Manufacturing PLA/PCL Blends by Ultrasonic Molding Technology

Ferrer, I.; Manresa, Ariadna; Méndez, José Alberto; Delgado-Aguilar, Marc; García-Romeu, Maria Luisa

doi:10.3390/polym13152412

Cited by 13 publications

(14 citation statements)

References 56 publications

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“…Annealing treatment of heating the tubes immersed in gypsum was performed at a temperature of 190°C, for 3 h to achieve a temperature inside the mould of about 100°C (which corresponds to T g – glass transition temperature). 12,28 The temperature measurement and control of both moulds during the annealing were performed using a FLIR E5 thermal imaging camera (−20°C–+400°C), see Figure 7. The thermal coefficient ε r = 0.44 29 for air was set on the camera (emissivity table for infrared thermometer readings) because the mould temperature was measured after removal from the dryer, that is the moulds were cooled to ambient temperature.…”

Section: Materials and Specimensmentioning

confidence: 99%

Enhancing mechanical properties of 3D printed thermoplastic polymers by annealing in moulds

Vorkapić

Mladenović

Ivanov

et al. 2022

Advances in Mechanical Engineering

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Five series of specimens with two different print orientations (−45/45 and 0/90) and two print layer thicknesses (0.1 and 0.2 mm) were made. In total 60 specimens with 100% filament infill were made. One specimen series (20 pieces) was isolated as a reference or thermally untreated. Before the thermal treatment (annealing), two specimen moulding methods were used: NaCl powder (granulation 63 mm: 20 pieces) and Calcium Sulphate (Gypsum: 20 pieces). During the annealing, specimens immersed in NaCl powder were heated in a drying oven to the filament melting point (for PLA: 200°C, with a duration interval of 30 min), while the treatment of the heated specimens in gypsum was performed at a temperature of around 190°C, with duration interval of 3 h with the observed temperature inside the mould of about 100°C. An ultrasonic bath and a drying oven were used in the gypsum treatment. Temperature measurement and control during both annealing treatments were performed using a thermal imaging camera, while the temperature control inside the drying oven was performed using a digital thermometer. After treatment, the specimens in the moulds were cooled at room temperature, and the dimensions of annealing and untreated specimens were controlled. Surface morphology was characterised using scanning electron microscopy (SEM). The SEM analysis reveals improved internal structure after heat treatment of the PLA specimens. These results show that the investigated specimens after heat treatments had better structural properties than the referent specimens. Tensile testing on a universal testing machine in compliance with the ASTM D638 standard was also performed. The referent PLA specimen with −45/45 and layer thickness of 0.1 mm had the highest tensile stress value (64.08 MPa) while the specimen with minimal tensile stress value before fracture was 0/90, 0.2 mm (54.81 MPa). Heat treatment in gypsum showed the most significant increase in strength with −45/45 (0.1 mm) being the strongest (71.66 MPa) while the strongest specimen treated in sodium chloride was −45/45 (0.1 mm) with maximum tensile stress of 70.08 MPa. The mechanical characteristics of the PLA were characterised using the Vickers microhardness tester. The PLA microhardness value was calculated according to standards ASTM E384 and ISO 6507. The referent PLA specimen with −45/45 (0.2 mm) orientation shows the maximal microhardness value (125 MPa), and the minimal microhardness value was observed for the 0/90 (0.1 mm) orientation specimens (108 MPa). The heat treatment specimens in gypsum have a better hardness (185 MPa) than those treated in gypsum (165 MPa), with microhardness increasing by about 12%. The essence of the work is reflected in the additional filament processing to achieve a better structural and mechanical performance of the materials and reduce the anisotropy that is characteristic of 3D printing.

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Section: Materials and Specimensmentioning

confidence: 99%

Enhancing mechanical properties of 3D printed thermoplastic polymers by annealing in moulds

Vorkapić

Mladenović

Ivanov

et al. 2022

Advances in Mechanical Engineering

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“…In recent times, the research in advanced fields—for instance, medical applications—on biomaterials to replace or recover the tissue functions of the human body or in order to enhance the quality of life has risen substantially [ 4 ]. Regenerative medicine and tissue engineering, surgical implants or bone-fixing devices in orthopedic applications, porous structures in tissue engineering, implantable matrices for controlled medication release within the body, as well as absorbable sutures or closures are just a few of the applicable biomaterial applications [ 4 , 5 ]. In both basic research and clinical applications, polymer biomaterials have drawn a lot of attention.…”

Section: Introductionmentioning

confidence: 99%

“…In both basic research and clinical applications, polymer biomaterials have drawn a lot of attention. Polymers were utilized in the development of biomaterials due to their chemical structures’ adaptability, biocompatibility, biodegradability, and compatibility with required biomolecules [ 5 , 6 , 7 ]. Polymer biomaterials are classified according to their natural or synthetic origin [ 7 , 8 , 9 ].…”

