High density polyethylene and zirconium phosphate nanocomposites

Insights into the Improved Gas Barrier Properties of Polyurethane-Clay Nanocomposite-Coated Nylon: A Solid-State NMR Study

Herein, the reason for the improvement in the gas barrier properties of polyurethane (PU)-clay nanocomposite-coated nylon fabric compared to unfilled PU-coated nylon fabric is investigated by probing the changes in relaxation times of PU using solid-state nuclear magnetic resonance (SS NMR) spectroscopy. The interaction of the organically modified montmorillonite (MMT) clay (Cloisite 30B) with polyurethane (PU) in PU-clay (0.5/1/2 wt %) nanocomposites was probed with respect to the change in the spin-lattice relaxation time of protons in the PU chain due to the presence of paramagnetic species in clay (T1H, para). The better the dispersion of the clay in the PU matrix, the lower the T1H, para, due to the interaction between clay and the PU matrix. 0.5 wt % PU-clay has lower T1H, para, (6.4 s) compared to 1 wt % (18.3 s) and 2 wt % (14.3 s) filled systems. The SS NMR findings are in good agreement with field-emission scanning electron microscopy (FE-SEM) analyses. In SEM microscopic images, it is observed that the PU-0.5 wt % clay has better exfoliation of clay compared to the 1 and 2 wt % PU-clay nanocomposites. This is in agreement with improved gas barrier properties of the nanocomposite coated on the nylon fabric for 0.5 wt % clay (2300 mL/m2/day) compared with 1 wt % (2500 mL/m2/day) and 2 wt % clay (2600 mL/m2/day)-incorporated PU-coated fabrics and neat PU-coated nylon fabric (4500 mL/m2/day) at 260 GSM.

Bactericidal efficiency of porphyrin systems

Photodynamic Inactivation is an innovative technique used to combat bacterial and viral infections which involves the use of photosensitizing agents along with light to generate cytotoxic reactive oxygen species able to kill bacteria and viruses. In the first section of this minireview, porphyrin-based fluorophores are shown to be remarkable dye candidates for PDI (photodynamic inactivation) applications. The second section is dedicated to the description of porphyrin-based antimicrobial materials and their potentialities for industrial applications such as in food packaging or antimicrobial medical devices and hygiene. Finally, the failings and perspectives of PDI are analyzed to demonstrate how the PDI technique could be an efficient and ecologically friendly antimicrobial technique.

Effects of α-zirconium phosphate and zirconium organophosphonate on the thermal, mechanical and flame retardant properties of intumescent flame retardant high density polyethylene composites

The combination of synergistic agents with intumescent flame retardants (IFRs) is an excellent strategy for the development of high-performance flame retardant composites. Zirconium-based compounds are multifunctional materials with applications in various fields. In this study, zirconium-based compounds were synthesized and then combined with an IFR composed of ammonium polyphosphate (APP) and tris (2-hydroxyethyl) isocyanurate (THEIC) to prepare flame retardant high density polyethylene (HDPE) composites. α-Zirconium phosphate (α-ZrP) and two organic–inorganic hybrids (zirconium organophosphonate), Zr-ATMP and Zr-PA, were prepared using amino tri (methylene phosphonic acid) (ATMP) and phytic acid (PA), respectively, and their thermal, mechanical and flame retardant properties were characterized by thermogravimetric analysis, tensile test, limiting oxygen index (LOI) measurement and cone calorimetry test. The results showed that the LOI value of HD/IFR/Zr-ATMP composite reached a maximum of 26.2% using 25 wt% of flame retardant containing 3 wt% of Zr-ATMP. Of the three zirconium-based compounds, Zr-ATMP and α-ZrP can reduce the peak heat release rate compared with the composite containing only IFR. However, zirconium-based compounds showed no significant improvement of tensile strength.

Zirconium-based compounds are combined with intumescent flame retardant (IFR) to prepare flame retardant high density polyethylene composites.