Phosphorus/phosphorus-nitrogen flame retardants applied to polyurethane/rice husk eco-composites: thermal behavior, flame retardancy, and physico-mechanical properties

• Published in: Polymer bulletin (Berlin, Germany) Vol. 78; no. 5; pp. 2727 - 2743
• Main Authors: Son, Tung, Nguyen, Hien T. T., Phan, Huong T. Q., Pham, Chi T., Nguyen, Binh T., Pham, Lam H., Do, Thi Vi Vi, Vothi, Hai, Kim, Jinhwan, Hoang, Dong Quy
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.05.2021; Springer Nature B.V
• Subjects: Aluminum; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Complex Fluids and Microfluidics; Composite materials; Compressive strength; Cooling effects; Dilution; Flame retardants; Fourier transforms; Hydrogen; Mechanical properties; Nitrogen; Organic Chemistry; Original Paper; Phosphorus; Physical Chemistry; Polyesters; Polyethylene terephthalate; Polymer Sciences; Polymers; Polyurethane resins; Polyvinyl chloride; Pore size; Rice; Scanning electron microscopy; Soft and Granular Matter; Thermal stability; Thermodynamic properties; Thermogravimetric analysis; Vapor phases; Viscosity; United States > US; China; Japan; Diammonium hydrogen phosphate; Phosphorus/phosphorus-nitrogen flame retardants; Polyurethane/rice husk eco-composite; Aluminum hydrogen phosphite; Thermal stability
• ISSN: 0170-0839; 1436-2449
• DOI: 10.1007/s00289-020-03237-w

The objective of this work is to investigate the influence of two phosphorus/phosphorus-nitrogen flame retardants including diammonium hydrogen phosphate (DAP) and aluminum hydrogen phosphite (AHP) on the flame performance of polyurethane/rice husk (PUF-RH) eco-composites. The fire retardancy and thermal stability of the prepared composites were studied by UL-94, LOI, DSC, and TGA. The fire extinguished completely before reaching the 1-inch mark for PUF-RH containing 15 wt% DAP loading and thus the sample achieved the UL-94 HB. Meanwhile, PUR-RH and PUF-RH/AHP 15 completely burned and failed the UL-94 HB test. A UL-94 V-0 rating was obtained and LOI value significantly increased by 26.3% at 25 wt% loading of DAP for PUF-RH, which is consistent with enhanced thermal stability confirmed by TGA. DAP in PUF-RH mainly acts in fuel dilution and cooling effect, vapor phase, and condensed phase. Differences in experimental and calculated TG analyses strongly support an interaction between DAP and PUF-RH during their decomposition. The presence of DAP results in the composite with more regularity pore size and a higher density which could be reason for its improved compressive strength. DAP is a non-reactive additive in the polymer system; therefore, it does not influence the T g of PUF-RH.