Polymeric Microcapsules of Alachlor and Metolachlor:  Preparation and Evaluation of Controlled-Release Properties

Abstract

The microencapsulation of alachlor and metolachlor in the polymers cellulose acetate butyrate, ethyl cellulose, poly(methyl methacrylate), and poly(alpha-methylstyrene) with different emulsifiers is described. The controlled-release properties of these formulations were measured under greenhouse conditions on barnyardgrass, crowfootgrass, smallflower morningglory, and Palmer amaranth. The emulsifiers had little effect on the activity of the herbicides. The herbicidal activities of the poly(methyl methacrylate) and poly(alpha-methylstyrene) formulations were consistently lower on all weed species when compared to the activities of the cellulose acetate butyrate, ethyl cellulose, and commercial formulations. The ethyl cellulose formulation of alachlor exhibited controlled-release properties. The results with metolachlor were similar to those with alachlor except that none of the metolachlor formulations exhibited efficacy superior to that of the commercial formulation or controlled release properties.

A New Method to Synthesize Microcapsule and Its Application in Controllable Photodegradation of Polymers

“…Gelatin is a protein which contains -COO − and -NH 3 + groups and carries more positive charge from -NH 3 + below its isoelectric point. Gum arabic is a negative charged macromolecule containing lots of -COO − .…”

“…Tris(N, N-diethyldithiocarbamato) iron(III) (Fe(DEC) 3 ) is a superior photodegradant, first proposed by Scott 9 and was investigated in detail as photodegradant in polymers. [10][11][12][13] Fe(DEC) 3 can be simply synthesized by the reaction of FeCl 3 and sodium N, N-diethyldithiocarbamate (NaDEC) in aqueous solution.…”

“…[10][11][12][13] Fe(DEC) 3 can be simply synthesized by the reaction of FeCl 3 and sodium N, N-diethyldithiocarbamate (NaDEC) in aqueous solution. Interestingly, we arranged the reaction and the coacervation reaction of gelatin and gum arabic in the same reaction system.…”

“…[1][2][3][4][5][6] It is a recently developed concept that microencapsulated photodegradant was used in the controllable photodegradation of polymers 7 although microencapsulated antioxidants were adopted in polymers. 8 Usually the addition of photodegradant is accompanied with photostabilizers or antioxidants to overcome the problem of property decay of polymers during application.…”

“…Herein, a new method to synthesize microcapsules was proposed and microencapsulated iron(III) tris(N, N-diethyldithiocarbamate), Fe(DEC) 3 , was produced. Preliminary study on controlled photodegradation of low density polyethylene (LDPE) films has shown the advantages of microencapsulated photodegradant.…”