Preparation and expansion properties of a novel UV-curable intumescent flame-retardant coating

Journal of Thermal Analysis and Calorimetry - N,N′-bis(2,4-di(acryloyloxyethyl)-[1,3,5]-triazin-2-yl)-hexane-1,6-diamine(BDAETH) and 2,2-dimethyl-1,3-propanediol glycerol-methacrylate...     

Thermal degradation and combustion of a novel UV curable coating containing phosphorus

A novel phosphorus monomer (BDEEP) has been synthesized by allowing phosphorus oxychloride to react with 2-hydroxyethyl acrylate (HEA) and 1,4-Butane diol. Its structure was characterized by Fourier transformed infrared spectroscopy (FTIR) and ¹H nuclear magnetic resonance spectroscopy (¹H NMR). The UV-curing behavior was investigated by FTIR. The combustibility was examined by microscale combustion colorimeter (MCC). The heat release rate (HRR) and heat release capacity (HRC) are 42.1 w/g and 44.0 J/g K, respectively. The thermal degradation was characterized using thermogravimetric analysis/infrared spectrometry (TG-IR). The curve of TGA indicates that there are three characteristic degradation temperature stages for the cured film, which was further characterized by real time Fourier transform infrared (RTFTIR) measurement. It is proposed that the flame retardant action results from decomposition of phosphate to form poly(phosphoric acid), which catalyses the breakage of bonds adjacent to carbonyl groups to form the char, preventing the sample from burning further. The volatilized products formed on thermal degradation of BDEEP indicated that the volatilized products are CO, CO₂, water, alkane, carbonyl, phosphorus compounds and aromatic compounds according to the temperature of onset formation.     

A novel intumescent flame-retardant system containing metal chelates for polyvinyl alcohol

A novel flame retardant containing phosphorous-nitrogen structure, the ammonium salt of 2-hydroxyl-5,5-dimethyl-2,2-oxo-1,3,2-dioxapho sphorinane (PNOH), was synthesized and its structure was characterized by ¹H NMR and FTIR spectra. PNOH was used together with ammonium polyphosphate (APP) to prepare a novel intumescent flame retardant (IFR) for polyvinyl alcohol (PVA). When a few amounts (0.5%) of metal chelates were added, the flame retardancy of the IFR-PVA systems was significantly improved, having a high LOI value of 34.2 in a total IFR loading of 15 wt.%. In order to have an understanding of the resulting flame retardant effects, the thermal degradation behaviors of IFR-PVA systems were investigated by thermogravimetric analysis (TGA), and the morphology and structures of residues generated in different conditions were investigated by scanning electronic microscopy (SEM) and FTIR spectra. The results show that NiSAO can promote the thermal stability of the IFR-PVA; the residual char containing polyphosphoric or phosphoric acid is formed during the combustion; the formation of a continuous and dense char layer could inhibit the transmission of heat during contacting with flame and shows good flame retardancy.     

Preparation and thermal properties of a novel flame-retardant coating

A novel silicone and phosphate modified acrylate (DGTH) was synthesized and characterized by ¹H NMR and FTIR. It was found that DGTH could be cured both by UV radiation and moisture mode with FTIR. The flammability and thermal behavior of the cured film were studied by the limited oxygen index (LOI), thermogravimetric analysis (TG) and real time Fourier transform infrared (RT-FTIR). The LOI value of the cured film is 48 and the TG data shows that the cured film has three characteristic degradation temperature regions, attributing to the decomposition of phosphate and polyurethane to alcohols and isocyanates, thermal pyrolysis of alkyl chains, and decomposition of unstable structures in char, respectively. The RT-FTIR data implies that the degraded products of phosphate form poly(phosphoric acid) further catalyse the breakage of carbonyl groups to form an intumescent char, preventing the samples from further burning.     

Synthesis of a novel highly efficient flame-retardant coating for cotton fabrics with low combustion toxicity and antibacterial properties

Cellulose - The synthesis of multi-function flame retardants is widely increasing to fulfill industrial and economic goals. In this work, a novel flame retardant, melamine salt of tannic phosphate...     

