The rapid mass calorimeter: A route to high throughput fire testing

Abstract

Summary The rapid mass calorimeter based on reduced‐size specimens is proposed for accelerated fire testing and put up for discussion, particularly for flame retarded polymeric materials. A mass loss calorimeter is combined with a semiautomatic sample changer. Experiments on specimens of reduced size were conducted on poly(methyl methacrylate), poly(propylene), polyamide 66, poly(ether ether ketone), and pine sapwood square samples with edge lengths of 100, 75, 50, 25, 20, and 10 mm. Specimens of 20 × 20 mm2 were selected to achieve a crucial reduction in specimen size and a measuring protocol developed. A total of 71 different polymeric materials were investigated in the rapid mass calorimeter and cone calorimeter for comparison and several materials with different heat release rate characteristics in the pyrolysis combustion flow calorimeter to test this additional screening method as well. The important fire properties obtained in the rapid mass calorimeter show reasonable correlation with the cone calorimeter results but also with the oxygen index. All in all, the rapid mass calorimeter produces reliable and meaningful results and, despite acceleration and size reduction, still allows for a certain degree of burning behavior interpretation. Material savings of 96% and time savings of around 60%‐70% are achieved compared to measure cone calorimeter.

Phosphorus‐Containing Polymer Flame Retardants for Aliphatic Polyesters

“…Decrease in EHC and increase of CO yield leveled off with increasing P‐content and indicated that the gas phase effectivity of DOPO decreased at higher concentrations. This kind of leveling off has been reported before for flame inhibition by several P‐containing flame retardants and is a typical effect of P‐containing species in the gas phase . DOPO polyesters with C:O ratios between 3.5:1 and 1.5:1 in the polymer backbone were investigated.…”

“…As shown in Figure c, the relation between PHRR and P‐content and between THE and P‐content is non‐linear and presents the highest relative reduction of PHRR and THE for lower P‐content. The levelling off in the flame retardancy performance and thus much higher efficiency at low P‐contents has been reported for P‐containing flame retardants before . With increasing P‐content, PHRR and THE decreased further but the flame retardancy efficiency levelled off.…”

Phosphorus‐containing Salen‐Ni metal complexes enhancing the flame retardancy and smoke suppression of epoxy resin composites

“…Although the metal‐doped Salen structure exhibits good flame retardancy to the polymer material, it is not difficult to find that its flame‐retardant effect mainly plays a role in the condensed phase . As is well‐known that phosphorus‐based flame retardants have the significant flame‐retardant role both in gas and condensed phase . For gas‐phase flame‐retardant, it is believed that the phosphorus‐containing components and their derivatives can easily evolve into phosphorus‐based radicals (e.g., PO 2 • and PO•), which will further quench the other free‐radicals to realize the disruption of free‐radical chain reactions in gas‐phase .…”

Flame‐retardant effects of cyclic phosphonate with HALS and fumed silica in polypropylene

“…The FTIR spectra of S1, S5, and S9 at 365 °C ( T DTGma of PCO‐900) are shown in Figure (a). The bands with small intensities at 1084 and 1146 cm −1 for S‐5 suggest the existence of radical phosphorus species (PO 2− ) produced by the decomposition of PCO‐900 in the gas phase . At around 450 °C, the differences in spectra of PP composites at the wavenumber region 1500–1600 cm −1 were ascribed to the increased formation of (heterocyclic) ring structures that promote carbonization .…”