Pechhold kink

Figure 4. Convergence of the relaxation method. The energy of a crystalline array of polyethylene chains with the central one containing the defect indicated (relative to a nondefective array), see Figure 1. The Pechhold kink is in an array of two free coordirwtion shells (6 +12 = 18 chains), each chain is C,fl SO The other two defects are in an array of one free coordination shell plus a rigid second coordination shell, each chain is CtgHss-...

The mathematical representation of the elastic behavior of oriented heterogeneous solids can be somewhat improved through a more appropriate choice of the boundary conditions such as proposed by Hashin and Shtrikman [66] and Stern-stein and Lederle [86]. In the case of lamellar polymers the formalisms developed for reinforced materials are quite useful [87—88]. An extensive review on the experimental characterization of the anisotropic and non-linear viscoelastic behavior of solid polymers and of their model interpretation had been given by Hadley and Ward [89]. New descriptions of polymer structure and deformation derive from the concept of paracrystalline domains particularly proposed by Hosemann [9,90] and Bonart [90], from a thermodynamic treatment of defect concentrations in bundles of chains according to the kink and meander model of Pechhold [10—11], and from the continuum mechanical analysis developed by Anthony and Kroner [14g, 99]. 

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