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A straightforward but effective approach to fabricate shape‐memory polyurethane thermosets by tailoring the soft phase composition of two‐ and four‐armed polycaprolactone (PCL) polyols is described. As the crystallization of the PCL soft phase has an effect on driving the self‐assembly of H‐bonds, a good balance of tensile performance and thermo‐healability can be achieved by regulating the ratio between PCL‐diol and PCL‐tetrol in the soft phase. The inferior ability of crystallization of the segments near the branching point gives rise to enhancement of the both overall healability and toughness of the network. Healings of punctured holes and cuts are assessed using optical microscopy (OM), field‐emission scanning electron microscopy (FE‐SEM), tensile analysis, and two‐electrode impedence characterization. The obtained network with the best healing behavior has a soft phase composition with the PCL‐diol/PCL‐tetrol molar ratio of 2/1, a tensile toughness of 64 MPa J−1 and a healing efficiency (estimated by recovery of tensile strength) of nearly 80%. Highlights: The composition of the soft phase of polyurethane networks was tailored.Two‐ and four‐armed polycaprolactones were used for the network structure.A good balance between mechanical and healing performance was obtained.Healing of complete cuts showed tensile strength recovery of nearly 80%. [ABSTRACT FROM AUTHOR]

A green, cost-effective, and simple capillary zone electrophoresis (CZE) method was developed and validated for simultaneous determination of chloramphenicol, methylparaben, and propylparaben in eye-drops. With sodium tetraborate as background electrolyte (BGE), the apparent mobilities of chloramphenicol, methylparaben, and propylparaben increased and analysis time reduced when pH of BGE increased from 8.5 to 10.0 and concentration of BGE decreased from 40 mM to 15 mM, but complete separation of chloramphenicol from other matrix components was achieved only with sodium tetraborate concentration at 30 mM or higher and at pH = 9.3 or lower. The most suitable electrophoretic conditions for the intended application were a 30 mM sodium tetraborate solution, pH 9.3 as BGE, working voltage set at 25 kV, and UV detection at 280 nm at the cathodic extremity of the capillary. The final method was validated and proved to be reliable for assay of chloramphenicol, methylparaben, and propylparaben in eye-drops.

Thermoresponsive shape memory poly(ε-caprolactone) (PCL) networks with readily tunable properties are prepared exploiting the facile UV-initiated thiol-ene methodology. PCLs with multiple pendant double bonds at both chain ends are used to cross-link with multi-thiol compounds via photo-initiated thiol-ene reactions. Mechanical and shape memory properties can be altered through changes in the number of alkene side groups at the PCL chain termini and thiol cross-linker structure. In parallel with structural investigation by spectroscopic techniques, the relationships between the composition and material properties are investigated. The PCL thermoset materials exhibit excellent thermoresponsive shape memory performance by changing the operation temperature below or above the melting temperature of crystalline PCL segments, which varies in the range of 34-40 °C, and the highest shape retention and recovery ratios can reach 98-100%. [ABSTRACT FROM AUTHOR]