Flexural Modulus and Strength of Cold Cured Poly(methylmethacrylate) Reinforced with TiO2 Nano Particles

The most significant disadvantage of cold cured poly (methyl methacrylate) - PMMA is its poor mechanical properties, mainly in flexure. The aim of this work is to explore the modulus and flexural strength of modified cold cured PMMA modified with low TiO2 addition, which can also have antibacterial properties. Commercial cold cured PMMA resin, consisting of powder and liquid components, were modified by adding 0.05 %, 0.2 %, and 1.5 wt. % 20 nm hydrophobic TiO2. The specimen s flexural modulus and strength were tested, while heat properties were determined with DSC analysis. SEM and EDX were used to study fracture surfaces of tested specimens. In all modified specimens, an increased flexural modulus and flexural strength were recorded. In all specimens, the appearance of agglomerates was noted. Glass transition temperatures also increased, as the result of the appearance of polymer chains with reduced mobility around nanoparticles. 0.2 % of 20 nm TiO2 nanoparticle content proved to be the most efficient in increasing flexural modulus and strength.

Download Full-text

Physical Properties of Vanillin Incorporated Self-Curing Orthodontic Polymethylmethacrylate Resin

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.853.46 ◽

2020 ◽

Vol 853 ◽

pp. 46-50

Author(s):

Thongchai Poonpiriya ◽

Pornrachanee Sawaengkit ◽

Sroisiri Thaweboon ◽

Pornkiat Churnjitapirom

Keyword(s):

Flexural Strength ◽

Physical Properties ◽

Flexural Modulus ◽

Orthodontic Appliances ◽

Surface Porosity ◽

Significance Level ◽

Removable Orthodontic Appliances ◽

Pmma Resin ◽

One Way Anova

Polymethylmethacrylate (PMMA) resin is the main polymeric material used in removable orthodontic appliances. However, it can promote the adhesion of microbes due to its surface porosity and from long-term use. While vanillin incorporated PMMA resin has been reported to have antimicrobial effects against Candida albicans, the influence of vanillin incorporation on the physical properties of self-curing orthodontic PMMA resin has not been studied. Objective: To determine the flexural strength and flexural modulus of self-curing orthodontic PMMA resin incorporated with vanillin in different concentrations. Materials and methods: Three groups of self-curing orthodontic PMMA with incorporated vanillin concentrations of 0.1%, 0.5% as well as PMMA without vanillin as a control were prepared with ten specimens per group. Flexural strength and flexural modulus were tested by a 3-point bending machine according to ISO 20795-2:2013 specifications. One-way ANOVA and Tukey’s multiple comparison tests at a p<0.05 significance level were used to analyse the data. Results: The 0.1% vanillin incorporated group met ISO standard requirements (flexural strength = 60.48 MPa, flexural modulus = 1756.60 MPa), while the 0.5% vanillin incorporated group failed to pass this standard (flexural strength = 46.94 MPa, flexural modulus = 1423.49 MPa). The means of both flexural strength and flexural modulus showed significant differences among the three groups. Increasing the concentration of vanillin would decrease the flexural strength and flexural modulus of PMMA resin. Conclusion: The incorporation of vanillin into self-curing orthodontic PMMA resin can affect its physical properties, namely flexural strength and flexural modulus. At a concentration of 0.1% vanillin incorporation, PMMA resin displayed physical properties within the ISO standards.

Download Full-text

Combined effect of nano-SiO2 particles and steel fibers on flexural properties of concrete composite containing fly ash

Science and Engineering of Composite Materials ◽

10.1515/secm-2013-0179 ◽

2014 ◽

Vol 21 (4) ◽

pp. 597-605 ◽

Cited By ~ 7

Author(s):

Peng Zhang ◽

Ya-nan Zhao ◽

Chen-hui Liu ◽

Peng Wang ◽

Tian-hang Zhang

Keyword(s):

