Incorporation of a Decorin Biomimetic Enhances the Mechanical Properties of Electrochemically Aligned Collagen Threads

Author(s):  
Vipuil Kishore ◽  
John E. Paderi ◽  
Anna Akkus ◽  
Alyssa Panitch ◽  
Ozan Akkus

Damaged tendons often do not heal completely and lack full functionality. Tissue engineering employing collagen based biomaterials is a viable option to repair damaged tendons. However, most existing constructs lack the desired mechanical strength needed to reconstruct such load bearing tissues. We have previously reported a novel methodology to synthesize highly ordered electrochemically aligned collagen (ELAC) threads that are mechanically stronger and more amenable to cell migration compared to randomly oriented collagen constructs. While the ELAC mimics the orientational anisotropy of tendon it can be further improved by the incorporation of small leucine rich proteoglycans like decorin. Decorin consists of a protein core that binds to collagen and a glycosaminoglycan (GAG) chain. The GAG chains of adjacent collagen fibrils associate with one another to form crosslinks and are suggested to enhance the mechanical properties of tendon by allowing fibrillar slippage. Based on the structure of natural decorin, we have previously synthesized a novel peptidoglycan (DS-SILY) containing a collagen binding peptide (SILY) and a dermatan sulfate (DS) GAG chain. DS-SILY mimics decorin both structurally and functionally. In this study, we investigated the effects of the incorporation of DS-SILY on the mechanical properties and structural organization of ELAC threads by monotonic mechanical testing, swelling ratio and differential scanning calorimetry.

2021 ◽  
pp. 095400832110055
Author(s):  
Yang Wang ◽  
Yuhui Zhang ◽  
Yuhan Xu ◽  
Xiucai Liu ◽  
Weihong Guo

The super-tough bio-based nylon was prepared by melt extrusion. In order to improve the compatibility between bio-based nylon and elastomer, the elastomer POE was grafted with maleic anhydride. Scanning Electron Microscopy (SEM) and Thermogravimetric Analysis (TGA) were used to study the compatibility and micro-distribution between super-tough bio-based nylon and toughened elastomers. The results of mechanical strength experiments show that the 20% content of POE-g-MAH has the best toughening effect. After toughening, the toughness of the super-tough nylon was significantly improved. The notched impact strength was 88 kJ/m2 increasing by 1700%, which was in line with the industrial super-tough nylon. X-ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC) were used to study the crystallization behavior of bio-based PA56, and the effect of bio-based PA56 with high crystallinity on mechanical properties was analyzed from the microstructure.


MRS Advances ◽  
2017 ◽  
Vol 2 (49) ◽  
pp. 2689-2694
Author(s):  
Karla A. Gaspar-Ovalle ◽  
Juan V. Cauich-Rodriguez ◽  
Armando Encinas

ABSTRACTNanofibrous mats of poly ε-caprolactone (PCL) were fabricated by electrospinning. The nanofiber structures were investigated and characterized by scanning electron microscope, differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical analysis, static water-contact-angle analysis and mechanical properties. The results showed that the nanofibrous PCL is an ideal biopolymer for cell adhesion, owing to its biocompatibility, biodegradability, structural stability and mechanical properties. Differential scanning calorimetry results showed that the fibrous structure of PCL does not alter its crystallinity. Studies of the mechanical properties, wettability and degradability showed that the structure of the electrospun PCL improved the tensile modulus, tensile strength, wettability and biodegradability of the nanotemplates. To evaluate the nanofibrous structure of PCL on cell adhesion, osteoblasts cells were seeded on these templates. The results showed that both adhesion and proliferation of the cells is viable on these electrospun PCL membranes. Thus electrospinning is a relatively inexpensive and scalable manufacturing technique for submicron to nanometer diameter fibers, which can be of interest in the commodity industry.


Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1101 ◽  
Author(s):  
Przybysz ◽  
Hejna ◽  
Haponiuk ◽  
Formela

The modification of poly(ε-caprolactone) (PCL) was successfully conducted during reactive processing in the presence of dicumyl peroxide (DCP) or di-(2-tert-butyl-peroxyisopropyl)-benzene (BIB). The peroxide initiators were applied in the various amounts of 0.5 or 1.0 pbw (part by weight) into the PCL matrix. The effects of the initiator type and its concentration on the structure and mechanical and thermal properties of PCL were investigated. To achieve a detailed and proper explication of this phenomenon, the decomposition and melting temperatures of DCP and BIB initiators were measured by differential scanning calorimetry. The conjecture of the branching or cross-linking of PCL structure via used peroxides was studied by gel fraction content measurement. Modification in the presence of BIB in PCL was found to effectively increase gel fraction. The result showed that the cross-linking of PCL started at a low content of BIB, while PCL modified by high DCP content was only partially cross-linked or branched. PCL branching and cross-linking were found to have a significant impact on the mechanical properties of PCL. However, the effect of used initiators on poly(ε-caprolactone) properties strongly depended on their structure and content. The obtained results indicated that, for the modification towards cross-linking/branching of PCL structure by using organic peroxides, the best mechanical properties were achieved for PCL modified by 0.5 pbw BIB or 1.0 pbw DCP, while the PCL modified by 1.0 pbw BIB possessed poor mechanical properties, as it was related to over cross-linking.


1986 ◽  
Vol 76 ◽  
Author(s):  
C. W. Wilkins ◽  
H. E. Bair ◽  
M. G. Chan ◽  
R. S. Hutton

ABSTRACTWe have studied some of the physical and mechanical properties of cyclized polybutadiene (CBR) dielectrics by dynamic mechanical analysis, thermal mechanical analysis, thermogravimetry, infrared analysis, and differential scanning calorimetry. Of interest is the difference in properties between thin (<30 μm) films which have been cured under vacuum and those which have been cured in air. Our results indicate that curing under vacuum prevents oxidation and reduces crosslinking. Vacuum cured films have 20% smaller moduli and 200 lower glass transition temperature than do films produced in air.


e-Polymers ◽  
2006 ◽  
Vol 6 (1) ◽  
Author(s):  
Newton Luiz Dias Filho ◽  
Hermes Adolfo de Aquino

AbstractNon-isothermal dielectric analysis (DEA) and differential scanning calorimetry (DSC) techniques were used to study the epoxy nanocomposites prepared by reacting 1,3,5,7,9,11,13,15-octa[dimethylsiloxypropylglycidylether] pentaciclo [9.5.1.13,9.15,15 .17,13] octasilsesquioxane (ODPG) with methylenedianiline (MDA). Loss factor (ε”) and activation energy were calculated by DEA. The relationships between the loss factor, the activation energy, the structure of the network, and the mechanical properties were investigated. Activation energies determined by DEA and DSC, heat of polymerization, fracture toughness and tensile modulus show the same profile for mechanical properties with respect to ODPG content.


2016 ◽  
Vol 721 ◽  
pp. 23-27 ◽  
Author(s):  
Ilya Kobykhno ◽  
Oleg Tolochko ◽  
Ekaterina Vasilyeva ◽  
Andrei Didenko ◽  
Danila Kuznetcov ◽  
...  

The paper experimentally studies the effect of meta and para- substitution of the amino groups in the diamine used in the synthesis of multiblock copolymers. The way for synthesis of new multiblock copolymers with the possibility of replacing the diamine in the polymer structure was shown. Thermal and mechanical properties of synthesized copolymers had been characterized by means of differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical thermal analysis and by nanoindentation and tensile test.


Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1459
Author(s):  
Agbelenko Koffi ◽  
Fayçal Mijiyawa ◽  
Demagna Koffi ◽  
Fouad Erchiqui ◽  
Lotfi Toubal

Wood–plastic composites have emerged and represent an alternative to conventional composites reinforced with synthetic carbon fiber or glass fiber–polymer. A wide variety of wood fibers are used in WPCs including birch fiber. Birch is a common hardwood tree that grows in cool areas such as the province of Quebec, Canada. The effect of the filler proportion on the mechanical properties, wettability, and thermal degradation of high-density polyethylene/birch fiber composite was studied. High-density polyethylene, birch fiber and maleic anhydride polyethylene as coupling agent were mixed and pressed to obtain test specimens. Tensile and flexural tests, scanning electron microscopy, dynamic mechanical analysis, differential scanning calorimetry, thermogravimetry analysis and surface energy measurement were carried out. The tensile elastic modulus increased by 210% as the fiber content reached 50% by weight while the flexural modulus increased by 236%. The water droplet contact angle always exceeded 90°, meaning that the material remained hydrophobic. The thermal decomposition mass loss increased proportional with the percentage of fiber, which degraded at a lower temperature than the HDPE did. Both the storage modulus and the loss modulus increased with the proportion of fiber. Based on differential scanning calorimetry, neither the fiber proportion nor the coupling agent proportion affected the material melting temperature.


