Custom-Made Poly(urethane) Coatings Improve the Mechanical Properties of Bioactive Glass Scaffolds Designed for Bone Tissue Engineering

The replication method is a widely used technique to produce bioactive glass (BG) scaffolds mimicking trabecular bone. However, these scaffolds usually exhibit poor mechanical reliability and fast degradation, which can be improved by coating them with a polymer. In this work, we proposed the use of custom-made poly(urethane)s (PURs) as coating materials for 45S5 Bioglass®-based scaffolds. In detail, BG scaffolds were dip-coated with two PURs differing in their soft segment (poly(ε-caprolactone) or poly(ε-caprolactone)/poly(ethylene glycol) 70/30 w/w) (PCL-PUR and PCL/PEG-PUR) or PCL (control). PUR-coated scaffolds exhibited biocompatibility, high porosity (ca. 91%), and improved mechanical properties compared to BG scaffolds (2–3 fold higher compressive strength). Interestingly, in the case of PCL-PUR, compressive strength significantly increased by coating BG scaffolds with an amount of polymer approx. 40% lower compared to PCL/PEG-PUR- and PCL-coated scaffolds. On the other hand, PEG presence within PCL/PEG-PUR resulted in a fast decrease in mechanical reliability in an aqueous environment. PURs represent promising coating materials for BG scaffolds, with the additional pros of being ad-hoc customized in their physico-chemical properties. Moreover, PUR-based coatings exhibited high adherence to the BG surface, probably because of the formation of hydrogen bonds between PUR N-H groups and BG surface functionalities, which were not formed when PCL was used.

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Behavior of Steel Slag Concrete Subjected to Elevated Temperature

International Journal of Engineering and Advanced Technology - Regular Issue ◽

10.35940/ijeat.d7226.049420 ◽

2020 ◽

Vol 9 (4) ◽

pp. 1165-1170

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Compressive Strength ◽

High Temperatures ◽

Elevated Temperatures ◽

Coarse Aggregate ◽

Steel Slag ◽

Partial Replacement ◽

High Porosity ◽

Residual Mechanical Properties

Recycling of materials has become a major interest for engineers. At present, the amount of slag deposited in storage yard adds up to millions of tons/year leading to the occupation of farm land and serious pollution to the environment, as a result of the rapid growth in the steel industry. Steel slag is made at 1500- 1650°C having a honey comp shape with high porosity. Using steel slag as the natural aggregate with a lower waste material cost can be considered as a good alternative for sustainable constructions. The objective of this study is to evaluate the performance of residual mechanical properties of concrete with steel slag as coarse aggregate partial replacement after exposing to high temperatures .This study investigates the behavior of using granulated slag as partial or fully coarse aggregate replacement with different percentages of 0%, 15%, 30%, 50% and 100% in concrete when subjected to elevated temperatures. Six groups of concrete mixes were prepared using various replacement percentages of slag exposed to different temperatures of 400 °C, 600 °C and 800 °C for different durations of 1hr, 1.5hr and 2hr. Evaluation tests were compressive strength, tensile strength, and bond strength. The steel slag concrete mixes showed week workability lower than control mix. A systematic increasing of almost up to 21.7% in compressive strength, and 66.2% in tensile strength with increasing the percentage of steel slag replacement to 50%. And the results showed improvement on concrete residual mechanical properties after subjected to elevated temperatures with the increase of steel slag content. The findings of this study give an overview of the effect of steel slag coarse aggregate replacement on concrete after exposed to high temperatures.

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Mechanical Reliability and Modeling of Hydroxyapatite Acaffold

10.21203/rs.3.rs-986000/v1 ◽

2021 ◽

Author(s):

Johnson Kehinde Abifarin

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Weibull Distribution ◽

Biomedical Application ◽

Correlation Coefficients ◽

Distribution Analysis ◽

Mechanical Reliability ◽

Mechanical Hardness ◽

Eds Analysis ◽

Two Parameter

Abstract Significant contributions on the improvement of the mechanical properties of hydroxyapatite (HAp) have been widely reported. However, failure analysis (mechanical reliability) and modeling are missing. This article filled the gap by conducting Two-parameter Weibull distribution assisted by modeling to investigate the mechanical reliability of HAp. The employed HAp was characterized under SEM/EDS analysis. The results revealed the characteristics of HAp and also the nature of the synthesis route employed through its irregular morphology. The Two-parameter Weibull distribution analysis was conducted on the hardness and compressive strength of HAp scaffold. The characteristic hardness and compressive strength, coupled with their corresponding bounds, failure rates, and correlation coefficients were been presented. The Weibull analysis with the assistance of modeling revealed HAp fabricated under 10 KN compaction load and sintered at 1100 oC as the most reliable sample under hardness condition, while HAp fabricated under 15 KN compaction load and sintered at 1000 oC gave the most reliable characteristic under compression. However, 15 KN compaction load and 1100 oC sintering temperature showed the best reliability on the overall mechanical (hardness and compressive strength) reliability. Future study is recommended on the reliability of HAp scaffolds considering other mechanical properties that are essential for biomedical application.

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Mechanical Properties of Hydroxyapatite Reinforced 45S5

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.264.29 ◽

2017 ◽

Vol 264 ◽

pp. 29-32

Author(s):

Nurul Farhana Ibrahim ◽

Hasmaliza Mohamad ◽

Siti Noor Fazliah Mohd Noor ◽

Nurazreena Ahmad

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Bone Formation ◽

Bioactive Glass ◽

Bone Mineral ◽

Current Work ◽

Apatite Formation ◽

Natural Bone Mineral ◽

Natural Bone ◽

Induce Bone Formation

Hydroxyapatite (HA) has similar constituent with natural bone mineral and is able to evoke apatite formation on the bone interface. Similarly, bioactive glass (BG) such as 45S5 has the ability to induce bone formation when exposed to physiological environment. However, both materials have drawbacks in mechanical properties such as brittleness and low compressive strength. Hence, HA-BG composite has potential for enhance properties. The current work aims to assess the effects of BG addition in HA system focusing on mechanical properties.

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Physicochemical and Mechanical Properties of Composite of Chitosan Microspheres/Calcium Phosphate Cement

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.336-338.1654 ◽

2007 ◽

Vol 336-338 ◽

pp. 1654-1657

Author(s):

Rui Liu ◽

Li Min Dong ◽

Qing Feng Zan ◽

Chen Wang ◽

Jie Mo Tian

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Calcium Phosphate ◽

Bone Cement ◽

Setting Time ◽

Chemical Properties ◽

Phase Evolution ◽

Chitosan Microspheres ◽

Setting Times ◽

Calcium Phosphate Bone Cement

The aim of this work is to improve the mechanical properties of calcium phosphate bone cement (CPC) by appending chitosan microspheres to CPC base. That chitosan degrades rapidly than bone cement has been proved by previous investigations. Porous CPC has low compressive strength because of the pores in it weakening the structure. Additive chitosan microspheres can improve the mechanical properties by bearing the compress with the CPC base and produce pores after degradation. This study investigates the effect of chitosan microspheres on the setting time, mechanical properties, phase evolution and morphology of CPC. The additive proportion of chitosan microspheres ranges from 0 wt% to 30 wt%. Compared with original CPC, the modified CPC has higher compressive strength, without significantly affecting the chemical properties. The phase composition of the CPC is tested by XRD. The microstructures of CPC are observed using SEM. The final setting times range from 5~15 minutes and can be modulated by using different liquid and powder (L/P) ratio.

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Evaluation of Structural and Mechanical Properties of Porous Artificial Bone Scaffolds Fabricated via Advanced TBA-Based Freeze-Gel Casting Technique

Applied Sciences ◽

10.3390/app9091965 ◽

2019 ◽

Vol 9 (9) ◽

pp. 1965 ◽

Cited By ~ 8

Author(s):

Tae-Rim Kim ◽

Min-Su Kim ◽

Tae Sik Goh ◽

Jung Sub Lee ◽

Yun Hak Kim ◽

...

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Cancellous Bone ◽

Casting Process ◽

High Porosity ◽

Artificial Bone ◽

Porous Hydroxyapatite ◽

Casting Technique ◽

Bone Scaffolds ◽

Gel Casting

Porous hydroxyapatite (HA) artificial bone scaffolds were prepared via the freeze-gel casting process in order to improve their mechanical strengths. As a porogen, various volumes of poly (methyl methacrylate) (PMMA) powders were added to obtain high porosity, such as in cancellous bone. After fabrication, the porous and mechanical properties of the scaffolds were examined. The HA60 scaffold, with a porosity over 80%, had proper compressive strength and modulus and satisfied the range of properties of cancellous bone. Moreover, it was found that the investigated mechanical properties were affected by the scaffolds’ porosity. However, a section was found where the compressive strength was high despite the increase in the porosity. Specifically, HA30 had a porosity of 62.9% and a compressive strength of 1.73 MPa, whereas the values for HA60 were 81.9% and 3.23 MPa, respectively. The results indicate that there are factors that can preserve the mechanical properties even if the porosity of the scaffold increases. Therefore, in this study, various parameters affecting the porous and mechanical properties of the scaffolds during the manufacturing process were analyzed. It is expected that the improvement in the mechanical properties of the artificial bone scaffold having a high porosity can be applied to tissue engineering.

