Characteristics and Cell Growth Behavior of Gelatin/Polyvinyl Alcohol Porous Scaffolds

2021 ◽  
Vol 13 (5) ◽  
pp. 883-888
Author(s):  
Soyeun Kim ◽  
Deuk Yong Lee ◽  
Bae-Yeon Kim ◽  
Jung In Yoon
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Cell Growth ◽  
Polyvinyl Alcohol ◽  
Growth Behavior ◽  
Porous Scaffolds ◽  
Freeze Thaw ◽  
Swelling Rate ◽  
G Ratio ◽  
Acetal Group

Gelatin/polyvinyl alcohol (PVA) (g/P) porous scaffolds with a glutaraldehyde/g ratio of 3 were synthesized by freeze/thaw and lyophilization to evaluate the effect of the g/P ratio (10/0 to 7/3) on the mechanical properties and cell growth behavior of the scaffolds. Fourier transform infrared spectroscopy results showed that the g/P scaffolds exhibited good crosslinking between gelatin and gelatin (imine), PVA and PVA (acetal group), and gelatin and PVA (imine). The pore size decreased gradually from 170±63 μm, to 140±60 μm, 129±64 μm, and 74 ±23 μm by varying the g/P ratio from 10/0, to 9/1, 8/2, and 7/3, respectively. As the g/P ratio was changed from 10/0 to 7/3, the compressive strength and swelling rate increased gradually from 150± 17 kPa to 290 ±28 kPa and 1268± 11% to 1640 ±35%, respectively. Among the scaffolds, 7/3 g/P scaffolds with tailored properties are suitable for wound healing.

scholarly journals Effect of Silica Fume and Polyvinyl Alcohol Fiber on Mechanical Properties and Frost Resistance of Concrete

Buildings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 47
Author(s):  
Yan Tan ◽  
Ziling Xu ◽  
Zeli Liu ◽  
Jiuhong Jiang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Polyvinyl Alcohol ◽  
Silica Fume ◽  
Frost Resistance ◽  
Strength Test ◽  
Freeze Thaw ◽  
Polyvinyl Alcohol Fiber

To improve the mechanical properties and frost resistance of concrete, silica fume, and polyvinyl alcohol fiber compounded in concrete. The mechanical and frost resistance of concrete were comprehensively analyzed and evaluated for strength change, mass loss, and relative dynamic elastic modulus change by compressive strength test, flexural strength test, and rapid freeze-thaw test. The results showed that with the incorporation of silica fume and polyvinyl alcohol fiber, the compressive and flexural strengths of concrete were improved, and the decrease in mass loss rate and relative dynamic elastic modulus of concrete after freeze-thaw cycles were significantly reduced, which indicated that the compounding of silica fume and polyvinyl alcohol fiber improved the frost resistance of concrete. When the content of silica fume was 10% and the volume content of polyvinyl alcohol fiber was 1%, the comprehensive mechanical performance and frost resistance of concrete is the best. The compressive strength increased by 26.6% and flexural strength increased by 29.17% compared to ordinary concrete. Based on the test data, to study the macroscopic damage evolution of concrete compound silica fume and polyvinyl alcohol fiber under repeated freeze-thaw conditions. The Weibull distribution probability model and GM (1, 1) model were established. The average relative errors between the predicted and actual data of the two models are small and very close. It is shown that both models can reflect well the development of concrete damage under a freeze-thaw environment. This provides an important reference value and theoretical basis for the durability evaluation and life prediction of compound silica fume and polyvinyl alcohol fiber concrete in cold regions.

Physical Properties of Building Blocks from Hemp Shives Aggregate and Cementitious Binder, Manufactured in the Expanded Clay (Vibro Pressing) Production Line

2017 ◽  
Vol 908 ◽  
pp. 118-122 ◽  
Author(s):  
Giedrius Balčiūnas ◽  
Viktor Kizinievič ◽  
Justinas Gargasas
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Compressive Strength ◽  
Physical Properties ◽  
Production Line ◽  
Scientific Literature ◽  
Building Blocks ◽  
Freeze Thaw ◽  
Cementitious Binder ◽  
Pressing Technology

