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Halogen-free flame retardant rigid polyurethane foams (RPUF) were synthesized by substituting a part of polyther polyol with polyol-modified lignin and filled with phenolic encapsulated ammonium polyphosphate (PFAPP). Lignin was chemically modified with flame retardant elements, phosphorous, via a three-step reaction. The foams maintained a regular cell structure and had even smaller average cell size than pure foam. The effects of lignin polyol and PFAPP on the apparent density, compressive strength were discussed. The thermal stability, flame retardant properties and mechanical properties of the foams are improved. Compared with pure foam (0.2 % char residue at 700 °C), modified foam with lignin and PFAPP exhibits much higher char formation (42.7 % char residue at 700 °C). The FR properties of these modified foams were evaluated by cone calorimeter and limiting oxygen index (LOI). The modified lignin in foam system further reduces the heat release rate and shows the combustion process. The addition of 15 % PFAPP and 10 % modified lignin into RPUF led to a considerable increase of the compressive strength with respect to the neat RPUF. [ABSTRACT FROM AUTHOR]

A novel phosphorus-containing hyperbranched macromonomer (PHM), successfully synthesized via Michael addition polymerization of tri(acryloyloxyethyl) phosphate (TAEP) with n-butylamine (BA), was blended with epoxy acrylate resin (EA) to prepare UV curable flame retardant coatings. The study of thermal degradation of these coatings revealed that PHM can catalyze the degradation of EA, contributing to the formation of thermally stable char layer. The residues of EA3 (which contains 45 wt.% PHM) at various temperatures were analyzed by X-ray photoelectron spectroscopy (XPS) and the results displayed that the formation of phosphorus-carbon structure can well protect the carbonaceous char from thermal-oxidative degradation at 800 °C. Besides, the investigation of the flammability illustrated that the addition of PHM increased the limiting oxygen index (LOI) value and reduced the peak heat rate release (HRR) and total heat release (THR). [ABSTRACT FROM AUTHOR]

A novel phosphorus and silicon containing compound (KHPDH) has been synthesized by allowing phenyl dichlorophosphate to react with 3-triethoxysilylpropylamine and 2-hydroxyethyl acrylate (HEA). Through the sol-gel and UV-curing processes, KHPDH was incorporated into the structures of the epoxy acrylate,resulting in the formation of solid crosslinked organic/inorganic homogeneous hybrids. The solid Si NMR and DSC results demonstrate that the morphology of the mixed epoxy systems is homogeneous. The application of KHPDH as a flame retardant in epoxy acrylate not only gains satisfied flame retardancy, but also improves the hardness of epoxy acrylate. Moreover, the thermal properties of the hybrids were investigated by thermogravimetric analysis (TGA) and the thermal degradation of the materials was investigated by real time fourier transform infrared spectra (RTIR) and thermogravimetric analysis/infrared spectrometry (TG-IR). X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were used to explore chemical components as well as the morphologies of the residual char. It was found that the silicon migrated to the surface and formed protective silicon carbide layer. [ABSTRACT FROM AUTHOR]

Two kinds of novel phosphorus-containing polyether toughening agents were synthesized and characterized by H nuclear magnetic resonance (H NMR) and Fourier transform infrared spectra (FTIR). Afterwards, a series of phenolic foams with different loadings of phosphorus-containing toughening agents were prepared. The apparent density and scanning electron microscopy (SEM) results showed that the addition of 5 wt% toughening agents increased the expansion ratio and promoted the formation of uniform cells. The limiting oxygen index (LOI) values of modified phenolic foams decreased with the increase of modifier content, but it still remained at 40% even if the amount of modifier loadings was 10 wt%. UL-94 results showed all samples can pass V0 rating, indicating the modified foams still have great flame retardance. Microscale combustion calorimetry (MCC) results indicated that the peak heat release rate (PHRR) and total heat release (THR) of the modified foams were reduced by 42% and 35%, respectively, compared to the pure phenolic foams. Moreover, the thermal stability of samples was investigated by thermogravimetric analysis (TGA). The mechanical properties were evaluated and correlated with composition and structural features. [ABSTRACT FROM AUTHOR]

