Diisopropyl Fumarate Research Articles

Radical high polymerization of dialkyl fumarates with bulky substituents leading to less-flexible rod-like polymers

Dialkyl fumarates with bulky ester substituents were found to homopolymerize easily in the presence of 2,2′-azobisisobutyronitrile. Among these fumarates, diisopropyl fumarate (DiPF) homopolymerized with the above initiator (20mmol/1) in bulk at 40∼60°C to give homopolymers with number-average molecular weight of 70 000∼221 000. Similar results were also observed for di-t-butyl fumarate (DtBF) and Methyl-t-butyl fumarate (MtBF). These polymers were found to consist of a lessflexible rod-like (polyalkoxycarbonylmethylene) from the molecular model and the solution property measurements. These polymers which were colorless powders did not melt before thermal degradation, but they were soluble in most organic solvents. From TG thermogram observed in a nitrogen atmosphere, the DiPF polymer showed T(init.)=257°C and T(max.)=316°C, and the main degradation products at 400°C, except gaseous materials, were isopropanol and DiPF monomer (32:1 in mole ratio). These thermal degradation behavior was different from that for the polymers of DtBF and MtBF which underwent degradation from lower temperatures like 190°C. Acid and alkaline hydrolyses of the DiPF polymer were observed to occur very hardly.

Polymer Design by Iniferter Technique in Radical Polymerization: Synthesis of AB and ABA Block Copolymers Containing Random and Alternating Copolymer Sequences

The iniferter technique was applied to synthesis of the AB and ABA block copolymers containing various random and alternating copolymer sequences. Benzyl N,N-diethyldithiocarbamate (BDC), p-xylylene bis(N,N-diethyldithiocarbamate) (XDC) and 1,2,4,5-tetrakis(N,N-diethyldithiocarbamylmethyl)benzene (DDC) were used as mono-, bi- and tetrafunctional photoiniferters, respectively. The photopolymerizations with BDC and XDC proceeded via a living radical mechanism, and gave soluble mono- and bifunctional polymers (photoiniferters), respectively. However, DDC induced living radical polymerization of styrene with gelation. When various polymers and copolymers obtained by BDC and XDC were used as polymeric photoiniferters, the AB and ABA block copolymers containing random copolymer sequences were obtained in high yields. Similarly the alternating copolymerization of isobutyl vinyl ether with maleic anhydride in the presence of the alternating copolymers such as styrene and diisopropyl fumarate, which were obtained by BDC and XDC, as polymeric photoiniferters was found to give the AB and ABA block copolymers consisting of alternating copolymer sequences. DDC and the polymers and copolymers obtained by DDC could also act as an excellent cross-linking agent.