Additive manufacturing technologies revolutionize many aspects of our everyday life. Biomedical applications benefit a lot from 3D printing. From surgical guides, patterns to custom-made splints and ...casts, several medical devices can be easily produced or prototyped with FFF/FDM technologies. New materials regularly appear on the market; therefore, the scientifically accurate and practical information is not available, and we are lack of information regarding mechanical and thermal stability of the printed products. In addition, these parameters are essential in setting and optimizing the 3D printers. In our study, we aimed to analyze two different, unique PLA/CaCO
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composites in the form of additive manufacturing filament, with DTA. We tested the HDT form of PLA in pellet and filament form too. The results showed that these composites based on their thermal characteristics can be suitable for 3D print biomedical devices such as orthoses, casts, medical models and surgical guides too; therefore, their further examination should be important, regarding mechanical characteristics.
Among the strategies for reducing the negative effects on the environment effected by the uncontrolled consumption and low potential for the recovery of conventional plastics, the synthesis of new ...biodegradable and recyclable plastics represents one of the most promising methods for minimizing the negative effects of conventional non-biodegradable plastics. The spectrum of existing biodegradable materials is still very narrow; thus, to achieve greater applicability, research is being carried out on biodegradable polymer mixtures, the synthesis of new polymers, and the incorporation of new stabilizers for thermal degradation, alongside the use of other additives such as antibacterials or new and more sustainable plasticizers. Some studies analyze direct applications, such as shape memory foams, new cartilage implants, drug release, etc.The reader can find several studies on the degradation of biodegradable polymers under composting conditions; however, novel bacteria that degrade polymers considered non-biodegradable in other, unusual conditions (such as conditions of high salinity) are also presented.
Among the strategies for reducing the negative effects on the environment effected by the uncontrolled consumption and low potential for the recovery of conventional plastics, the synthesis of new ...biodegradable and recyclable plastics represents one of the most promising methods for minimizing the negative effects of conventional non-biodegradable plastics. The spectrum of existing biodegradable materials is still very narrow; thus, to achieve greater applicability, research is being carried out on biodegradable polymer mixtures, the synthesis of new polymers, and the incorporation of new stabilizers for thermal degradation, alongside the use of other additives such as antibacterials or new and more sustainable plasticizers. Some studies analyze direct applications, such as shape memory foams, new cartilage implants, drug release, etc.The reader can find several studies on the degradation of biodegradable polymers under composting conditions; however, novel bacteria that degrade polymers considered non-biodegradable in other, unusual conditions (such as conditions of high salinity) are also presented.
Ramie fiber-reinforced polylactic acid (PLA) composites were successfully prepared by hot compression molding. Different treatment techniques were used to modify the surface of ramie fiber. The ...influence of diammonium phosphate (DAP) on the interfacial adhesion between ramie fiber and PLA composites was investigated by the contact angle measurements, FTIR and SEM analyses. The contact angle measurement results showed that alkali treatment combined with DAP was very efficient in decreasing the hydrophilicity of fibers. After treatment, the hydrophilicity of untreated ramie fiber from 5.9 ± 1.3 decreased to 2.0 ± 0.8 mJ/m
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. The wettability of alkali/silane/DAP-treated ramie fiber/PLA composite was higher (95.4° ± 1.3°) than that of pure ramie fiber/PLA composite (87.3° ± 1.9°). The FTIR results were consistent with the wetting measurements as the increment of hydrophilicity. Thermal analysis indicated that DAP-modified ramie fiber/PLA composites exhibited a lower thermal decomposition temperature, unique decomposition behavior and more residual char formation at decomposition temperature. The tensile, flexural and impact properties of DAP-modified ramie fiber composites were comparable to those of untreated ramie fiber composite. Moreover, proper alignment and uniform distribution of ramie fibers within the PLA matrix were found to be excellent. The morphological structures observed by SEM showed that well-modified ramie fibers enhanced the failure of the PLA composites in tensile, flexural and impact tests.
In this work, the hydrophobization of lignocellulosic jute fibers was achieved via the laccase/TEMPO-mediated grafting of octadecylamine (OA) on their surface, with the aim to improve the interfacial ...compatibility with nonpolar polylactic acid (PLA) resins in fiber-reinforced composites. The modified jute fibers were analyzed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS). The characteristic vibrations of methylene groups and the increase in the surface C/O ratio of the jute fibers after the enzymatic treatment indicated that OA molecules were successfully grafted onto the jute fiber surface mediated by the laccase/TEMPO system. It was shown that the grafted jute fibers had increased surface hydrophobicity and reduced polarity with water contact angle of 124.2 °, diiodomethane contact angle of 94.1 ° and surface free energy of 11.44 mJ/m
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, which were attributed to the presence of the OA nonpolar alkyl chains on their surface. The tensile, bending, and dynamic mechanical properties of the hydrophobized jute/PLA composites were enhanced, which suggested stronger interfacial adhesion between the jute fibers and the PLA matrix. The mechanical stability was investigated by water immersion measurements and it was found that the modified jute/PLA composites were better in this regards than the control jute/PLA composites. Therefore, this enzymatic hydrophobic modification could be used as an effective and eco-friendly method to produce natural lignocellulosic fiber-reinforced composites with excellent performance.
