Synthesis of a new class of double-hydrophilic block copolymers with calcium binding capacity as builders and for biomimetic structure control of minerals

摘要

Small black copolymers consisting of a hydrophilic poly(ethylene glycol) block and a second, also hydrophilic, moiety which strongly interacts with alkaline earth ions were synthesized by diverse reaction sequences based on poly(ethylene glycol) monomethyl ethers (MW = 2000 and 5000 g/mol, respectively). These starting blocks were transferred to the poly(ethylene glycol) monomethyl monoglycidyl ether or to poly(ethylene glycols) with one terminal acid chloride group. Both intermediates were subsequently reacted with poly(ethyleneimine) (MW = 700 g/mol) and bromoacetic acid to yield poly(ethylene glycol)-block-poly(N-carboxymethyl)ethyleneimine (PEG-b-PEIPA, average MW = 3800 resp. 6800 g/mol) as a polymeric analog of EDTA. The terminal epoxy group is also convenient for the connection of simple peptide sequences. For the desired purpose of ion binding, poly(aspartic acid) (PAsp) was applied, resulting in the block copolymer PEO-b-PAsp. A simple testing procedure concerning the inhibition of calcium carbonate precipitation was applied for the prepared structures. A. comparison with commercial builders for water treatment such as poly(acrylic acid)-co-(maleic anhydride) or poly(aspartic acid) stresses the superb calcium carbonate crystallization inhibition efficiency (up to the 20 fold) of the double hydrophilic block copolymer stabilizers. References: 24