The preparation is reported of two series of oligo(oxyethylene) methacrylates containing residues of 2,4-D and CMPA herbicides covalently bound via an ester bond to oligoether side groups having different degree of oligomerization (DPn = 2, 4, 8). The two series of monomers, when submitted to free radical polymerization gave the corresponding homopolymers, that exhibited a water uptake generally lower than 50%. A series of linear and crosslinked polymeric herbicides was also prepared by copoly-merization of the CMPA-containing tetraoxyethylene methacrylate with different comonomers, such as dioxyethylene and octaoxyethylene monomethacrylate, acrylamide, methylene bisacrylamide and 4-vinylpyridine. All the synthesized polymeric herbicides were tested for their release properties in aqueous solution buffered at pH 4, 7 and 9. The herbicide release profiles have been discussed in relation to the polymer inherent structural features and compared with the corresponding polymers obtained by 2,4-D and CMPA binding to preformed poly [oligo(oxyethylene) methacrylate]s. In any case the release kinetics do not fit a simple diffusional scheme and they can be reproduced by the contemporary occurrence of two exponential decay processes, differing by three orders of magnitude in their absolute rates
Herbicide containing methacrylates: synthesis, polymerization and release investigation
SOLARO, ROBERTO;CHIELLINI, EMO
1991-01-01
Abstract
The preparation is reported of two series of oligo(oxyethylene) methacrylates containing residues of 2,4-D and CMPA herbicides covalently bound via an ester bond to oligoether side groups having different degree of oligomerization (DPn = 2, 4, 8). The two series of monomers, when submitted to free radical polymerization gave the corresponding homopolymers, that exhibited a water uptake generally lower than 50%. A series of linear and crosslinked polymeric herbicides was also prepared by copoly-merization of the CMPA-containing tetraoxyethylene methacrylate with different comonomers, such as dioxyethylene and octaoxyethylene monomethacrylate, acrylamide, methylene bisacrylamide and 4-vinylpyridine. All the synthesized polymeric herbicides were tested for their release properties in aqueous solution buffered at pH 4, 7 and 9. The herbicide release profiles have been discussed in relation to the polymer inherent structural features and compared with the corresponding polymers obtained by 2,4-D and CMPA binding to preformed poly [oligo(oxyethylene) methacrylate]s. In any case the release kinetics do not fit a simple diffusional scheme and they can be reproduced by the contemporary occurrence of two exponential decay processes, differing by three orders of magnitude in their absolute ratesI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.