2020 ◽  
Vol 1 (104) ◽  
pp. 30-40
Author(s):  
P. Choryłek ◽  
P. Postawa

Purpose: of the research is to physically modify the composition of bone cements with glassy carbon and cancellous bone to improve its performance, reduce polymerization temperature and reduce the ability of cements the effect of admixture on the phenomenon of relaxation. Design/methodology/approach: SpinePlex bone cement was modified with glassy carbon powder with 20-50 μm granulation with Maxgraft®. Maxgraft cancellous bone has been ground to 20-50 μm grains. Samples of unmodified cements (reference) and modified with glassy carbon and cancellous bone were prepared for the tests. The glassy carbon powder and ground cancellous bone were premixed with the cement copolymer powder, and then the premix prepared this way was spread in a liquid monomer. To delay the polymerization process, all components were cooled before mixing to 15°C. The addition of glassy carbon was 0.4 g and the addition of cancellous bone was 0.2 g per 20 g of cement powder, i.e. about 1.96% by mass. Polymerization temperature, relaxation and differential scanning calorimetry tests were performed on the samples made. Findings: Additives used allow: to reduce the polymerization temperature, as well as rheological properties. During the studies it was found that the additive which can meet the requirements is glassy carbon in form of powder and cancellous bone. Research limitations/implications: The results presented in the publication require further advanced research, which will be the subject of further modification attempts by the research team. Practical implications: The conducted tests showed a significant effect of glassy carbon as a modifier on the mechanical properties of cement after its solidification, but also on the course of the polymerization process. Temperature registration tests during crosslinking, tests of mechanical properties (behaviour of cement samples under load) and DSC differential scanning calorimetry analysis confirmed that the addition of glassy carbon had an effect on each of these aspects. Originality/value: The original in these studies is the possibility to improve fundamental properties of the selected bone cements by using different than commonly used additives.


2020 ◽  
Vol 90 (3) ◽  
pp. 31101
Author(s):  
Shiv Kumar Pal ◽  
Neeraj Mehta ◽  
John C. MacDonald ◽  
Dipti Sharma

In this endeavor, we have synthesized novel quaternary glassy Se78-xTe20Sn2Gex (0 ≤ x ≤ 6) alloys by the well-known rapid cooling of melt under quenching technique, to study the effect of Germanium on thermodynamic and thermo-mechanical properties. In particular, we employed Differential Scanning Calorimetry (DSC) technique for the investigation of thermodynamic parameters (e.g., specific heat Cp and enthalpy ΔH) in the glass-transition-region (GTR). Differential Scanning Calorimetry (DSC) experiment was run under non-isothermal conditions. The thermo-mechanical parameters i.e., micro-hardness, micro-void volume, the energy of creation of micro-void, elasticity, density, compactness, and molar volume are also calculated. It was observed that there is a large increment in Cp values in the GTR. Further analysis shows that the Cp values above the GTR (i.e., Cp  = Cpe equilibrium specific heat) and below the GTR (i.e., Cp  = Cpg glass specific heat) are vastly composition dependent. The increment in specific heat value after Ge incorporation is explained in terms of molar volume.


2012 ◽  
Vol 624 ◽  
pp. 264-268 ◽  
Author(s):  
Duo You Zhang ◽  
Peng Liu ◽  
Chun Fa Ouyoung ◽  
Qun Gao ◽  
Kang Sheng Zheng ◽  
...  

PNA012 is a new nucleating agent on polybutylene terephthalate. The effect of different dosage of PNA012 on crystallization and mechanical properties were investigated by means of differential scanning calorimetry, universal testing machine, melt flow indexer and vicat softening testing machine. It was revealed that the PNA012 could substantially accelerate the crystallization of PBT. Compared with the pure PBT,the crystallization temperature of PBT/PNA012 rises from 196.3 °C to 199.7 °C and crystallization degree from 34.2% to 39.9%. The tensile Strength of PBT/PNA012 is increased 9.7%. The Bending Strength has a rise of 9.3% and the heat distortion temperatures of PBT/PNA012 is increased from 115.07°C to 125.94°C.


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