Regular structure transitions

All of the commercial polymers are linear and although most have regular structures they are all, at least for practical intents and purposes, amorphous. The high in-chain aromaticity leads to high values of the Tg, the Amoco product Udel having a of about 190°C whilst the ICI polymer has an even higher value of about 230°C. The Amoco materials have a condary transition at -100°C and that of the ICI polymer is -70°C. Typical M values are about 23 000. 

The approximately random placement of side groups in atactic polymers prevents them from developing regular structures. For this reason, atactic polymers are non-crystalline and behave as rubbers or glasses, depending on whether they are above or below their glass transition temperature. 

Only the measurements of Bengtson are available for the 3p 2 ) 5s-3p ( P) 5p fine structure transitions in 5r/(Table 3). No comparative data from other sources have been found in the literature for fine structure transitions in //(Table 4), and thus we have made use of the regular behaviour of the oscillator strengths for analysing /-value data. 

Crystal growth is the process of the birth and development of a solid phase with a regular structure out of a disordered and irregular state, and thus it can be regarded as a first-order phase transition. 

Irregularities such as branch points, co-monomer units, and cross-links lead to amorphous polymers. These have less regular structures and typically do not have true melting points. Instead, they have glass transition temperatures at which the rigid and glass-like material becomes a viscous liquid as the temperature is raised. 

When a system is sufficiently far from equilibrium, it may arrive at a bifurcation of states and move to ordered structures. Transitions between different modes of dynamic organizations are called bifurcation. If the system continues to move away from equilibrium, the structures become more complex, leading to a chaotic situation in the macroscopic sense. Some regularity may involve in such chaotic behavior. To study the behavior of systems far from equilibrium, a new interdisciplinary field called synergetics was developed. Synergetics is concerned with the cooperation of individual parts of the system that produce macroscopic spatial and temporal structures, which are mainly dissipative. 

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