Normal Radical Polymerization Research Articles

New photoresponsive (meth)acrylate (co)polymers containing azobenzene pendant sidegroups with carboxylic and dimethylamino substituents—II. Synthesis and characterization of polymers and copolymers

The title (co)polymers, used for our investigations on their photoresponsive behaviour were obtained by free radical (co)polymerization. The monomer was either an acrylate or a methacrylate to which an azobenzene group, modified with a para-placed dimethylamino or a carboxylic pendant group, was attached with or without an aliphatic spacer. The acrylates were copolymerized with methylacrylate (MA) as comonomer, methacrylates with methylmethacrylate (MMA). The (co)polymerization conditions, the characterization of the synthesized (co)polymers and the results of kinetic experiments on some of the homopolymerizations are presented. In the latter we have found deviations from normal radical polymerization kinetics, which may be attributed to aggregation of the monomers.

Kinetics of Polymerization of Acrylamide in Aerosol OT W/O Microemulsions

Abstract Time dependence of the conversion of acrylamide (AAm) initiated with potassium peroxodisulfate (KPS) was examined at various [AAm] and [KPS] in W/O microemulsions of 1,4-bis(2-ethylhexyl) sodium sulfobutanedioate in cyclohexane media at 45 °C. The rate of polymerization (Rp) calculated from the conversion-time profiles yielded the following equation: Rp ∝ [AAm]1.0[KPS]0.5. From these values of reaction orders for AAm and KPS, it was found that the polymerization of acrylamide in W/O microemulsions can be regarded as normal radical polymerization and biradical termination between polymer radicals.

Polyreactions in ordered systems: Polymerization of octadecyl methacrylate in monolayers at the gas–water interface

AbstractThe ultraviolet‐initiated polymerization of octadecyl methacrylate (ODMA, octadecyl 2‐methyl‐2‐propenoate) as a monomolecular layer at the gas‐water interface was studied. The polymerization was carried out at 27°C at the nitrogen‐water interface; air inhibits the polymerization. At 27°C the ODMA monolayer exhibits three different states which were characterized by surface pressure‐area diagrams and by surface potential measurements. The ODMA monolayer was polymerized under constant surface pressure in the range between 0 and 10 dyne/cm. The polymerization was followed by recording the contraction of the film. The conversion was determined by comparison of the area per monomer unit during polymerization with the area of mixed monolayers formed from ODMA and poly‐ODMA as well as by infrared spectroscopy. The polymerization in the condensed state of the monolayer (at high surface pressure) is considerably faster than in the expanded state (at low surface pressure). As the polymer has a condensing effect on the monomer in the mixed monolayer, autocatalysis is suggested at low surface pressures. The resulting polymer was studied by x‐ray diffraction. The structure of the freshly collapsed film is determined by the conformation of the polymer at the interface; the data after crystallizing the same sample from the melt point to higher tacticity of the poly‐ODMA prepared in monolayers than that of poly‐ODMA prepared by normal radical polymerization in solution.