| SYNTHESIS |
Fumaric acid prepolymer was prepared by adding 40 g (0.34 mole) of fumaric acid to 500 ml refluxing acetic anhydride. The reaction was continued for five hours. The clear yellow-brown solution was left to crystallize at -20.degree. C. for three days. The white crystalline precipitate was then filtered and washed with dry ether to yield 25 g (45% yield). The melting point of the prepolymer was 75.degree. C, IR (KBr, pelat, cm.sup.-1).nu..sub.C.dbd.C 3070 (sharp), .nu..sub.anhydride 1800, 1735. 'H-NMR (CDC13, ppm) 6.92 (s,2H), 2.32 (s,6H). A solution of 22 mmole acetyl chloride (1.6 ml in 10 ml chloroform) was added to a stirring mixture of 1.16 g (10 mmole) sebacic acid and 2.5 g (22 mmole) poly(4-vinylpyridine) (PVP) in 15 ml chloroform immersed in an ice water bath. The reaction was continued overnight at room temperature. The mixture was then filtered and the filtrate evaporated to dryness. Excess acetyl chloride was removed by vacuum over 24 hours. The residue was washed with diethylether: petroleum ether (1:1). 1.5 g was recovered (80% yield). The prepolymer had a melting point of 70.degree. C., IR (KBr, pelat, cm.sup.1) anhydride 1800, 1740 'H-NMR (CDCl.sub.13, ppm) 6.92 (s,2H), 2.32 (s,6H). Copolymers were similarly prepared by polymerizing a mixture of prepolymers at 180.degree. C. under vacuum. In a typical study, 2.0 g (10 mmole) fumaric acid (FA) prepolymer was mixed with 2.3 g (10 mmole) sebacic acid (SA) prepolymer and polymerized at 180.degree. C. under 100 microns vacuum for 25 minutes. The crude copolymers were dissolved in methylene chloride or chloroform (10 g polymer in 50 ml organic solution) and poured dropwise into 500 ml stirring petroleum ether. The light tan precipitate was separated by filtration, washed with diethylether and dried in a vacuum oven at 35.degree. C. for 24 hours. |
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