Cone calorimetry tests

Including 4-bromophenol in the phenol-formaldehyde resol system impacts the cross-link density of the cured product. In a systematic study of this copolymer, a comparison was made among the polymers obtained using phenol only, a 9 1 mole ratio of phenol to 4-bromophenol and a 1 1 mole ratio of phenol to 4-bromophenol. Comparisons included measurement of interlaminar shear strength and cone calorimetry tests of composites prepared using these phenolic resins and S2-glass fiber plain weave. 

Figure 12.5 Photos of the residues collected after cone calorimetry tests at 35 kW/m for PMMA-AI2O3 for different amounts.

Figure 13.14 Residue of epoxy/LDH after cone calorimetry test (A) white porous structure of mixed oxides on the internal face (B) black compact carbonaceous residue on the external face. Reproduced...

The use of urea is well documented in the literature [74, 75], as well as the effect of phosphorus-based FRs is strongly affected by the presence of metals [47,49-51,53-56, 62,74-76]. As an example, Gao et al. [76] have recently investigated complexes of cellu-lose-THPC-urea-ammonium dihydrogen phosphate (ADP) with transition metal ion Co and lanthanide metal ions such as La , Ce , Nd and Sm . The experimental data from TG, DTA, DTG and cone calorimetry tests have shown that for the complexes of cellulose-THPC-urea-ADP with the metal ions, the activation energies and thermal decomposition temperatures are higher than those of cellulose-THPC-urea-ADP this finding demonstrates that these metal ions can increase the thermal stability of cellulose-THPC-urea-ADP. Furthermore, these lanthanide metal ions can further increase the thermal stability of samples, unlike the transition metal ion Co . 

Scudamore MJ, Briggs PJ, Prager FH. Cone calorimetry—a review of tests carried out on plastics for the Association of Plastic Manufacturers in Europe. Fire Mater. 1991 15 65-84. 

Bourbigot et al.85 at Lille have used poly(vinylsilsesquioxane) (POSS) in PP (110 wt%) to melt spin filaments, which were then knitted into fabrics. POSS was thermally stable and no degradation was detected in the processing conditions. They have tested the flammability of the fabrics using cone calorimetry. POSS presence had minimal effect on peak heat and total heat release values of PP fabric, but delayed the TTI. This behavior of POSS is opposite to that of layered silicates, which have minimal effect on TTI, but reduce PHRR. Authors claim that POSS does not act as a FR but only as a heat stabilizer via a decrease of the ignitability. 

Researchers in the Lille group have also been successful in preparing yarns from polypropyl-ene/multiwalled carbon nanotubes (MWNT) (1% and 2% by mass) nanocomposites.6-86 Fabrics knitted from these yarns were tested by cone calorimetry. PHRR reduced by 50% for a fraction of nanotubes of only 1 wt % but the TTI of the nanocomposite was shorter. This is shown in Figure 24.9. 

Cone calorimetry according to the ASTM E1354138 or ISO 5660139 standards are commonly used in the laboratory to screen flammability of materials by measuring heat release characteristics of the compound.116140 This device is similar to FPA but does not have the versatility of FPA. The cone calorimeter can determine the ignitability, heat release rates, effective heat of combustion, visible smoke, and C02 and CO development of cable materials. This test has been used extensively for wire and cable material evaluation. The microscale combustion calorimeter (MCC), also known as pyrolysis combustion flow calorimeter (PCFC), was recently introduced to the industry for screening heat release characteristics of FR materials.141142 This device only requires milligram quantities of test specimen to measure the heat release capacity (maximum heat release potential). Cone calorimetry and MCC have been used in product development for flammability screening of wire and cable compounds.118... 

Correlations were also established between UL 94, LOI, MCC, and cone calorimetry for both halogenated and nonhalogenated FR wire and cable compounds.149 The study (Figure 26.5) indicated that LOI has poor correlation with MCC parameters due to different flame combustion mechanisms in the LOI (incomplete combustion) and the MCC (forced complete combustion) tests. This correlation was improved by taking into account the burning efficiencies (i.e., combustion and heat transfer efficiencies) of the polymer compounds.150... 

As a consequence of a very serious fire under the steel roofs in a large car plant in USA the Underwriters Laboratories Inc., developed a new UL test method, which uses oxygen consumption cone calorimetry to quantify roof covering materials. This test was used to quantify the contribution of roof covering materials to the fire under the roof by capturing effluent from beneath the roof assembly and recording the rate of heat production in kW/min. 

In further work Wachowicz [26] compared large-scale gallery testing with cone calorimetry in the evaluation of the flammability of conveyor belts. A good correlation is shown between results of conveyor belt flammability during combustion in a fire testing gallery and predicted HRR based on bench scale cone calorimetry. 

Intumescence of polyethylene (PE) and PP has been reviewed using as intumescent agents zeolites [36], melamine phosphate and pentaerythritol [37]. Ammonium polyphosphate-pentaerythritol [38], zinc borate and ammonium polyphosphate [39], and APP [40], limiting oxygen index (LOI) [36, 37], cone calorimetry [36] and the UL 94 test [25, 36, 37] have all been used in these studies. 

EG leads to formation of a char layer characterised by the presence of worms resulting from its expansion. It was found that the higher the filler content the lower the compression strength. The presence of APP or MC results in worsening of thermal conductivity while the presence of EG leads to an increase in thermal conductivity. Cone calorimetry and the LOI test were used to study the fire behaviour. The best... 

ISO 5660-1 (2002) Reaction-to-Fire Tests - Heat Release, Smoke Production and Mass Loss Rate - Part 1 Heat Release Rate (Cone Calorimetry Method). 

Limitations of applicability. In some tests, the overall behaviour is dependent on the possible spread of fire within the specimen area. An example is the SBI test in which heat release data are quite comparable with cone calorimetry if those from the product tested are such that it will not spread fire much beyond the area of highest exposure behind the flame in the SBI comer. However, this simple correlation is most probably not valid anymore for a product that will spread fire under the SBI method. 

While a complete survey of the testing techniques for flame retardants is beyond the scope of this chapter, testing methods such as cone calorimetry, the requirements of the UL 94 testing protocols, and radiant heat panels deserve mention here. 

Cone calorimetry (CC) is one of the most effective medium-sized polymer fire behavior tests. The principle of cone calorimeter experiments is based on the measurement of the decreasing oxygen concentration in the combustion gases of a sample subjected to a given heat flux, in general from 10 to 100 kW/m [83]. Figure 4 illustrates the experimental set-up of a cone calorimeter. Standardized in the United States (ASTM E 1354), the cone calorimeter test is also the subject of an international standard (ISO 5660). 

Using factorial analysis, samples of the mohair/silk (MS) fabric were variously treated with a selection of flame retardants, back-coating formulations and adhesive, mounted on a typical aramid honeycomb board specimen, and each composite was tested using cone calorimetry at the preferred heat flux of 50 kW (shown to be equivalent to the 35 kW m flux used in the OSU calorimeter). 1 An optimum combination of flame retardant, back-coating and adhesive at specific application levels was found to yield the lowest heat release values, and this system was applied to each of the above six fabrics. Testing in both the OSU at 35 kW m heat flux and at 50 kW m" in the cone calorimeter gave the results for peak heat release in Table 4.5 below. From this it is seen that all fabrics have PHRR values < 65 kW m" and that OSU and cone calorimeter results are equivalent. 

Table 4.5 PHRR values for fabric/board composites tested to FAR 25.853 Part IV Appendix F and cone calorimetry ...

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