Scientific literature mostly aims at investigation of composites with fibre hemp shives (FHS) aggregate and lime binder, although, such materials are characterised by pretty low mechanical properties. In order to obtain higher mechanical properties of a composite, it is appropriate to use cementitious binder. This work investigates physical properties of blocks from hemp shives aggregate and cementitious binder, manufactured in the expanded clay production line using vibro pressing technology. Following properties of the blocks are determined: freeze-thaw resistance, compressive strength, thermal conductivity and density. Thermal resistance according to EN ISO 6946 for the block with cavities is calculated as well. It is found that compressive strength of FHS-cement blocks may be up to 3.18 MPa when the density is of ~850 kg/m3 and thermal conductivity up to 0.135 W/(m∙K). It is found as well that the decrease of compressive strength is 8.7% after 25 freeze-thaw cycles.

scholarly journals Influence of Water Pressure on the Mechanical Properties of Concrete after Freeze-Thaw Attack under Dynamic Triaxial Compression State

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Ruijun Wang ◽  
Yan Li ◽  
Yang Li ◽  
Fan Xu ◽  
Xiaotong Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Strain Rate ◽  
Water Pressure ◽  
Mass Loss Rate ◽  
Triaxial Compression ◽  
Ultimate Compressive Strength ◽  
Peak Strain ◽  
Freeze Thaw ◽  
Dynamic Triaxial Compression

This study aims at determining the effect of water pressure on the mechanical properties of concrete subjected to freeze-thaw (F-T) attack under the dynamic triaxial compression state. Two specimens were used: (1) a 100 mm × 100 mm × 400 mm prism for testing the loss of mass and relative dynamic modulus of elasticity (RDME) after F-T cycles and (2) cylinders with a diameter of 100 mm and a height of 200 mm for testing the dynamic mechanical properties of concrete. Strain rates ranged from 10−5·s−1 to 10−3·s−1, and F-T cycles ranged from 0 to 100. Three levels of water pressure (0, 5, and 10 MPa) were applied to concrete. Results showed that as the number of F-T cycles increased, the mass loss rate of the concrete specimen initially decreased and then increased, but the RDME decreased. Under 5 MPa of water pressure and at the same strain rate, the ultimate compressive strength decreased, whereas the peak strain increased with the increase in the number of F-T cycles. This result is contrary to the variation law of ultimate compressive strength and peak strain with the increase in strain rate under the same number of F-T times. With the increase in F-T cycles or water pressure, the strain sensitivity of the dynamic increase factor of ultimate compressive strength and peak strain decreased, respectively. After 100 F-T cycles, the dynamic compressive strength under all water pressure levels tended to increase as the strain rate increased, whereas the peak strain decreased gradually.

Structure and Mechanical Properties of Retrograded Rice Starch and Cow Bone Powder Composite Sponge

2018 ◽  
Vol 923 ◽  
pp. 84-88
Author(s):  
Sittiporn Punyanitya ◽  
Rungsarit Koonawoot ◽  
Anucha Ruksanti ◽  
Sakdiphon Thiensem ◽  
Anirut Raksujarit
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Porous Material ◽  
Bone Repair ◽  
Physical And Mechanical Properties ◽  
Powder Composite ◽  
Rice Starch ◽  
Bone Powder ◽  
Swelling Rate ◽  
Cow Bone

To study the effect of addition purified cow bone (CB) powder (20, 30, 40 and 50 wt%) in slurry suspension of retrograded rice starch (RRS). The composite sponges were used as in bone repair. The RRS-CB composite sponges were prepared from the mixture of RRS, CB and additive into distill water. The prepared samples were characterized including SEM, XRD, physical and mechanical properties. The results of optimized condition have shown the samples of 40 wt% CB that had the swelling rate as 102± 0.01%, area of expansion was 20 ± 0.03 % for 72 hours and the compressive strength was 64.35±0.05KPa. In addition, it was found that this content resulted in sufficient soft porous material, foldable by hand and self recovered body.

scholarly journals Degradation of Roller-Compacted Concrete Subjected to Freeze-Thaw Cycles and Immersion in Potassium Acetate Solution

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Wuman Zhang ◽  
Jingsong Zhang ◽  
Shuhang Chen ◽  
Sheng Gong
Keyword(s):  
Mechanical Properties ◽  
Weight Loss ◽  
Compressive Strength ◽  
Impact Energy ◽  
Impact Test ◽  
Potassium Acetate ◽  
Acetate Solution ◽  
Freeze Thaw ◽  
Roller Compacted Concrete ◽  
The Impact

