Viscoelastic properties of poly(styrene-co-vinylphosphonate) ionomers

Dynamic ionic behavior of gel-free diolefin rubber-based carboxylate ionomers prepared via olefin metathesis

Constructing dynamic ionic bonding interactions is acknowledged as an efficient strategy to improve the physical-mechanical characteristics of rubber materials, and to provide them with some novel features such as self-healing. However, currently reported grafting-modification approaches such as free-radical and anionic reactions inevitably induced the generation of rubber gels, which is unfavorable for their practical applications. In this work, we fabricated a gel-free carbonylated diolefin rubber based on the olefin metathesis reaction. Furthermore, a diolefin rubber-based ionomer was prepared through the complexation of carbonylated diolefin rubber and sodium hydroxide. Compared with pure diolefin rubber, the resultant ionomers exhibited a higher glass transition temperature (T_g), higher mechanical strength and higher damping properties. Moreover, these ionomers were provided with apparent self-healing behavior. This was primarily because of the increased dynamic ionic bonding interactions induced by the formation of multi-ion-pair cluster structures, a unique intermolecular interaction that exists in the ionomers. Consequently, the gel-free diolefin rubber-based ionomers offer some brand-new applications, such as artificial skin and high-performance "green" tires.

ZnCl2-mediated stereo- and chemoselective synthesis of vinylphosphonates

A highly chemo- and stereoselective synthesis of diethyl (E)-2-(alkylidene)-2-phosphonoacetonitriles via the Knoevenagel condensation reaction of carbonyl compounds with diethyl cyanomethylphosphonate in the presence of zinc chloride has been achieved. By the presented method, various E-isomers of arylmethylidene phosphonates rather than Horner-Wadsworth-Emmons olefination products were obtained in good to excellent yields. Their E configurations were determined by X-ray diffraction and NMR analyses. In addition, DFT calculations provided insights into the chemo- and stereoselectivity of the reaction.

Hydrophosphorylation of aliphatic alkynes catalyzed by CuNPs/ZnO for the synthesis of vinyl phosphonates. A DFT study on the reaction mechanism

A DFT study on the reaction mechanism for the synthesis of vinyl phosphonates catalyzed by CuNPs/ZnO. Essential role of the solvent and the catalyst support.

Cluster Morphology-Polymer Dynamics Correlations in Sulfonated Polystyrene Melts: Computational Study

Reaching exceptionally long times up to 500 ns in equilibrium and nonequilibrium molecular dynamics simulations studies, we have attained a fundamental molecular understanding of the correlation of ionomer clusters structure and multiscale dynamics, providing new insight into one critical, long-standing challenge in ionic polymer physics. The cluster structure in melts of sulfonated polystyrene with Na^{+} and Mg^{2+} counterions are resolved and correlated with the dynamics on multiple length and time scales extracted from measurements of the dynamic structure factor and shear rheology. We find that as the morphology of the ionic clusters changes from ladderlike for Na^{+} to disordered structures for Mg^{2+}, the dynamic structure factor is affected on the length scale corresponding to the ionic clusters. Rheology studies show that the viscosity for Mg^{2+} melts is higher than for Na^{+} ones for all shear rates, which is well correlated with the larger ionic clusters' size for the Mg^{2+} melts.

Direct synthesis of β-ketophosphonates and vinyl phosphonates from alkenes or alkynes catalyzed by CuNPs/ZnO

Ligand- and base-free direct synthesis of β-keto- and vinyl phosphonates catalysed by CuNPs/ZnO under air. Selectivity dependent on alkyne nature.