Expandable Graphite Flakes as an Additive for a New Fire Retardant Coating for Wood and Cellulose Materials – Comparison Analysis

Abstract

The aim of this study was to observe the effectiveness of a new intumescent fire retardant (IFR) formulation for wood and cellulose material, while maintaining its mechanical properties, as well as to affair the effectiveness of the proposed formulation towards ignitability of the referred materials using the parameters of heat release rate (HRR), mass loss (ML) time to ignition (Ti) and time to flame out (Tf). Oxygen Index (OI) was also part of measurements. Whatman filter paper (WFP) and pinewood were used for comparison analysis; three different IFR formulations where designed and exerted to assert the influence of each formulation to the parameters of HRR, ML, Ti and Tf for both materials. WFP and wood samples were coated through the dipping method. After seasoning and drying all samples were submitted to mass loss calorimeter (MLC) measurements. Histogram for each parameter was obtained for all formulations and materials. Preliminary results showed improvements of fire properties of WFP. Control sample did ignite in 9 s (in average); coated samples however, showed a remarkably prolonged Ti = 17 s (in average), representing an increase of 88.88%; Similar results were observed in terms Tf (s). However, it was observed anomalies for the HRR (KW/m2) and MLR (g/s) parameters. An inverse profile of histogram for some IFR formulations was observed at the initial time and at the end of the experiment. The IFR formulations are clearly slowing burning performance of the materials; anomalies in the profile HRR, MLR and HC is due to irregularities within the extremities of the material structure (porosity and permeability).