Tailoring Copolymer Properties by Gradual Changes in the Distribution of the Chains Composition Using Semicontinuous Emulsion Polymerization
Autor: | María E. Hernández-Hernández, Francisco J. Aranda-García, Carlos F. Jasso-Gastinel, Luis J. González-Ortiz, Luis Octavio Sahagún-Aguilar, Alvaro H. Arnez-Prado, Fernando A. López-Dellamary Toral |
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Jazyk: | angličtina |
Rok vydání: | 2017 |
Předmět: |
Materials science
Polymers and Plastics Radical polymerization gradual composition changes Emulsion polymerization 02 engineering and technology mechanical properties 010402 general chemistry 01 natural sciences Article semicontinuous polymerization lcsh:QD241-441 chemistry.chemical_compound lcsh:Organic chemistry Polymer chemistry Copolymer Molecule free radical Acrylate copolymer Comonomer synergic performance General Chemistry Dynamic mechanical analysis 021001 nanoscience & nanotechnology 0104 chemical sciences composition distribution Chemical engineering Polymerization chemistry 0210 nano-technology |
Zdroj: | Polymers, Vol 9, Iss 2, p 72 (2017) Polymers Polymers; Volume 9; Issue 2; Pages: 72 |
ISSN: | 2073-4360 |
Popis: | To design the properties of a copolymer using free radical polymerization, a semicontinuous process can be applied to vary the instantaneous copolymer composition along the conversion searching for a specific composition spectrum of copolymer chains, which can be termed as weight composition distribution (WCD) of copolymer chains. Here, the styrene-n-butyl acrylate (S/BA) system was polymerized by means of a semicontinuous emulsion process, varying the composition of the comonomer feed to obtain forced composition copolymers (FCCs). Five different feeding profiles were used, searching for a scheme to obtain chains rich in S (looking for considerable modulus), and chains rich in BA (looking for large deformation) as a technique to achieve synergy in copolymer properties; the mechanostatic and dynamic characterization discloses the correspondence between WCD and the bulk properties. ¹H-nuclear magnetic resonance (¹H-NMR) analysis enabled the determination of the cumulative copolymer composition characterization, required to estimate the WCD. The static test (stress-strain) and dynamic mechanical analysis (DMA) were performed following normed procedures. This is the first report that shows very diverse mechanostatic performances of copolymers obtained using the same chemical system and global comonomer composition, forming a comprehensive failure envelope, even though the tests were carried out at the same temperature and cross head speed. The principles for synergic performance can be applied to controlled radical copolymerization, designing the composition variation in individual molecules along the conversion. |
Databáze: | OpenAIRE |
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