Seeded Semibatch Emulsion Copolymerization of n-Butyl Acrylate and Methyl Methacrylate

Abstract

The kinetics and polymer microstructure of the seeded semibatch emulsion copolymerization of n-BA/MMA were investigated in this work. Free monomer concentration was determined online by means of FT-Raman spectrosocopy. The kinetics, gel fraction, and molecular weight distribution were determined for several semibatch reactions of different monomer composition. The experiments show that, when the amount of MMA in the recipe was increased (from 90/10 to 50/50 n-BA/MMA by moles), the instantaneous conversion increased, whereas the gel content decreased and the sol molecular weight exhibited no defined trend. A mathematical model was used to analyze the experimental data.

Independent control of sol molar mass and gel content in acrylate polymer/latexes

“…Copolymerization of butyl acrylate with styrene [12] and methyl methacrylate [13] led to a decrease of the gel fraction for increasing concentrations of these comonomers (10 wt% of St or MMA reduced gel content to almost nil). On the other hand, the sol molar mass increased with the comonomer concentration.…”

Unexpected Crosslinking During Acetoacetoxy Group Protection on Waterborne Crosslinkable Latexes

“…In order to shed some light on this issue, the Michael addition reaction was simulated. For this purpose, the mathematical model developed by Elizalde et al30 for the seeded emulsion polymerization of BA/MMA was updated. The model was modified to account for the Michael reaction between AcAc functional groups and TDBs in a second stage (different to that of polymerization) of ammonia addition.…”

“…On the other hand, the initial amount of AAEMA for the simulation of the effect of the Michael addition reaction on the gel content (stage 2) was considered that of the formulation. The AAEMA consumed during the Michael addition reaction was computed as In the original model30, the gel content was calculated by the difference between the total amount of polymerized monomer units and the monomer units in the lower polymer chain generations (the model used a modified numerical fractionation technique31,32). The computation of the moments of the dead polymer chains was modified to account for the Michael addition reaction by including the following reaction in the kinetic scheme where M i is a dead chain of length i .…”

The influence of the polymerization on properties of an ethylacrylate/2-ethyl hexylacrylate pressure-sensitive adhesive suspension

“…Inherent properties, such as copolymer composition and microstructure, MW and MWD are among the most influential parameters affecting the PSA properties [3]. An important problem regarding the use of the acrylic monomer system is the formation of a gel phase during the polymerization process [5]. Recent studies show that the acrylate chain-growth kinetics is complicated by the intermolecular and intramolecular (backbiting) transfer to polymer and this process leads to formation of gel phase in the adhesive [6][7][8][9].…”