Fire Resistance Of Composites Research Articles

Rigid polyurethane foam composites based on bivalent metal phytate: thermal stability, flame retardancy, and fire toxicity

ABSTRACT As the main form of phosphorus in plant seeds, phytic acid has potential value in flame retardant field. In this study, a series of bivalent metal phytate (PA-M) flame retardants were prepared using phytic acid and divalent metal salts as raw materials. FTIR, SEM-EDS, XRD, and TG tests confirmed that copper phytate (PA-Cu), zinc phytate (PA-Zn), cobalt phytate (PA-Co) and nickel phytate (PA-Ni) were successfully synthesized. Furthermore, flame retardant rigid polyurethane foam (RPUF/PA-M) composites were prepared by one-step water-blown technology using PA-M as flame retardant. TG test results showed that RPUF/PA-Cu30 had the highest char residue at 700 C, which was 26.2 wt%, significantly higher than 12.4 wt% of RPUF. Cone calorimetry, smoke density test, and TG-FTIR analysis confirmed that RPUF/PA-Co30 composite exhibited excellent smoke suppression and toxicity reduction performance when 30 phr PA-Co was added. Compared with RPUF, the THR, TSR, and SDR of RPUF/PA-Co30 were decreased by 13.9%, 27.3% and 43.9%, respectively, and the release of toxic gases (isocyanate compounds, aromatic compounds, CO and HCN) and combustible gases (hydrocarbons and esters) were significantly reduced. The analysis of char residues of RPUF/PA-M composites suggested that PA-M could promote the formation of dense carbon layer with high graphitization degree and improved the fire resistance of composites. This work provided a new way for fabricating fire safety RPUF composites.

Mechanical properties and fire-resistance of composites with marble particles

The main aim of this work is to manufacture a composite material based on a natural material (marble) with acceptable mechanical properties and fire resistance, for being used in habitat industry as floor or wall in buildings. Marble used as raw material is the waste powder of quarry or plate manufacturing. To achieve this objective, polyester matrix composites with 50 wt.% of marble and 3 wt.% of glass fiber (short fiber or mesh) were prepared. The novelty of this study is the high percentage of ceramic material added to a polymer matrix composite and the fire resistance study. Samples were characterized mechanically through flexural test, Charpy impact test, compression test and wear resistance by pin-on-disk test. Fracture surfaces were analyzed by scanning electron microscope (SEM), and wear tracks were studied by SEM and 3D optical profilometer. Besides, samples were subjected to fire test using a Bunsen burner at 900 °C for 20 min. Sample temperature at the opposite-to-fire test side was measured with an infrared thermometer. Results show that marble improves mechanical properties of polyester and the effect of the glass fiber depends on its morphology (fiber or mesh). Fire resistance is high, and the fire goes out when the flame is turned off. Furthermore, the mesh maintains the integrity of the sample.

Thermal Properties and Fire Resistance of Jute-Reinforced Composites

The thermal behaviour, fire resistance and mechanical properties of jute-reinforced composites with vinylester and resol matrix were studied. Organically modified clay was added to the polymeric matrix in order to enhance the properties of the composites. An inhomogeneous distribution of the nanoreinforcement in the polymer was observed by X-ray diffraction. Thermogravimetric analyses revealed that the addition of clay to the resol resin by sonication enhanced the thermal resistance of the jute-reinforced composite at temperatures higher than 300°C. The fire resistance of the composites was evaluated by means of a cone calorimeter. A diminution in the peak of the heat release rate was observed when clay was added to the polymeric matrix. On the other hand, neither the time to ignition nor the total heat evolved was significantly reduced by the clay addition. Additionally, an increment in the flexural modulus as well as in the flexural strength of the resol composites was observed when the clay was added to the matrix. The fiber–matrix interface of the composites was studied by scanning electron microscopy. It was observed that as the clay dispersion degree was increased the interface quality was diminished in the resol composites.

Thermal degradation and fire resistance of unsaturated polyester, modified acrylic resins and their composites with natural fibres

The thermal degradation and fire resistance of different natural fibre composites were studied. Unsaturated polyester (UP) and modified acrylic resins (Modar) were used as matrix composites. The smoke emission of the materials was also analysed, as well as, the performance against the fire of the biocomposites and glass reinforced composites was compared. Thermal degradation indicated that the Modar matrix composites were more resistant to temperature than the composites with UP matrix. Flax fibre, due to their low lignin content, exhibit the best thermal resistance among the natural fibres studied. From the results obtained about the thermal and fire resistance of the composites it is possible to conclude that the flax fibre seems to be the most adequate to be used, due to the long time to ignition and the long period prior to reach the flashover. On the other hand, the jute fibre composites showed a short duration but a quick growing fire with the lowest smoke emission. The low smoke is an important advantage, which reduces one of the main hazards of fire.

Effect of particle size on the properties of Mg(OH)2‐filled rubber composites

AbstractA novel nanomagnesium hydroxide powder and three kinds of micro‐Mg(OH)2, with different particle sizes, were chosen as fillers and mixed with ethylene–propylene–diene monomer rubber (EPDM) to form a series of composites by a traditional rubber‐processing technique. The results showed that the mechanical properties of composites improved with decreasing particle size. The nanocomposites were far stronger than the microcomposites, which also supported the view that rubber reinforcement requires nanoreinforcement. The effect of particle size on the fire resistance of composites was investigated by cone calorimetry and limiting oxygen index analysis, which showed that the particle size of powder had an impact on the fire resistance of composites. For the composites filled with untreated powder, the peak value of heat release rate decreased and Tign increased with decreasing particle size. In conclusion, the fire resistance of nanocomposites was better than that of microcomposites. Surface modification of particles sometimes substantially improved the mechanical properties of nanocomposites, but had no effect on either the mechanical properties of microcomposites or the fire resistance of nanocomposites and flame retardance. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2341–2346, 2004