Synthesis of a triblock copolymer: Poly(ethylene glycol)‐poly(alkylene phosphate)‐poly(ethylene glycol) as a modifier of CaCO3 crystallization

Triblock copolymer poly(ethylene glycol)‐poly(alkylene phosphate)‐poly(ethylene glycol) was prepared by first reacting hexamethylene glycol with dimethyl‐H‐phosphonate at conditions of transesterification and then replacing the CH3OP(O)(H)O‐… end‐groups by monomethyl ether of poly(ethylene glycol). The course of reaction was studied by 31P NMR indicating complete conversion. After oxidation the poly(alkylene H‐phosphonate was converted into the final triblock polyphosphate. This triblock copolymer was used as a modifier of CaCO3 crystallization. Unusual semi open empty spheres resulted, composed of small crystallites of the size (diameter) equal to 40–90 nm.