The cationic polymerization of isobutylene (IB) was systematically studied in a 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim][PF6]) ionic liquid at −10 °C.

Styrene cationic polymerizations initiated by cumyl alcohol (CumOH)/B(C6F5)3 are systematically studied in aqueous suspension and emulsion. Theoretical calculations and experimental research suggest that CumOH/B(C6F5)3 has higher initiating activity than H2O/B(C6F5)3. During emulsion polymerization of styrene, molecular weight and polymerization rate decrease with the addition of surfactants. These polymerization processes share the same features. Specifically, all elemental reactions (initiation, propagation, and termination) in aqueous media occur at the droplet interface. End structure analysis indicates that chain transfer reactions to water and a‐proton elimination and chain transfer reactions to monomer occur. The possible mechanism for the styrene cationic polymerization in aqueous media is demonstrated.

Aqueous cationic polymerizations of vinyl ethers (isobutyl vinyl ether (IBVE), 2-chloroethyl vinyl ether (CEVE), and n-butyl vinyl ether (n-BVE)) were performed for the first time by a CumOH/B(C6F5)3/Et2O initiating system in an air atmosphere. The polymerization proceeded in a reproducible manner through the careful design of experimental conditions (adding initiator, co-solvents, and surfactant or decreasing the reaction temperature), and the polymerization characteristics were systematically tested and compared in the suspension and emulsion. The significant difference with traditional cationic polymerization is that the polymerization rate in aqueous media using B(C6F5)3/Et2O as a co-initiator decreases when the temperature is lowered. The polymerization sites are located on the monomer/water surface. Density functional theory (DFT) was applied to investigate the competition between H2O and alcohol combined with B(C6F5)3 for providing a theoretical basis. The effectiveness of the proposed mechanism for the aqueous cationic polymerization of vinyl ethers using CumOH/B(C6F5)3/Et2O was confirmed.

The codling moth Cydia pomonella is a major pest of global significance impacting pome fruits and walnuts. It threatens the apple industry in the Loess Plateau and Bohai Bay in China. Sterile insect technique (SIT) could overcome the limitations set by environmentally compatible area-wide integrated pest management (AW-IPM) approaches such as mating disruption and attract-kill that are difficult to suppress in a high-density pest population, as well as the development of insecticide resistance. In this study, we investigated the effects of X-ray irradiation (183, 366, 549 Gy) on the fecundity and fertility of a laboratory strain of C. pomonella, using a newly developed irradiator, to evaluate the possibility of X-rays as a replacement for Cobalt60 (60Co-γ) and the expanded future role of this approach in codling moth control. Results show that the 8th-day is the optimal age for irradiation of male pupae. The fecundity decreased significantly as the dosage of radiation increased. The mating ratio and mating number were not influenced. However, treated females were sub-sterile at a radiation dose of 183 Gy (20.93%), and were almost 100% sterile at a radiation dose of 366 Gy or higher. Although exposure to a radiation dose of 366 Gy resulted in a significant reduction in the mating competitiveness of male moths, our radiation biology results suggest that this new generation of X-ray irradiator has potential applications in SIT programs for future codling moth control.

Ionic liquids have been extensively investigated as clean solvents for chain polymerization reactions, such as radical polymerization, anionic polymerization, and cationic polymerization. However, the low solubilities of the monomers in ionic liquids often impede the efficiency of these reactions. In this study, the solubilities of two typical vinyl monomers, namely, p-methylstyrene (p-MeSt) and isobutyl vinyl ether (IBVE) were studied in 1750 possible ionic liquids (combinations of 50 cations with 35 anions) by the conductor-like screening model for real solvents. The effects of the cation structures, anion structures, and ion chain length on the solubility were systemically studied. The interaction energies and σ profiles were also employed to explain major factors affecting solubility. The results revealed that a larger size of the nonpolar region of the cation or anion results in higher solubilities for p-MeSt and IBVE, as does a longer alkyl chain in cation or anion. In this study, a theoretical method for selecting ionic liquids for chain polymerization was established.

The co-initiator B(C6F5)3 first complexed with ether. Then the complex deprives the OH− of CumOH at the water–oil interface, and initiates the polymerization of p-methylstyrene at the interface.

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