The coaxial electrospinning of two kinds of materials is one of the most popular fabrication methods to endow the composites with desirable properties. For the biodegradable and coaxial-electrospun ...poly(lactic acid) (PLA) and poly(butylene succinate) (PBS) composite membranes, the effects of spinning parameters and the membrane density on the structure and mechanical property were still uncovered. In this work, biodegradable PLA and PBS composites were fabricated by means of coaxial-electrospinning followed by rolling press. The effects of PLA solution flow rate on the porous and crystal structure of the membrane were initially investigated. It was found that the pore size and porosity were independent on the flow rate. The crystallinity of PLA in the membrane increased with the increasing flow rate while that of PBS decreased, which brought about the composite membrane with enlarged tensile strength and reduced elongation. Then the influence of membrane density adjusted by the roller press was explored. Results showed that the porous structure greatly varied with the density. The larger the density was, the smaller the pore size and porosity were. Meanwhile, when the density was over 322 kg/m
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, the tensile strength and elongation of the coaxial membrane were both higher than that of pure PLA and PBS, achieving the complementary effect of PBS and PLA on mechanical property. The investigation concentrated on the biodegradable PLA and PBS composites is beneficial to the composite materials with complementary properties for various applications.
Graphical Abstract
In this work, the effects of inner solution flow rate and membrane density on the porous, crystal structure and mechanical property of coaxial-electropsun PBS/PLA nanofibrous membranes were investigated. The mechanical property of the composite membrane was greatly improved by the increase of PLA flow rate and high density, and the coaxial-electropsun membrane could achieve the mutual complementation of strengths of PBS and PLA.
The interest in antimicrobial packaging materials based on polylactic acid (PLA) polymers has increased due to the need to improve food safety and environment quality and also to find alternatives to ...synthetic polymers made from petrochemicals. PLA films by addition of different fillers (grape wastes and celery fibers) were obtained. The mechanical, thermal, surface, and antimicrobial properties of the films were evaluated. The incorporation of inexpensive fillers into the PLA matrix could reduce costs and the studied formulations offer approaches to realize composites with high performances and antimicrobial response, suitable for film food-active packaging materials, especially by use of grape wastes.
The aim of this study is to evaluate the effect of different surface modifications on mechanical properties of sisal fiber reinforced PLA (SF/PLA) composites. Using theoretical models Young’s modulus ...of the SF/PLA composites has been predicted. Tensile properties of single fiber showed a reduction in the tensile strength and modulus by 25% and 26% respectively as compared to the untreated sisal fiber owing to surface treatments. Optimization of fiber loading has also been studied for SF/PLA composites. The tensile strength increased by 10% for 15 wt% of fiber loading with the combined treatment of alkali and HIU as compared to the untreated fiber reinforced PLA composites. Tensile modulus of 30 wt% of fiber loading showed 75.4% increment as compared to pure PLA. Young’s modulus of the composites has also been predicted by using the theoretical models which fit well to the obtained experimental values. This investigation confirms that the surface treatments of SF/PLA composites with alkali and HIU are effective to improve their mechanical properties
In this investigation, the effect of different surface treatments on morphology, water absorption and biodegradable properties of sisal fiber reinforced PLA (SF/PLA) composites were studied. ...Field-emission scanning electron microscopy (FE-SEM) analysis confirmed the good dispersion of different surface treated sisal fibers in the PLA composites which improved the interfacial adhesion between sisal fibers and PLA matrix. Water absorption is reduced significantly for combined treated SF/PLA composites by 136% as compare to untreated composites. Environmental degradation was studied for SF/PLA composites by composting the samples into the soil. FE-SEM analysis shows the fiber reinforced composites were degraded faster than the pure PLA. It is also worth noted that the combination of alkali and HIU treated fiber composites show slower degradation as compare to untreated one. A significant weight loss could be seen (17.87% weight loss for untreated SF/PLA composites) after soil composting for 120 days. This investigation clearly confirms that the surface treatments of sisal fibers with the combination of alkali and high intensity ultrasound (HIU) are effective to improve filler dispersion, water resistance and biodegradability of SF/PLA composites
In this study, the change in the tensile fracture behavior of HAp/PLA composites, interface-controlled using pectin and chitosan, was evaluated for the case of the early-stage hydrolysis. Here, the ...reaction between the HAp particles and modification polymers was controlled using o-nitrobenzyl alcohol. Tensile tests after immersion in a pseudo biological environment indicated that the interface-control method employed in this study improved the fracture properties of HAp/PLA composites significantly, inducing the large plastic deformation. In addition, the effects of early-stage hydrolysis on fracture behavior and mechanism are discussed from the viewpoint of interfacial structures for the interface-controlled HAp/PLA composites. Observations of fracture morphologies and surfaces suggest that the interface-control employed in this study successfully improved interfacial bonding, enabling the effective usage of the deformability of the PLA matrix. The interface-control method employed in this study also maximized the fracture strain through the combination of improved interfacial bonding and an increase in the ductility of the PLA matrix after a 2-week immersion. Test results also suggest that the cancelation induced by the degradation of chitosan accelerated the degradation of the PLA matrix after a longer immersion.
