Thermodynamics of crystallizing oligomer and polymer multi-component systems

Crystallization seggregation of chain ends and chains is always observed in oligomer multi-component systems. The driving forces of these processes can be classified by use of the thermodynamics of eutectoid systems. If folded-chain crystallization does not appear, a defined relationship between the chain length-and the crystal thickness distributions is predicted with its typical influence on the melting transition. With local equilibrium there is the opportunity for a quantitative description of the melting transition of eutectoid copolymers of ethylene by means of the same thermodynamics as used for the oligormers in spite of the existing crystal newtork. There is only need of taking into consideration a varied solubility in the microphases. Swelling phenomena are treated quantitatively on the same lines, thus, yielding the same relationship between the length distribution of the crystallizable sequences and the crystal thickness distribution as in the pure copolymeres. The melting transition is shown to depend on the swelling deformation in the non-crystallized regions which gives direct evidence for the existence of the molecular crystal network. Hence, local crystallization seggregation of non-crystallizable units is found to be in principles present in all the systems involved, thus, indicating its general importance.