Two sets of roller-compacted concrete (RCC) samples cured for 28 days were subjected to freeze-thaw (F-T) cycles and immersion in laboratory conditions. F-T cycles in water and water-potassium acetate solution (50% by weight) were carried out and followed by the flexural impact test. The weight loss, the dynamic elastic modulus (Ed), the mechanical properties, and the residual strain of RCC were measured. The impact energy was calculated based on the final number of the impact test. The results show that the effect of F-T cycles in KAc solution on the weight loss and Ed of RCC is slight. Ed, the compressive strength, and the flexural strength of RCC with 250 F-T cycles in KAc solution decrease by 3.8%, 23%, and 36%, respectively. The content (by weight) of K+ at the same depth of RCC specimens increases with the increase of F-T cycles. The impact energy of RCC specimens subjected to 250 F-T cycles in KAc solution decreases by nearly 30%. Microcracks occur and increase with the increase of F-T cycles in KAc solution. The compressive strength of RCC immersed in KAc solution decreases by 18.8% and 32.8% after 6 and 12 months. More attention should be paid to using KAc in practical engineering because both the freeze-thaw cycles and the complete immersion in KAc solution damage the mechanical properties of RCC.

scholarly journals Polycaprolactone Foam Functionalized With Chitosan Microparticles – a Suitable Scaffold for Cartilage Regeneration

2016 ◽  
pp. 121-131 ◽  
Author(s):  
E. FILOVÁ ◽  
B. JAKUBCOVÁ ◽  
I. DANILOVÁ ◽  
E. KUŽELOVÁ KOŠŤÁKOVÁ ◽  
T. JAROŠÍKOVÁ ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cell Growth ◽  
Dna Content ◽  
Viscoelastic Properties ◽  
Cartilage Regeneration ◽  
Biomechanical Properties ◽  
Porous Scaffolds ◽  
Chitosan Microparticles ◽  
Salt Leaching ◽  
Cell Growth And Differentiation

For biodegradable porous scaffolds to have a potential application in cartilage regeneration, they should enable cell growth and differentiation and should have adequate mechanical properties. In this study, our aim was to prepare biocompatible scaffolds with improved biomechanical properties. To this end, we have developed foam scaffolds from poly-Ɛ-caprolactone (PCL) with incorporated chitosan microparticles. The scaffolds were prepared by a salt leaching technique from either 10 or 15 wt% PCL solutions containing 0, 10 and 20 wt% chitosan microparticles, where the same amount and size of NaCl was used as a porogen in all the cases. PCL scaffolds without and with low amounts of chitosan (0 and 10 wt% chitosan) showed higher DNA content than scaffolds with high amounts of chitosan during a 22-day experiment. 10 wt% PCL with 10 and 20 wt% chitosan showed significantly increased viscoelastic properties compared to 15 wt% PCL scaffolds with 0 and 10 wt% chitosan. Thus, 10 wt% PCL scaffolds with 0 wt% and 10 wt% chitosan are potential scaffolds for cartilage regeneration.

scholarly journals Frost resistance of cement-sand and concrete beams during unilateral freezing

2021 ◽  
Vol 2 (1) ◽  
pp. 64-74
Author(s):  
Nepomyach Alexander Nikolaevich ◽  
Vyrovoy Valeriy Nikolaevich ◽  
Chistyakov Artem Aleksaedrovich
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Frost Resistance ◽  
Bending Strength ◽  
Concrete Beams ◽  
Transmission Rate ◽  
Beam Structure ◽  
Freeze Thaw ◽  
Damage Coefficient ◽  
Negative Temperatures

Abstract The work investigates changes in the beam structure under the action of local freezing, which leads to a change of the mechanical properties of the material and, consequently, of the beam structure. Two types of beam samples were used: from cement-sand mortar and from concrete. The work investigates the change in the development of deformations depending on the conditions of freezing of samples. The second accelerated method for assessing frost resistance was chosen according to DSTU B В.2.7-47-96. An accelerated method was chosen for assessing frost resistance at the temperature of -20 ±2 C°. After every five freeze-thaw cycles, the following changes were monitored: mass, water absorption, ultrasound transmission rate, damage coefficient, tensile bending strength, splitting strength, compressive strength, carbonization depth. The results showed that both in concrete and in mortar samples, the compressive strength after freezing was lower by 8% and 15% accordingly. The experimental results obtained confirm the assumptions made that the frost resistance of the material depends on the conditions of exposure of negative temperatures on products and structures and it can be used in a wider range of construction which will push regional development.

