scholarly journals Thermoplastic Polymers with Nanosilver Addition—Microstructural, Surface and Mechanical Evaluation during a 36-Month Deionized Water Incubation Period

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 361
Author(s):  
Magdalena Ziąbka ◽  
Michał Dziadek
Keyword(s):  
Mechanical Properties ◽  
Contact Angle ◽  
Silver Nanoparticles ◽  
Incubation Period ◽  
Water Environment ◽  
Mechanical Tests ◽  
Deionized Water ◽  
Thermoplastic Polymers

Three types of thermoplastic polymers, acrylonitrile butadiene styrene (ABS), polymethyl methacrylate acrylic (PMMA) and high-density polyethylene (HDPE), were enriched with silver nanoparticles (AgNPs) of 0.5 wt.% and 1.0 wt.%, respectively. The polymers and the composites were manufactured via injection molding. Regarding the potential of these polymers as matrices for long-term use as biomaterials, the aim of this study was to examine their stability in the in vitro conditions during a three-year incubation period in deionized water. In this work, microstructural observations were performed, and mechanical properties were assessed. Surface parameters, such as roughness and contact angle, were comprehensively investigated. The microstructural evaluation showed that the silver additive was homogeneously dispersed in all the examined matrices. The 36-month immersion period indicated no microstructural changes and proved the composites’ stability. The mechanical tests confirmed that the composites retained comparable mechanical properties after the silver incorporation. The Young’s modulus and tensile strength increased during long-term incubation. The addition of silver nanoparticles did not alter the composites’ roughness. The contact angle increased with the rising AgNP content. It was also shown that the materials’ roughness increased with the incubation time, especially for the ABS- and HDPE-based materials. The water environment conditions improved the wettability of the tested materials. However, the silver nanoparticles’ content resulted in the contact angle decreasing during incubation. The conducted studies confirmed that the mechanical properties of all the polymers and composites did not deteriorate; thus, the materials may be considered stable and applicable for long-term working periods in aqueous environments.

scholarly journals Long-Term Stability of Two Thermoplastic Polymers Modified with Silver Nanoparticles

Nanomaterials ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 61 ◽  
Author(s):  
Magdalena Ziąbka ◽  
Michał Dziadek
Keyword(s):  
Mechanical Properties ◽  
Silver Nanoparticles ◽  
Surface Properties ◽  
Acrylonitrile Butadiene Styrene ◽  
Thermoplastic Polymers ◽  
Preparation Technology ◽  
Time Intervals ◽  
Long Term Stability ◽  
Non Destructive

The aim of this study was to investigate the mechanical properties of polymeric composites prepared via extrusion and injection moulding. Four stable thermoplastic polymers were used as composites matrices (two kinds of polymethyl methacrylate and two kinds of co-polymer acrylonitrile-butadiene-styrene). Silver nanoparticles AgNPs were used as a modifying phase. Mechanical properties of testes materials were determined during the uniaxial stretching. Surface properties such as roughness and contact angle were also evaluated. The materials’ stability was assessed using scanning electron microscopy and non-destructive ultrasonic testing. All measurements were carried out at time intervals, determining both the initial parameters and after 6 and 12 months of incubation in deionized water. The obtained results proved that neither the preparation technology nor the amount of the modifier adversely affect the mechanical properties of the tested composites. The incorporated modifier does not change the surface properties significantly. The studies conducted after the materials’ incubation in water indicate their stability.

New manufacturing process to develop antibacterial dyed polyethylene terephthalate sutures using plasma functionalization and chitosan immobilization

2021 ◽  
pp. 152808372110505
Author(s):  
Nesrine Bhouri ◽  
Faten Debbabi ◽  
Abderrahmen Merghni ◽  
Esther Rohleder ◽  
Boris Mahltig ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polyethylene Terephthalate ◽  
Manufacturing Process ◽  
Antibacterial Effect ◽  
Inhibition Zone ◽  
The United States ◽  
Mechanical Tests ◽  
Inflammatory Reactions ◽  
Plasma Functionalization

The main purpose of this paper is to develop a new manufacturing process leading to have antibacterial dyed non-absorbable braided polyethylene terephthalate (PET) sutures using biocompatible and non-toxic products. This manufacturing process allows better visibility of sutures in the surgical field and reduces the risk of infections and inflammatory reactions without affecting the mechanical properties while meeting the United States Pharmacopeia (USP) requirements. Plasma functionalization, acrylic acid (AA) grafting, and bioactive chitosan (CH) coating were used before the dyeing process with a biocompatible non-toxic acid dye, approved by the Food and Drug Administration (FDA). The influence of experimental parameters on the suture properties and the K/S values of the dyed sutures are investigated. Infrared spectroscopy confirms the presence of new bonds to immobilize chitosan on the surface of the suture. Mechanical tests confirm that the mechanical properties of sutures have not been affected. The in vitro antibacterial effect of dyed PET sutures showed an inhibition zone of 11 mm against S. aureus, 4 mm against P. aeruginosa, and 1 mm against E. coli. This study reveals that the new finishing process of sutures is a promising method to achieve an antibacterial effect with a uniform shade and smooth surfaces.

