The reversible addition fragmentation chain transfer (RAFT) polymerization of acrylamide (AM) in aqueous two-phase system was successfully carried out in polyethylene glycol (PEG) aqueous solution. Because of phase transition involved in the polymerization process, the ln([M]₀/[M])-time plots were indicated in two-stages significantly. Both the initial homogeneous polymerization and the subsequent heterogeneous polymerization were under good control. The effects of various synthesis parameters such as polymerization temperature, concentration of CTA, and initiator on RAFT polymerization behaviors have been investigated. Furthermore, the evolution process of the droplet morphologies after separation was examined by transmission electron microscope. The results showed that the nuclei were formed throughout the whole heterogeneous polymerization and stable sphere particles with an average size of about 1 μm were produced finally. More importantly, it was also found that the viscosity played a significant role in the stabilization of the dispersion of polymer particles. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43000.

Poor interfacial properties and uncontrollable phase morphology encountered during the fabrication of poly(butylene adipate-co-terephthalate) (PBAT)/thermal plastic starch (TPS) biocomposites, result unfortunately in low mechanical performances and thus limit its applications. Here an approach in terms of phase morphology controlling, i.e., extrusion compounding followed by oscillation shear injection molding (OSIM), is proposed to construct in situ TPS fiber and skin-core structure consisting of TPS fiber and droplet in skin layer, and spherical TPS in core layer, which tremendously benefits the mechanical properties. Specifically, the tensile strength, modulus and ductility for the biocomposites with various loadings of TPS, even when TPS loading as high as 55 wt %, outperform pure PBAT sample fabricated by conventional injection molding (CIM) with the increment of 51%, 308% in strength and modulus, respectively. Meanwhile, the elongation at breakage can maintain at 196%. The unprecedented establishment of high-performance PBAT/TPS biocomposites is in great need for potential applications, such as green packaging. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43312.

The UV-initiated RAFT polymerizations of a series of poly(ethylene glycol) dimethacrylates (PEGDMA) were investigated using differential scanning photocalorimetry (DPC) at room temperature. The rate of the RAFT system was much lower than that of a conventional free radical polymerization. A mild autoacceleration occurred as the addition reaction became diffusion controlled. The influence of the spacer length (CH₂CH₂O)_x between the vinyl moieties of the dimethacrylates on the polymerization kinetics was examined. The polymerization rate of PEGDMA decreased with an increased x value from 4 to 9, but it increased with a further increased x value from 9 to 14. Mechanical properties of the resulting polymers were also examined by dynamic mechanical analysis (DMA). It was concluded that the presence of the RAFT agent during polymerization of multifunctional monomers did not have an effect on the heterogeneity of the polymer network. In comparison with three different PEGDMAs, the PEGDMA with the longest spacer formed the most homogeneous networks with a lower crosslinking density. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Soluble, branched (methyl) methacrylate copolymers have been prepared via facile, one-step, batch solution free radical polymerizations taken to high conversion. Methyl methacrylate (MMA) or methacrylate has been copolymerized with the branching comonomer (BCM) using a trithiocarbonate (TTC) to inhibit gelation. The BCMs employed were tripropylene glycol diacrylate (TPGDA) and trihydroxymethylpropyl triacrylate (TMPTA). Soluble branched copolymers containing unreacted double bonds have been produced and characterized by ¹H-NMR spectroscopy. These two brancher monomers have been shown to produce regularly branched material with the small molar mass distributions in the presence of TTC. The results of DSC and Mark–Houwink constant α analyses support the production of the branched architectures. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

In the present work, the effectiveness of five trithiocarbonates (TTCs) as mediating agents in the reversible addition fragmentation chain transfer (RAFT) polymerization and photopolymerization of styrene (St) were investigated. The five TTCs including S,S′-bis(α, α′-dimethyl-α″-acetic acid) trithiocarbonate (TTC1), bis(2-oxo-2-phenyl-ethyl) trithiocarbonate (TTC2), 3-(2-carboxyethylsulfanylthiocarbonylsulfanyl)-propionic acid (TTC3), 2-(2-carboxyethylsulfanylthiocarbonylsulfanyl)propionic acid (TTC4), and 2-(2-carboxyethylsulfanylthiocarbonylsulfanyl)-2-methylpropionic acid (TTC5) were synthesized, in which the substitution patterns (groups Z and R) of the TTCs were varied. The dynamic behavior of TTC1, TTC2, TTC4, and TTC5-mediated polymerization of St was well described by pseudo first-order kinetics. In the presence of TTC1, TTC2, TTC4, and TTC5, the polydispersity indices changed with increasing conversion in the range of 1.10–1.25 typical for RAFT-prepared (co)polymers, and were well below the theoretical lower limit of 1.50 for a normal free radical polymerization. Transfer coefficients of TTCs in St polymerization at 70°C were estimated by using the Mayo method. Density functional theory calculations successfully predicted the effect of the structure of TTCs on the activity of RAFT agents in a qualitative manner. The calculated results for RAFT agents agreed well with the experimental results. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009