Synthesis and properties of a novel hyperbranched polyphosphate acrylate applied to UV curable flame retardant coatings

A series of hyperbranched polyphosphate acrylates (HPPAs) being used for UV curable flame retardant coatings were prepared by the reaction of tri(acryloyloxyethyl) phosphate (TAEP) with piperazine at given ratios, and characterized using FTIR, ¹H NMR and GPC measurements. HPPA was blended with TAEP in different ratios to obtain a series of UV curable resins. Their maximum photopolymerization rates and final unsaturation conversion (P^f) in the cured films at the presence of a photofragmenting initiator were investigated. The results showed that the P^f increased along with HPPA content and the pure HPPA has the maximum value of 82.1% in the photo-DSC analysis. The data from dynamic mechanical thermal analysis showed that HPPA has good miscibility with TAEP. The crosslinking density and T_g of the cured film decrease along with the content of HPPA in the blend. The mechanical properties of the cured films were also investigated. Less than 20% HPPA addition improved both the tensile strength and elongation at break without damaging the modulus. The HPPA₂₀TAEP₈₀ film with 20% HPPA addition has the highest tensile strength of 31.7 MPa and an elongation at break two times that of cured TAEP. The flame retardancy of the UV cured films was investigated by the limiting oxygen index (LOI). The cured TAEP/HPPA samples greatly expanded when burning, and the degree of expansion increased along with HPPA content. However, the LOI values decreased from 47.0 to 34.0 along with HPPA content, which can be ascribed to that the flame retardancy of TAEP is mainly acting in the gas phase, whereas HPPA mainly acting in condensed phase, and the gas phase mechanism holds the dominant effect while their blends are burning.     

Synergistic effects of zeolites on a novel intumescent flame-retardant low-density polyethylene (LDPE) system

A char forming agent and silica-gel microencapsulated APP were selected to form novel intumescent flame-retardant system (IFR) to prepare flame-retardant low-density polyethylene (LDPE) composites, and then the influence of zeolites on the thermal and flame-retardant properties of flame-retardant LDPE composites were studied. With the addition of 1 wt% zeolites to LDPE/IFR system, the LOI value increases from 29.0 to 34.0 %. The results of cone calorimetry show that the heat release rate peak and total heat release of the intumescent flame-retardant LDPE composite with 1 wt% zeolites decreases remarkably compared with that of without zeolites. The scanning electron microscopy indicates zeolites with suitable content can improve the quality of the char layer of flame-retardant LDPE composite which is more coherent and dense. The zeolites with the appropriate content can remarkably improve the flame-retardant properties of the LDPE composites.     

The synergistic effect of adjuvant on the intumescent flame-retardant ABS with a novel charring agent

A laboratory-made poly-N,N′-ethyleneterephthalamide (PETA) was used as a novel charring agent and it was combined with ammonium polyphosphate (APP) to prepare the intumescent flame retardant (IFR). For improving the flame retardant efficiency of IFR on acrylonitrile–butadiene–styrene copolymer (ABS), several adjuvant (Adj), such as zeolite 4A (4A), aluminum phosphinate (AlPi), organic montmorillonite, and 2,2′-bis(2-oxazoline), was added, and the synergistic effect was investigated by the limiting oxygen index (LOI), the UL-94 (vertical flame) test, the thermogravimetric analysis (TG), and the scanning electron microscopy (SEM). The results showed that the LOI values of ABS/IFR/Adj (70/30/2) system exceeded 30, and they passed the V-0 rating in the UL-94 test. The TG data demonstrated that the thermal stability and the mass residue of ABS/IFR/Adj were effectively enhanced. Besides, the SEM indicated that adjuvant promoted the formation of the compact, uniform, dense, and intumescent charred layer after burning. After that, the synergistic effect of AlPi and 4A on APP/PETA was investigated by Thermogravimetry-Fourier transform infrared spectroscopy.     

Preparation and flammability of a novel intumescent flame-retardant poly(ethylene-co-vinyl acetate) system

A phosphorus-containing flame retardant, 4-(5,5-dimethyl-2-oxo-1,3,2-dioxaphosphorinan-2-yloxymethyl)-2,6,7-trioxa-1-phospha-bicyclo[2.2.2]octane-1-oxide (MOPO), was synthesized successfully and characterized. The flame retardancy and thermal behavior of a new intumescent flame-retardant (IFR) system for EVA, which was made of MOPO and ammonium polyphosphate (APP), were investigated by limiting oxygen index (LOI) test, vertical burning test (UL-94), cone calorimeter, and thermogravimetric analysis (TGA). An LOI value of 28.4 and UL-94 V-0 rating can be achieved when the total loading of MOPO and APP was 30 wt.%. The results from cone calorimeter indicate that both the heat release rate (HRR) and the total heat release (THR) of IFR-EVA decreased significantly compared with those of neat EVA. TG curves showed that the amount of residues increased significantly when intumescent additives were added; it also could be found that the LOI values increased with the increase in char residues. Meanwhile, morphology of the residues obtained from burning IFR-EVA in LOI test was studied through the SEM observations and rich compact char layers could explain the excellent flame retardance.     

