scholarly journals Alginate-Based Composite and Its Biomedical Applications

2021 ◽  
Author(s):  
Yaling Deng ◽  
Ningning Yang ◽  
Oseweuba Valentine Okoro ◽  
Amin Shavandi ◽  
Lei Nie
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Cell Proliferation ◽  
Wound Dressing ◽  
Chondrogenic Differentiation ◽  
Structural Changes ◽  
Biomedical Application ◽  
Essential Properties ◽  
The Impact

Alginate has received much attention due to its biocompatibility. However, the properties of pure alginate are limited, such as weak mechanical strength, which limits its application. Alginate-based composite effectively overcomes the defect of pure alginate. The molecular weight and microstructure can be designed. More importantly, the essential properties for clinical application are improved, including mechanical properties, biocompatibility, gelation ability, chondrogenic differentiation and cell proliferation. This chapter will describe development of alginate-based composite in biomedical application. In the fields of wound dressing, drug delivery, and tissue engineering, the impact of structural changes on performance has been stated. To provide readers with understanding of this chapter, the structure and characterization of alginate will be included.

scholarly journals Improving Rheological and Mechanical Properties of Various Virgin and Recycled Polypropylenes by Blending with Long-Chain Branched Polypropylene

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1137
Author(s):  
Sascha Stanic ◽  
Thomas Koch ◽  
Klaus Schmid ◽  
Simone Knaus ◽  
Vasiliki-Maria Archodoulaki
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Tensile Test ◽  
Reactive Extrusion ◽  
Original Material ◽  
Melt Flow Rate ◽  
Single Screw Extruder ◽  
Pp Blends ◽  
The Impact ◽  
Long Chain

Blends of two long-chain branched polypropylenes (LCB-PP) and five linear polypropylenes (L-PP) were prepared in a single screw extruder at 240 °C. The two LCB-PPs were self-created via reactive extrusion at 180 °C by using dimyristyl peroxydicarbonate (PODIC C126) and dilauroyl peroxide (LP) as peroxides. For blending two virgin and three recycled PPs like coffee caps, yoghurt cups and buckets with different melt flow rate (MFR) values were used. The influence of using blends was assessed by investigating the rheological (dynamic and extensional rheology) and mechanical properties (tensile test and impact tensile test). The dynamic rheology indicated that the molecular weight as well as the molecular weight distribution could be increased or broadened. Also the melt strength behavior could be improved by using the two peroxide modified LCB-PP blends on the basis of PODIC C126 or PEROXAN LP (dilauroyl peroxide). In addition, the mechanical properties were consistently enhanced or at least kept constant compared to the original material. In particular, the impact tensile strength but also the elongation at break could be increased considerably. This study showed that the blending of LCB-PP can increase the investigated properties and represents a promising option, especially when using recycled PP, which demonstrates a real “up-cycling” process.

scholarly journals Copper Containing Glass-Based Bone Adhesives for Orthopaedic Applications: Glass Characterization and Advanced Mechanical Evaluation

2020 ◽  
Author(s):  
Sahar. Mokhtari ◽  
Anthony.W. Wren
Keyword(s):  
Mechanical Properties ◽  
Photoelectron Spectroscopy ◽  
Structural Changes ◽  
Viscoelastic Behavior ◽  
Polymer Chains ◽  
Nano Particles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Compression Data

AbstractThis study addresses issues with currently used bone adhesives, by producing novel glass based skeletal adhesives through modification of the base glass composition to include copper (Cu) and by characterizing each glass with respect to structural changes. Bioactive glasses have found applications in fields such as orthopedics and dentistry, where they have been utilized for the restoration of bone and teeth. The present work outlines the formation of flexible organic-inorganic polyacrylic acid (PAA) – glass hybrids, commercial forms are known as glass ionomer cements (GICs). Initial stages of this research will involve characterization of the Cu-glasses, significant to evaluate the properties of the resulting adhesives. Scanning electron microscopy (SEM) of annealed Cu glasses indicates the presence of partial crystallization in the glass. The structural analysis of the glass using Raman suggests the formation of CuO nanocrystals on the surface. X-ray diffraction (XRD) pattern and X-ray photoelectron spectroscopy (XPS) further confirmed the formation of crystalline CuO phases on the surface of the annealed Cu-glass. The setting reaction was studied using Fourier transform infrared spectroscopy (ATR-FTIR). The mechanical properties of the Cu containing adhesives exhibited gel viscoelastic behavior and enhanced mechanical properties when compared to the control composition. Compression data indicated the Cu glass adhesives were efficient at energy dissipation due to the reversible interactions between CuO nano particles and PAA polymer chains.

