Metal‐containing coordination polymers. XI. Crystallization and melting behavior of a semicrystalline polyester and its Mg (II) complexes

The effect of metal ion content and thermal history on the crystallization and melting behavior of a semicrystalline low‐molecular‐weight poly(butylene adipate) and its Mg complexes was studied by wide‐angle x‐ray diffractometry and differential scanning calorimetry. Both the polyester and the metal‐containing derivatives are dimorphous, and a β to α transformation takes place as the annealing temperature is increased. The dependence of the degree of crystallinity on the thermal history is more pronounced at higher Mg contents because of the effect of metal ions on the rate of crystallization. Melting of specimens with nonequilibrium structure is accompanied by simultaneous recrystallization processes such as perfection of crystallites and transformation of the crystal forms. The rates of these processes decrease with increasing metal content. The crystallizability is also reduced in the presence of Mg. Above the stoichiometrically equivalent Mg content, an abrupt change in the percentage of crystallinity accompanied by a considerable alteration in the microstructure of the crystalline phase occurs.