Thermal behavior and degradation mechanism of poly(bisphenyl acryloxyethyl phosphate) as a UV curable flame-retardant oligomer

Poly(bisphenyl acryloxyethyl phosphate) (BPAEP) was blended in different ratios with urethane acrylate EB220 to obtain a series of UV curable flame-retardant resins. The thermal degradation mechanisms of their cured films in air were studied by thermogravimetric analysis, in situ FTIR and direct pyrolysis/mass spectrometry measurements. The results showed that BPAEP/EB220 blends have lower initial decomposition temperatures (T_di) and higher char residues than pure EB220, while BPAEP has the lowest T_di and the highest char residue. The degradation process of BPAEP was divided into three characteristic temperature regions, attributed to the decomposition of phosphate, ester group and alkyl chain, and aromatic structure in the film.     

Synthesis and polymerization of a novel perfluorinated monomer

Perfluoro(5-methylene-2,2-dimethyl-1,3-dioxolane) (1) was synthesized by utilizing a direct fluorination reaction. Compound 1 was an entirely novel monomer with difluoromethylene at position 5 on the dioxolane ring as an unprecedented polymerization site. It successfully polymerized with tetrafluoroethylene to afford copolymers, which had T_g values in the range of 60-90 °C. The content of monomer 1 in the obtained polymers was less than 20 mol%, which seemed insufficient for giving various unique properties to polymers. However, each polymer was expected to be a superior material because of their advanced thermal stability. Comparison with copolymers of 2,2-bis(trifluoromethyl)-4,5-difluoro-1,3-dioxole and tetrafluoroethylene is also discussed.     

Synthesis and properties of UV curable polyvinylsilazane as a precursor for micro‐structuring

Photosensitive acrylated polyvinylsilazanes were prepared by reacting a diacrylate containing compound, 1,1‐bis (acryloyloxyethyl) ethyl isocyanate (BAEI), with polyvinylsilazane (PVSZ) and utilized as an inorganic photoresist for generating SiCN‐based ceramic microstructures. The acrylate‐modified polymers (m‐PVSZ) were characterized by ¹H‐NMR, ¹³C‐NMR and FT‐IR methods to determine the chemical reaction mechanism. Differential photo‐calorimeter and FT‐IR analysis were employed to examine its photosensitive properties. Line patterns were fabricated by a UV nano‐imprinting method; multi‐layered octagon structures were fabricated by a two‐photon absorption stereolithography process. The results indicate that m‐PVSZ is quite a novel inorganic photoresist for the fabrication of micro ceramic structures. Copyright © 2015 John Wiley & Sons, Ltd.     

Synthesis and properties of UV curable waterborne hyperbranched aliphatic polyester

The UV curable waterborne hyperbranched polyester (WBHP) consisting of a multi-hydroxy functional aliphatic polyester core, which is endcapped with methacrylic and salt-like groups in different ratios was synthesized. The core is second generation of hyperbranched aliphatic polyester Boltorn™ H20 with approximately 16 hydroxyl groups. The effects of different ratios of chemical structure of end groups were studied by evaluating various properties of WBHP such as solubility in water, dynamic viscosity, UV curing rate and final unsaturation conversion. A natural good control over the solubility of the samples was possible by salt-like functionality and raising the temperature. The investigation of solubility characteristics of the modified hyperbranched polyester illustrated that those with higher concentration of salt-like moiety were more soluble while those of having lower salt-like moiety were less soluble. The viscosity of the resin WBHP was reduced rapidly by dilution with water and raising temperature. Water showed a favorable viscosity reduction effect as compared to monomer and its blend with water. The polymerization rate of the resins under UV irradiation in the presence of a photoinitiator showed an increasing trend with higher concentration of methacrylate functionality.     

