scholarly journals The Addition of Poly(Vinyl Alcohol) Fibers to Apatitic Calcium Phosphate Cement Can Improve Its Toughness

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1531 ◽  
Author(s):  
Jun Luo ◽  
Julien Faivre ◽  
Håkan Engqvist ◽  
Cecilia Persson
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Calcium Phosphate ◽  
Vinyl Alcohol ◽  
Setting Time ◽  
Fiber Reinforcement ◽  
Poly Vinyl Alcohol ◽  
Work Of Fracture ◽  
Hydroxyapatite Cement ◽  
Diametral Tensile Strength

Calcium phosphate cements, and in particular hydroxyapatite cements, have been widely investigated for use as bone void fillers due to their chemical similarity to bone and related osteoconductivity. However, they are brittle, which limits their use to non-load-bearing applications. The aim of the current study was to improve the toughness of hydroxyapatite cements through fiber reinforcement. The effect of the addition of hydrophilic, poly(vinyl-alcohol) (PVA) fibers to hydroxyapatite cement was evaluated in terms of mechanical properties, including compressive strength, diametral tensile strength and toughness (work of fracture), as well as setting time, phase composition and cement morphology. The fiber reinforcement enhanced the fracture resistance of the hydroxyapatite cement, but also simultaneously reduced the compressive strength and setting time of the cements. However, cement with 5 wt % of fibers (of the powder component) could be considered a good compromise, with a compressive strength of 46.5 ± 4.6 MPa (compared to 62.3 ± 12.8 MPa of that without fibers), i.e., still much greater than that of human trabecular bone (0.1–14 MPa). A significantly higher diametral tensile strength (9.2 ± 0.4 MPa) was found for this cement compared to that without fibers (7.4 ± 1.5 MPa). The work of fracture increased four times to 9.1 ± 1.5 kJ/m2 in comparison to the pristine apatite. In summary, the hydroxyapatite cements could be reinforced by suitable amounts of PVA fibers, which resulted in enhancing the material’s structural integrity and ductility, and increased the material’s resistance to cracking.

scholarly journals Incorporation of Poly(Vinyl Alcohol) for The Improved Properties of Hydrothermal Derived Calcium Phosphate Cements

2018 ◽  
Vol 18 (2) ◽  
pp. 354
Author(s):  
Nurul Nabilah Razali ◽  
Iis Sopyan
Keyword(s):  
Calcium Phosphate ◽  
Vinyl Alcohol ◽  
Setting Time ◽  
Poly Vinyl Alcohol ◽  
Dihydrogen Phosphate ◽  
Distilled Water ◽  
Ammonium Dihydrogen Phosphate ◽  
Hydrothermal Route ◽  
Ringer’S Solution ◽  
Setting Times

Calcium phosphate cement (CPC) has been synthesized via a straightforward hydrothermal route. Calcium oxide and ammonium dihydrogen phosphate were used as calcium and phosphate precursors. The precursors were refluxed in distilled water at 90–100 °C and dried overnight until the calcium phosphate powder was formed. CPC was then produced by mixing the powder and distilled water at the powder-to-liquid (P/L) ratio of 1.5. Poly(vinyl alcohol) (PVA) of 1 to 7% (w/w) was added and its effect on physical properties was investigated. It was proved that PVA addition up to 7% (w/w) has shortened the setting time but decreased the injectability. The PVA free CPC has the initial and final setting times of 71 and 187 min, respectively and the injectability of 99.92%. The compressive strength also increased with the amount of PVA added in CPC. In addition, soaking CPC in Ringer's solution for 7, 14 and 21 days also gave remarkable effects on cohesion, microstructure and mechanical properties of the cement.

Microstructure and properties of polyhydroxybutyrate-calcium phosphate cement composites

2011 ◽  
Vol 65 (5) ◽  
Author(s):  
Ľubomír Medvecký ◽  
Radoslava Štulajterová ◽  
Sergey Kutsev
Keyword(s):  
Tensile Strength ◽  
Calcium Phosphate ◽  
Simulated Body Fluid ◽  
Body Fluid ◽  
Setting Time ◽  
Cement Composites ◽  
Mechanical Mixing ◽  
Soaking Time ◽  
Composite Mixture ◽  
Diametral Tensile Strength