Structural Modifications of the Aluminium Alloy in Conditions of Additional Shock Impulse Load

2013 ◽  
Vol 592-593 ◽  
pp. 598-601 ◽  
Author(s):  
Volodymyr Hutsaylyuk ◽  
Mykola Czausow ◽  
Lucjan Śnieżek ◽  
Andrii Pylypenko ◽  
Tomasz Ślęzak ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Room Temperature ◽  
Structural Changes ◽  
Physical Nature ◽  
Structural Modifications ◽  
Equilibrium Processes ◽  
Impulse Load ◽  
Aluminum Alloy 2024 ◽  
The Impact

This work has been done to research the physical nature of the mechanism of structural changes of the aluminum alloy 2024-T3 at the conditions of additional impulse load. There was revealed an anomaly growth in plasticity of the material after such type load realization at the room temperature. Based on fractographical research the impact of dynamic non-equilibrium processes on the structural changes of the material and its macro-mechanical properties was analyzed.

Characterization of Structure and Mechanical Properties of MoSi2-SiC Nanolayer Composites

1993 ◽  
Vol 322 ◽  
Author(s):  
H. Kung ◽  
T. R. Jervis ◽  
J-P. Hirvonen ◽  
M. Nastasi ◽  
T. E. Mitchell
Keyword(s):  
Mechanical Properties ◽  
Structural Changes ◽  
Crystallization Process ◽  
Mechanical Response ◽  
Cross Sectional ◽  
Annealing Conditions ◽  
Transmission Electron ◽  
Layer Structures ◽  
Amorphous Structures

AbstractA systematic study of the structure-mechanical properties relationship is reported for MoSi2-SiC nanolayer composites. Alternating layers of MoSi2 and SiC were synthesized by DCmagnetron and if-diode sputtering, respectively. Cross-sectional transmission electron microscopy was used to examine three distinct reactions in the specimens when exposed to different annealing conditions: crystallization and phase transformation of MoSi2, crystallization of SiC, and spheroidization of the layer structures. Nanoindentation was employed to characterize the mechanical response as a function of the structural changes. As-sputtered material exhibits amorphous structures in both types of layers and has a hardness of 11GPa and a modulus of 217GPa. Subsequent heat treatment induces crystallization of MoSi2 to form the C40 structure at 500°C and SiC to form the a structure at 700°C. The crystallization process is directly responsible for the hardness and modulus increase in the multilayers. A hardness of 24GPa and a modulus of 340GPa can be achieved through crystallizing both MoSi2 and SiC layers. Annealing at 900°C for 2h causes the transformation of MoSi2 into the Cllb structure, as well as spheroidization of the layering to form a nanocrystalline equiaxed microstructure. A slight degradation in hardness but not in modulus is observed accompanying the layer break-down.

scholarly journals Imaging-Based Biomarkers: Characterization of Post-Kawasaki Vasculitis in Infants and Hypertension Phenotype in Rat Model

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Roch Listz Maurice ◽  
Nagib Dahdah ◽  
Johanne Tremblay
Keyword(s):  
Mechanical Properties ◽  
Arterial Wall ◽  
Turning Point ◽  
Aortic Wall ◽  
Brown Norway ◽  
Carotid Stiffness ◽  
Old Rats ◽  
The Impact

Background. Investigating the mechanical properties of the arteries is essential in cardiovascular diseases. Recent imaging modalities allow mapping mechanical properties within the arterial wall.Aims. We report the potential ofimaging-based biomarker(ImBioMark) to investigate the effect of aging on the rat. We also present preliminary data with ImBioMark characterizing vascular sequelae of Kawasaki disease (KD) in young humans.Methods. We investigatedin vivothe effect of aging on male Brown Norway (BN) rats' (n=5) carotid stiffness. In a second experiment, the impact of KD on the ascending aorta (AA) was examined in KD children (n=2) aged 13 ± 1.41 years old compared to KD-free children (n=5) aged 13.13 ± 0.18 years old.Results. The stiffness of BN's carotid artery was three times stiffer in the old rats, with a turning point at 40 weeks old (P=0.001). KD had a very significant impact on the AA stiffness with strain estimates of 2.39 ± 0.51% versus 4.24 ± 0.65% in controls (P<0.001).Conclusion. ImBioMark phenotypes hypertension in rat models noninvasivelyin vivowithout resorting to euthanasia. Quantifying aortic wall remodeling is also feasible in humans. Future investigations target human cardiovascular disease.

scholarly journals MR imaging of model drug distribution in simulated vitreous

2015 ◽  
Vol 1 (1) ◽  
pp. 236-239 ◽  
Author(s):  
Sandra Stein ◽  
Christian Simroth-Loch ◽  
Sönke Langner ◽  
Stefan Hadlich ◽  
Oliver Stachs ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Ex Vivo ◽  
Drug Distribution ◽  
Injection Technique ◽  
Innovative Therapy ◽  
Age Related ◽  
The Impact

