RESUMO
In this article, the optical and structural properties of iPP/TiO2 nanocomposite fibres, considering three distinct extrusion speeds (25, 50 and 78 m/min) in addition to blank isotactic polypropylene samples were determined. Employing computed tomographic scans, localised optical defects in the nanocomposite fibres are unveiled, while refractive indices are examined by analysing transmitted intensity with incident light vibrating parallel and perpendicular to the fibre axis. The internal structure is further characterised through birefringence and density calculations. Mechanical properties, specifically stiffness, are probed by measuring elastic modulus values along the fibre. The investigation extends to the presence of TiO2 nanoparticles in the isotactic polypropylene matrix, inspecting their influence on the uniform morphology along and across the fibre. While the addition of TiO2 nanoparticles has many advantages, including enhanced properties, the study shows adverse effects on the morphological integrity of the fibres, particularly at higher extrusion rates. Micrographs are included to visually illustrate these findings, providing a comprehensive understanding of the complex interaction between extrusion rates, TiO2 nanoparticle incorporation, and the resulting optical and structural properties in iPP fibres.
RESUMO
There are many challenges faced the soft tissue adhesives in the medical application field. For example, there is a limited effective binding between the medical adhesive and different types of soft tissues. Chitosan (CS) and dopamine (DA) were used as structural units for synthesizing nanocomposites utilized as a wet tissue adhesive. To produce dopamine-chitosan-iron oxide nanocomposites (DA-CS-Fe3O4 NCs), DA was loaded onto chitosan-iron oxide nanocomposites. The nanocomposites have been prepared using ionic gelation method under vigorous homogenization and characterized by different techniques. Fourier-transform infrared spectroscopy (FTIR) have shown that DA-CS- Fe3O4 NCs could attach to the tissue through two possible functional groups, namely, the catechol and amine groups. The results of in vitro scratch wound-healing assay suggested that the prepared DA-CS- Fe3O4 NCs facilitate cell migration (the wound-closure percentage reached 96% at 72 h). All experimental results confirm that DA-CS- Fe3O4 NCs are strongly recommended for use as a soft medical tissue adhesive in wound healing and surgeries such as vascular surgery. In addition, the results of the whole blood clotting, antibacterial assessment, live and dead assay, cytotoxicity test, and wound-healing assay indicate that DA-CS-Fe3O4 NCs can be used as a multifunctional biomedical adhesive.
Assuntos
Quitosana , Nanocompostos , Adesivos Teciduais , Quitosana/química , Dopamina , Antibacterianos/farmacologia , Antibacterianos/química , Cicatrização , Nanocompostos/químicaRESUMO
Monocryl is a bio-absorbable suture composed of a polyglycolide and poly-epsiloncaprolactone copolymer material and is considered a promising candidate for soft tissues approximation. Consequently, the physical, mechanical, and morphological properties are essential for the surgeons to select the suitable suture for their surgical perform. In this article, Mach Zehnder interferometer equipped with a mechanical drawing device are used for evaluating the mechanical properties and a better understanding of how the Monocryl suture reacts to loading. The two-dimensional fast Fourier transform is applied to extract the phase from the captured interference microinterferograms at different draw ratios. The extracted phase helps to determine some opto-mechanical and structural properties of Monocryle suture. Quantitative structure-activity relationships model is employed for investigating the biological activity of the tested suture. The stress-strain behavior of Monocryl suture has a J-shaped behavior which compatible with the behavior of the soft tissues. The molecular electrostatic potential maps showed that Monocryl model structure is proved to be electrophilic interplays.
Assuntos
Dioxanos , Suturas , Poliésteres , Ácido PoliglicólicoRESUMO
In this work, the shear bands formed during the stretching of isotactic polypropylene fibers are studied. The digital photoelasticity technique is applied to provide full-field visualization of the stress of the shear bands regions. The mechanical testing device is modified to be suitable for mechanical measurements. The effect of different parameters, that is, the stretching rates and the ambient temperature on the formation of shear bands is investigated. Finally, the influence of heating pre-existed shear bands is studied. Photoelastic patterns of the shear bands at these conditions are included for illustration.