基于FEVE树脂的含氟光固化树脂的合成

以对甲苯磺酸为催化剂,对羟基苯甲醚为阻聚剂,甲苯为共沸脱水剂,FEVE树脂和丙烯酸为原料,通过FEVE树脂的羟基与丙烯酸发生酯化反应制备了含氟光固化树脂。讨论了羧基与羟基摩尔比、催化剂用量、共沸脱水剂用量和反应时间对酯化反应转化率的影响。通过FT-IR、1H-NMR对聚合物结构进行确认。结果表明当羧基与羟基摩尔比为1.6:1,对甲苯磺酸质量分数为0.15%,甲苯质量分数为25%,反应时间6h时,反应转化率为87.9%。     

Synthesis of a novel ferrocene derivative having flame-retardant and smoke-suppressant properties

Reaction of ferrocene with chlorendic anhydride (1,4,5,6,7,7-hexachloro-5-norbornene-2,3-dicarboxylic acid anhydride) under Friedel–Crafts reaction conditions affords a new monosubstituted dervative of ferrocene which has significant flameretardant and smoke-suppressant properties when incorporated into poly(vinyl chloride) (PVC). The monocarboxylic acid from the above reaction undergoes smooth methylation with diazomethane to give the corresponding methyl ester. ¹H and ¹³C NMR spectra of these compounds have been compared with those obtained from similar compounds, namely β-ferrocenoylpropanoic acid and its methyl ester. Distant asymmetric centres in the chlorendic anhydride substituent markedly affect the proton spectra of the ferrocene derivative.     

3D-map modelling for the melting points prediction of intumescent flame-retardant coatings

The applicability of 3D map modelling for melting point prediction was studied. The melting points in the ammonium polyphosphate–pentaerythritol–melamine chemical system of intumescent flame-retardant coatings over a wide range of concentrations were collected. The ternary diagram (triangle) of the melting points was plotted and an approximated 3D map was built for the range 205–345°C. The present work contains the thermal data for the observed ternary system and provides a new graphic system for making predictions for intumescent flame-retardant coatings. The applicability of the calculated 3D map for obtaining experimental samples of fire-retardant paints with a low melting point for thin steel constructions was shown.     

Theoretical investigation of triazine based a star shape pyrrole monomer

In this work, we report a comprehensive theoretical investigation of electroactive star shaped pyrrole functionalized triazine monomer with two main goals. First goal of this work is to explore the physical and chemical properties of the monomer, then to investigate correlation between the experimental and the theoretical properties of monomer. The scale factor which is calculated from B3LYP/cc-pVDZ was determined as 0.985 for FT-IR and it is an important and reliable contribution to the literature. It is determined that the most appropriate basis set for this molecule. The other novel objective of this research is to investigate temperature effect on displacement of chlorine atoms in 2,4,6-trichloro-1,3,5-triazine. This method applied for the first time in the literature for triazines is especially crucial to the synthesis of unsymmetrical triazines.     

Synthesis and thermal properties of silicon-containing epoxy resin used for UV-curable flame-retardant coatings

A novel silicon-containing trifunctional cycloaliphatic epoxide resin tri(3,4-epoxycyclohexylmethyloxy) phenyl silane (TEMPS) was synthesized and characterized by FTIR, ¹H NMR, ¹³C NMR, and ²⁹Si NMR spectroscopic analysis. A series of flame-retardant formulations by blending TEMPS with a commercial epoxide resin DGEBA (EP828) in different ratios were prepared, and exposed to a medium pressure lamp to form the cured films in the presence of diaryliodonium hexafluorophosphate salt as a cationic photoinitiator. The thermal degradation behaviors of the cured films were evaluated by thermogravimetric analysis. The char yields under nitrogen and air atmospheres increased along with the TEMPS content. The limiting oxygen index (LOI) value increased from 22 for EP828 to 30 for TEMPS80, demonstrating the improved flame retardancy. The data from the dynamic mechanical thermal analysis showed that TEMPS had good miscibility with EP828. The T _s and T _g both decreased from 93 and 138 to 78 and 118 °C, respectively. The crosslinking density (ν _e) increased along with the TEMPS content. The mechanical property measurements indicated that the addition of TEMPS led to a decrease in the tensile strength and an increase in the elongation-at-break.