Fly Ash ◽

Flexural Strength ◽

Modulus Of Elasticity ◽

Steel Fiber ◽

Flexural Modulus ◽

Fiber Content ◽

Steel Fibers ◽

Combined Effect ◽

Nano Particles ◽

Flexural Properties

AbstractThis paper presents an experimental study to evaluate the combined effect of nano-SiO2 particles and steel fibers on flexural properties of concrete composites containing fly ash. In this study, five different nano-SiO2 contents (1%, 3%, 5%, 7%, and 9%) and five different steel fiber contents (0.5%, 1%, 1.5%, 2%, and 2.5%) were used. The results indicate that addition of nano-SiO2 and steel fibers decreases the workability of the concrete composites containing fly ash, and both the slump and slump flow decrease gradually with the increase in nano-SiO2 and steel fiber content. Besides, the addition of nano-SiO2 can greatly increase the flexural strength and flexural modulus of elasticity of concrete composites containing fly ash. There is a tendency for the increase in the flexural strength flexural modulus of elasticity with an increase in the nano-SiO2 content when the nano-SiO2 content is below 5%, while both of the two flexural parameters begin to decrease after the nano-SiO2 content above 5%. Furthermore, steel fibers have great improvement on the flexural properties of concrete composites containing fly ash and nano-particles. The flexural strength and flexural modulus of elasticity of concrete composites containing fly ash and nano-SiO2 are more than those of the concrete composite without steel fibers. Both of the two flexural parameters increase with the increase in steel fiber content when the steel fiber content is below 2%, while the flexural parameters begin to decrease after the steel fiber content is above 2%.

Download Full-text

Biogenic Synthesis of Gold Nanoparticles from Aspartic Acid - A Preliminary Study

Journal of Pharmaceutical Research International ◽

10.9734/jpri/2020/v32i1830685 ◽

2020 ◽

pp. 21-27

Author(s):

K. Ajith Kamath ◽

Iffat Nasim ◽

S. Rajesh

Keyword(s):

Gold Nanoparticles ◽

Aspartic Acid ◽

Plasmon Resonance ◽

Metallic Nanoparticles ◽

Antibacterial Properties ◽

Nano Particles ◽

Magnetic Stirrer ◽

Ultra Fine Particle ◽

Average Size ◽

20 Nm

A nanoparticle is an ultra-fine particle with at least one dimension between 1-100 nanometers (nm). Metallic nanoparticles are considered as most promising as they contain remarkable antibacterial properties. Gold nanoparticles are of high importance in research. Aspartic acid is an alpha amino acid and contains one amino group and one carboxylic group. The aim of the current study was to bio synthesize gold nanoparticles using aspartic acid. Gold Chloride (AuCl3) and Aspartic acid (C₄H₇NO₄) were used for the study. AuCL3 solution (0.266 M) was slowly added to 250 aspartic acid with stirring at 45°C. The mixture of the solutions was kept in a long-necked borosilicate flask and continuously stirred on a magnetic stirrer. The formation of gold nanoparticles was confirmed by the change of the colorless solution to a reddish hue. Characterization of the newly formed nanoparticles was then done. After approximately 9 hour incubation and intermittent stirring with a magnetic stirrer the solution color changed from colorless to a reddish hue, which indicated the formation of AuNPs. The spectrometric reading was recorded at a scanning range of 400–700 nm. AuNPs nanoparticles at 24 hours showed an increased intensity and a Surface Plasmon Resonance (SPR) band at 575 nm. The gold nanoparticles by Transmission electron microscopy were confirmed to be spherical in shape and of 20 nm. A simple and efficient method for the synthesis of AuNPs from the aspartic acid was demonstrated. Nano particles were formed in approx. 9 hours with peak absorbance at 24 hours at 575nm. The synthesized nanoparticles were spherical in shape, with an average size of 20 nm. The synthesized nanoparticles showed excellent plasmon resonance and optical properties.