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Mechanical properties of porous concrete with variations of coarse aggregate gradation

MATEC Web of Conferences ◽

10.1051/matecconf/201927601027 ◽

2019 ◽

Vol 276 ◽

pp. 01027

Author(s):

Hazairin ◽

Erma Desmaliana ◽

Bernardinus Herbudiman ◽

Wira Yudha Saputra

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Bending Strength ◽

Coarse Aggregate ◽

Experimental Results ◽

Fine Aggregate ◽

High Porosity ◽

Aggregate Gradation ◽

Porous Concrete ◽

Air Content

Porous concrete is an innovation in sustainable concrete technology, which has high porosity concrete without fine aggregate. Porous concrete used in rain gardens, planter boxes, permeable pavements at urban open spaces could absorb rainwater so it can reduce run-off. This experimental study purposes to determine the compressive, split-tensile, flexural strengths, and permeability of porous concrete with various gradation of coarse aggregates. This study used a concrete mixture with coarse aggregate gradation variations of gap, continuous, and uniform on the water cement ratio of 0.4. The test specimens used three cylinders of 15x30cm for compressive and split-tensile strengths, except for uniform gradations used three cylinders of 10x20cm. Beam specimens of 15x15x60cm used for bending strength test by third point loading method. The tested mechanical properties are 7, 14, and 28 days-compressive strengths, 28 days split-tensile strength, and 28 days bending strength. The experimental results also show the average compressive strengths of porous concrete with variation of gradations of gap, continuous, and uniform for 28 days is 14.6 MPa, 13.0 MPa, and 10.6 MPa, respectively. Volumetric flow rate of porous concrete with gap, continuous, and uniform aggregate gradations is 28.4 ml/s, 32.1 ml/s, and 39.3 ml/s, respectively. The experimental results show that gap gradation is recommended due to its better compressive and flexural strengths. In porous concrete, aggregate gradations influence the air content. The highest air content results the lowest compressive strength of concrete. The designed air content should be controlled to maintain the expexted compressive strength of porous concrete.

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Study of the mechanical and chemical properties of potassium manganese phosphate glasses

MATEC Web of Conferences ◽

10.1051/matecconf/201814901081 ◽

2018 ◽

Vol 149 ◽

pp. 01081 ◽

Cited By ~ 1

Author(s):

W. Ahmina ◽

M. El Moudane ◽

M. Zriouil ◽

M. Cherraj ◽

M. Taibi

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Young’S Modulus ◽

Young's Modulus ◽

Glass Structure ◽

Chemical Properties ◽

Acid Resistance ◽

Phosphate Glasses ◽

Alkali Resistance ◽

Soluble Phosphate

Homogeneous phosphate glasses having the general formula 20K2O-xMnO-(80-x)P2O5 were synthesized using a melt-quenching method. The amorphous nature of the samples was asserted by X–ray diffraction. The glasses are studied in order to evaluate the influence of MnO addition on the chemical and mechanical properties, such as, dissolution rate, average compressive strength (Rc), Young’s modulus (E) and limit strain (εlim). Some studies show that the addition of MnO significantly reduces the degradation rate (DR) of soluble phosphate glasses and enhanced chemical stability of both alkali-resistance and acid-resistance. MnO interfere with the chemical structure of the glass, and consequently improve their mechanical properties. Indeed, the mechanical measurements showed that the glass structure was modified by the addition of MnO oxide, becoming more rigid, and as a result, increasing the compressive strength (Rc), Young’s modulus (E). These new materials could be an important opportunity for applications in the fields of building, construction, civil engineering, etc…

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Mechanical properties of resin composites containing bioactive glass and experimental nano zinc-silica complex

International Dental Research ◽

10.5577/intdentres.2021.vol11.suppl1.21 ◽

2021 ◽

Vol 11 (Suppl. 1) ◽

pp. 137-142

Author(s):

