Mechanical Performance of Styrene-2-Ethylhexyl Acrylate Polymers Synthesized by Semicontinuous Emulsion Polymerization Varying Feed Composition

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

“…Additionally, as stated in this work, the correlation between WCD profiles and the mechanical properties above described using FRP reactions (establishing the structure characteristics required for synergic behavior) has an equivalent with controlled radical polymerization (CRP). Recently, for the S/BA system using also a semicontinuous emulsion process with a multistage feeding technique [18,19,20]), Guo et al tested two types of gradient copolymers obtained by CRP that exhibited yielding and elastic deformation [24], whose copolymer chains composition varied from one component to the other, according to their former report [25]. Although they did not present a discussion about their behavior related to the specific structures of those gradient copolymers, the explanation for that behavior is in accordance with the synergic contribution of the components proven here (as it was also demonstrated in chemical blends); the presence of long segments of each one of the components along with transition chain segments of intermediate compositions of monomers A and B in between each molecule, should lead to the optimization of polymer properties.…”

“…All latexes were dried by evaporation at room temperature; the collected high molecular weight polymers (such as the ones reported before [18,19,20]), were used to prepare samples by compression molding (Schwabenthan polystat 200T) to carry out all mechanical tests. Stress-strain measurements were performed at 25 °C following the procedure of the American Society for Testing Materials (ASTM D638, samples Type IV, crosshead speed: 0.0083 cm/s; Universal testing machine SFM10).…”

“…Additionally, with a gradual variation in feeding composition, the formation of chains with intermediate compositions of monomers A and B can also be attained; such chains may serve as compatibilizers to reduce the tendency to separate the polymer bulk into two phases. With that aim, using the styrene-2-ethylhexyl acrylate system with a seeded multistage semicontinuous emulsion process, promising results were reported years ago using linear feeding profiles for the comonomers with variations in global composition [18]; besides, seed type or particle size may also be varied [19]. If the cumulative composition of the copolymer chains is followed along the reaction and used to estimate the WCD of the copolymer bulk, the copolymer properties can be correlated to that composition spectrum.…”

A Methodology Towards Mechanical Properties Optimization of Three-Component Polymers by the Gradual Variation of Feed Composition in Semi-Continuous Emulsion-Free Radical Polymerization

“…In fact, the great potential to design the properties of a copolymer using that method was demonstrated, disclosing the different types of stress-strain behavior that can be obtained by variations in the feeding profiles while maintaining constant the global copolymer composition [7]. Briefly, the high modulus along with significant values in ultimate deformation that can be obtained denote that a synergistic performance can be achieved with that methodology [8,9].…”

“…Based on the former reasonings relative to the effects obtained by forcing the copolymers' composition [1,[6][7][8][9], in this work, a methodology for the synthesis of a three-component polymer material is proposed, using a seeded, semi-continuous free-radical emulsion polymerization aimed at changing the moduli and deformation capacity to improve toughness (i.e., mechanical properties optimization) with respect to the material formed by an industrial method [17], using the styrene (S), n-butyl acrylate (BA), and 4-vinylbenzyl chloride (VBC) system, where the three components are sequentially fed by pairs, using S as the common monomer.…”