Resorcinol Formaldehyde Polymers Submitted by: Jerry A. Sears, Wayne Memorial High School, Wayne, Mich. 48184 Checked by: Linda L. Shepard, Hiram College, Hirami Ohio 44234
PREPARATION
Have available 40y0 formaldehyde solution, resorcinol, 0.1 M HC1, and 1 M NaOH. Provide a porcelain evaporating dish, tongs, and two plastic, disposable beakers (approximately 30 ml in capacity).
the formation of an orange-white polymer is noted. The reaction is very exothermic and the solid polymer foams up in the beaker. CAUTION: Spattering may occur.
DEMONSTRATION
REMARKS
In the evaporating dish place 3 g of resorcinol, 4 ml of formaldehyde solution and 4 ml of water. Heat until the resorcinol dissolves and the solution begins to boil. Using tongs, pour the hot solution into a plastic disposable beaker. Add 1 ml of 1 A4 NaOH and stir for a few seconds. The polymerization reaction is exothermic and the solution soon begins to boil. A change in color is noted. The liquid becomes more viscous until polymerization is complete and a solid resin is formed. CAUTION: Spattering may occur. Repeat the procedure, and after the solution has been poured into a disposable beaker, add 1 ml of 0.1 M HC1. Stir for a few seconds. The solution begins to boil and
After the polymers have been thoroughly washed, the two preparations can be contrasted. The polymer prepared with NaOH is a light red color and is very brittle. After aging for a few days the color darkens considerably. The polymer prepared using HCI is a light orange color and although somewhat brittle, it is much stronger than the polymer prepared with NaOH. The color also darkens with aging. Caution should be exercised in handling the solids as it is possible that liquid may remain in some of the cavities formed during the reaction. It is advisable to provide for t,he removal of the vapors formed during the reaction. Jownol of Chamcal Education. Auwat 1.971
Volume 48, Number 8, August 1971
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A499
