POLYMERIZATION IN THE CRYSTALLINE STATE. II. ALKALI ACRYLATES AND METHACRYLATES

Journal Article · Thu Mar 01 04:00:00 EST 1962 · J. Polymer Sci.

DOI:https://doi.org/10.1002/pol.1962.1205716553· OSTI ID:4840444

Morawetz, H; Rubin, I D

Alkali acrylates and methacrylates were irradiated with gamma rays from a Co/sup 60/ source at -78 deg C and their subsequent polymerization was studied in vacuo in the temperature range 0 to 155 deg C. Potassium acrylate proved to be the most rapidly polymerizing solid monomer studied to date; it reacted at 0 deg C faster than the lithium salt at 101 deg C or the sodium salt at 120 deg C. The reaction rate of the acrylates decayed rapidly at low polymer yields which were, for long polymerization times, linear in the logarithm of time. The activation energy for the polymerization of potassium acry late was 16.7 kcal/ mole. Sodium methacrylate was more reactive than potassium methacrylate; the lithium salt of methacrylic acid was entirely inert. The sodium methacrylate polymerization had an initial accelerating phase. Studies of x-ray diffraction of the polymerizing potassium acrylate showed only minor changes in the diffraction pattern of the monomer, the size of the unit cell remaining almost unchanged. Poly(potassium acrylate) produced in the solid state showed four diffuse diffraction rings which were not observed in samples prepared from poly(acrylic acid) obtained by polymerizing a benzene solution of the monomer. The pronounced difference in the characteristics of the polymerization process of different salts of the same monomeric anion pointed to a control of the reaction by the geometry of the crystal lattice. The evidence suggests that the polymer lies in an amorphous phase but that the reactive ends of growing chains are anchored in the monomer lattice. Electron spin resonance spectra are similar for irradiated potassium acrylate and sodium methacrylate, but the potassium acrylate spectrum changes gradually from a three-peak to a single-peak structure when the sample is heated to 100 deg C, while the other two salts have spectra which are not affected by a similar heating cycle. The absence of the characteristic ESR spectrum of polymethacrylate radicals in irradiated sodium methacrylate suggests that under the experimental conditions used few of the primary radicals were able to initiate chains. A five-peak ESR spectrum was observed in irradiated sodium acrylate. (auth)

• Research Organization: Polytechnic Inst., Brooklyn
• NSA Number: NSA-16-018964
• OSTI ID: 4840444
• Journal Information: J. Polymer Sci., Journal Name: J. Polymer Sci. Vol. Vol: 57
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ACRYLATES
ACRYLIC ACID
ALKALI METALS
BENZENE
CHEMICAL REACTIONS
CHEMISTRY
COBALT 60
CRYOGENICS
CRYSTALS
DIFFRACTION
ELECTRONS
ENERGY
EXCITATION
EXPANSION
FREE RADICALS
GAMMA SOURCES
HEATING
IRRADIATION
LATTICES
LITHIUM COMPOUNDS
METHACRYLIC ACID
POLYMERIZATION
POLYMERS
POTASSIUM COMPOUNDS
PREPARATION
REACTION KINETICS
RESONANCE
SODIUM COMPOUNDS
SOLIDS
SOLUTIONS
SPECTRAL SHIFT
SPIN
TEMPERATURE
VACUUM
X RADIATION