AbstractThe in vitro and in vivo characterization of intravitreal injections plays an important role in developing innovative therapy approaches. Using the established vitreous model (VM) and eye movement system (EyeMoS) the distribution of contrast agents with different molecular weight was studied in vitro. The impact of the simulated age-related vitreal liquefaction (VL) on drug distribution in VM was examined either with injection through the gel phase or through the liquid phase. For comparison the distribution was studied ex vivo in the porcine vitreous. The studies were performed in a magnetic resonance (MR) scanner. As expected, with increasing molecular weight the diffusion velocity and the visual distribution of the injected substances decreased. Similar drug distribution was observed in VM and in porcine eye. VL causes enhanced convective flow and faster distribution in VM. Confirming the importance of the injection technique in progress of VL, injection through gelatinous phase caused faster distribution into peripheral regions of the VM than following injection through liquefied phase. VM and MR scanner in combination present a new approach for the in vitro characterization of drug release and distribution of intravitreal dosage forms.

Coal Powder and Ethylene-Propylene-Diene Monomer Reinforced Hybrid Polypropylene Composites

2019 ◽  
Vol 956 ◽  
pp. 192-200
Author(s):  
Yu Feng Bai ◽  
Xin Xin Cao ◽  
Ming Lu Xu ◽  
Xiao Fang He ◽  
Guo Hui Cai
Keyword(s):  
Mechanical Properties ◽  
Contact Angle ◽  
Structural Changes ◽  
Mechanical And Thermal Properties ◽  
Ethylene Propylene Diene Monomer ◽  
Initial Decomposition Temperature ◽  
Ethylene Propylene ◽  
Blending Method ◽  
Coal Powder ◽  
The Impact

For the better mechanical and thermal properties of polypropylene (PP), PP sea-island structured composites with elastomer ethylene-propylene-diene monomer (EPDM) and coal powder were prepared by melt-blending method. Coupling agent γ-methacryloxypropyltrimethoxysilane (KH-570) was used as modifier to improve the superficial capacity of coal powder. The structural changes and properties of modified coal powder and composites were characterized and analyzed by Fourier Transform Infrared Spectroscopy (FTIR), surface contact angle analysis, scanning electron microscope (SEM), thermogravimetric analysis (TGA) and mechanical testing. Results show that the modified coal powder has good hydrophobicity and sea-island structure is beneficial in improving the comprehensive performance of composites. The contact angle increases from 33.8° to 91.6° after modification. The initial decomposition temperature (T0) and largest weight loss temperature (Tmd) both have an increase with coal powder content and the maximum are 431.02 °C and 465.33 °C. The mechanical properties tend to go up first and then down with the addition of coal powder. PP/26EPDM/4coal composite has best mechanical properties as well as the impact strength and elongation at break are 60.9 MPa, 615.0%, respectively.

CONNECTION BETWEEN STRUCTURAL CHANGES OF IRRIADIATED POLYETHER ETHER KETONE AND MECHANICAL PROPERTIES

Tribologia ◽  
2018 ◽  
Vol 278 (2) ◽  
pp. 95-101
Author(s):  
Aneta NIEMIEC
Keyword(s):  
Mechanical Properties ◽  
Glass Transition ◽  
Structural Changes ◽  
Radiation Energy ◽  
Degree Of Crystallinity ◽  
Scanning Calorimetry ◽  
Polyether Ether Ketone ◽  
Ether Ketone ◽  
The Impact ◽  
The Degree Of Crystallinity

The article presents the results of research on the impact of structural changes in polyether ether ketone (PEEK) on its mechanical properties. The polymer was exposed to gamma radiation at a dose of 50 and 150 kGy, and the radiation energy was 4 MeV. Changes in the degree of crystallinity and the related changes in the glass transition and melting temperature for the polymer were determined by differential scanning calorimetry (DSC). Mechanical properties were determined using the micro-mentoring method. The tests showed a change in the degree of crystallinity in the range of several degrees and a significant increase in the glass transition temperature. In terms of mechanical properties, the reduction of hardness and Young’s modulus was observed. Observed changes, especially in terms of changes in the structure of the polymer under the influence of radiation, are difficult to explain, which requires conducting further research, especially in the range of irradiation parameters used. Further research is important because PEEK is used in many fields, especially in conditions conducive to corrosion and the influence of radiation.

Physico-mechanical properties of wound dressing material and its biomedical application

2011 ◽  
Vol 4 (7) ◽  
pp. 1369-1375 ◽  
Author(s):  
Haydar U. Zaman ◽  
J.M.M. Islam ◽  
Mubarak A. Khan ◽  
Ruhul A. Khan
Keyword(s):  
Mechanical Properties ◽  
Wound Dressing ◽  
Biomedical Application
Sign in / Sign up

Export Citation Format

Share Document