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Tailoring Copolymer Properties by Gradual Changes in the Distribution of the Chains Composition Using Semicontinuous Emulsion Polymerization

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Chemical Engineering Department, Universidad de Guadalajara, 44100 Guadalajara, Mexico
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Chemistry Department, Universidad de Guadalajara, 44100 Guadalajara, Mexico
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Author to whom correspondence should be addressed.
Academic Editor: Graeme Moad
Polymers 2017, 9(2), 72; https://doi.org/10.3390/polym9020072
Received: 21 December 2016 / Revised: 31 January 2017 / Accepted: 13 February 2017 / Published: 22 February 2017
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. View Full-Text
Keywords: copolymer; free radical; mechanical properties; semicontinuous polymerization; composition distribution; gradual composition changes; synergic performance copolymer; free radical; mechanical properties; semicontinuous polymerization; composition distribution; gradual composition changes; synergic performance
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MDPI and ACS Style

Jasso-Gastinel, C.F.; Arnez-Prado, A.H.; Aranda-García, F.J.; Sahagún-Aguilar, L.O.; López-Dellamary Toral, F.A.; Hernández-Hernández, M.E.; González-Ortiz, L.J. Tailoring Copolymer Properties by Gradual Changes in the Distribution of the Chains Composition Using Semicontinuous Emulsion Polymerization. Polymers 2017, 9, 72.

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