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A series of water-dispersible blocked polyisocyanates were synthesized from toluene 2,4-diisocyanate (TDI), isophorone diisocyanate (IPDI), dimethylol propionic acid, methyl ethyl ketoxime (MEKO), ethyl cellosolve (EC), and e-caprolactam (CL). The physical properties, such as the viscosity, pH, and storage stability, of the blocked-polyisocyanate adducts were measured. All aqueous dispersions of the blocked polyisocyanates showed good storage stability. The prepared blocked polyisocyanates were characterized by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry, and thermogravimetric analysis techniques. The FTIR confirmed that the ANCO groups of the original TDI and IPDI molecules were completely blocked by the blocking agents. The thermal analysis measurements revealed that both the blocked TDI-and IPDI-based polyisocyanates started to deblock at about 55-85 C. Compared to the CL-blocked polyisocyanates, the MEKOand EC-blocked polyisocyanates had lower thermal dissociation temperatures and faster deblocking rates. We also found that the initial deblocking temperatures of the TDI-based adducts were lower than those of the IPDI-based adducts. The water resistance and tensile properties of the composite films from the blocked-polyisocyanate crosslinkers and hydroxyl-polyurethane emulsion (HPUE) matrix were studied. The tensile strength increased and the elongation at break were lower in the composites compared to the pure HPUE film.

A novel macromolecular intumescent flame retardant (MIFR) was synthesized. Unsaturated polyester (UP) filled with MIFR as flame-retardant additive was prepared. The effects of MIFR on properties such as tensile strength, impact strength, flame-retardant behavior, thermal stability, and morphology of char were studied. Its flammability and burning behavior were characterized by UL 94 and limiting oxygen index. Twenty-four percent of MIFR were doped into UP to get 30.5% of limiting oxygen index and UL 94 V-0, whereas its tensile strength and the impact strength were decreased by only 7.2% and 7.0%, respectively. Activation energy for the decomposition of samples was obtained by using the Kissinger equation. The results for UP containing MIFR, compared with UP, show that the weight loss, thermal stability, and the decomposition activation energy decreased, and the char yield increased, showing that MIFR can catalyze decomposition and carbonization of UP to form an effective charring layer to protect the underlying substrate. J. VINYL ADDIT. TECHNOL., 00:000-000, 2014.

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We presented here a facile strategy for fabricating boronic acid-functionalized nanoparticles based on the complexation of phenylboronic acids in poly(3-methacrylamido phenylboronic acid) (PMAPBA) and glucose moieties in dextran via boronic acid-diol interactions. The formation of boronate crosslinked nanoparticles was confirmed by Fourier transform infrared spectrometry, thermal analysis, transmission electron micrographs, dynamic light scattering and UV spectrometry. The nanoparticles were well dispersed as individual, spherically shaped particles with an average size of 100 nm. The glucose-sensitivity was revealed by the swelling behavior of the nanoparticles at different glucose concentrations. Furthermore, insulin was encapsulated in the nanoparticles with a loading capacity up to 22%, and the structure of insulin had not been distorted in the loading procedure. The insulin release increased with the enhancement of the glucose level in the medium. More importantly, the nanoparticles had good cytocompatibility, as demonstrated by in vitro experiments. The facility of this strategy together with the high loading capacity, glucose-sensitivity and cytocompatibility of the produced nanoparticles should greatly boost their application in drug delivery.

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Poly(N-isopropyl acrylamide) (PNIPAAm)-graft-poly(ethylene oxide) (PEO) hydrogels crosslinked by poly(-caprolactone) diacrylate were prepared, and their microstructures were investigated. The swelling/deswelling kinetics and compression strength were measured. The relationship between the structure and properties of hydrogel are discussed. It was found that the PEO comb-type grafted structure reduced the thermosensitivity and increased the compression strength. The addition of poly(-caprolactone) (PCL) accelerated the deswelling rate of the hydrogels. Meanwhile, the entanglement of PCL chains restrained the further swelling of the network of gels. The PCL crosslinking agent and PEO comb-type grafted structure made the behavior of the hydrogels deviate from the rubber elasticity equations.