Oxidative copolymerization: microstructure analysis of the terpolymer of styrene, methyl methacrylate, and oxygen

This paper reports the first study of the microstructure of a copolyperoxide by nuclear magnetic resonance spectroscopy. The copolyperoxides of styrene and methyl methacrylate (MMA) of various compositions have been synthesized. An analysis of the resonance signal of the backbone methylene protons gave the diad sequence probabilities which led to the calculation of the oxidative copolymerization reactivity ratios for styrene and MMA and the microstructural parameters like average chain length of the repeat unit sequences, run number, etc. The results point to the tendency of the SO1 and MO:! units to alternate in the chain. Compared to poly(styrene peroxide), the aromatic C1 seems to be stereosensitive in the terpolymers

Microstructure of copolyperoxides of α-methylstyrene with styrene and methyl methacrylate

This paper reports a study on the microstructure of two series of copolyperoxides of α-methylstyrene, with styrene and with methyl methacrylate. The copolyperoxides were synthesized by the free radical-initiated oxidative copolymerization of the vinyl monomer pairs. The copolyperoxide compositions obtained from the 1H and 13C NMR spectra led to the determination of the reactivity ratios. The product of the reactivity ratios indicates that α-methylstyrene forms a block copolyperoxide with styrene and a random copolyperoxide with methyl methacrylate. Microstructural parameters like average sequence length, run number, etc. have been determined for the latter copolyperoxide from analysis of its 13C NMR spectrum. The aromatic quaternary and carbonyl carbons were found to be sensitive to triad sequences. The end groups of the copolyperoxides have been identified by 1H NMR as well as FTIR spectroscopic techniques. The thermal degradation of the copolyperoxides has been studied by differential scanning calorimetry, which confirms the alternating peroxide units in the copolyperoxide chain

Synthesis and mesogenic behavior of metal-containing liquid crystalline networks

A new hydroxy functionalized liquid crystalline (LC) polyazomethine has been synthesized by the solution polycondensation of a dialdehyde with a diamine. The polymer was characterized by IR, 1H-, and 13C-NMR spectroscopy. Studies on the liquid crystalline properties reveal the nematic mesomorphic behavior. This polymer functions as a polymeric chelate and forms a three-dimensional network structure through the metal complexation. Influence of various metals and their concentration on the liquid crystalline behavior of the network has been studied. Networks up to 30 mol % of the metal show LC phase transitions; above this the transitions are suppressed and the network behaves like an LC thermoset