Download Full-text

Investigation of Ring and Star Polymers in Confined Geometries: Theory and Simulations

Entropy ◽

10.3390/e23020242 ◽

2021 ◽

Vol 23 (2) ◽

pp. 242

Author(s):

Joanna Halun ◽

Pawel Karbowniczek ◽

Piotr Kuterba ◽

Zoriana Danel

Keyword(s):

Star Polymers ◽

Polymer Chains ◽

The Other ◽

Nano Particles ◽

Dilute Solution ◽

Confined Geometries ◽

Density Profiles ◽

Ideal Ring ◽

Ring Polymer ◽

Monomer Density

The calculations of the dimensionless layer monomer density profiles for a dilute solution of phantom ideal ring polymer chains and star polymers with f=4 arms in a Θ-solvent confined in a slit geometry of two parallel walls with repulsive surfaces and for the mixed case of one repulsive and the other inert surface were performed. Furthermore, taking into account the Derjaguin approximation, the dimensionless layer monomer density profiles for phantom ideal ring polymer chains and star polymers immersed in a solution of big colloidal particles with different adsorbing or repelling properties with respect to polymers were calculated. The density-force relation for the above-mentioned cases was analyzed, and the universal amplitude ratio B was obtained. Taking into account the small sphere expansion allowed obtaining the monomer density profiles for a dilute solution of phantom ideal ring polymers immersed in a solution of small spherical particles, or nano-particles of finite size, which are much smaller than the polymer size and the other characteristic mesoscopic length of the system. We performed molecular dynamics simulations of a dilute solution of linear, ring, and star-shaped polymers with N=300, 300 (360), and 1201 (4 × 300 + 1-star polymer with four arms) beads accordingly. The obtained analytical and numerical results for phantom ring and star polymers are compared with the results for linear polymer chains in confined geometries.

Download Full-text

Enhanced flexural properties of aramid fiber/epoxy composites by graphene oxide

Nanotechnology Reviews ◽

10.1515/ntrev-2019-0043 ◽

2019 ◽

Vol 8 (1) ◽

pp. 484-492 ◽

Cited By ~ 1

Author(s):

Yinqiu Wu ◽

Bolin Tang ◽

Kun Liu ◽

Xiaoling Zeng ◽

Jingjing Lu ◽

...

Keyword(s):

Graphene Oxide ◽

Flexural Strength ◽

Interfacial Shear Strength ◽

Flexural Modulus ◽

Weight Fraction ◽

Interfacial Shear ◽

Aramid Fiber ◽

Epoxy Composites ◽

Flexural Properties ◽

Pure Epoxy

Abstract The reinforcing effect of graphene oxide (GO) in enhancing the flexural strength and flexural modulus of aramid fiber (AF)/epoxy composites were investigated with GO-AFs at a weight fraction of 0.1-0.7%. The flexural strength and flexural modulus of the composite reached 87.16 MPa and 1054.7 MPa, respectively, which were about 21.19% and 40.86% higher than those of the pure epoxy resin, respectively. In addition, the flexural properties and interfacial shear strength (IFSS) of composite reinforced by GO-AFs were much higher than the composites reinforced by AFs due to GO improved the interfacial bonding between the reinforcement material and matrix.

Download Full-text

Deformation Behavior and Fracture Patterns of Laminated PEEK- and PI-Based Composites with Various Carbon-Fiber Reinforcement

Polymers ◽

10.3390/polym13142268 ◽

2021 ◽

Vol 13 (14) ◽

pp. 2268

Author(s):

Pavel V Kosmachev ◽

Vladislav O Alexenko ◽

Svetlana A Bochkareva ◽

Sergey V Panin

Keyword(s):

