Amorphous chain segments

Re-organization of amorphous chain segments adjacent to crystallite surfaces leads to crystallite thickening. These segments align themselves to form additional crystalline unit cells that increase the c dimensions of the crystallites. 

In the broadest terms, the rate of polymer crystallization is increased by factors that increase the free energy difference between the amorphous and crystalline states and factors that favor the re-organization of amorphous chain segments. The factors that influence the crystallization rate fall into two categories molecular characteristics and external conditions. Molecular... 

Kreiiuss and Frisch also have tmated the effect of crystallinity on transport in tubhety polymers using the so-called free-volume approach, which is discussed helow. In essence, their ideas suggest that intro-daction of crystallinity reduces the freedom of motion of amorphous chain segments between crystals. By... 

Although the infrared method can give only (P2(cosd)) or cos 9f ), it has the important advantage over refractive-index measurements that various absorption peaks can be used to give information about different parts of the molecule or different types of units, e.g. crystallites or amorphous chain segments. 

Ma, L., He, C., Suzuki, T. et al. 2003. Molecular mobility of amorphous chain segments of ethylene-methyl methacrylate copolymer films as a function of temperature estimated by positron-annihilation, x-ray diffraction and C NMR. Macromolecules 36 8056-8065. 

The addition of plasticizers can reduce the degree of brittleness. The addition will increase the mobility of amorphous chain segments, which can effectively lower Tg. Another technique that can be used is modification of the polymer through... 

The moisture regain of a typical sUk fiber is about 9.9% due to the high concentration of polar side groups in amino add residues. Water molecules absorbed by silk fibers would reside in the amorphous domains and compete with the amino adds in the amorphous chain segments for inter- and intramolecular interaction (Robson, 1985). SUk sutures also have very good handling properties with exceUent knot security. 

To demonstrate that variation of the amorphous chain segments contributed to the band at 2016cm" S the 2016 were plotted against 1894 in Fig. 5. With increasing is94 the 2016 decreases linearly for the... 

Summarizing the above results from this important new method one may say that amorphous chain segments exist in appreciable numbers which carry up to about twenty times the average stress. There are upper limits of molecular stress which in the case of polyamide 6 seem to be given by the chain strength (21 GN/m ). With... 

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