ISSN:
0032-3888
Keywords:
Chemistry
;
Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Styrene/butyl acrylate copolymers with layer morphology were synthesized using an emulsion copolymerization process, The kinetic parameters studied include monomers composition, initiator and transfer agent content, feeding time, and monomer addition sequence. The final product consists of a homopolymer nucleus surrounded by concentric shells of copolymers with different composition; the initial composition is quite rich in the monomer that forms the nucleus while the process ends with an enriched layer of the second homopolymer. Since the middle copolymer layer tends to increase the compatibility among the original homopolyers, we expected to have a set of core-shell products with completely different properties. However, the experimental results showed that this was not the case. The composition effect on the viscoelastic properties shows, on one hand, that an increase in the butyl acrylate content lowers the elastic response of the final product, and on the other hand, that the elasticity increases with copolymer content. As the initiator content in the reaction media increases, the viscosity of the coreshell products decreases because of the existence of a media flooded with free radicals. If the butyl acrylate is first added, a graft polymerization is favored because of the polar nature of this homopolymer and, therefore, the molecular weight level increases.
Additional Material:
13 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pen.760270612