Extended Long-Term Culture of MSC-Laden Agarose Constructs Does Not Produce Functional Tissue Comparable to Primary Chondrocytes

2010 ◽  
Author(s):  
Alice H. Huang ◽  
Robert L. Mauck
Keyword(s):  
Mechanical Properties ◽  
3D Culture ◽  
Biochemical Properties ◽  
Clinical Use ◽  
Promising Alternative ◽  
Chondrogenic Medium ◽  
Primary Chondrocytes ◽  
The Poor

Articular cartilage lines the surfaces of joints and transmits the forces arising from locomotion. The poor ability of cartilage to self-repair has motivated efforts to engineer replacements that recapitulate this load-bearing function. While chondrocyte-laden constructs have been generated with near-native mechanical properties, limitations in chondrocyte availability may preclude their clinical use. Therefore, mesenchymal stem cells (MSCs), which can undergo chondrogenesis in 3D culture, have emerged as a promising alternative [1]. However, although MSCs deposit a cartilaginous matrix, mechanical and biochemical properties are lower than those achieved with chondrocytes [1, 2]. Using microarray analysis, we recently showed that limitations in functional MSC chondrogenesis may stem from incomplete or incorrect molecular induction; molecular differences were observed between donor-matched differentiated chondrocytes and newly differentiated MSCs over 8 weeks of culture [2]. While some genes remained consistently low in MSCs compared to chondrocytes, others gradually increased with time, approaching chondrocyte levels by 8 weeks. As these molecules may underlie the functional disparity between chondrocytes and MSCs, we hypothesized that longer culture durations may improve MSC-seeded construct properties and chondrogenesis. To test this hypothesis, we characterized the evolution of functional properties of MSC- and chondrocyte-seeded constructs over 4 months of in vitro culture in pro-chondrogenic medium.

scholarly journals Effect of Sandblasting on the Long-Term Corrosion Resistance of Ti G4 in Artificial Saliva

2021 ◽  
Vol 6 (1) ◽  
pp. 5
Author(s):  
Patrycja Osak ◽  
Maciej Zubko ◽  
Julian Kubisztal ◽  
Joanna Maszybrocka ◽  
Bożena Łosiewicz
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Machine Surface ◽  
Electrochemical Impedance ◽  
Artificial Saliva ◽  
Electron Work Function ◽  
Titanium Implants ◽  
Bone Contact

Titanium Grade 4 (G4) is the most commonly used material for dental implants due to its excellent biocompatibility and mechanical properties. However, titanium implants require a rough surface that can increase the biomechanical potential of implant–bone contact and affect protein adsorption speed. In this work, the effect of sandblasting of the Ti G4 surface on the long-term corrosion resistance in artificial saliva of pH = 7.4 at 37 °C was studied. The X-ray diffraction (XRD) single-{hkl} sin2ψ method was used to measure the sandblasted Ti residual stress. In vitro corrosion resistance tests were conducted for 21 days using the open circuit potential method, polarization curves, and electrochemical impedance spectroscopy. Using the Kelvin scanning probe, the electron work function was determined. Analysis of the obtained results showed an improvement in the corrosion resistance of the sandblasted Ti G4 compared to Ti with the machine surface. The increase in corrosion resistance was related to the residual compressive stress of 324.7 MPa present in the sandblasted Ti surface. Sandblasting caused plastic deformation of the Ti surface, which resulted in the improvement in mechanical properties, as evidenced by the increase in the hardness of the sandblasted Ti compared to Ti with the machine surface.