Mehmet Gökberkkaan Demirel ◽

Makbule Tuğba Tunçdemir

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Flexural Strength ◽

Bioactive Glass ◽

Resin Composite ◽

Testing Machine ◽

Control Sample ◽

Dental Composite ◽

Resin Composites ◽

Nano Zinc

Aim: Secondary caries is an important problem in dental composite restoration, and nanoparticles are commonly added to the structures of resin composites to improve their antimicrobial properties. The aim of this study is to evaluate the mechanical properties of composite materials containing bioactive glass (BAG) and an experimental nano zinc-silica (NZS) complex. Methodology: An experimental resin composite containing 70 wt% filler was produced and used as a control sample. This experimental resin composite was then modified by adding different amounts of BAG (10%), NZS (10%), and both BAG and NZS (10% + 10%). NZS was synthesized in situ by milling zinc and silica to nanoscale level. Compressive strength and flexural strength were investigated using a universal testing machine. Data were analyzed using one-way ANOVA and the Tukey post-hoc test. Results: There were no statistically significant differences in compressive strength caused by the filler amount, but statistically significant changes were found in flexural strength. Although the addition of antimicrobial agents to resin composites reduces their physical properties, this is not a clinically unacceptable limit. Conclusion: NZS exhibits better mechanical properties than does BAG, but both materials can be used safely in restorative materials. How to cite this article: Tunçdemir MT, Demirel MG. Mechanical properties of resin composites containing bioactive glass and experimental nano zinc-silica complex. Int Dent Res 2021;11(Suppl.1):137-42. https://doi.org/10.5577/intdentres.2021.vol11.suppl1.21 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

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Study of the effect of diatomite on physico-mechanical properties of concrete

Cerâmica ◽

10.1590/0366-69132020663772561 ◽

2020 ◽

Vol 66 (377) ◽

pp. 50-55

Author(s):

A. R. S. Macedo ◽

A. S. Silva ◽

D. S. da Luz ◽

R. L. S. Ferreira ◽

C. S. Lourenço ◽

...

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Silica Content ◽

Mass Concrete ◽

High Porosity ◽

X Ray Diffraction ◽

Specific Mass ◽

X Ray ◽

Alternative Materials ◽

Fine Particle Size

Abstract Concretes present great potential to be used in many areas of civil construction. Their properties can be improved by substitution or addition of alternative materials to the Portland cement. The diatomite is a sedimentary material composed mainly by silica and amorphous impurities, presenting very fine particle size, high porosity, and low specific mass. Concrete was produced in a ratio of 1:1:2 (cement: sand: gravel) with the addition of diatomite at contents of 5% and 10% by cement weight and a water/cement ratio of 0.54. The physico-mechanical properties of the concretes were evaluated by tests of compressive strength and water absorption by immersion. Also, X-ray diffraction and scanning electron microscopy were carried out to analyze the main phases in the cement paste. The results indicated that the addition of diatomite in the concrete increased the compressive strength due to the silica content in the material and reduced slightly the porosity.

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Investigation of the Strength Properties of Palm Kernel Shell Ash Concrete

Engineering, Technology & Applied Science Research ◽

10.48084/etasr.238 ◽

2012 ◽

Vol 2 (6) ◽

pp. 315-319 ◽

Cited By ~ 6

Author(s):

F. A. Olutoge ◽

H. A. Quadri ◽

O. S. Olafusi

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Portland Cement ◽

Construction Materials ◽

Palm Kernel ◽

Chemical Properties ◽

Physical And Mechanical Properties ◽

Partial Replacement ◽

Cement Concrete ◽

Palm Kernel Shell

Many researchers have studied the use of agro-waste ashes as constituents in concrete. These agro-waste ashes are siliceous or aluminosiliceous materials that, in finely divided form and in the presence of moisture, chemically react with the calcium hydroxide released by the hydration of Portland cement to form calcium silicate hydrate and other cementitious compounds. Palm kernel shell ash (PKSA) is a by-product in palm oil mills. This ash has pozzolanic properties that enables it as a partial replacement for cement but also plays an important role in the strength and durability of concrete. The use of palm kernel shell ash (PKSA) as a partial replacement for cement in concrete is investigated. The objective of this paper is to alleviate the increasing challenges of scarcity and high cost of construction materials used by the construction industry in Nigeria and Africa in general, by reducing the volume of cement usage in concrete works. Collected PKSA was dried and sieved through a 45um sieve. The fineness of the PKSA was checked by sieving through 45um sieve. The chemical properties of the ash are examined whereas physical and mechanical properties of varying percentage of PKSA cement concrete and 100% cement concrete of mix 1:2:4 and 0.5 water-cement ratios are examined and compared. A total of 72 concrete cubes of size 150 × 150 × 150 mm³ with different volume percentages of PKSA to Portland cement in the order 0:100, 10:90 and 30:70 and mix ratio of 1:2:4 were cast and their physical and mechanical properties were tested at 7, 14, 21 and 28 days time. Although the compressive strength of PKSA concrete did not exceed that of OPC, compressive strength tests showed that 10% of the PKSA in replacement for cement was 22.8 N/mm2 at 28 days; which was quite satisfactory with no compromise in compressive strength requirements for concrete mix ratios 1:2:4. This research showed that the use of PKSA as a partial replacement for cement in concrete, at lower volume of replacement, will enhance the reduction of cement usage in concretes, thereby reducing the production cost. This research was carried out at the University of Ibadan, Ibadan, Nigeria.

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