Copolymers from styrene and a mixture of p -and m-chloromethylstyrene were reacted with sodium cyclopentadienide in THF and precipitated in methanol at temperatures lower than -20 "C to obtain soluble cyclopentadienylated polymers. Due to extensive gelation, the content of cyclopentadienyl groups could not be increased to more than 4 mol-Vo except with extremely low molecular weight polymers. An improved method, in which the copolymer was cyclopentadienylated in the presence of metallic sodium, gave soluble polymers with up to 29 mol-Vo cyclopentadienyl groups. Pendant cyclopentadienyl groups undergo Diels-Aldedretro-Diels-Alder addition to give thermoreversible cross-linked polymers. The amount of gel fraction of a 4 mol-Vo cyclopentadienylated polymer as a function of the heating time was examined in the temperature range of 40 -80 OC. The DSC curve of a 29 mol-To cyclopentadienylated polymer showed an exothermic peak due to the Diels-Alder reaction and an endothermic peak starting around 390"C, a temperature higher than that found for the degradation of polystyrene.
3,4-Methylenedioxybenzyl methacrylate (3) was synthesized from 3,4-methylenedioxybenyl alcohol (2) and methacryloyl chloride. 3 was radically polymerized with tributylborane and copolymerized in cyclohexanone at room temperature under nitrogen. The following monomer reactivity ratios were determined (M, = 3: r, = 0,68 and rz = 0,40 for M, = styrene, r, = 0,78 and r2 = 0,16 for M, = acrylonitril, and rl = 0,28 and r, = 1,47 for methyl methacrylate.Polymeric derivatives having 3,4-dihydroxybenzyl units in the side chains were prepared from homo-and copolymers of 3. The thermal stability and redox behaviour of these polymers were investigated.002.5-1 16X/81/0182/2715/$03.O0
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