RESUMO
Polyamide-6 fiber was modified by grafting it with poly(methyl methacrylate) PMMA polymer. The grafting process is widely used in industry to introduce new properties and overcome some obstacles, for instance, in storing energy applications. Multiple-beam interference techniques are very precise techniques to characterize the different properties of polymeric fibers. Fringes of equal chromatic order FECO technique was used to study the effect of grafting process on the dispersion properties of polyamides fibers. A mechanical drawing device was attached to the FECO system to evaluate the mechanical deformation impact on the samples and on their dispersion properties. The dispersion properties were evaluated by measuring their refractive indices, Cauchy's constants, average excitation energy, dispersion energy, lattice energy, interband oscillator wavelength, static dielectric constant, and Abbe's dispersion number. The results show that grafting polyamide-6 with PMMA produced a new material with a different structure and different dispersion properties. Microinterferograms, graphs and tables were given for illustrations.
RESUMO
Recently, scientific research has confirmed that a single polymer material cannot meet the ambitions of all surgical requirements. Thus, combinations of different types of polymeric materials are used in order to manufacture different suture materials. A copolymer of Polyglycolide (PGA) and trimethylene carbonate (TMC) is one of the simplest bioabsorbable monofilament sutures. The optical properties of PGA/TMC copolymer surgical suture were investigated by using multiple-beam interferometric of Fizeau type. The mechanical properties were measured by a suture-drawing apparatus attached to the multiple-beam interferometric system. The refractive indices, stress-strain curve, elastic shear modulus, Young's modulus and crosslink density were investigated for the PGA/TMC surgical suture at various draw ratios. The biological activities were conducted by Quantitative Structure Activity Relationships (QSAR) descriptors. Molecular Electrostatic Potential (MESP) maps were used to describe the reactivity and functional active sites for the given molecule. The behavior of stress-strain curve confirms the compatibility of the suture with the sternum which proves that this suture is a good candidate for cardiac operations. RESEARCH HIGHLIGHTS: Fizeau fringes is accurate in characterizing properties of PGA/TMC surgical suture. The biological activities were conducted by (QSAR) descriptors. The compatibility measurements lead to it is a good candidate for cardiac operations.
Assuntos
Engenharia Tecidual , Dioxanos , Poliésteres , Ácido PoliglicólicoRESUMO
In this article we present an opto-thermo-mechanical characterization of isotactic polypropylene monofilament during failure by fracture. The digital photoelasticity, the two-beam Pluta polarising interference microscope and the computed tomography are used to provide quantitative data and visual models of the fracture regions of isotactic polypropylene fibers suffering failure by fracture at different thermal and mechanical conditions. Birefringence values and the intrinsic stress-anisotropy are measured at the fracture surface. 3D models of the fracture regions are reconstructed. Photoelastic patterns and two-beam interferograms are included for illustration.
RESUMO
Mach-Zehnder interferometer technique is utilized to study the impact of grafting of the nylon-6 fibers with poly (methyl methacrylate) (PMMA) polymer on the optical, geometrical, and structural properties. He-Ne laser diffraction technique is applied to study the changes in the fiber thickness of two samples (nylon-6 blank and nylon-6 grafted with PMMA) at different positions along the fiber length. The geometrical parameters are investigated by determining the cross-sectional shape of the two samples. The results of the interferometric and the diffraction techniques show that there is no variation in the thickness of nylon-6 fiber but variations in the thickness of the grafted nylon-6 fiber are obvious. The optical and physical properties along the axis of these fibers are characterized by measuring their refractive indices, birefringence, polarizability per unit volume, dielectric constant, surface reflectivity and the refractive index profile. The results show that PMMA polymer changed the optical, geometrical, and structural properties of the nylon-6 blank fiber. Microinterferograms are given for illustrations.
RESUMO
Digital holographic interferometry (DHI), X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR) and scanning electron microscopy (SEM) were used to study the effects of gamma irradiation on the physical and structural properties of basalt fibers. For this purpose, set samples of basalt fibers were subjected to different doses of gamma irradiation (3, 10, 25, and 40 kGy). The Mach-Zehnder interferometer was used to capture holographic patterns which are used then to determine the unwrapped phase. From the unwrapped phase distributions, the optical path difference within the irradiated basalt samples was determined. Thus, refractive indices, and birefringence of irradiated basalt fibers were determined at different irradiation doses using DHI method. XRD technique was used to investigate the effect of irradiation doses on the crystalline behavior of fibers. FTIR was performed to each of the basalt samples to evaluate the changes in the surface chemical properties due to radiation exposure doses. The morphology of irradiated fibers was examined using SEM. The results indicate that basalt fiber has a resistance to gamma radiation. There are no significant effects on the physical, structural and chemical properties were demonstrated of basalt fibers in the doses range of irradiation.