Carbon Fiber ◽

Flexural Strength ◽

Laminated Composites ◽

Flexural Modulus ◽

Strength Properties ◽

Fe Model ◽

Carbon Fabric ◽

Model Framework ◽

Order Of Magnitude ◽

Stress States

Laminated composites based on polyetheretherketone (PEEK) and polyimide (PI) matrices were fabricated by hot compression. Reinforcing materials (unidirectional carbon-fiber (CF) tapes or carbon fabric) and their layout patterns were varied. Stress–strain diagrams after three-point flexural tests were analyzed, and both lateral faces of the fractured specimens and fractured surfaces (obtained by optical and scanning electron microscopy, respectively) were studied. It was shown that the laminated composites possessed the maximum mechanical properties (flexural elastic modulus and strength) in the case of the unidirectional CF (0°/0°) layout. These composites were also not subjected to catastrophic failure during the tests. The PEEK-based composites showed twice the flexural strength of the PI-based ones (0.4 and 0.2 GPa, respectively), while the flexural modulus was four times higher (60 and 15 GPa, correspondently). The reason was associated with different melt flowability of the used polymer matrices and varied inter- (intra)layer adhesion levels. The effect of adhesion was additionally studied by computer simulation using a developed two-dimensional FE-model. It considered initial defects between the binder and CF, as well as subsequent delamination and failure under loads. Based on the developed FE-model, the influence of defects and delamination on the strength properties of the composites was shown at different stress states, and the corresponding quantitative estimates were reported. Moreover, another model was developed to determine the three-point flexural properties of the composites reinforced with CF and carbon fabric, taking into account different fiber layouts. It was shown within this model framework that the flexural strength of the studied composites could be increased by an order of magnitude by enhancing the adhesion level (considered through the contact area between CF and the binder).

Download Full-text

Comparison of Mechanical Properties of PMMA Disks for Digitally Designed Dentures

Polymers ◽

10.3390/polym13111745 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1745

Author(s):

Tamaki Hada ◽

Manabu Kanazawa ◽

Maiko Iwaki ◽

Awutsadaporn Katheng ◽

Shunsuke Minakuchi

Keyword(s):

Mechanical Properties ◽

Flexural Strength ◽

Water Sorption ◽

Water Solubility ◽

Flexural Modulus ◽

Manufacturing Method ◽

Heat Curing ◽

Significant Difference ◽

Cad Cam ◽

Curing Method

In this study, the physical properties of a custom block manufactured using a self-polymerizing resin (Custom-block), the commercially available CAD/CAM PMMA disk (PMMA-disk), and a heat-polymerizing resin (Conventional PMMA) were evaluated via three different tests. The Custom-block was polymerized by pouring the self-polymerizing resin into a special tray, and Conventional PMMA was polymerized with a heat-curing method, according to the manufacturer’s recommended procedure. The specimens of each group were subjected to three-point bending, water sorption and solubility, and staining tests. The results showed that the materials met the requirements of the ISO standards in all tests, except for the staining tests. The highest flexural strength was exhibited by the PMMA-disk, followed by the Custom-block and the Conventional PMMA, and a significant difference was observed in the flexural strengths of all the materials (p < 0.001). The Custom-block showed a significantly higher flexural modulus and water solubility. The water sorption and discoloration of the Custom-block were significantly higher than those of the PMMA-disk, but not significantly different from those of the Conventional PMMA. In conclusion, the mechanical properties of the three materials differed depending on the manufacturing method, which considerably affected their flexural strength, flexural modulus, water sorption and solubility, and discoloration.

Download Full-text

The Performance of Filava-Polysiloxane, Silres® H62C Composite in High Temperature Application

Journal of Composites Science ◽

10.3390/jcs5060144 ◽

2021 ◽

Vol 5 (6) ◽

pp. 144

Author(s):

Klaudio Bari ◽

Thozhuvur Govindaraman Loganathan

Keyword(s):

