Synthesis of gradient copolymers with simultaneously tailor‐made chain composition distribution and glass transition temperature by semibatch ATRP: From modeling to application

Abstract

Recent studies have demonstrated that gradient copolymers exhibit unique thermal properties. Although these properties can be determined by copolymer composition, other factors such as chain and sequence lengths and their distributions can also influence them. Accordingly, the synthesis of gradient copolymers requires simultaneously tailor-made chain structure and thermal properties. In this work, we carried out a systematic study on the preparation of poly(methyl methacrylate-grad-2-hydroxyethyl methacrylate) [poly(MMA-grad-HEMA)] with synchronously tailor-made chain composition distribution and glass transition temperature (Tg) through semibatch atom transfer radical polymerization. First, a comprehensive model for simultaneously predicting gradient copolymer microstructure and Tg was presented using the concept of pseudo-kinetic rate coefficients and Johnston equation. The model was validated by comparing simulation results with the classical reference data. Furthermore, the model was used to guide the experimental synthesis of the poly(MMA-grad-HEMA) gradient copolymers potentially as excellent damping material. The thermal properties of these gradient copolymer samples were evaluated. (c) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012National Natural Science Foundation of China [20406016, 21076171

Electrochemical Atom Transfer Radical Polymerization in Miniemulsion with a Dual Catalytic System

“…24–31 Moreover, ATRP can control copolymer composition (e.g., block and gradient copolymers), topology (e.g., stars and bottlebrushes), and location of functional groups (e.g., α -, ω -, or both, periphery or core functional stars, and side-group functional brushes). 32–37 A wide range of monomers is available for ATRP, including (meth)acrylates, styrenes, acrylamides, acrylonitrile, and methacrylic acid. 38–42 …”

Understanding Toughness in Bioinspired Cellulose Nanofibril/Polymer Nanocomposites

“…a comparison of the tensile curves between CNF nanopapers and the nanocomposites at35 and 50 wt% of polymer content, respectively. Furthermore, we calculate the work of fracture or toughness (U t ) from the area under the tensile σ-ε curves for all compositions(Figure 5c).While the relationship between U t and polymer content for an individual set of nanopapers for one copolymer is fairly linear (orange-red vertical gradient), the overall trend inverts upon incorporation of EG units and when going from high to low T g .…”

Gradient Sequence π-Conjugated Copolymers

“…To date, most gradient sequence copolymers have been synthesized from vinyl-containing monomers (37)(38)(39)(40). These reports have demonstrated that the gradient sequence materials exhibit unique properties compared to their block, random and alternating counterparts.…”