(180l) Model-Based Monomer Feeding Strategies On Tailoring Styrene/Butyl Acrylate Copolymer with Controlled Sequence Distribution Via RAFT Miniemulsion Polymerization

Model-based Monomer Feeding Strategies on Tailoring Styrene/Butyl
Acrylate Copolymer with Controlled Sequence Distribution via RAFT Miniemulsion
Polymerization

Xiaohui Li¹,
Wen-Jun Wang¹, Bo-Geng Li¹,
and Shiping Zhu²

¹ State Key Laboratory of Chemical
Engineering, Institute of Polymer and Polymerization Engineering, Department of
Chemical & Biological Engineering , Zhejiang University, Hangzhou,
Zhejiang, China 310027

²Department
of Chemical Engineering, McMaster University, Hamilton, Canada L8S 4L7

Abstract Copolymer chain sequence distribution (CSD) plays an important role in
tuning material properties.  The
advent of controlled/living free radical polymerization (CLRP) has opened an
alternative opportunity to precisely control CSD.  However, it is changeling to achieve a
defined CSD control on copolymers during CLRP (mini)emulsion
copolymerization.  In this work, a
kinetic model for reversible addition-fragmentation chain transfer (RAFT)
miniemulsion copolymerization was developed.  The model was confirmed with the
experimental results of RAFT miniemulsion copolymerization of styrene (St) and
butyl acrylate (BA).  The
3-benzyltrithiocarbonyl propionic acid and potassium persulfate were
respectively used as a chain transfer agent and an
initiator, while sodium dodecyl sulfate served as a surfactant and hexadecane
performed as a costabilizer.  The
conversions, molecular weights and distribution, numbers
of nucleation particles, average numbers of free radical per particle, and copolymer
compositions could be predicted using the model.  The model was further combined with a
semi-batch reactor model.  A
model-based monomer feeding strategy was thus developed to tailor St/BA copolymers
with precisely designed CSD.  Series
of St/BA copolymers having uniform and linear gradient structures were
successfully synthesized.  The glass
transition behaviors of the tailor-made St/BA copolymers were also
investigated.

This work is
financially supported by National Natural Science Foundation of China (Key
Grant 20936006, Grant 21074116), Chinese State Key Laboratory of Chemical
Engineering at Zhejiang University (Grants SKL-ChE-08D02 and SKL-ChE-12T05),
and the Program for Changjiang Scholars and Innovative Research Team in
University in China (IRT0942).