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

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.

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1531 ◽  
Author(s):  
Jun Luo ◽  
Julien Faivre ◽  
Håkan Engqvist ◽  
Cecilia Persson

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.


2014 ◽  
Vol 809-810 ◽  
pp. 477-484
Author(s):  
Zhao Qing Qi ◽  
Hong Tao Wang ◽  
Jun Liang Dang ◽  
Shi Hao Zhang ◽  
Jian Hua Ding

The capacity of 10%, 30%, and 50% ammonium dihydrogen phosphate were replaced with an equal amount of three phosphate (potassium dihydrogen phosphate, sodium dihydrogen phosphate, disodium hydrogen phosphate) respectively. Magnesium phosphate cement was made by phosphate of replaced, which strength, setting time, fluidity, hydration temperature, and the hydration products was researched. The results show that: MPC was made that replaced with the equal amount of three kind of phosphate, which has good mechanical properties. Setting time and fluidity change along with the replacment. Three kind of phosphate replace ammonium dihydrogen phosphate, which change the hydration process of MPC. When ammonium dihydrogen phosphate was replaced by an equal amount of disodium hydrogen phosphate, the temperature of hydration is only 69.4 °C. XRD showed that the diffraction peaks of composite’s magnesium phosphate cement increases.


2013 ◽  
Vol 65 (4) ◽  
Author(s):  
Syazwan Liyana Sulaiman ◽  
Zawati Harun ◽  
Sufizar Ahmad ◽  
Hariati Taib

The application of photocatalytic beads in wastewater treatment application has gained attention of many researchers. In this study, the synthesised poly(vinyl alcohol)/chitosan/Titanium oxide (PVA/CS/TiO2) beads has been considered as a promising alternative to conventional means of wastewater treatment. The present study has successfully synthesised PVA/CS/TiO2 beads through simple dropwise method in which varied concentration of CS from 1.0 g to 2.5 g. Morphological analysis of the synthesised PVA/CS/TiO2 beads investigated by the FE-SEM technique revealed that porous beads were obtained regardless of the varied CS concentration content. Furthermore, solubility and swelling properties investigation of the beads were also performed within the prescribed time of 24h in three different medium which were acidic, distilled water and alkaline solution. Result of solubility test proved that PVA/CS/TiO2 beads were insoluble only in distilled water and alkaline solution. However, the beads were found to dissolve in acidic solution due to the CS content. Meanwhile, the swelling test revealed that increased concentration of CS leads to swelling of beads in distilled water and alkaline solution. Results revealed that beads with the highest CS composition which is 2.5 g recorded 82.6% and 118.4% of swelling in distilled water and alkaline solution, respectively. In the mean time, beads with the lowest CS composition which is 1.0 g only swell for 65.8% and 93.3% in distilled water and alkaline solution, respectively. As a conclusion, the synthesised beads in this study is feasible to be applied in natural to alkaline environment.


2020 ◽  
Vol 8 (15) ◽  
pp. 4239-4250
Author(s):  
Sónia de Lacerda Schickert ◽  
João Castro Pinto ◽  
John Jansen ◽  
Sander C. G. Leeuwenburgh ◽  
Jeroen J. J. P. van den Beucken

A novel injectable calcium phosphate cement, reinforced with poly(vinyl alcohol) fibers has been developed and demonstrated in vitro and ex vivo bio-mechanical suitability for vertebral augmentation procedures.


2006 ◽  
Vol 16 (1) ◽  
pp. 101-105 ◽  
Author(s):  
Junyan Gong ◽  
Linbao Luo ◽  
Shu-Hong Yu ◽  
Haisheng Qian ◽  
Linfeng Fei

2014 ◽  
Vol 608 ◽  
pp. 280-286
Author(s):  
Nudthakarn Kosachan ◽  
Angkhana Jaroenworaluck ◽  
Sirithan Jiemsirilers ◽  
Supatra Jinawath ◽  
Ron Stevens

Calcium phosphate cement has been widely used as a bone substitute because of its chemical similarity to natural bone. In this study, calcium phosphate cement was prepared using dicalcium phosphate dihydrate (CaHPO4.2H2O) and calcium carbonate (CaCO3) as starting raw materials. The cement pastes were mixed and the chemistry adjusted with two different aqueous solutions of sodium hydroxide (NaOH) and disodium hydrogen phosphate (Na2HPO4). Concentrations of the solution were varied in the range 0.5 to 5.0 mol/L with the ratio of solid/liquid = 2 g/ml. The cement paste was then poured into a silicone mold having a diameter of 10 mm and a height 15 mm. Setting times for the cement were measured using a Vicat apparatus. XRD, FT-IR, and SEM techniques were used to characterize properties and microstructure of the cement. From the experimental results, it is clear that different concentrations of Na2HPO4 and NaOH have affected the setting times of the cement. The relationship between concentration of NaOH and Na2HPO4 and setting time, including final properties of the cement, is discussed.


Author(s):  
Eva Trumsina ◽  
Zane Zelca ◽  
Silvija Kukle

In the market a wide variety of products are find that contains/releases metal nanoparticles, therefore topical become researches on it impacts on the environment and human health. In the textile industry important step is the development of testing methodology to monitor the quantity of nanoparticles that get into the environment from nanoparticles containing textile materials. In the study analyzed the method based on the use of conductometer for textiles testing with nano-size metal oxides content to determine the persistence of nanoparticles/ions in the water after textile soaking/washing. Compared results acquired in the experiments with nanofibre webs manufactured by electrospinning from pure polyvinyl alcohol (PVA) and PVA/ZnO composite. The nanofibre webs were soaked in distilled water and obtained samples of water tested with conductometer. The results of the experiments confirm that measurements taken with the conductometer are fairly stable and repeatable; the equipment is suitable for measurements in distilled water for nanoparticles/ions detection. The measurements of the solution’s specific electric conductance allows to pinpoint the nanoparticles/ions concentration, but for this purpose, must be created the database that contains the resources needed for the calculations and methodology for sample preparation.


2005 ◽  
Vol 284-286 ◽  
pp. 109-112 ◽  
Author(s):  
Byung Hyun Lee ◽  
Min Chul Kim ◽  
Kyoung Nam Kim ◽  
Kwang Mahn Kim ◽  
Seong Ho Choi ◽  
...  

The mixed pastes of binary calcium phosphate glass with Ca/P ratio of 0.6 and distilled water were set after about 4 hr, while never set when calcium phosphate glass with Ca/P lower than 0.5. Their compressive strength was ranged from 16.0 to 23.3 MPa. When Na2HPO4 solution was used instead of distilled water as liquid phase, the setting time became drastically much shorter. As the mole concentration of Na2HPO4 solution increased from 0.25 M to 2 M, setting time was shortened to 35 min from almost 3 hr, but compressive strength decreased from 28.8 MPa to 13.2 MPa. At constant mole concentration, as the mass ratio of a powder to liquid ratio increased, setting time was shortened and maximum compressive strength was measured when a powder/liquid ratio was 2.5. However, no crystallized phases were detected either during setting or after complete setting. The XRD , FT-IR and SEM examinations indicated that calcium phosphate glass dissolved and then glass phase precipitated again. We concluded, therefore, that Na2HPO4 just affected the kinetics of dissolution and precipitation of CPG. The mechanism of hardening has yet to be studied.


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