AbstractThe biopolymer (polyhydroxybutyrate) microparticles-calcium phosphate composites were prepared by mechanical mixing of the basic composite components with the addition of hardening liquid after ethanol-composite mixture suspension moulding. The composite microstructures were more compact than the pure cement samples as confirmed by the lower values of specific areas and mesopore volumes. Both the specific areas and mesopore volumes decreased with soaking time in a simulated body fluid. The low polyhydroxybutyrate degradation in composites was found after soaking in simulated body fluid, which was terminated after one week. The formation of a dense apatite layer bonded directly to the surface of polyhydroxybutyrate microparticles was observed. The highest diametral tensile strength (13 MPa) and compressive strength (95 MPa) values of up to 50 % higher than in pure cement were measured in samples with 10 % of polyhydroxybutyrate. The addition of polyhydroxybutyrate microparticles had no effect on the setting time.

scholarly journals Assessment of the mechanical properties of glass ionomer cements for orthodontic cementation

2012 ◽  
Vol 17 (6) ◽  
pp. 154-159 ◽  
Author(s):  
Marcel M. Farret ◽  
Eduardo Martinelli de Lima ◽  
Eduardo Gonçalves Mota ◽  
Hugo Mitsuo S. Oshima ◽  
Gabriela Maguilnik ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Bond Strength ◽  
Shear Bond Strength ◽  
Glass Ionomer Cements ◽  
Glass Ionomer ◽  
Resin Modified Glass Ionomer ◽  
Strength Tests ◽  
Diametral Tensile Strength

OBJECTIVE: To evaluate the mechanical properties of three glass ionomers cements (GICs) used for band cementation in Orthodontics. METHODS: Two conventional glass ionomers (Ketac Cem Easy mix/3M-ESPE and Meron/Voco) and one resin modified glass ionomer (Multi-cure Glass ionomer/3M-Unitek) were selected. For the compressive strength and diametral tensile strength tests, 12 specimens were made of each material. For the microhardness test 15 specimens were made of each material and for the shear bond strength tests 45 bovine permanent incisors were used mounted in a self-cure acrylic resin. Then, band segments with a welded bracket were cemented on the buccal surface of the crowns. For the mechanical tests of compressive and diametral tensile strength and shear bond strength a universal testing machine was used with a crosshead speed of 1,0 mm/min and for the Vickers microhardness analysis tests a Microdurometer was used with 200 g of load during 15 seconds. The results were submitted to statistical analysis through ANOVA complemented by Tukey's test at a significance level of 5%. RESULTS: The results shown that the Multi-Cure Glass Ionomer presented higher diametral tensile strength (p < 0.01) and compressive strength greater than conventional GICs (p = 0.08). Moreover, Ketac Cem showed significant less microhardness (p < 0.01). CONCLUSION: The resin-modified glass ionomer cement showed high mechanical properties, compared to the conventional glass ionomer cements, which had few differences between them.

scholarly journals Pentaerythritol Tetrasalicylate in the Chemical Composition of Root Canal Sealers

2018 ◽  
Vol 29 (1) ◽  
pp. 48-53
Author(s):  
Manuela Gonçalves de Souza e Silva ◽  
Eliseu Aldrighi Münchow ◽  
Rafael Pino Vitti ◽  
Mário Alexandre Coelho Sinhoreti ◽  
Evandro Piva ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Young’S Modulus ◽  
Root Canal ◽  
Methyl Salicylate ◽  
Young's Modulus ◽  
Setting Time ◽  
Molar Ratio ◽  
Resonance Spectroscopy ◽  
Root Canal Sealers ◽  
Diametral Tensile Strength

Abstract The aim of this study was to synthesize and evaluate physicochemical properties of a new salicylate derivative in experimental calcium-based root canal sealers. Two salicylate derivatives were synthesized for the transesterification reaction of methyl salicylate with two different alcohols (1,3-butylenoglicol disalicylate-BD and pentaerythritol tetrasalicylate -PT) in molar ratio 1:3 and 1:6, respectively. The products (BD and PT), were characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance spectroscopy (RMN). Calcium-based experimental sealers were prepared with the same catalyst paste (60% of MTA, 39% of n-ethyl-o-toluenesulfonamide, and 1% titanium dioxide) and four different concentrations of BD and PT in the base pastes (40/0 - control, 35/5, 30/10 and 20/20) with 60% of bismuth oxide. The experimental sealers were evaluated for setting time, solubility (24 h, 7, 14 and 30 days), diametral tensile strength and Young’s Modulus. Data were analyzed by one- or two-way ANOVA with Tukey’s test (p<0.05). The addition of PT reduced the materials setting time. After 24 h the sealer 40/0 and 35/5 had higher solubility, and after 14 and 28 days the sealer 20/20 showed the lowest solubility (p<0.05). After 7 days the sealer 20/20 stabilized its solubility. The sealer 40/0 presented the highest values and the 20/20 presented the lowest values of diametral tensile strength and Young’s modulus (p<0.05). The addition of PT to calcium-based root canal sealers provides benefits to the setting time and solubility.

