A Novel Organophosphorus Hybrid with Excellent Thermal Stability: Core-Shell Structure, Hybridization Mechanism, and Application in Flame Retarding Semi-Aromatic Polyamide.
An organophosphorous hybrid (BM@Al-PPi) with unique core-shell structure was prepared through hybridization reaction between boehmite (BM) as the inorganic substrate and phenylphosphinic acid (PPiA) as the organic modifier. Fourier transform infrared spectra (FTIR), solid state (31)P and (27)Al magic angle spinning nuclear magnetic resonance, X-ray diffraction, and element analysis were used to investigate the chemical structure of the hybrids, where the microrod-like core was confirmed as Al-PPi aggregates generated from the reaction between BM and PPiA, and those irregular nanoparticles in the shell belonged to residual BM. Compared with the traditional dissolution-precipitation process, a novel analogous suspension reaction mode was proposed to explain the hybridization process and the resulting product. Scanning electronic microscopy further proved the core-shell structure of the hybrids. BM exhibited much higher initial decomposition temperature than that of Al-PPi; therefore, the hybrid showed better thermal stability than Al-PPi, and it met the processing temperature of semi-aromatic polyamide (HTN, for instance) as an additive-type flame retardant. Limiting oxygen index and cone calorimetric analysis suggested the excellent flame-retardant performance and smoke suppressing activity by adding the resulting hybrid into HTN.
Linear coordination polymers based on aluminum phosphates: synthesis, crystal structure and morphology.
Several aluminum tris(diorganophosphates) have been synthesized and characterized via elemental analysis, NMR, FT-IR and Raman spectroscopy, as well as powder XRD, and SEM. Single-crystal X-ray diffraction studies revealed that the aluminum tris(diethylphosphate) crystal structure comprises two crystallographically nonequivalent catena-Al[O2P(OEt)2]3 chains propagating along the c-axis. Their parallel orientation favors the formation of closely packed hexagonal domains. PXRD data suggest that other homologues have a similar structure, with the interchain distance closely corresponding to the dimensions of organic ligands. They are also susceptible to a reversible dissociation to ionic species under the effect of primary amines. This feature can be utilized for the synthesis of epoxy nanocomposites.
Characterization of Aqueous Dispersions and Gels Made of Sodium Caseinate and Basil Seed Gum: Phase Behavior, Rheology, and Microstructure
The interactions between sodium caseinate (NaCas) and basil seed gum (BSG) in the presence of calcium chloride (CaCl 2 ) were investigated. The phase behavior of the mixed aqueous dispersions and their gels revealed a homogeneous mixture, obtained at the higher concentrations of both CaCl 2 and BSG. The Herschel-Bulkley model sufficiently fitted the flow behavior of the mixture solution data. Apparent viscosity increased significantly ( p  < 0.05) by increasing the concentration of BSG, where the addition of CaCl 2 had no significant effect on the viscosity of the samples ( p  > 0.05). Furthermore, there was an increase in thixotropy due to the higher concentrations of BSG and CaCl 2 . Based on the frequency sweep test, at the low frequencies, a more gel-like behavior was observed in the case of the higher concentrations of either BSG or CaCl 2 . The rheological and SEM data suggested that the stronger structure of NaCas-BSG gel in the presence of the higher concentrations of CaCl 2 was related to the induction of complex formation between the two biopolymers.