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From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding
Published on: March 24, 2018
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Effective Halogen-Free Flame-Retardant Additives for Crosslinked Rigid Polyisocyanurate Foams: Comparison of Chemical
Johannes U Lenz1, Doris Pospiech1, Hartmut Komber1
1Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Str. 6, 01069 Dresden, Germany.
Materials (Basel, Switzerland)
|January 8, 2023
Summary
This study compares phosphorus flame retardants (FR) in polyisocyanurate (PIR) foams. DOPO is more effective as a filler, while BPPO excels when incorporated into the PIR network.
Area of Science:
- Materials Science
- Polymer Chemistry
- Fire Safety Engineering
Background:
- Rigid polyisocyanurate (PIR) foams are widely used but require flame retardants for enhanced fire safety.
- Phosphorus-containing flame retardants (P-FRs) offer an alternative to halogenated options, but their efficacy depends on chemical structure and integration into the polymer matrix.
Purpose of the Study:
- To investigate the impact of different phosphorus-containing flame retardant structures on the properties, thermal decomposition, and fire behavior of rigid PIR foams.
- To compare the performance of novel non-NCO-reactive and NCO-reactive dibenzo[d,f][1,3,2]dioxaphosphepine 6-oxide (BPPO) and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) based FRs against standard FRs and PIR foams without FR.
Main Methods:
- Systematic synthesis and incorporation of various BPPO- and DOPO-containing compounds into PIR foam formulations.
- Evaluation of foam properties, including mechanical strength and thermal stability.
- Analysis of thermal decomposition pathways using techniques like TGA.
- Assessment of fire behavior through standardized testing.
Main Results:
- The position and reactivity of the flame retardant within the PIR polymer network significantly influence its effectiveness.
- DOPO-based FRs demonstrated higher efficacy when acting as a filler or a dangling group (non-reactive end) in the PIR network.
- BPPO-based FRs showed superior performance when chemically incorporated as a diol subunit, becoming an integral part of the PIR network.
Conclusions:
- The chemical structure and integration method of phosphorus flame retardants are critical factors determining their performance in PIR foams.
- Tailoring the FR structure and its interaction with the PIR matrix allows for optimized fire safety properties.
- This research provides valuable insights for designing next-generation, high-performance flame-retarded PIR materials.
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