Frost resistance of roller compacted concrete in airport runway subjected to ethylene glycol solution

2019 ◽  
Vol 66 (1) ◽  
pp. 40-44 ◽  
Author(s):  
Wuman Zhang ◽  
Jingsong Zhang ◽  
Shuhang Chen
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Ethylene Glycol ◽  
Immersion Test ◽  
Bending Test ◽  
Content Type ◽  
Freeze Thaw ◽  
Roller Compacted Concrete ◽  
Practical Engineering ◽  
Airport Runway

Purpose Ethylene glycol (EG) solution is a common deicing fluid of the aircrafts. Roller compacted concrete (RCC) used in the runway and the parking apron will be subjected to freeze-thaw cycles in EG solution. The purpose of this study is to find whether RCC can be damaged by the action of freeze-thaw cycles or long-term immersion in EG solution. Design/methodology/approach Freeze-thaw cycles test and immersion test in EG solution by weight were used to accelerate the degradation of RCC. A compression test and a three-point bending test were carried out in the laboratory to evaluate mechanical properties of RCC. The changes of microstructure were monitored by using scanning electron microscopy and energy-dispersive X-ray analysis. Findings The results show that RCC specimens have little weight change in both freeze-thaw cycles test and immersion test. The dynamic modulus of elasticity, the compressive strength and the flexural strength of RCC with 250 freeze-thaw cycles in EG solution are decreased by 4.2, 15 and 39 per cent, respectively. The compressive strength is decreased by 35 per cent after 12 months of immersion in EG solution. Micro-cracks occur and increase with the increase in freeze-thaw cycles and immersion test. Originality/value The mass ratio of the elements in the crystal is very close to the proportion of elements in CaC2O4 (C:O:Ca = 1:1.26:1.6). More attention should be paid to using EG in practical engineering because both the freeze-thaw cycles and the complete immersion in EG solution damage the mechanical properties of RCC.

Experimental Study of Mechanical Properties of Concrete after Freeze-Thaw Exposures

2014 ◽  
Vol 912-914 ◽  
pp. 131-135
Author(s):  
Xiang Ping Fu ◽  
Xiao Xue Liu ◽  
Yi Ze Sun ◽  
Pei Huang ◽  
Yu Chen Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Compressive Strength ◽  
Elasticity Modulus ◽  
Concrete Specimen ◽  
Concrete Compressive Strength ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Freeze Thaw ◽  
Cold Area

The experiment studies how the freeze-thaw cycles influence concrete compressive strength and elasticity modulus with different water-cement ratio under the air-entraining agent and zero of that value respectively. It can be found that modulus of elasticity and compressive strength of the concrete specimen reduced significantly when there is air-entraining agent; the durability of freeze-thaw resistance, however, makes great improvement; as the cement increases, both of them improves effectively. Through the comparison of concrete compressive strength and elastic modulus with different water-cement ratio and air-entraining agent, the optimal water-cement ratio and air-entraining agent were determined. The results of experiment can be used in concrete engineering design in severe cold area.

scholarly journals Effects of Low Volume Fraction of Polyvinyl Alcohol Fibers on the Mechanical Properties of Oil Palm Shell Lightweight Concrete

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Ming Kun Yew ◽  
Hilmi Bin Mahmud ◽  
Bee Chin Ang ◽  
Ming Chian Yew
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Polyvinyl Alcohol ◽  
Oil Palm ◽  
Lightweight Concrete ◽  
Volume Fraction ◽  
High Strength ◽  
Palm Shell ◽  
Oil Palm Shell ◽  
Low Volume

This paper presents the effects of low volume fraction(Vf)of polyvinyl alcohol (PVA) fibers on the mechanical properties of oil palm shell (OPS) high strength lightweight concrete mixtures. The slump, density, compressive strength, splitting tensile strength, flexural strength, and modulus of elasticity under various curing conditions have been measured and evaluated. The results indicate that an increase in PVA fibers decreases the workability of the concrete and decreases the density slightly. The 28-day compressive strength of oil palm shell fiber-reinforced concrete (OPSFRC) high strength lightweight concrete (HSLWC) subject to continuous moist curing was within the range of 43–49 MPa. The average modulus of elasticity (E) value is found to be 16.1 GPa for all mixes, which is higher than that reported in previous studies and is within the range of normal weight concrete. Hence, the findings of this study revealed that the PVA fibers can be used as an alternative material to enhance the properties of OPS HSLWC for building and construction applications.

Sign in / Sign up

Export Citation Format

Share Document