High Transition-Temperature

TABLE 4. High Temperature Transition Temperatures and Melting Point of Rare Earth Metals 

Nature of High Temperature Transitions of the Aromatic Polyesters.. 227 

Grossmann HP, Pechhold WR (1986) The high temperature transition of polyethylene into a condis jhase, described on the basis of the duster-entre y hypothesis (QEH). Colloid and Polymer Sea., 264 415 

Hussein IA, Williams MC (2004) Melt flow indexer evidence of high-temperature transitions in molten high-density polyethylene. J Appl Polym Sci 91 1309 

The induction time for the initial endothermic bond breaking reaction can be calculated using the high pressure, high temperature transition state theory. Experimental unimolecular gas phase reaction rates under low temperature (<1000K) shock conditions obey the usual Arrhenius law  

Since BCZY15 behaves approximately as a combination of the two component compositions, the magnitudes of the BaCOs-presence temperature range and high-temperature transition hysteresis are approximately equal to the greater of the two 

On the other hand, 4-hydroxybenzoic acid and syringic acid give infusible polymers exhibiting high temperature transitions at 330 and 320 °C, respectively. The polymer obtained from 3,5-dichloro-4-hydroxybenzoic acid exhibits neither a melting point nor a transition below 400 °C. 

Fig. 23. Heat capacities of two cycloalkanes in the transition regions. The low temperature polymorphs are fully ordered. The high temperature transitions lead to the isotropic melts. The condis crystals exist between the two endotherms (Scanning calorimetry, heating rate 10 K/min, drawn after data of Ref.171>)

The relaxatioa temperature appears to iacrease with increa sing HFP coateat. Relaxatioa iavolves 5—13 of the chaia carboa atoms. Besides a and y relaxations, one other dielectric relaxation was observed below —150° C, which did not vary ia temperature or ia magnitude with comonomer content or copolymer density (55). The a relaxation (also called Glass 1) is a high temperature transition (157°C) andy relaxation (Glass 11) (internal friction maxima) occurs between —5 and 29°C. 

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