Radical Polymerization Of Macromonomers Research Articles

Synthesis of Grafted Biodegradable Poly(ε-caprolactone) as Antibacterial and Antifungal Agent

Graft copolymer containing ester and amide linkages was synthesized by ring opening polymerization of e-caprolactone, followed by reaction with acrylamide and synthesis of macromonomer and further radical polymerization of macromonomer. The synthesized graft copolymer was characterized and its bactericidal and fungicide degradation efficiency was examined. It was shown that biodegradation of the graft copolymer depends on the microorganism and the molecular organization of the polymer.

Effect of the functionality of junctions on the elasticity of polymacromonomer networks: Computer simulation

The elastic properties of polymer networks formed via the radical polymerization of macromonomers with two polymerizable end groups are studied via computer simulation. It is shown that variation in the average functionality of network junctions, favg, in a wide range (∼5–55) leads to a significant change in the shear modulus of the network. According to experiments with real networks (gels of poly(ethylene oxide) macromonomers), the shear modulus increases as favg increases. This effect is not due only to a decrease in the fluctuations of positions of network junctions. The main cause of the increase in the modulus is that the modulus component due to interaction between polymer chains (entanglements) increases as the functionality of junctions in the investigated networks increases. The conclusion is made that these networks gain entanglements during the formation of network junctions with high functionality rather than inherit them from the solution of macromonomer chains.

Rodlike Macromolecules through Spatial Overlapping of Thiophene Dendrons

Two novel dendritic macromonomers 7 and 8 functionalized with electroactive conjugated thiophene oligomers were synthesized by stepwise cross-coupling reactions and the introduction of a vinyl group at the focal point. Both macromonomers were polymerized into dendronized polymers 9 and 10 by using a radical polymerization method. The photophysical and redox behaviors of dendronized polymers 9 and 10 are significantly different from those of the corresponding macromonomers. This difference may result from the spatial overlapping of thiophene dendrons through π-π interactions when the dendrons are connected to a polymer backbone. The dendronized polymers can organize into large-area two-dimensional sheets with a thickness of 4.8 nm. Polymer 9, which has all-dendritic thiophene side chains, exhibited enhanced conductivity by partial doping with iodine or nitrosonium tetrafluoroborate (NOBF(4)). The novel amphiphilic dendronized polymer 15 was synthesized by the atom-transfer radical polymerization of macromonomer 7 from a poly(ethylene glycol) (PEG) macroinitiator and was found to have a self-organized structure in water.

ESR study on radical polymerization and its application to microemulsion systems

Well-resolved electron spin resonance (ESR) spectra of propagating radicals of vinyl and diene compounds were observed in a single scan by a conventional CW-ESR spectrometry without the aid of computer accumulation and the specially designed cavity and cells Although solvents which could be used for ESR measurements were restricted to nonpolar solvents, such as benzene, toluene, and hexane, new information on dynamic behavior and reactivity of the propagating radicals in the radical polymerization of vinyl and diene compounds were obtained. Thus, values of propagation rate constants (k p ) for vinyl and diene compounds were determined by an ESR method. Some of the k p values were in a fair agreement with those obtained by a pulsed laser polymerization (PLP) method. Furthermore, polymer chain effect on apparent k p was clearly observed in the radical polymerization of macromonomers and in the microemulsion polymerization. In ESR measurement on inclusion polymerization system, important information on the origin of the 9-line spectrum observed in the radical polymerization of methacrylate propagating radicals was obtained.

End-group analysis of polymacromonomer formed in the radical polymerization of styrene-type PMMA macromonomers by using 2H NMR spectroscopy

Isotactic (iso-) and syndiotactic (syn-) poly(methyl methacrylate) (PMMA) macromonomers having styrene group as a polymerizable function were polymerized with perdeuterated 2,2′-azobisisobutyronitrile in toluene at 60°C. The resultant polymacromonomers were analyzed by 2H NMR spectroscopy to determine the number of initiator fragment in a polymacromonomer chain (N) and initiator efficiency (f). The N values were less than unity (0.50∼0.72), indicating the chain transfer reaction to occur in the radical polymerization of macromonomer. The f values were 0.18∼0.28 and much smaller than that for styrene polymerization (0.5∼0.7). Iso-macromonomer gave larger N and f values than syn- one, suggesting that the tacticity of macromonomer affects the reaction pathway probably owing to the difference in chain mobility between iso- and syn-PMMA chains.