TY - JOUR A1 - Bruzzano, S. A1 - Sieverling, N. A1 - Wieland, Ch. A1 - Jaeger, W. A1 - Thünemann, Andreas A1 - Springer, J. T1 - Cationic polymer grafted starch from nonsymmetrically substituted macroinitiators N2 - The aim of this work was the synthesis of starch macroinitiators for cationic polymer grafted starches that: (i) are free of cationic homopolymer, and (ii) display a high degree of conversion of the cationic monomer. We show that this can be achieved by a free-radical polymerization reaction using the cationic monomer N-methacryloyloxyethyl-N,N-dimethyl-N-benzylammonium chloride (MADAM-BQ) and a new starch-based macroazoinitiator. For this purpose, the acid chloride of 4-tert-butylazo-4-cyanovaleric acid was synthesized and bound covalently to starch (predominantly in the C6 position) to form a nonsymmetrically substituted macroinitiator that was used to polymerize MADAM-BQ in aqueous media. Essentially no MADAM-BQ homopolymer was formed. The initiator decomposes thermally to starch radicals of high reactivity and low-molar mass radicals that do not initiate polymerization. The reason for the different reactivities of the radicals is presumably due to the nonsymmetric constitution of the starch-bound azo groups. The graft polymerization of MADAM-BQ in aqueous solution performs according to an ideal overall kinetic. The structure of the synthesized starch-graft-poly(MADAM-BQ) products is similar to that of block copolymers because of the low radical efficiency of the starch initiators in aqueous solution. Especially, starch substrates with a higher content of azo groups did not lead to graft products with shorter graft distances because the state of solution of these macroinitiators becomes worse and aggregation occurs with an increasing degree of substitution. KW - Starch KW - Azo macroinitiators PY - 2005 U6 - https://doi.org/10.1021/ma048063f SN - 0024-9297 SN - 1520-5835 VL - 38 SP - 7251 EP - 7261 PB - American Chemical Society CY - Washington, DC AN - OPUS4-10536 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -