Defects chain folds

Figure 5.5. Schematics of dry gel lamellae for (a) PE with chain folds and loops at the surface (b) PE/i-PP blend showing PP entanglements on the defective surface of PE lamellae (Baltd Calleja et al., 1990a.)...

Figure 12. (F—E) Characteristic FTIR spectrum of 110 chain folds in solution-grown single crystals of n-alkane Ci98H3g8 (spectrum of extended-chain crystals subtracted from that of once-folded crystals) (PESC) solution-grown single crystals of polyethylene (bulk PE) melt-crystallized linear polyethylene. All bands are CH2 wagging defect modes except the CH3 band at 1378 cm-1. Spectra recorded at 110 K (from ref 68 by permission of Elsevier Science Publ.)...

Over the last two decades a number of diseases have been linked to defective protein folding (Gregersen et al. 2005). Following ribosomal synthesis of linear polypeptide chains of... 

The process of crystallization in polymers involves chain folding. This creates inherent defects in the resulting crystal. Consequently, the actual melting point is lower than the ideal thermodynamic melting point. 

Figure 5-21. Some possible lattice defects with chain folding. 1, Chain ends 2, disordered surface layer 3, dislocations 4, interlamellar linkages.

The amorphous component of the crystalline polymer solid contains beyond the amorphous component of single crystals, i.e. crystal defects (linear vacancies, kinks, and interstitials), chain folds and free chain ends, as new elements the rejected non-crystallisable impurities and tie molecules. The former concentrate on the outer boundaries of lamella stacks and spherulites, the latter in the amorphous layers separating the lamellae of the same stack. With the exception of impurities all other components of the amorphous phase are intimately connected with the crystals and cannot be physically separated from them or moved independently of them. 

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