Hyperbranched Polyurethane Acrylate Applied to UV Curable Flame Retardant Coatings

UV curable hyperbranched prepolymers based on amine-ester, ester-amide and ether-amide started with AB_2-type monomers have been prepared by the authors. A series of work on allyl ether maleate hyperbranched polyesters for UV curing coatings by Hult and his colleagues has been reported. However, the UV cured films from those materials are all flammable when attached to fire without addition of flame retardants.

Lithium bis(trifluoromethanesulfonyl)imide blended in polyurethane acrylate photocurable solid polymer electrolytes for lithium-ion batteries

The increased demand of electronic devices promotes the development of advanced and more efficient energy storage devices, such as batteries. Lithium-ion batteries (LIBs) are the most studied battery systems due to their high performance. Among the different battery components, the separator allows the control of lithium ion diffusion between the electrodes. To overcome some drawbacks of liquid electrolytes, including safety and environmental issues, solid polymer electrolytes (SPEs) are being developed. In this work, a UV photocurable polyurethane acrylate (PUA) resin has been blended with lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) up to 30 wt% LiTFSI content to reach a maximum ionic conductivity of 0.0032 mS/cm at room temperature and 0.09 mS/cm at 100 ℃. Those values allowed applying the developed materials as photocurable SPE in Swagelok type Li/C-LiFePO_(4) half-cells, reaching a battery discharge capacity value of 139 mAh.g^(−1) at C/30 rate. Those results, together with the theoretical studies of the discharge capacity at different C-rates and temperatures for batteries with LiTFSI/PUA SPE demonstrate the suitability of the developed photocurable SPE for LIB applications.

PROPERTIES AND MORPHOLOGY OF UNSATURATED POLYESTER/ACRYLATE-TERMINATED POLYURETHANE/ORGANO-MONTMORILLONITE NANOCOMPOSITES

Unsaturated polyester resin （UPR）/acrylate-terminated polyurethane （ATPU）/organo-modified montmorillonite （OMMT） nanocomposites were prepared by the in situ intercalative polymerization method. Samples were prepared by the sequential mixing, i.e. mixture of the ATPU and styrene （S） and OMMT were prepared in the first step; UPR was then added to the pre-intercalates of ATPU/S/OMMT. Results indicate that the mechanical properties and thermal properties of UPR/ATPU/OMMT nanocomposites greatly depend on the amount of ATPU and OMMT. Results show that the addition of ATPU could increase the impact strength of UPR/ATPU composites, but the tensile strength, flexural strength and heat resistance of the materials are obviously decreased. When the weight ratio between UPR, ATPU and OMMT were 82：15：3, the impact strength and heat distortion-temperature of nanocomposite were greatly improved, meanwhile there was little change for other properties of the nanocomposites. The synergistic enhancement effects of ATPU and OMMT on the composites were observed. The structures and morphology of the composites were investigated by X-ray diffraction, scanning electron microscopy and transmission electron microscopy.

Plasma-enhanced interfacial engineering of FeSiAl@PUA@SiO_(2)hybrid for efficient microwave absorption and anti-corrosion

Microwave absorption materials are prone to degradation in extremely humid and salty environments,and it is still challenging to develop a dense and firm interface to protect microwave absorbers.Herein,a robust FeSiAl@PUA@SiO2(PUA:acrylic polyurethane)gradient hybrid was prepared through plasma-enhanced chemical vapor deposition(PECVD)to achieve efficient microwave absorption and anti-corrosion properties.The organic/inorganic dual coat of PUA/SiO2 not only facilitated the interface polarization but also effectively reduced the dielectric constant and optimized impedance matching.Owing to the unique hybrid structure,the(PECVD-FeSiAl@PUA)@SiO_(2) exhibited highly efficient microwave absorbing performance in frequency bands covering almost the entire Ku-bands(12-18 GHz)with a minimum reflection loss(RLmin)of−47 dB with a matching thickness of 2.3 mm.The organic/inorganic dual protection effectively shields against the corrosive medium,as the corrosion potential and the polarization resistance increased from−0.167 to−0.047 V and 8,064 to 16,273Ω·cm^(2),respectively.While the corrosion current decreased from 3.04×10^(−6) to 2.16×10^(−6) A/cm^(2).Hence,the plasma-enhanced densification of PUA created a strong bridge to integrate FeSiAl and organic/inorganic components acquiring dual-function of efficient microwave absorption and anticorrosion,which opened a promising platform for potential practical absorbers.