Local porosity analysis of disordered porous matrices

1994 ◽  
pp. 197-206
Author(s):  
Massimiliano Giona ◽  
Alessandra Adrover
Keyword(s):  
Local Porosity ◽  
Porous Matrices ◽  
Porosity Analysis

PLGA+HA/βTCP scaffold incorporating simvastatin: a promising biomaterial for bone tissue engineering

2020 ◽  
Author(s):  
Mariane Beatriz Sordi ◽  
Ariadne Cristiane Cabral da Cruz ◽  
Águedo Aragones ◽  
Mabel Mariela Rodríguez Cordeiro ◽  
Ricardo de Souza Magini
Keyword(s):  
Tissue Engineering ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Thermal Analyses ◽  
Chemical Properties ◽  
Biological Properties ◽  
Scanning Calorimetry ◽  
Evaporation Technique ◽  
Porosity Analysis ◽  
Biphasic Ceramic

The aim of this study was to synthesize, characterize, and evaluate degradation and biocompatibility of poly(lactic-co-glycolic acid) + hydroxyapatite / β-tricalcium phosphate (PLGA+HA/βTCP) scaffolds incorporating simvastatin (SIM) to verify if this biomaterial might be promising for bone tissue engineering. Samples were obtained by the solvent evaporation technique. Biphasic ceramic particles (70% HA, 30% βTCP) were added to PLGA in a ratio of 1:1. Samples with SIM received 1% (m:m) of this medication. Scaffolds were synthesized in a cylindric-shape and sterilized by ethylene oxide. For degradation analysis, samples were immersed in PBS at 37 °C under constant stirring for 7, 14, 21, and 28 days. Non-degraded samples were taken as reference. Mass variation, scanning electron microscopy, porosity analysis, Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetry were performed to evaluate physico-chemical properties. Wettability and cytotoxicity tests were conducted to evaluate the biocompatibility. Microscopic images revealed the presence of macro, meso, and micropores in the polymer structure with HA/βTCP particles homogeneously dispersed. Chemical and thermal analyses presented very similar results for both PLGA+HA/βTCP and PLGA+HA/βTCP+SIM. The incorporation of simvastatin improved the hydrophilicity of scaffolds. Additionally, PLGA+HA/βTCP and PLGA+HA/βTCP+SIM scaffolds were biocompatible for osteoblasts and mesenchymal stem cells. In summary, PLGA+HA/βTCP scaffolds incorporating simvastatin presented adequate structural, chemical, thermal, and biological properties for bone tissue engineering.

scholarly journals Porosity Analysis of Additive Manufactured Parts Using CAQ Technology

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1142
Author(s):  
Peter Pokorný ◽  
Štefan Václav ◽  
Jana Petru ◽  
Michaela Kritikos
Keyword(s):  
Manufacturing Process ◽  
Scanning Speed ◽  
Additive Technologies ◽  
Integration Time ◽  
Detector Resolution ◽  
Porosity Analysis ◽  
3D Scans ◽  
Printing Direction ◽  
Non Destructive

Components produced by additive technology are implemented in various spheres of industry, such as automotive or aerospace. This manufacturing process can lead to making highly optimized parts. There is not enough information about the quality of the parts produced by additive technologies, especially those made from metal powder. The research in this article deals with the porosity of components produced by additive technologies. The components used for the research were manufactured by the selective laser melting (SLM) method. The shape of these components is the same as the shape used for the tensile test. The investigated parts were printed with orientation in two directions, Z and XZ with respect to the machine platform. The printing strategy was “stripe”. The material used for printing of the parts was SS 316L-0407. The printing parameters were laser power of 200 W, scanning speed of 650 mm/s, and the thickness of the layer was 50 µm. A non-destructive method was used for the components’ porosity evaluation. The scanning was performed by CT machine METROTOM 1500. The radiation parameters used for getting 3D scans were voltage 180 kV, current 900 µA, detector resolution 1024 × 1024 px, voxel size 119.43 µm, number of projections 1050, and integration time 2000 ms. This entire measurement process responds to the computer aided quality (CAQ) technology. VG studio MAX 3.0 software was used to evaluate the obtained data. The porosity of the parts with Z and XZ orientation was also evaluated for parts’ thicknesses of 1, 2, and 3 mm, respectively. It has been proven by this experimental investigation that the printing direction of the part in the additive manufacturing process under question affects its porosity.

scholarly journals Rheology and Water Absorption Properties of Alginate–Soy Protein Composites

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1807
Author(s):  
Estefanía Álvarez-Castillo ◽  
José Manuel Aguilar ◽  
Carlos Bengoechea ◽  
María Luisa López-Castejón ◽  
Antonio Guerrero
Keyword(s):  
Soy Protein ◽  
Water Solubility ◽  
Divalent Cations ◽  
Low Cost ◽  
Soy Protein Isolate ◽  
Protein Isolate ◽  
Guluronic Acid ◽  
Wide Range ◽  
Anionic Polysaccharides ◽  
Porous Matrices

Composite materials based on proteins and carbohydrates normally offer improved water solubility, biodegradability, and biocompatibility, which make them attractive for a wide range of applications. Soy protein isolate (SPI) has shown superabsorbent properties that are useful in fields such as agriculture. Alginate salts (ALG) are linear anionic polysaccharides obtained at a low cost from brown algae, displaying a good enough biocompatibility to be considered for medical applications. As alginates are quite hydrophilic, the exchange of ions from guluronic acid present in its molecular structure with divalent cations, particularly Ca2+, may induce its gelation, which would inhibit its solubilization in water. Both biopolymers SPI and ALG were used to produce composites through injection moulding using glycerol (Gly) as a plasticizer. Different biopolymer/plasticizer ratios were employed, and the SPI/ALG ratio within the biopolymer fraction was also varied. Furthermore, composites were immersed in different CaCl2 solutions to inhibit the amount of soluble matter loss and to enhance the mechanical properties of the resulting porous matrices. The main goal of the present work was the development and characterization of green porous matrices with inhibited solubility thanks to the gelation of alginate.

Study of Porosity of Carbon Reinforced Plastic Composites Using Broadband Ultrasound Structuroscopy Techniques

2017 ◽  
Vol 755 ◽  
pp. 44-51
Author(s):  
Anton S. Bychkov ◽  
Alexander A. Karabutov ◽  
Elena V. Savateeva ◽  
Yulia G. Sokolovskaya ◽  
Vasily P. Zarubin ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
Metal Matrix ◽  
Elastic Moduli ◽  
Epoxy Composites ◽  
Ultrasonic Spectroscopy ◽  
Isotropic Composite ◽  
Plastic Composites ◽  
Reinforced Plastic ◽  
Local Porosity ◽  
Longitudinal Acoustic Waves

Theoretical assessments are given for the use of the through-transition technique of broadband ultrasonic spectroscopy to determine porosity of heterogeneous materials. Experimental measurements of local porosity of composites using the through-transition technique are presented. Dependences of elastic moduli on the concentration of hardening particles and porosity of metal matrix isotropic composite found. Experimental relationship between the phase velocity of longitudinal acoustic waves and the power of structural noise in samples of graphite epoxy composites is obtained.

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