UV Curable Flame Retardant Resins Research Articles

Combustion and Thermal Behavior of Polyurethane Acrylate Modified with a Phosphorus Monomer

A series of UV curable flame retardant resins were obtained by blending bis(2-acryloxyethyl) 2.6.7-trioxa-1-phosphabicyclo[2.2.2.]octane-4-methylol-1-oxide phosphate (MDMPE) in certain ratios with a commercial polyurethane acrylate (PUA). It has been found that the cured film shows good flame retardancy when the MDMPE is at 30% additive level. The cone calorimeter results show that the heat release rate decreases in comparison with the pure PUA. The thermogravimetric analysis (TGA) and real time Fourier-transform infrared spectroscopy measurements (RTFTIR) results show that the phosphate group in MDMPE first degrades to form poly(phosphoric acid) before the degradation of PUA. Then, the formed poly(phosphoric acid) effectively promotes the conversion of PUA to form char, which prevents the sample from further burning. It can be concluded that MDMPE could catalyze the degradation of PUA to form char residue, and could be used as a UV curable flame retardant which acts by a condensed phase mechanism.

Effect of poly(bisphenol A acryloxyethyl phosphate) on the activation energy in thermal degradation of urethane acrylate

Poly(bisphenol A acryloxyethyl phosphate) (BPAAEP) was blended in different ratios with a commercial urethane acrylate to obtain a series of UV curable flame-retardant resins. The thermal oxidative degradation mechanism of their cured films in air were studied by thermogravimetric analysis at several heating rates between 5 and 20°C min−1. The activation energies were determined using Kissinger method, Friedman method, Flynn-Wall method, Horowitz-Metzger method and Ozawa method. The results showed that the activation energies of the blends were lower than that of pure urethane acrylate at lower degree of degradation, whereas the higher activation energies were obtained at higher degree of degradation.

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.

Different effects of tri(acryloyloxyethyl) phosphate on the thermal degradation of photopolymerized epoxy acrylate and polyurethane acrylate films

AbstractTri(acryloyloxyethyl) phosphate (TAEP) was blended in different ratios with epoxy acrylate EB600 and polyurethane acrylate EB270 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 Fourier‐transform infrared spectroscopy, and direct pyrolysis/mass spectrometry measurements. The results showed that the phosphate group in TAEP first degraded to form poly(phosphoric acid) before the degradation of EB600. Then, the formed poly(phosphoric acid) effectively promoted the conversion of EB600 to form char, which prevented the sample from further burning. However, urethane group in EB270 degraded simultaneously with phosphate group in TAEP, leading to not effectively increase the conversion of EB270 to char during the thermal degradation. It was thus found that the addition of TAEP more effectively improved the thermal stability, flame retardance, and the char yield during combustion of EB600 than those of EB270. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3130–3137, 2006

Kinetics and mechanism of thermal oxidative degradation of UV cured epoxy acrylate/phosphate triacrylate blends

Tri(acryloyloxyethyl)phosphate (TAEP) was blended in different ratios with a commercial epoxy acrylate to obtain a series of UV curable flame retardant resins. The thermal oxidative degradation mechanism of their cured films in air was studied by thermogravimetric analysis and in situ Fourier-transform infrared spectroscopy. The cured film with TAEP addition showed improved thermal stability at elevated temperature with higher char yield. The kinetics of their thermal decomposition were evaluated by Kissinger, Friedman and Vachuska–Voboril methods. The results showed that the activation energies of the blends were lower than that of pure epoxy acrylate at lower degree of degradation, whereas higher activation energies were obtained at higher degree of degradation.

Combustion behaviour and thermal properties of UV cured methacrylated phosphate/epoxy acrylate blends

Methacrylated phosphates (MAPs) were blended in certain ratios with a commercial epoxy acrylate to obtain UV curable flame retardant resins. The flame retardancy and thermal properties of their UV cured films were investigated by the combustion behaviour, limiting oxygen index (LOI), thermal degradation and glass transition temperature ( T g). The results showed that the peak and average heat release rates decreased to the approximate levels of pure MAPs when 17 wt.% of MAPs was added, and no obvious effects were observed from the films with higher loading levels. The LOI increased along with the content of MAPs, and the total heat release, contrarily, decreased. The total smoke production was suppressed by MAPs addition as it leads to an effective decrease of mass loss, although MAPs have no effect on the specific extinction area. The T g decreased with increasing content of MAPs due to the reduction in rigidity of the polymer chains, and the lower cross-link density of the cured film.