Excellent Fireproof Characteristics and High Thermal Stability of Rice Husk-Filled Polyurethane with Halogen-Free Flame Retardant

Autor: Binh T. Nguyen, Chi T. Pham, Jinhwan Kim, DongQuy Hoang, Lam H. Pham, Cuong N. Hoang, Huong T. Q. Phan, Thi Vi Vi Do, Nguyen Ngan Nguyen
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: Polymers, Vol 11, Iss 10, p 1587 (2019)
Polymers
Volume 11
Issue 10
ISSN: 2073-4360
Popis: The thermal stabilities, flame retardancies, and physico-mechanical properties of rice husk-reinforced polyurethane (PU&ndash
RH) foams with and without flame retardants (FRs) were evaluated. Their flammability performances were studied by UL94, LOI, and cone calorimetry tests. The obtained results combined with FTIR, TGA, SEM, and XPS characterizations were used to evaluate the fire behaviors of the PU&ndash
RH samples. The PU&ndash
RH samples with a quite low loading (7 wt%) of aluminum diethylphosphinate (OP) and 32 wt% loading of aluminum hydroxide (ATH) had high thermal stabilities, excellent flame retardancies, UL94 V-0 ratings, and LOIs of 22%&ndash
23%. PU&ndash
RH did not pass the UL94 HB standard test and completely burned to the holder clamp with a low LOI (19%). The cone calorimetry results indicated that the fireproof characteristics of the PU foam composites were considerably improved by the addition of the FRs. The proposed flame retardancy mechanism and cone calorimetry results are consistent. The comprehensive FTIR spectroscopy, TG, SEM, and XPS analyses revealed that the addition of ATH generated white solid particles, which dispersed and covered the residue surface. The pyrolysis products of OP would self-condense or react with other volatiles generated by the decomposition of PU&ndash
RH to form stable, continuous, and thick phosphorus/aluminum-rich residual chars inhibiting the transfer of heat and oxygen. The PU&ndash
RH samples with and without the FRs exhibited the normal isothermal sorption hysteresis effect at relative humidities higher than 20%. At lower values, during the desorption, this effect was not observed, probably because of the biodegradation of organic components in the RH. The findings of this study not only contribute to the improvement in combustibility of PU&ndash
RH composites and reduce the smoke or toxic fume generation, but also solve the problem of RHs, which are abundant waste resources of agriculture materials leading to the waste disposal management problems.
Databáze: OpenAIRE
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