High Temperature ◽

Flexural Strength ◽

Flexural Modulus ◽

Fire Retardant ◽

Bending Test ◽

Ongoing Research ◽

Flexural Testing ◽

Temperature Application ◽

High Temperature Tensile ◽

In Fire

The research aim is to investigate the performance of novel enriched mineral fibres (Filava) in polysiloxane SLIRES H62 resin. Specimens were manufactured using a vacuum bagging process and oven cured at 250 °C. Specimens were prepared for flexural testing according to BS EN ISO 14125:1998 to obtain flexural strength, modulus, and elongation. The mechanical strength was compared to similar composites, with the aim of determining composite performance index. The flexural modulus (9.7 GPa), flexural strength (83 MPa), and flexural strain (2.9%) were obtained from a three-point bending test. In addition, the study investigates the thermal properties of the composite using a state-of-art Zwick Roell high temperature tensile rig. The results showed Filava/Polysiloxane Composites had an ultimate tensile strength 400 MPa, Young’s modulus 16 GPa and strain 2.5% at 1000 °C, and no smoke and ash were observed during pyrolysis. Ongoing research is currently taking place to use Filava-H62 in fire-retardant enclosure for lithium-ferro-phosphate Batteries used in electric trucks.

Download Full-text

Curcumin: Modern Applications for a Versatile Additive

Coatings ◽

10.3390/coatings11050519 ◽

2021 ◽

Vol 11 (5) ◽

pp. 519

Author(s):

Florentina Monica Raduly ◽

Valentin Raditoiu ◽

Alina Raditoiu ◽

Violeta Purcar

Keyword(s):

Bacterial Infections ◽

Natural Compound ◽

Review Paper ◽

Curcuma Longa ◽

Antibacterial Properties ◽

Point Of View ◽

Nano Particles ◽

Synergistic Activity ◽

Quality Of Food

The recent development of several methods for extracting curcumin from the root of the plant Curcuma longa has led to intensified research on the properties of curcumin and its fields of application. Following the studies and the accreditation of curcumin as a natural compound with antifungal, antiviral, and antibacterial properties, new fields of application have been developed in two main directions—food and medical, respectively. This review paper aims to synthesize the fields of application of curcumin as an additive for the prevention of spoilage, safety, and quality of food. Simultaneously, it aims to present curcumin as an additive in products for the prevention of bacterial infections and health care. In both cases, the types of curcumin formulations in the form of (nano)emulsions, (nano)particles, or (nano)composites are presented, depending on the field and conditions of exploitation or their properties to be used. The diversity of composite materials that can be designed, depending on the purpose of use, leaves open the field of research on the conditioning of curcumin. Various biomaterials active from the antibacterial and antibiofilm point of view can be intuited in which curcumin acts as an additive that potentiates the activities of other compounds or has a synergistic activity with them.

Download Full-text

Mechanical properties and toughening mechanisms of epoxy/graphene nanocomposites

Journal of Polymer Engineering ◽

10.1515/polyeng-2014-0134 ◽

2015 ◽

Vol 35 (3) ◽

pp. 257-266 ◽

Cited By ~ 10

Author(s):

Rahim Eqra ◽

Kamal Janghorban ◽

Habib Daneshmanesh

Keyword(s):

Mechanical Properties ◽

Fracture Surface ◽

Flexural Strength ◽

Young’S Modulus ◽

Young's Modulus ◽

Graphene Nanosheets ◽

Flexural Modulus ◽

Mechanical Tests ◽

Toughening Mechanism ◽

Graphene Nanocomposites

Abstract Because of extraordinary physical, chemical and mechanical properties, graphene nanosheets (GNS) are suitable fillers for optimizing the properties of different polymers. In this research, the effect of GNS content (up to 1 wt.%) on tensile and flexural properties, morphology of fracture surface, and toughening mechanism of epoxy were investigated. Results of mechanical tests showed a peak for tensile and flexural strength of samples with 0.1 wt.% GNS such that the tensile and flexural strength improved by 13% and 3.3%, respectively. The Young’s modulus and flexural modulus increased linearly with GNS content, although the behavior of the Young’s modulus was more remarkable. Morphological investigations confirmed this behavior because the GNS dispersion in the epoxy matrix was uniform at lower contents and agglomerated at higher contents. Finally, microscopical observation showed that the major toughening mechanism of graphene-epoxy nanocomposites was crack path deflection, which changed the mirror fracture surface of the pure epoxy to rough surface.

Download Full-text