Polymeric Herbicide±Montmorillonite Composite: Synthesis, Characterization and Release Studies Ahmed Rehab* Chemistry Department, Faculty of Science, Tanta University, Postal No. 31527, Tanta, Egypt ABSTRACT WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW The production of polymeric herbicide intercalated onto montmorillonite interlayer through the process of cation exchange, in order to produce chemically bound poly- meric herbicide with clay, has been reported. This was carried out by cation exchange of clay with onium salts of preformed polymeric pentachlorophenyl methacrylate. The products were characterized by various techniques including IR spectroscopy and elemental microanalysis. The interlayer spacing was determined by X-ray diffraction and thermogravimetric analysis TGA) and calcination investigated the thermal stability. The morphology of the composite was investigated by scanning electron microscopy. The swelling behaviors in different solvents and release of pentachlorophenol PCP) in different medium have been described. Copy- right  2001 John Wiley & Sons, Ltd. KEYWORDS: polymer±clay composite; intercalated polymers; polymeric herbicide; controlled release for- mulation; montmorillonite-polymer INTRODUCTION WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW Polymer±clay materials have received considerable interest because the interaction between them have pronounced effects on the properties of both clay and polymer systems. Clay has been extensively used in the polymer industry either as a reinforcing agent to improve the physico-mechanical proper- ties of the final polymer or as a filler to reduce the amount of the polymer used in the shaped structures; i.e. to act as a diluent for the polymer, thereby, lowering the economic high cost of the polymer systems. The interaction of various substances in mon- tmorillonite is a technique for novel applications such as model enzyme immobilization [1], hetero- genization of transition-metal catalysis [2, 3], and detoxification of pesticides [4, 5]. Also, the interac- tion of pesticides with clay as attempts to under- stand the soil±pesticide interaction has been described [6]. During the last years, various polymer-sup- ported or microencapsulated biocides have been introduced in the field of agriculture to limit the undesirable side effects arising from conventional application of agricultural chemicals and related biocides. Delivery of agrochemical from controlled release formulations is more than a promising concept offering advantages for health, nutrition, environmental pollution control, and economic development [7±9]. Recently, the synthesis of reactive functionalized polymers has attracted interest for their potential and successful utilization in a variety of fields [10±13]. The release of pentachlorophenol from synthetic polymeric sys- tems [14±17], and natural polymeric systems has been studied [18±20]. Copyright  2001 John Wiley & Sons, Ltd. Received 22 March 2000 Revised 24 August 2000 Accepted 6 September 2000 POLYMERS FOR ADVANCED TECHNOLOGIES Polym. Adv. Technol. 12, 535±543 2001) DOI:10.1002/pat.124 *Correspondence to: A. Rehab, Chemistry Department, Faculty of Science, Tanta University, Postal No. 31527, Tanta, Egypt.