Mechanical Properties of X80 Grade UOE Pipe for Long-Term Exposure at Elevated Temperature

2004 ◽  
Author(s):  
Ryuji Muraoka ◽  
Mitsuhiro Okatsu ◽  
Nobuyuki Ishikawa ◽  
Shigeru Endo ◽  
Shinichi Kakihara ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperatures ◽  
Mechanical Tests ◽  
Heat Treatments ◽  
Oil Sand ◽  
Operation Condition ◽  
Long Time ◽  
Simulated Condition ◽  
Installation Cost

Recently, X80 grade UOE pipes have been planned to apply to steam injecting oil sand recovery systems to increase the volume of steam to be injected and lowering installation cost. The pipes for systems are subjected to high temperature for a long time, such as 350-C, for 20 years. Before real applications of the pipes, it is important to ensure the reliability of the pipes during and after long-term operations. In this study, in order to establish simulation conditions for 350-C × 20 years of operation, the change in microstructure and resulting mechanical properties of X80 grade pipes after a long-term exposure at elevated temperatures were investigated. Then, mechanical properties of the pipes subjected to the established simulated condition were examined. Change in the microstructure was quite small after exposure of 400-C and lower temperatures. Tensile strengths of the base metal and seam weld after up to 400-C of heat treatment can be arranged with the Larson-Miller parameter composed with temperature and holding time of the heat treatments. Therefore, heat treatments at 400-C for shorter than 20 years can be simulation conditions for the operation condition of the systems. As a result of mechanical tests simulating long-term exposure, satisfied performance of X80 grade pipes can be obtained.

Mechanical Properties of Experimental Non-Latex Orthodontic Elastic Bands

2020 ◽  
Vol 897 ◽  
pp. 185-189
Author(s):  
Sasatorn Malanon ◽  
Surachai Dechkunakorn ◽  
Niwat Anuwongnukroh ◽  
Pongdhorn Sea-Oui ◽  
Puchong Thaptong ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tooth Movement ◽  
Orthodontic Tooth Movement ◽  
Mechanical Tests ◽  
Lower Percentage ◽  
Internal Diameter ◽  
Cross Sectional ◽  
Force Decay ◽  
Extension Force

. Elastics, a source of continuous orthodontic force, are divided into two types, latex and non-latex, which are made from natural rubber and synthetic rubber, respectively. The major advantage of natural latex elastics is its resiliency to intraoral tractive forces. However, as the incidence of allergic reactions to natural latex has become more widely recognized, non-latex orthodontic elastics have been developed as an alternative. The aim of this study is to investigate the in vitro mechanical properties of Thai non-latex orthodontic elastics as compared to commercially available products. 30 samples of each two Thai non-latex elastics (MTEC1, MTEC2) and two commercial elastics (AO, GAC) with a specified diameter of ¼ inches were used. Width, cross-sectional thickness (CT), and internal diameter (ID) of all samples were measured. Mechanical tests were then carried out to determine the initial extension force (F0), 24-hour residual force (F24), and percentage of force decay. The data were analyzed with one-way ANOVA and Tukey’s test (p < 0.05). Statistically significant differences in elastic width among all four groups except between the Thai non-latex groups (MTEC1 and MTEC2) were found. AO elastics showed the greatest CT followed by GAC, MTEC2 and MTEC1. ID was significantly highest in GAC elastics and lowest in MTEC1 elastics. Although MTEC1 elastics had the lowest F0, the force still falls within the acceptable range for tooth movement (100-250g or 0.981–1.471N). MTEC2 elastics had the greatest F24 and also the lowest percentage of force decay followed by MTEC1, GAC, and AO elastics, which displayed the highest force decay, though no significant differences were found between the two commercial elastics. Thai non-latex elastics are suitable for orthodontic tooth movement due to its lower percentage of force decay after 24 hours.

Influence of the Embedding Media on the Results of Standard In Vitro Fatigue Tests on the Femoral Components

1994 ◽  
Vol 208 (3) ◽  
pp. 131-137 ◽  
Author(s):  
M Viceconti ◽  
A Toni ◽  
A Giunti
Keyword(s):  
Mechanical Properties ◽  
Stress Analysis ◽  
Mechanical Tests ◽  
Fatigue Tests ◽  
Strain Gauges ◽  
Static Properties ◽  
Static Mechanical ◽  
Hip Stems ◽  
Dental Applications

The aim of the present investigation was to determine the effects of the embedding material mechanical properties on the in vitro fatigue endurance of femoral hip stems as determined following ISO standards. Acrylic cements are usually employed as embedding media; due to the high cost of surgical cements, acrylic cements for dental applications are commonly used. Two acrylic cements for dental applications were tested to determine their static mechanical properties and compared with those found for three surgical cements. The same two dental cements were also compared as embedding media in a series of ISO 7206/3 fatigue tests on a mini-size Cr-Co stem; prosthesis stress analysis using strain gauges was also performed. The mechanical tests on the different cements showed that behind the definition of acrylic cement are materials with considerably different mechanical static properties. The fatigue campaign confirmed the influence of embedding media on the results obtained from the ISO 7206/3 fatigue test. Under a load of 4200 N the stem failed after four million cycles when using one cement; it did not fail after ten million cycles when using another cement. Stress analysis with strain gauges substantially confirmed these findings.

