An investigation of the radiation polymerization of methyl methacrylate-kaolin clay composites

"A kinetic and characterization study has been made on the effects of gamma-rays (Co⁶⁰) on the polymerization of a 50-50 weight mixture methyl methacrylate (MMA) kaolin clay system. The effect of dose rate (7.35 - 24.9 rads per second), temperature (25 to 75ºC) and total dose on the percentage conversion of monomer to polymer was studied. The rate of formation of polymer at 25ºC in the composite system was found to be faster when compared to a bulk MMA system at the same experimental conditions. This acceleration showed that the clay had a catalytic effect on the formation of polymer. The effect decreased as temperature increased. Rate data and apparent activation energies are reported. Two types of polymethylmethacrylate (PMMA) were formed in the composite. One type was called homopolymer and could be removed from the composite by extraction with organic solvents. The other type was called inserted polymer and could only be removed by dissolving the clay matrix with hydrofluoric acid. Characterization studies showed that the homo and inserted polymer exhibited the following characteristics: 1. NMR spectra showed that both polymers had increased isotacticity as compared to bulk polymer 2. the viscosity average molecular weights of the homopolymer ranged from (0 .4 x 10⁶ to 5 x 10⁶) depending upon the dose rate, temperature and total dose received. 3. gel permeation chromatography studies confirmed the increase of molecular weight for the homopolymer and showed the same peak molecular weights and distribution for the inserted polymer. 4. infrared spectroscopy showed no differences in the structure of either type of polymer. X-ray, particle size gravimetric thermal analysis (DTA-TGA) and surface area measurements were used to characterize the clay. Mechanical tests, DTA-TGA and scanning electron microscopy were used to characterize the entire composite. A discussion on the potential uses of PMMA-kaolin clay composites is presented along with suggested future work in this area of research"--Abstract, pages ii-iii.

Name thesis:degree_name

Ph. D. in Chemical Engineering

Grantor

University of Missouri--Rolla

Year dc:date.available

2016

Author dc:creator

• Beeson, James Jackson

• Chemical Engineering

Repository record dc:identifier

https://scholarsmine.mst.edu/doctoral_dissertations/2073

OAI identifier oai:identifier

oai:scholarsmine.mst.edu:doctoral_dissertations-3075