Micron-sized polymer particles from tanzanian cashew nut shell liquid. Part I: Preparation, functionalization with chloroacetic acid and utilization as cation exchange resin
Micron-sized polymer particles (MSPP) were prepared by formaldehyde condensation polymerization of cashew nut shell liquid (CNSL) previously emulsified with sodium lauryl sulphate. The sizes of the MSPP were found to range from 0.1 to 4.4 mm. Increasing the emulsifier concentration had the effect of increasing the average particle size as well as the rate of polymerization. On the other hand, the polymerization rate decreased as the amount of the catalyst (sodium hydroxide) increased. The MSPP were also found to be insoluble and stable in many organic solvents and in some inorganic reagents. The average number of surface OH groups was found to be 2.29 x 1018 per milligram of polymer particles. Micron-sized carboxylated cation exchange resins (MCCER) were obtained by treating MSPP with monochloroacetic acid in an alkaline medium. The MCCER were found to exchange up to about 86 mg of calcium ion per gram of polymer at 30 ºC while the MSPP could exchange up to only about 6 mg of calcium ion per gram of polymer, at the same temperature. Compared to MSPP, the MCCER showed more than a thirteen-fold improvement in cation exchange capacity.
KEY WORDS: Micron-sized polymer particles, Cashew nut shell liquid, Polymer functionalization, Cation exchange resins
Bull. Chem. Soc. Ethiop. 2004, 18(1), 81-90.