scholarly journals Mechanical Properties of Thermoplastic Polymers for Aligner Manufacturing: In Vitro Study

2020 ◽  
Vol 8 (2) ◽  
pp. 47 ◽  
Author(s):  
Francesco Tamburrino ◽  
Vincenzo D’Antò ◽  
Rosaria Bucci ◽  
Giulio Alessandri-Bonetti ◽  
Sandro Barone ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Yield Stress ◽  
Artificial Saliva ◽  
In Vitro Study ◽  
Tensile Tests ◽  
Operating Conditions ◽  
Thermoplastic Polymers ◽  
The Impact

The use of metal-free thermoplastic materials plays a key role in the orthodontic digital workflow due to the increasing demand for clear aligner treatments. Three thermoplastic polymers commonly used to fabricate clear aligners, namely Duran®, Biolon® and Zendura®, were investigated to evaluate the effect of thermoforming (T.), storage in artificial saliva (S.A.S.) and their combination on their mechanical properties. Elastic modulus and yield stress of the specimens were characterized. Each material was characterized for each condition through tensile tests (ISO527-1). The results showed that thermoforming does not lead to a significant decrease in yield stress, except for Zendura® that showed about a 30% decrease. An increase of the elastic modulus of Duran® and Zendura®, instead, was observed after thermoforming. The same increase was noticed for the yield stress of Duran®. For S.A.S. specimens, the elastic modulus generally decreases compared to supplier condition (A.S.) and simply thermoformed material. A decrease of yield stress, instead, is significant for Zendura®. The results demonstrated that the impact of the operating conditions on the mechanical properties can vary according to the specific polymer. To design reliable and effective orthodontic treatments, the materials should be selected after their mechanical properties are characterized in the simulated intraoral environment.

scholarly journals Biocomposites conductive scaffold based on PEDOT:PSS/nHA/chitosan/PCL: Fabrication and characterization

2019 ◽  
Vol 15 (2) ◽  
pp. 146-149
Author(s):  
Alireza Lari ◽  
Naznin Sultana ◽  
Chin Fhong Soon
Keyword(s):  
Mechanical Properties ◽  
Contact Angle ◽  
Composite Scaffold ◽  
Biological Evaluation ◽  
Sem Analysis ◽  
Human Skin Fibroblast ◽  
Fabrication Technique ◽  
Pore Sizes ◽  
Material Component

Biomaterial-based scaffolds with suitable characteristics are highly desired in tissue engineering (TE) application. Biocomposites based on polymer and ceramics increase the chance for modulating the properties of scaffold. In recent years, researchers have considered conductive polymers to be used in TE application, due to their conductivity. This property has a good impact on tissue regeneration. A suitable design for bone substitute that consists of considerations such as material component, fabrication technique and mechanical properties. The previous studies on PEDOT:PSS/nHA/CS showed high wettability rate but low mechanical properties. Polycaprolactone (PCL) is a biodegradable and biocompatible polymer with a low wettability. The incorporation of PCL inside biocomposite can lead to the decrement in wettability and increment in mechanical property. In addition, this paper would examine the feasibility of blending of PCL and chitosan to fabricate PEDOT:PSS/nHA/CS composite scaffold. The fabrication technique of freezing/ lyophilization was used in this study. The scaffolds were characterized morphologically using scanning electron microscopy (SEM). Wettability was studied using a contact angle instrument. The attenuated total reflectance fourier transform infrared spectroscopy (ATR-FTIR) spectra interpreted the presence of polymeric ingredients within composite scaffold. Conductivity of the scaffolds was measured using a Digital Multimeter. In-vitro biological evaluation of the scaffolds was studied using human skin Fibroblast (HSF) cell line. The morphological study of biocomposite PEDOT:PSS/nHA/CS/PCL scaffold revealed random pore sizes and 66% porosity. Contact angle of the scaffold was increased and the swelling property and pore sizes were decreased after blending of PCL polymer. The viability of HSF cells on biocomposite PEDOT:PSS/nHA/CS/PCL scaffold was 85%. After 7 days, SEM analysis revealed the presence of cells on the surface of scaffold. In conclusion, the results suggested that PEDOT:PSS/nHA/CS/PCL biocomposite scaffold was non-toxic to cells and has suitable properties.

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