Section: Introductionmentioning

confidence: 99%

“…Given their ability to meet a variety of functional requirements for medical devices, including mechanical properties, biodegradability, and biocompatibility, synthetic polymers are increasingly being employed in the medical sector. An additional deciding aspect is the bioactivity or antimicrobial properties when polymers or particle-reinforced coatings are applied [ 5 , 9 , 15 , 16 ]. PLA and PCL are extensively utilized synthetic polymers whose properties are being explored for biomedical applications.…”

Section: Introductionmentioning

confidence: 99%

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Investigating the Effect of PCL Concentrations on the Characterization of PLA Polymeric Blends for Biomaterial Applications

et al. 2022

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Polylactic acid (PLA) and polycaprolactone (PCL) are synthetic polymers that are extensively used in biomedical applications. However, the PLA/PCL blend produced by ball milling, followed by pressure compaction and sintering, has not been extensively explored. The goal of this research is to investigate the effect of the composition of biomaterials derived from PLA and PCL prepared by ball milling, followed by pressure compaction and sintering, on mechanical and physical properties. PCL and PLA with various concentrations were blended utilizing a ball milling machine for 2 h at an 80-rpm rotation speed. The obtained mixture was placed in a stainless steel 304 mold for the compacting process, which uses a pressure of 30 MPa to create a green body. The sintering procedure was carried out on the green body created at 150 °C for 2 h using a digital oven. The obtained PLA/PCL blend was tested using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscopy (SEM), density, porosity, and three-point bending. Following the interaction between PCL and PLA in the PLA/PCL blend, the FTIR spectra and XRD diffractograms obtained in this work revealed a number of modifications in the functional groups and crystal phase. The 90PLA specimen had the best mechanical properties, with a maximum force and displacement of 51.13 N and 7.21 mm, respectively. The porosity of the PLA/PCL blend decreased with increasing PLA concentration so that the density and flexural properties of the PLA/PCL blend increased. The higher PCL content decreased the stiffness of the PLA molecular chain, consequently reducing its flexural properties.

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“…The polymer materials that are destined for ecologically friendly products must present a pertinent degradation rate so that they may be easily recycled, converted into other useful derivatives or destroyed without pollution [ 32 ]. The ability of mixed PLA-based materials to be considered biodegradable is demonstrated by their capacity to be regenerated [ 33 ], recycled [ 34 ] or transformed into ecological materials by mixing [ 35 , 36 , 37 , 38 ]. Therefore, our study envisages the identification of a proper system with which the manufacturers may produce appropriate items with a certain degree of stability.…”

Section: Introductionmentioning

confidence: 99%

Stability Study of the Irradiated Poly(lactic acid)/Styrene Isoprene Styrene Reinforced with Silica Nanoparticles

Lupu

Mariș

Zaharescu³

et al. 2022

Materials

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In this paper, the stability improvement of poly(lactic acid) (PLA)/styrene-isoprene block copolymer (SIS) loaded with silica nanoparticles is characterized. The protection efficiency in the material of thermal stability is mainly studied by means of high accurate isothermal and nonisothermal chemiluminescence procedures. The oxidation induction times obtained in the isothermal CL determinations increase from 45 min to 312 min as the polymer is free of silica or the filler loading is about 10%, respectively. The nonisothermal measurements reveal the values of onset oxidation temperatures with about 15% when the concentration of SiO2 particles is enhanced from none to 10%. The curing assay and Charlesby–Pinner representation as well as the modifications that occurred in the FTIR carbonyl band at 1745 cm−1 are appropriate proofs for the delay of oxidation in hybrid samples. The improved efficiency of silica during the accelerated degradation of PLA/SIS 30/n-SiO2 composites is demonstrated by means of the increased values of activation energy in correlation with the augmentation of silica loading. While the pristine material is modified by the addition of 10% silica nanoparticles, the activation energy grows from 55 kJ mol−1 to 74 kJ mol−1 for nonirradiated samples and from 47 kJ mol−1 to 76 kJ mol−1 for γ-processed material at 25 kGy. The stabilizer features are associated with silica nanoparticles due to the protection of fragments generated by the scission of hydrocarbon structure of SIS, the minor component, whose degradation fragments are early converted into hydroperoxides rather than influencing depolymerization in the PLA phase. The reduction of the transmission values concerning the growing reinforcement is evidence of the capacity of SiO2 to minimize the changes in polymers subjected to high energy sterilization. The silica loading of 10 wt% may be considered a proper solution for attaining an extended lifespan under the accelerated degradation caused by the intense transfer of energy, such as radiation processing on the polymer hybrid.

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Manufacturing PLA/PCL Blends by Ultrasonic Molding Technology

Cited by 13 publications

References 56 publications

Enhancing mechanical properties of 3D printed thermoplastic polymers by annealing in moulds

Enhancing mechanical properties of 3D printed thermoplastic polymers by annealing in moulds

Investigating the Effect of PCL Concentrations on the Characterization of PLA Polymeric Blends for Biomaterial Applications

Stability Study of the Irradiated Poly(lactic acid)/Styrene Isoprene Styrene Reinforced with Silica Nanoparticles

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