Effect of Thermocycling on the Thermal Degradation Kinetics of Goatskin Collagen Matrices

2011 ◽  
Vol 704-705 ◽  
pp. 870-876
Author(s):  
Xue Jing Zheng ◽  
Jie Liu ◽  
Kun Wang ◽  
Ke Yong Tang

In the present study, the goatskin collagen matrices were tanned by chrome powder and chestnut extract. The samples were then thermocycled in a container at different temperature ranges with a dwell time of 5 h for different cycles. The thermal degradation behaviors of the collagen matrices before and after the thermocycling were investigated. The Coates-Redfern Method was applied to study the thermal degradation kinetics of different samples. The results indicate that the thermocycling exerted more dramatic effect on the native collagen matrices than on tanned samples. The tanning process endows the samples with extra crosslinking structure, and therefore, less sensitivity to thermocycling treatment. It was found that the thermal treatment at moderate temperature (0~50˚̓˹˰̵̵̵̴͈͂̈́˰̵̼̹̼̈́̈́˰̶̵̵̹̼̳̾̾ͅ˰̿̾˰̸̵̈́˰̸̵̱̼̈́͂̽˰̴̵̷̴̱̱̹͂̈́̿̾˰̱̳̹̱̹̈́͆̈́̿̾˰̵̵̷̵̹̾͂̓˰˸ΔE) of the sample. However, for the samples thermocycled at high upper limit temperature (0~150˚̓˹˼˰ΔE was decreased significantly.

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1597
Author(s):  
Iman Jafari ◽  
Mohamadreza Shakiba ◽  
Fatemeh Khosravi ◽  
Seeram Ramakrishna ◽  
Ehsan Abasi ◽  
...  

The incorporation of nanofillers such as graphene into polymers has shown significant improvements in mechanical characteristics, thermal stability, and conductivity of resulting polymeric nanocomposites. To this aim, the influence of incorporation of graphene nanosheets into ultra-high molecular weight polyethylene (UHMWPE) on the thermal behavior and degradation kinetics of UHMWPE/graphene nanocomposites was investigated. Scanning electron microscopy (SEM) analysis revealed that graphene nanosheets were uniformly spread throughout the UHMWPE’s molecular chains. X-Ray Diffraction (XRD) data posited that the morphology of dispersed graphene sheets in UHMWPE was exfoliated. Non-isothermal differential scanning calorimetry (DSC) studies identified a more pronounced increase in melting temperatures and latent heat of fusions in nanocomposites compared to UHMWPE at lower concentrations of graphene. Thermogravimetric analysis (TGA) and derivative thermogravimetric (DTG) revealed that UHMWPE’s thermal stability has been improved via incorporating graphene nanosheets. Further, degradation kinetics of neat polymer and nanocomposites have been modeled using equations such as Friedman, Ozawa–Flynn–Wall (OFW), Kissinger, and Augis and Bennett’s. The "Model-Fitting Method” showed that the auto-catalytic nth-order mechanism provided a highly consistent and appropriate fit to describe the degradation mechanism of UHMWPE and its graphene nanocomposites. In addition, the calculated activation energy (Ea) of thermal degradation was enhanced by an increase in graphene concentration up to 2.1 wt.%, followed by a decrease in higher graphene content.


Materials ◽  
2017 ◽  
Vol 10 (11) ◽  
pp. 1246 ◽  
Author(s):  
Samson M. Mohomane ◽  
Tshwafo E. Motaung ◽  
Neerish Revaprasadu

2002 ◽  
Vol 86 (4) ◽  
pp. 957-961 ◽  
Author(s):  
Priyadarsi De ◽  
Sujay Chattopadhyay ◽  
Giridhar Madras ◽  
D. N. Sathyanarayana

2018 ◽  
Author(s):  
Abdullah Al-Yami ◽  
Vikrant Wagle ◽  
Walmy Cuello Jimenez ◽  
Paul Jones

2019 ◽  
Vol 39 (2) ◽  
pp. 105-116 ◽  
Author(s):  
Hongyan Li ◽  
Yongqiang Fu ◽  
Hongli Liu ◽  
Cong Sun ◽  
Ruyi Li ◽  
...  

AbstractThe thermo-oxidative and thermal degradation kinetic parameters of polymethyl methacrylate-methacryloxyethyltrimethyl ammonium chloride/silica aerogel composites (PMMA-MTC/SA) were investigated in this paper and were compared with the thermal stability and thermal conductivity of different types of composites. As a composite with electrostatic interaction, the thermo-oxidative and thermal degradation activation energies (E) of PMMA-MTC/SA were 173.97 and 188.05 kJ/mol, respectively. The results indicated that the electrostatic interaction could indeed enhance the thermal stability of silica/polymethyl methacrylate composites on the premise of good mechanical properties and heat insulation performance. It is of great significance for the further development of silica-based thermal insulation composites.


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