Expandable Graphite as a Multifunctional Flame-Retarding Additive for Highly Filled Thermal Conductive Polymer Formulations

Tomiak F, Schneider K, Schoeffel A, Rathberger K, Drummer D (2022)

Publication Type: Journal article

Publication year: 2022

Journal

Polymers MDPI

Book Volume: 14

Journal Issue: 8

DOI: 10.3390/polym14081613

Abstract

Expandable graphite (EG) and graphite (G) were assessed as multifunctional additives improving both flame retardancy and thermal conductivity in highly filled, thermal conductive polymeric materials based on polyamide 6 (PA6). Fire testing was conducted using modern UL-94, LOI and cone calorimeter test setups. It is demonstrated that thermal conductivity can significantly influence the time to ignition, although offering little fire resistance once ignited even in highly filled systems. Thus, for PA6 formulations containing solely 70 wt.% G, the peak heat release rate (pHRR) measured in cone calorimeter tests was 193 kW/m(2), whereas PA6 formulations containing 20 wt.% EG/50 wt.% G did not exhibit a measurable heat development. Particular attention was paid to effect separation between thermal conductivity and residue formation. Good thermal conductivity properties are proven to be particularly effective in test scenarios where the heat impact is comparatively low and the testing environment provides good heat dissipation and convective cooling possibilities. For candle-like ignition scenarios (e.g., LOI), filling levels of >50 wt.% (G or EG/G) are shown to be sufficient to suppress ignition exclusively by thermal conductivity. V0 classifications in UL-94 vertical burning tests were achieved for PA6 formulations containing >= 70 wt.% G, >= 25 wt.% EG and >= 20 wt.% EG/25 wt.% G.

Authors with CRIS profile

Florian Tomiak Lehrstuhl für Kunststofftechnik Kevin Schneider Lehrstuhl für Kunststofftechnik Dietmar Drummer Lehrstuhl für Kunststofftechnik

Involved external institutions

Georg H. LUH GmbH DE Germany (DE)

How to cite

APA:

Tomiak, F., Schneider, K., Schoeffel, A., Rathberger, K., & Drummer, D. (2022). Expandable Graphite as a Multifunctional Flame-Retarding Additive for Highly Filled Thermal Conductive Polymer Formulations. Polymers, 14(8). https://dx.doi.org/10.3390/polym14081613

MLA:

Tomiak, Florian, et al. "Expandable Graphite as a Multifunctional Flame-Retarding Additive for Highly Filled Thermal Conductive Polymer Formulations." Polymers 14.8 (2022).

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