The morphology of emulsion polymerized latex particles
Under monomer starved feed conditions, emulsion polymerization of perdeuterated methyl methacrylate and styrene in the presence of preformed polymethylmethacrylate latexes resulted in particles with a core-shell morphology, as determined by small-angle neutron scattering (SANS) analysis for a hollow sphere. The locus of polymerization of the added deuterated monomer is therefore at the particle surface. In similar measurements a statistical copolymer of styrene and methyl methacrylate was used as seed particles for further polymerization of trideuteromethyl methacrylate. The resulting polymer latex was again shown to have a core-shell morphological structre as determined by SANS. SANS experiments were also undertaken on polystyrene latexes polymerized by equilibrium swelling methods, with deuterated polymer forming the first or second step. The experiments covered a molecular weight range of 6 x 10/sup 4/ < M < 6 x 10/sup 6/ g/mol. For M > 10/sup 6/ the molecular weights are consistent with the experimental errors, indicating that the deuterium labeled molecules are randomly distributed in the latex. These results led to the finding that the polymer chains were constrained in the latex particles by factors of 2 to 4 from the relaxed coil dimensions. For M < 10/sup 6/ g/mol SANS gave zero angle scattering intensities much higher than expected on the basis of a random distribution of labeled molecules. Several models were examined, including the possible development of core-shell structures at lower molecular weights. 25 refs., 6 figs., 3 tabs.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Lehigh Univ., Bethlehem, PA (USA); Hercules, Inc., Wilmington, DE (USA). Hercules Research Center; Eastman Kodak Co., Rochester, NY (USA)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 5679915
- Report Number(s):
- CONF-871190-1; ON: DE88002672
- Resource Relation:
- Conference: Workshop on neutron scattering, Los Alamos, NM, USA, 3 Nov 1987; Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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LATEX
MOLECULAR STRUCTURE
MORPHOLOGY
POLYMERIZATION
PMMA
POLYSTYRENE
COPOLYMERS
DEUTERIUM
DEUTERIUM COMPOUNDS
EMULSIONS
EQUATIONS
METHYL METHACRYLATE
MOLECULAR WEIGHT
MONOMERS
NEUTRON DIFFRACTION
PARTICLE SIZE
SMALL ANGLE SCATTERING
STYRENE
SURFACES
SUSPENSIONS
ALKYLATED AROMATICS
AROMATICS
CARBOXYLIC ACID ESTERS
CHEMICAL REACTIONS
COHERENT SCATTERING
COLLOIDS
DIFFRACTION
DISPERSIONS
ELASTOMERS
ESTERS
HYDROCARBONS
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
MATERIALS
METHACRYLIC ACID ESTERS
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC POLYMERS
PETROCHEMICALS
PETROLEUM PRODUCTS
PLASTICS
POLYACRYLATES
POLYMERS
POLYOLEFINS
POLYVINYLS
RUBBERS
SCATTERING
SIZE
STABLE ISOTOPES
SYNTHETIC MATERIALS
360602* - Other Materials- Structure & Phase Studies