A novel phosphorus, nitrogen-containing compound, poly(4, 4′-diaminodiphenyl methane phenyl dichlorophosphate) (PDMPD) with high thermal stability was synthesized. The PDMPD was then incorporated into polystyrene (PS) to be used as halogen-free flame retardant. Moreover, small amounts of two boron-containing compounds, Zinc borate (ZnB) and boron phosphate (BP) were combined with PDMPD,to explore effective flame-retardant formulations for PS. The flammability and the thermal properties of the composites were evaluated using limiting oxygen index (LOI) test, microscale combustion calorimeter (MCC) and thermogravimetric analysis (TGA) respectively. A Fourier transform infrared (FTIR) spectroscopy coupled with a thermogravimetric analyzer (TG-IR) was also used to study the gas phase from the degradation of PS composites. Furthermore, the char residues of the samples were investigated by scanning electron microscopy (SEM) and FTIR. The results showed that the incorporation of PDMPD can significantly decrease the flammability of virgin PS, and enhance the thermal stability at high temperature region, in both nitrogen and air atmosphere. A combination of PDMPD with small amounts of boron compounds can further decrease the flammability. [ABSTRACT FROM AUTHOR]

In the article, acrylonitrile-butadiene-styrene/polyvinyl chloride/organophilic Fe-montmorillonite (ABS/PVC/Fe-OMT) nanocomposites were prepared by melt intercalation method. In order to determine if the presence of iron ion in the structure of organophilic montmorillonite (OMT) lattice can affect thermal, flame retardance and smoke suppressant properties in the ABS/PVC blends. ABS/PVC/organophilic natural montmorillonite (Na-OMT) nanocomposites were prepared as the comparable sample. Fe-MMT and Na-MMT were treated by cetyl trimethylammonium bromide (CTAB). The information on morphologies and structures of ABS/PVC/OMT nanocomposites was obtained using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The thermal properties of the nanocomposites were characterized by thermogravimetric analysis, and flame retardant properties were obtained via limiting oxygen index (LOI), UL-94 vertical burning test and smoke density. The nanocomposites, based on Fe-OMT, exhibited better flame retardance, better smoke suppressant properties, and lower degradation degree than those of pure ABS/PVC blends and the ABS/PVC/Na-OMT nanocomposites. [ABSTRACT FROM AUTHOR]

UV-curable waterborne polyurethane acrylate (WPUA) modified with octavinyl polyhedral oligomeric silsesquioxane (OVPOSS) was prepared via photopolymerization between OVPOSS and WPUA. Structural and morphological features of WPUA/OVPOSS coatings were assessed using Fourier transform infrared spectroscopy, transmission electron microscopy and X-ray diffraction. Thermal properties of the WPUA/OVPOSS hybride coatings have been improved over the pure waterborne polyurethane acrylate analyzed by thermal gravimetric analysis. Performance of the coatings was also evaluated using water absorption, hardness, contact angle, X-ray photoelectron spectroscopy (XPS). The data showed that the WPUA/OVPOSS coatings possessed better water resistance and thermal oxidative stability in comparison with pure WPUA. [ABSTRACT FROM AUTHOR]

The bisphenol A epoxy acrylate resin containing a small amount of organically modified alpha-zirconium phosphate (α-ZrP) was cured within seconds upon UV irradiation at ambient temperature. The UV-curing behavior was investigated by fourier transformedinfrared spectroscopy (FTIR). The microstructures were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The transparency and the combustion were examined by the UV-vis transmission spectra and Microscale Combustion Calorimeter (MCC), respectively. The ultraviolet-visible spectra of the cured films showed no obvious absorbance over a range of 400-800 nm, which revealed that the cured films were transparent. The results of MCC revealed that heat release rate (HRR) of the films decreased with the contents of organic α-ZrP (OZrP). Thermal behavior of the cured films was studied by thermogravimetric analysis (TGA), which indicated that with increasing the contents of OZrP, the char yields of UV-cured films were enhanced. Viscoelastic property of photocured nanocomposites was evaluated by dynamic-mechanical analysis. The effects of OZrP on the properties of UV curable films were critically evaluated in this paper. [ABSTRACT FROM AUTHOR]