Hard phase vitrification

Hot-melt thermoplastic elastomer systems (23. 24) are also effective coating materials. These materials are generally based on copolymers that are comprised of hard (crystalline or glassy) and rubbery (amorphous) segments contained in separate phases. The hard-phase regions form physical cross-links below their crystallization or vitrification temperature, and the system therefore has elastomeric properties. The moduli and low-temperature characteristics of these materials can be tailored to compare reasonably well with silicone rubbers at -40 C. However, they are limited in high-temperature applicability because of enhanced creep or flow due to softening. 

The obtained results show that a microphase separation of hard and elastic blocks is observed in PC PTMO block copolymer resins. As PC and PTMO blocks can crystallize, both vitrification temperature and melting temperature of different phases is fixed. 

The morphology of the product may depend on the time order of the events phase separation, crystallization of the hard block, and/or vitrification, if any (41). 

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