INFLUENCE OF A DOUBLE-HYDROPHILIC BLOCK COPOLYMER WITH SULFONIC GROUPS ON THE CRYSTALLIZATION OF CaCO3
双亲水性嵌段共聚物对CaCO3 结晶的影响

A hybrid double-hydrophilic block copolymer(DHBC) of PEG-b-PEI-SO_3H with sulfonic groups was synthesized and investigated as a modifying additive for CaCO_3 crystallization.The DHBC was well characterized by FTIR.Primary investigations indicated that this hybrid double hydrophilic block copolymer(DHBC) possessed strong modifying ability for both polymorphism and morphologies of inorganic crystals due to the especial structure with sulfonic groups.The crystal morphologies were investigated by SEM and TEM.The SEM and TEM results indicated that pure hollow round ring calcite was obtained after 1 day,while mussel-like and spherical-like calcium carbonates were produced after 3 or 5 days.When the reaction time was 7 days,almost pure spherical particles were obtained.The crystal phases were fully characterized with FTIR,XRD.The XRD results indicated that the calcium carbonate obtained after 1 day was calcite,and not only calcite but also vaterite was formed after 3 or 5 days,pure vaterite was produced after 7 days.These results were accordant with the FTIR measurement.When the reaction time was 1 day,the peaks at 875 cm-1 and 712 cm-1 indicated the calcium carbonate obtained was calcite.With prolonging of reaction time from 1 day to 3 or 5 days,the peaks at 875 cm-1,745 cm-1 and 712 cm-1 identified the calcite as well as vaterite crystals.While the 875 cm-1 and 745 cm-1 peaks appeared after 7 days,but the peak at 712 cm-1 disappeared,which showed that the pure vaterite was produced.