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Phytic acid and amino acid belonging to the biomass material have a wide range of sources in nature. In this work, three kinds of basic amino acids, which are arginine, lysine, and histidine, were used to prepare different bio-based phytic acid−basic amino acid salts (PaArg, PaLys, and PaHis) via a saltforming reaction. After the incorporation of PaArg, PaLys, and PaHis into polypropylene (PP), PaArg showed a higher efficiency than PaLys and PaHis in endowing PP with flame retardancy. At 22 wt % PaArg, the limiting oxygen index (LOI) value of functional PP was 26.0%, and its UL-94 rating reached V-0 in the vertical burning test. In the fire hazard test, PaLys showed a higher efficiency than PaArg and PaHis in reducing the fire hazard of PP during burning. The peak value of the heat release rate for PP containing 25 wt % PaLys was decreased by 70.7% compared with that of PP, and its fire growth rate was reduced by 86.9%. Analysis on the fire-safety mechanism revealed that the high char-forming rate and the quality of the residue dominated the superior flame-retardant efficiency of PaArg in UL-94 and LOI tests; high strength of the formed char layer, diluting effect of nonflammable gases, and incomplete combustion action led to the superior efficiency of PaLys in decreasing the fire hazard of PP. This work confirms that fully bio-based phytic acid−basic amino acid salt based on the accurate molecular design may endow PP with fire safety under different burning scenes.

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Aiming at meeting the specific market demands and expanding the downstream application of melamine-formaldehyde (MF) resins, a series of (3-aminopropyl) triethoxysilane (APTES) grafted MF (MF-Si) resins were synthesized via an effective method that minimized the hydrolysis of APTES and overcame the polarity discrepancy of APTES with MF resin matrix. The structure of MF-Si resins was characterized by FTIR spectroscopy, Raman spectroscopy, 1 H nuclear magnetic resonance (NMR), and solid state 13 C NMR. It was found that APTES moieties in MF-Si materials afforded increased hydrophobicity, water resistance, and the thermal stability was not affected. With the increasing amount of APTES, the water contact angle of MF-Si films increased from 70.56 to 105.92 and the surface free energy decreased from 46.8 to 23.5 mN/m. The temperature of maximum weight loss rate (T dmax ) of MF-Si materials decreased slightly from 371.15 to 353.70 C and the ultimate residual weight of MF-Si materials increased from 12.51 to 30.04% at 800 C under N 2 .

We propose and demonstrate a multifrequency radio frequency (RF) spectrum estimation technology. With photonic assistance, a multifrequency RF signal ranging from 0 to 1 GHz is highly spectrally compressed and sensed using a single analog-to-digital converter with analog bandwidth of 42.6 MHz. By calculating the cross correlation of pseudo random binary sequence and the encoded signal, up to 40 RF tones are precisely recognized without large computational load. The employment of optical mixing decreased the cost and increased the performance compared to its electrical counterpart. The theory and performance are also discussed.

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