Novel copolymers of styrene. 15. Halogen ring-disubstituted propyl 2- cyano-3-phenyl-2-propenoates

Novel halogen ring-disubstituted propyl 2-cyano-3-phenyl-2-propenoates, RPhCH=C(CN)CO2C3H7 (where R is 2-fluoro-5-methyl, 3-iodo-4-methoxy, 5-iodo-2methoxy, 3,5-dichloro, 3,4-difluoro, 3,5-difluoro, 2-chloro-4-fluoro, 2-chloro-6-fluoro, 3chloro-2-fluoro, and 3-chloro-4-fluoro) were prepared and copolymerized with styrene. The propenoates were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-disubstituted benzaldehydes and propyl cyanoacetate, and characterized by CHN elemental analysis, IR, Hand C-NMR. All the propenoates were copolymerized with styrene (M1) in solution with radical initiation (ABCN) at 70C. The composition of the


Copolymerization
Copolymers of the ST and the PCPP monomers were prepared in 25-mL glass screw cap vials at ST/PCPP = 3 (mol) the monomer feed using 0.12 mol/L of ABCN at an overall monomer concentration 2.44 mol/L in 10 mL of toluene. The copolymerization was 9 conducted at 70ºC. After a predetermined time, the mixture was cooled to room temperature, and precipitated dropwise in methanol. The composition of the copolymers was determined based on the nitrogen content.
Copolymerization (Sch. 1) of ST and the ring-disubstituted PCPP resulted in formation of copolymers (Table 1)

Structure and thermal properties
The structure of ST-PCPP copolymers was characterized by IR and NMR spectroscopy. A comparison of the spectra of the monomers, copolymers and polystyrene shows, that the 11 reaction between the monomers and ST is a copolymerization. IR spectra of the copolymers show overlapping bands in 3200-2820 cm -1 region corresponding to C-H stretch vibrations.
The  Table 1. Information on the degradation of the copolymers was obtained from thermogravimetric analysis. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 200-500ºC range with residue (1-3% wt), which then decomposed in the 500-800ºC range. The decomposition products were not analyzed in this study, and the mechanism has yet to be investigated.

Conclusions
Novel trisubstituted ethylenes, ring-disubstituted propyl 2-cyano-3-phenyl-2-propenoates were prepared and copolymerized with styrene. The compositions of the copolymers were calculated from nitrogen analysis and the structures were analyzed by IR, H 1 and 13 C-NMR.
The thermal gravimetric analysis indicated that the copolymers decompose in in two steps, first in the 200-500C range with residue (1-3%wt), which then decomposed in the 500-800ºC range.