Healing Model

Destructive mechanical tests commonly are used to characterize autohesion of polymers. In the mechanical tests, two polymer surfaces normally are pressed together at a given temperature for a specified length of time. The fracture stress or fracture energy of the interface then is measured using the appropriate test. 

If wetting is instantaneous and the instantaneous wetting load at initial time is negligible, then the autohesive bond fracture stress, cr, is proportional to the fourth root of contact time and the fracture energy, GIC, is proportional to the square root of contact time as shown in the following equations  

Wool and O Connor [33] stated that the self-diffusion coefficient should follow a Williams-Landel-Ferry (WLF) temperature dependence providing that the mode of failure remains the same between samples healed at different temperatures between Tg and Tg + 100°C. Using a reference temperature of 196°C (469 K), the WLF relationship for PI700 polysulfone can be written as follows [38]  

The interply bond strength for thermoplastic matrix composites has been shown to be dependent upon the processing parameters, pressure, temperature, and contact time. If the temperature distribution in the composite is nonuniform during processing, the ply interfaces will bond (or heal) at different rates. Thus, for a specified processing cycle, it is important to know precisely the temperature and degree of autohesive bonding at every point in the composite laminate in order to estimate the required process time. 

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Figure 7.23 Degree of healing versus the square root of time. Symbols are data from Reference 38. Solid lines are predicted by healing model...

Human Organ Culture Wound Healing Model... 

In vitro duplication of the FBR with much physiological fidelity is seemingly complicated by its relative simplicity compared to the in vivo implant wound healing scenario. Full cascades of cell-cell signaling responses, multiple cell types, and the phased kinetics of various cell-based inflammatory responses are completely missing from most models reported to date. Therefore, in vivo animal implant healing models have been developed in attempts to get more accurate information closer to the actual situation in human FBR. 

Induced models Porcine wound healing models [38]... 

Textural analysis was performed by N2 physisorption at -196°C with a Carlo Erba 1990. The surface area of calcined samples was calculated with B.E.T. method and the pore distribution with Dollymore-Heal model. 

Voyiadjis, G., Shojaei, A., and Li, G. (2011) A thermodynamic consistent damage and healing model for self healing materials. International Journal of Plasticity, 27, 1025-1044. 

Newton, P., Watson, J., Wolowacz, R., Wood, E., 2004. Macrophages restrain contraction of an in vitro wound healing model. Inflammation 28, 207-214. 

Oryan, A., Mohammadalipour, A., Moshiri, A. and Tabandeh, M. 2014. Topical Application of Aloe vera Accelerated Woimd Healing, Modeling, and Remodeling. Annals of Plastic Surgery, p.l. 

W. Xu, X. Sun, E. Stephens, I. Mastorakos, M. A. Khaleel, and H. Zbib, /. Power Sources, 218, 445 (2012). A Mechanistic-Based Healing Model for Self-Healing Glass Seals Used in Solid Oxide Fuel Cells. 

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