Ahuja
Keyword(s):  
Particle Size ◽  
Process Parameters ◽  
Fused Deposition Modeling ◽  
Dimensional Accuracy ◽  
Rapid Tooling ◽  
Scanning Calorimetry ◽  
Fused Deposition ◽  
Significant Process ◽  
Deposition Modeling ◽  
Sic Reinforcement

In this work, multifactor optimization of fused deposition modeling (FDM) process parameters has been reported for in-house prepared feedstock filament comprising of SiC/Al2O3 reinforced in recycled low-density polyethylene (LDPE) matrix with different particle sizes (i.e. single particle size (SPS), double particle size (DPS), and triple particle size (TPS) in different proportions). This study has been conducted on Al2O3-based DPS reinforcement in LDPE, which came out as a better solution during pilot experimentation in comparison to SPS, TPS, and SiC reinforcement, for printing of functional prototypes as rapid tooling (RT). The result of study suggests that infill angle in the FDM process is the most significant process parameter (contributing around 93%) for preparation of RT as regards dimensional accuracy and hardness is concerned. The RT so prepared is thermally stable as evident from differential scanning calorimetry analysis. Further, the photomicrographs observed in different planes suggest that, at the proposed settings, RT has a uniform distribution of reinforcement in LDPE matrix and can be gainfully used in light machining applications.

scholarly journals Bioactive Potential of 3D-Printed Oleo-Gum-Resin Disks:B. papyrifera,C. myrrha, andS. benzoinLoading Nanooxides—TiO2, P25, Cu2O, and MoO3

2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Diogo José Horst ◽  
Sergio Mazurek Tebcherani ◽  
Evaldo Toniolo Kubaski ◽  
Rogério de Almeida Vieira
Keyword(s):  
Pure State ◽  
Fused Deposition Modeling ◽  
Metal Oxide Nanoparticles ◽  
Scanning Calorimetry ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
Microscopy Analysis ◽  
3D Printed ◽  
Bioactive Potential ◽  
Hot Melt

This experimental study investigates the bioactive potential of filaments produced via hot melt extrusion (HME) and intended for fused deposition modeling (FDM) 3D printing purposes. The oleo-gum-resins from benzoin, myrrha, and olibanum in pure state and also charged with 10% of metal oxide nanoparticles, TiO2, P25, Cu2O, and MoO3, were characterized by ultraviolet-visible (UV-Vis) and Fourier transform infrared (FTIR) spectroscopy, energy-dispersive X-ray microanalysis (EDXMA), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). Disks were 3D-printed into model geometries (10 × 5 mm) and the disk-diffusion methodology was used for the evaluation of antimicrobial and antifungal activity of materials in study against the clinical isolates:Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, andCandida albicans. Due to their intrinsic properties, disks containing resins in pure state mostly prevent surface-associated growth; meanwhile, disks loaded with 10% oxides prevent planktonic growth of microorganisms in the susceptibility assay. The microscopy analysis showed that part of nanoparticles was encapsulated by the biopolymeric matrix of resins, in most cases remaining disorderly dispersed over the surface of resins. Thermal analysis shows that plant resins have peculiar characteristics, with a thermal behavior similar to commercial available semicrystalline polymers, although their structure consists of a mix of organic compounds.

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