Bio-based phytic acid/amino acid complex coating for antimicrobial and flame-retardant cotton fabrics.

Here, a novel multifunctional coating containing bio-based phytic acid (PA), L-glutamic acid (L-Glu), and trimesoyl chloride (TMC) is constructed by a simple soaking strategy, giving cotton fabrics excellent flame retardancy, washability, and antibacterial properties. The coating layer on the cotton surface was prepared via the electrostatic and hydrogen bonding between PA and L-Glu, accompanied by the interface polymerization between PA, L-Glu, and TMC. Among them, the limiting oxygen index value of the treated cotton fabrics (C2 and C2-TMC) was as high as 40 %. During the vertical flammability test, both C2 and C2-TMC cotton showed self-extinguished behavior with a short damaged length (≤50 mm). Remarkably, the LOI of C2-TMC sustained a high value (30 %) even after 300 laundering cycles, maintaining its self-extinguishing behavior in the vertical combustion test. Additionally, in the cone calorimetry test, peak heat release rate and total heat release of treated cotton were lower than control cotton. Surprisingly, after 30 or 60 laundering cycles, the C2-TMC cotton exhibited excellent antibacterial activity against Escherichia coli, Staphylococcus aureus, and Candida albicans due to the continuous exposure of PA and L-Glu. Moreover, the coating layer on the cotton surface had little impact on the mechanical properties and feel of the fabric.

A novel P/N/Si/Zn-containing hybrid flame retardant for enhancing flame retardancy and smoke suppression of epoxy resins.

Currently, additively efficient flame retardants are being developed to enhance the smoke suppression, flame retardancy, and thermal properties of composite materials. To this end, the current study designed and prepared a novel P/N/Si/Zn-containing organic-inorganic hybrid denoted as APHZ. Its inorganic part was 2-methylimidazole zinc salt (ZIF-8), which improved its smoke suppression and catalytic carbonization. The organic part (P/N/Si-containing compound) promoted its flame retardancy and interfacial compatibility between APHZ and epoxy resin (EP). The test results revealed that EP/APHZ-3 composites achieved a V-0 rating and a notable LOI value of 30.7% when introducing 3 wt% APHZ into the EP matrix. Cone calorimetry tests (CCT) further demonstrated that the average heat release rate (av-HRR), total smoke production (TSP), and CO production (COP) of EP/APHZ-3 were reduced by 23.3%, 14.0%, and 21.1%, respectively. Meanwhile, the char residual was increased by 60.6%, as compared to pure EP. Furthermore, the flame-retardant mechanism of EP/APHZ composites was investigated by the XPS, TG-FTIR, and Raman spectroscopy techniques. The observed synergistic effect of the imidazole skeleton ZIF-8 and P/N/Si-containing compound in APHZ facilitated the generation of a dense multi-element char layer, with the condensed phase flame-retardant mechanism playing a dominant role. These findings contribute to developing and designing high-performance flame-retardant EP.

In-situ synthesis of calcium borate/cellulose acetate-laurate nanocomposite as efficient extreme pressure and anti-wear lubricant additives.

In this study, calcium borate (CB) nanoparticles were in-situ grown onto cellulose acetate-laurate (CAL) template to prepare CB/CAL nanocomposite with uniform dispersion of CB nanoparticles by hydrothermal method. As-prepared CB/CAL nanoparticles were characterized by field emission scanning electron microscope, Fourier transforms infrared spectrometry, X-ray diffraction, and energy-dispersive X-ray spectroscopy. With average wear scar diameter (WSD), coefficient of friction (COF) and maximum non-seizure load (PB) as evaluation criterions, CB/CAL, CAL, and CB were used as lubricant additives in poly-alpha-olefin (PAO) base oil to comparatively investigate the tribological properties with a four-ball tribotester. It was found that under the load of 490 N, the WSD and COF of PAO + CB/CAL (concentration of 0.6 wt%) reduced by 25.9% and 48.7%, respectively, and PB increased by 79.6% compared with pure PAO base oil. CB/CAL nanocomposite exhibited superior lubricating performances than CB and CAL. In addition, the synergistic lubricating mechanism of CB/CAL nanocomposite as lubricant additive was explored.

Water-in-oil gel emulsions from a cholesterol derivative: structure and unusual properties.

As the first example of cholesterol derivatives, butane-1,4-dicarboxamide of di-cholesteryl L-alaninate has been shown to form water-in-oil type gel emulsions. The oils can be n-alkanes (7 < or = n < or = 10) and commercial fuels. Importantly, the preparation of the gel emulsions is a simple agitation process at room temperature, heating, cooling, addition of a co-solvent, or other additional procedures is not necessary. SEM, optical and con-focal laser scanning fluorescence microscopy measurements revealed the foam-like structures of the gel emulsions. Rheological studies demonstrated that these gel emulsions are mechanically stable, and exhibit typical viscoelastic properties. Surprisingly, the storage modulus, G' and the yield stress of the gel emulsions decrease along with increasing the volume ratio of the dispersed phase, water, a property different from the gel emulsions reported in the literatures. From the view point of application, the present gel emulsions are superior to others because of the simplicity in preparation and the non-ionic nature of the emulsifier, which will definitely benefit the practical applications.