Synthesis and characterization of styrene‐butyl acrylate polymers, varying feed composition in a semicontinuous emulsion process

Abstract

Two-stage polymerization has been used to improve properties of two-component polymers. In this work, a semicontinuous emulsion process varying feed composition along the reaction is used to produce copolymer chains of different composition as conversion proceeds. Polymer composition and evidence of branching were determined by 1 H-NMR. Polymer molecular weight values determined by GPC are beyond the range where mechanical properties depend on molecular weight. Mechanodynamic properties show a copolymer type behavior with a synergistic effect around the 50/50 styrene/butyl acrylate composition ratio. For such composition, mechanical performance superiority of variable composition copolymer with respect to two-stage polymer was confirmed with stress-strain tests carried out at several temperatures.

Redox initiation in semicontinuous polymerization to search for specific mechanical properties of copolymers

“…Nevertheless, FCC synthesis has been performed using thermal decomposition initiators at 70°C, to get a convenient radicals generation rate, and be able to maintain an adequate polymerization rate for moderate or long reaction times (4-12 h), to then avoid an excessive monomer accumulation in the polymerization locus (18)(19)(20). This initiation mode usually requires long times for the polymerization process, which involves high energy costs.…”

Sequence Distribution and Cumulative Composition of Gradient Latex Particles Synthesized by a Power-Feed Technique

“…Various techniques have already been explored to precisely control these chain tailor-made structures, − including both innovative polymerization method, such as nitroxide mediated polymerization (NMP), , atom transfer radical polymerization (ATRP), − reversible addition–fragmentation chain transfer polymerization (RAFT), − and single-electron transfer and single-electron transfer degenerative chain transfer living radical polymerization. , More recently, the combination of controlled/living radical copolymerization (CLRcoP) with a specific polymerization program has been widely utilized to achieve that purpose and the synthesized copolymer structures are now theoretically and practically fine-tuned by combining ATRP or RAFT with the appropriate polymerization program. − Since its particular “living” intrinsic of CLRcoP, the synthesized polymer chain, without chain transfer and termination, would be subject to a gradient structure in a series of identical polymer chains. However, the widely used transition-metal catalysts limit the application in polymers, since catalysts are expensive and hard to remove from the polymers, resulting in changes in electronic and mechanical properties of final polymer product, as well as their color.…”