Hyperbranched Polyesters with Carboxylic or Sulfonic Acid Functional Groups for Crystallization Modification of Calcium Carbonate

Hyperbranched aliphatic polyesters functionalized with carboxylic or sulfonic acid groups have been synthesized and employed as crystallization modifiers for calcium carbonate. The functionalized polyesters exhibit remarkable polymorph selectivity and morphology control. Stable spherical vaterite particles of diameter less than 10 µm with narrow size distribution were easy to produce on a large scale. With an increase in the concentration and monomer/core ratio of the polyester, the vaterite content increases accordingly with promoted morphology control to monodisperse spheres. The CaCO 3 concentration and the initial pH can also influence the morphology and polymorphism of the produced calcium carbonate. Under certain conditions, well‐defined core‐shell structured vaterite spheres are obtained with obvious radial organization by nano‐aggregation of about 70 ± 10 nm crystallites, which may mediate and combine the nano‐aggregation and crystal growth formation mechanism of vaterite polymorph. magnified image