Premium
Graft copolymers of starch with mixtures of acrylamide and the nitric acid salt of dimethylaminoethyl methacrylate
Author(s) -
Fanta George F.,
Burr Robert C.,
Doane W. M.,
Russell C. R.
Publication year - 1972
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1972.070161110
Subject(s) - monomer , polymer chemistry , copolymer , methacrylate , polymer , chemistry , polymerization , starch , swelling , grafting , nuclear chemistry , materials science , organic chemistry , composite material
Mixtures of acrylamide and the nitric acid salt of dimethylaminoethyl methacrylate (DMAEMA·HNO 3 ) have been graft polymerized onto unmodified wheat starch with ferrous ammonium sulfate–hydrogen peroxide initiation. Graft polymerizations were carried out with both unswollen starch granules and granules that had been swollen by heating in water to 60°C. Ungrafted synthetic polymers were removed from graft copolymers by cold‐water extraction and were characterized by their M̄ n and DMAEMA·HNO 3 content. Graft copolymers were characterized with respect to per cent add‐on, M̄ n and DMAEMA·HNO 3 content of grafted polymer, and grafting frequency. Ungrafted synthetic polymers contained a mole percentage of DMAEMA·HNO 3 equal to or greater than that present in the initial monomer mixtures; whereas in most grafted polymers the mole‐% DMAEMA·HNO 3 in the grafted branches was less than that in the starting monomers. At all monomer ratios examined, polymer grafted to swollen starch granules contained a higher percentage of DMAEMA·HNO 3 then polymer grafted to unswollen starch. The influence of starch granule swelling on the molecular weight and frequency of grafted branches was correlated with the composition of the initial monomer mixture. It was determined that the effect of granule swelling on graft copolymer structure would be minimal when 25–30 mole‐% DMAEMA·HNO 3 was used. In an acetonitrile–water solvent system, reactions with 20 and 50 mole‐% DMAEMA·HNO 3 produced graft copolymers with less DMAEMA·HNO 3 in grafted branches than corresponding graft polymerizations run in water. The flocculation of 3% aqueous suspensions of diatomaceous silica was examined with selected starch graft copolymers.