Primary Study of an Injectable In Situ Composite of Collagen/Calcium Phosphate Porous Scaffold for Bone Substitute

2006 ◽  
Vol 309-311 ◽  
pp. 857-860 ◽  
Author(s):  
Q. Yao ◽  
Dong Xiao Li ◽  
K.W. Liu ◽  
Bo Zhang ◽  
H. Li ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Calcium Phosphate ◽  
Ph Value ◽  
Porous Scaffold ◽  
Setting Time ◽  
Primary Study ◽  
In Situ Composite ◽  
Setting Process ◽  
Main Material

This study was to develop an injectable biocompatible and porous calcium phosphate collagen composite cement scaffold by in situ setting. TTCP was prepared as main material of the CPC powder, and the collagen solution was added into the phosphoric acid directly to form the liquid phase. The injectable time (tI), setting time (tS) and setting temperature (TS), along with the PH value were recorded during the setting process. The compressive strength, morphology and porosity were tested. With the increase of collagen, this novel CPC get a tI of 5mins to 8mins, tS of 20mins to 30mins, compressive strength from 1.5MPa to 4MPa, and the porosity from 40% to 60%. This study gave a possibility to form a porous scaffold of collagen/CPC composite with the nature of injectability and setting in situ.

scholarly journals Regulation Mechanism of Graphene Oxide on the Structure and Mechanical Properties of Bio-Based Gel-Spun Lignin/Poly (Vinyl Alcohol) Fibers

2021 ◽  
Author(s):  
Yanhong Jin ◽  
Yuanyuan Jing ◽  
Wenxin Hu ◽  
Jiaxian Lin ◽  
Yu Cheng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Graphene Oxide ◽  
Young’S Modulus ◽  
Vinyl Alcohol ◽  
Young's Modulus ◽  
Lignin Content ◽  
Poly Vinyl Alcohol ◽  
Regulation Mechanism ◽  
Composite Fibers

Abstract Lignin has been used as a sustainable and eco-friendly filler in composite fibers. However, lignin aggregation occurred at high lignin content, which significantly hindered the further enhancement of fiber performance. The incorporation of graphene oxide (GO) enhanced the mechanical properties of the lignin/poly(vinyl alcohol) (PVA) fibers and affected their structure. With the GO content increasing from 0 to 0.2%, the tensile strength of 5% lignin/PVA fibers increased from 491 MPa to 631 MPa, and Young's modulus increased from 5.91 GPa to 6.61 GPa. GO reinforced 30% lignin/PVA fibers also showed the same trend. The tensile strength increased from 455 MPa to 553 MPa, and Young's modulus increased from 5.39 GPa to 7 GPa. The best mechanical performance was observed in PVA fibers containing 5% lignin and 0.2% GO, which had an average tensile strength of 631 MPa and a Young’s modulus of 6.61 GPa. The toughness values of these fibers are between 9.9-15.6 J/g, and the fibrillar and ductile fracture microstructure were observed. Structure analysis of fibers showed that GO reinforced 5% lignin/PVA fibers had higher crystallinity, and evidence of hydrogen bonding among GO, lignin, and PVA in the gel fibers was revealed. Further, water resistance and swelling behavior of composite PVA fibers were studied to further evidence the structure change of composite fibers.

The pH-Dependent Properties of the Biphasic Calcium Phosphate for Bone Cements

2014 ◽  
Vol 21 ◽  
pp. 3-16 ◽  
Author(s):  
Nuan La Ong Srakaew ◽  
Sirirat Tubsungnoen Rattanachan
Keyword(s):  
Compressive Strength ◽  
Liquid Phase ◽  
Calcium Phosphate ◽  
Phase Analysis ◽  
Calcium Phosphate Cement ◽  
Biphasic Calcium Phosphate ◽  
Setting Time ◽  
Bone Cements ◽  
Apatite Formation ◽  
Apatite Cement

Self-setting calcium phosphate cement (CPC) has been used in bone repair and substitution due to their excellent biocompatibility, bioactive as well as simplicity of preparation and use. The inherent brittleness and slow degradation are the major disadvantages for the use of calcium phosphate cements. To improve the degradation for the traditional CPC, the apatite cement formula incorporated with β-tricalcium phosphate (β-TCP) with varying concentration were studied and the effect of the pH value of liquid phase on the properties of this new calcium phosphate cement formula was evaluated. The apatite cements containing β-TCP for 10 and 40 wt.% were mixed into the aqueous solution with different pH values and then aging in absolute humidity at 37°C for 7 days. The setting time and phase analysis of the biphasic calcium phosphate were determined as compared to the apatite cement. For proper medical application, the compressive strength, the phase analysis and the degradation of the CPC samples at pH 7.0 and 7.4 were evaluated after soaking in the simulated body fluid (SBF) at 37°C for 7 days. The results indicated that the properties of the samples such as the setting time, the compressive strength related to the phase analysis of the set cements. The high degradation of the CPC was found in the cement with increasing β-TCP addition due to the phase after setting. Apatite formation with oriented plate-like morphology was also found to be denser on the surface of the biphasic bone cements after soaking in SBF for 7 days. The obtained results indicated that the cement containing β-TCP mixed with the liquid phase at pH 7.4 could be considered as a highly biodegradable and bioactive bone cement, as compared to the traditional CPC.

Characterization and comparison of properties of cryogenic conditioned CNT reinforced thermoset (epoxy) and thermoplastic (poly vinyl alcohol) composite yarns

2021 ◽  
pp. 002199832110417
Author(s):  
Wei Chen ◽  
Yifan Wang ◽  
Kun Zhang ◽  
Fujun Xu
Keyword(s):  
Tensile Strength ◽  
Vinyl Alcohol ◽  
Thermoplastic Composite ◽  
Advanced Materials ◽  
Poly Vinyl Alcohol ◽  
Practical Applications ◽  
Mechanical And Electrical Properties ◽  
Composite Yarn ◽  
Thermoset Epoxy ◽  
New Generation

Carbon nanotube (CNT) fiber/yarn reinforced composites are considered as a new generation of advanced materials for applications in aerospace and space industry. In this study, two types of CNT composite yarns were produced by twisting CNT films and infiltrating with thermoset epoxy (EP) and thermoplastic poly vinyl alcohol (PVA) resins. The tensile strength of CNT/PVA and CNT/EP composite yarn was 409.91 MPa and 206.87 MPa, much higher than that of pure CNT yarn (129.94 MPa). After mono-cryogenic condition, the mechanical and electrical properties of CNT/EP and CNT/PVA composite yarns were both enhanced due to the structure reorder of the CNT bundles and improvement of interfacial bonding. However, after 60 times cyclic-cryogenic conditions, CNT/EP composite yarn showed a ∼10% degradation of tensile strength; while CNT/PVA composite yarn exhibited 6% increment. This study provides fundamental data of the CNT reinforced thermoset and thermoplastic composite yarns for their practical applications in cryogenic environment.

Neutral Liquid Containing Chitosan and Polyol for Calcium Phosphate Cement

2018 ◽  
Vol 782 ◽  
pp. 9-14 ◽  
Author(s):  
Yoshiyuki Yokogawa ◽  
Kentaro Fujii ◽  
Ryota Izumiki ◽  
Seiya Shibata ◽  
Tasuku Takayasu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Calcium Phosphate ◽  
Calcium Phosphate Cement ◽  
Acidic Solution ◽  
Chitosan Solution ◽  
Freeze Dried ◽  
Transparent Liquid ◽  
Chitosan Content ◽  
Work Of Fracture ◽  
Push Out

The self-hardening calcium phosphate cement (CPC) has widely been used in bone defect repairs. CPC tends to decay or disintegrate upon early contact with blood or body fluids, and the gelation of CPC paste using sodium alginate, chitosan, or collagen may overcome such a wash-out property. The incorporation of chitosan in CPC paste increased the compressive strength and work-of-fracture. However, the viscosity of CPC paste increased with an increase of chitosan content, and acidic liquid is not favorable, as chitosan must be dissolved in an acidic solution. The CPC paste using the liquid prepared from freeze-dried chitosan powder was easily push out from the syringe, but the content of chitosan was reduced. An addition of polyol-phosphate salt to chitosan solution produces a transparent liquid at physiological pH, and the chitosan content was found to be increased. Chitosan content of liquid was increased from 0.09% to 0.54 % by adding polyol to liquid, and the compressive strength of CPC was also increased.

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