Abstract
Rigid polyurethane foam (RPUF) was an organic porous material, which was applied in many fields for excellent thermal insulation and mechanical properties, especially in building insulation. However, the poor fire performance significantly suppresses its further application. In this work, aluminum diethylphosphinate (ADP) combined with expanded graphite (EG) to form a synergistic flame retarded system, which was introduced to fabricate flame retarded rigid polyurethane foam composites (FR-RPUF) by one-step water-blown method. Furthermore, thermal insulation, thermal stability, fire performance, and decomposition products of RPUF and FR-RPUF composites were systematically investigated. It was found that FR-RPUF composites possessed LOI of 25.9 vol% with V-1 rating in UL-94 test when 10 php of ADP and 20 php of EG were added, which were better than RPUF composites with ADP or EG added alone. MCC test showed that RPUF/ADP24/EG6 had the lowest PHRR value of 159.85 W/g, which was 52.01 W/g lower than that of pure RPUF. Gas phase products investigation implied that the combination of ADP and EG could decrease toxic and combustible gases intensities, thus significantly enhancing fire safety of FR-RPUF composites. SEM test indicated that ADP and EG promoted the formation of dense and continuous char residue, which significantly inhibited heat and substance transfer in combustion, thus significantly enhancing fire performance of FR-RPUF composites.
Highlights
Rigid polyurethane foams (RPUF), as a novel organic porous material, are widely applied in building, pipeline engineering, refrigerator, and other fields for its excellent thermal insulation performance and mechanical properties (Hejna et al, 2018; Wang et al, 2018; Li et al, 2020; Wang et al, 2020)
Expandable graphite (EG) is combined with aluminum diethylphosphinate (ADP) to form a novel synergistically flame retarded system, which is further introduced in RPUF
It is worth noting that RPUF/ADP12/expandable graphite (EG) (Akdogan et al, 2020), RPUF/ADP10/EG20, RPUF/ADP7.5/EG22.5, and RPUF/ADP6/EG24 composites have greater limiting oxygen index (LOI) values compared with RPUF/ADP30 and RPUF/EG30. These results indicate that there exists a good synergistic flame retardant effect between ADP and EG
Summary
Rigid polyurethane foams (RPUF), as a novel organic porous material, are widely applied in building, pipeline engineering, refrigerator, and other fields for its excellent thermal insulation performance and mechanical properties (Hejna et al, 2018; Wang et al, 2018; Li et al, 2020; Wang et al, 2020). RPUF is to be ignited and released kinds of toxic and combustible gases, which would result in heavy casualties in the fire (Barkoula et al, 2008; Liu and Wang, 2018). This shortcoming significantly restricts the further application of RPUF and RPUF composites in many fields, especially in building constructions. Many researchers try to enhance flame retardancy of RPUF (Wang et al, 2018; Bhoyate et al, 2019). Additive and reactive strategies are the common ways to enhance fire performance of RPUF and its composites.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
