Flame Retarded Rigid Polyurethane Foams Composites Modified by Aluminum Diethylphosphinate and Expanded Graphite

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.

A liquid phosphorous flame retardant combined with expandable graphite or melamine in flexible polyurethane foam

“…This is because the synergistic effect was exerted by BDMPP and EG. The gluing effect of BDMPP strengthened the integrality and continuity of the EG char layer 32,33 …”

A liquid phosphorous flame retardant combined with expandable graphite or melamine in flexible polyurethane foam

“…This is because the synergistic effect was exerted by BDMPP and EG. The gluing effect of BDMPP strengthened the integrality and continuity of the EG char layer 32,33 …”

Rigid polyurethane foam compounds with excellent fire performance modified by a piperazine pyrophosphate/expandable graphite synergistic system

“…In the first stage, that is, from room temperature to 335°C, the weight loss is attributed to the shedding of water molecules; PAPP contains POH and OH·NH, which release H 2 O molecules after heating 27,28 . The second stage from 335°C to 440°C is mainly ascribed to the dehydrogenation of the piperazine ring, resulting in breakage of the CC and CN bonds, 29 forming a cross‐linked char residue. At the same time, pyrophosphate decomposed into phosphoric acid and polyphosphate 19 .…”

“…The degradation of RPUF occurred in two stages. The first stage involved the decomposition of hard segments, 29 which underwent dehydration with increasing temperature and produced hydrocarbons to release CO 2 . The second stage involved the degradation of the soft segments 30,31 .…”

A Systematic Review and Bibliometric Analysis of Flame-Retardant Rigid Polyurethane Foam from 1963 to 2021

“…These papers do not have a particularly uniform orientation in terms of subject matter. Some of the works focused on modifying phosphorus-containing materials [ 76 , 117 ] and others on the modification of ammonia-containing materials [ 112 , 113 ]. In addition to this, there were also some works on the detailed performance investigation of traditional RPUF [ 108 , 111 ].…”

“…# 3 Phosphate: The content of this cluster was mainly concerned with the effects of using different phosphates on the properties of RPUF. For example, Hu et al [ 117 ] used aluminum diethylphosphinate; Zhang et al [ 118 ] chose castor oil phosphate. Generally speaking, there are two types of phosphorus-containing flame retardant: additive type and reactive type.…”

A liquid phosphorous flame retardant combined with expandable graphite or melamine in flexible polyurethane foam

“…This is because the synergistic effect was exerted by BDMPP and EG. The gluing effect of BDMPP strengthened the integrality and continuity of the EG char layer 32,33 …”

Rigid polyurethane foam compounds with excellent fire performance modified by a piperazine pyrophosphate/expandable graphite synergistic system

“…In the first stage, that is, from room temperature to 335°C, the weight loss is attributed to the shedding of water molecules; PAPP contains POH and OH·NH, which release H 2 O molecules after heating 27,28 . The second stage from 335°C to 440°C is mainly ascribed to the dehydrogenation of the piperazine ring, resulting in breakage of the CC and CN bonds, 29 forming a cross‐linked char residue. At the same time, pyrophosphate decomposed into phosphoric acid and polyphosphate 19 .…”

“…The degradation of RPUF occurred in two stages. The first stage involved the decomposition of hard segments, 29 which underwent dehydration with increasing temperature and produced hydrocarbons to release CO 2 . The second stage involved the degradation of the soft segments 30,31 .…”

A Systematic Review and Bibliometric Analysis of Flame-Retardant Rigid Polyurethane Foam from 1963 to 2021

“…These papers do not have a particularly uniform orientation in terms of subject matter. Some of the works focused on modifying phosphorus-containing materials [ 76 , 117 ] and others on the modification of ammonia-containing materials [ 112 , 113 ]. In addition to this, there were also some works on the detailed performance investigation of traditional RPUF [ 108 , 111 ].…”

“…# 3 Phosphate: The content of this cluster was mainly concerned with the effects of using different phosphates on the properties of RPUF. For example, Hu et al [ 117 ] used aluminum diethylphosphinate; Zhang et al [ 118 ] chose castor oil phosphate. Generally speaking, there are two types of phosphorus-containing flame retardant: additive type and reactive type.…”

A liquid phosphorous flame retardant combined with expandable graphite or melamine in flexible polyurethane foam

“…This is because the synergistic effect was exerted by BDMPP and EG. The gluing effect of BDMPP strengthened the integrality and continuity of the EG char layer 32,33 …”

Rigid polyurethane foam compounds with excellent fire performance modified by a piperazine pyrophosphate/expandable graphite synergistic system

“…In the first stage, that is, from room temperature to 335°C, the weight loss is attributed to the shedding of water molecules; PAPP contains POH and OH·NH, which release H 2 O molecules after heating 27,28 . The second stage from 335°C to 440°C is mainly ascribed to the dehydrogenation of the piperazine ring, resulting in breakage of the CC and CN bonds, 29 forming a cross‐linked char residue. At the same time, pyrophosphate decomposed into phosphoric acid and polyphosphate 19 .…”

“…The degradation of RPUF occurred in two stages. The first stage involved the decomposition of hard segments, 29 which underwent dehydration with increasing temperature and produced hydrocarbons to release CO 2 . The second stage involved the degradation of the soft segments 30,31 .…”

A Systematic Review and Bibliometric Analysis of Flame-Retardant Rigid Polyurethane Foam from 1963 to 2021

“…These papers do not have a particularly uniform orientation in terms of subject matter. Some of the works focused on modifying phosphorus-containing materials [ 76 , 117 ] and others on the modification of ammonia-containing materials [ 112 , 113 ]. In addition to this, there were also some works on the detailed performance investigation of traditional RPUF [ 108 , 111 ].…”

“…# 3 Phosphate: The content of this cluster was mainly concerned with the effects of using different phosphates on the properties of RPUF. For example, Hu et al [ 117 ] used aluminum diethylphosphinate; Zhang et al [ 118 ] chose castor oil phosphate. Generally speaking, there are two types of phosphorus-containing flame retardant: additive type and reactive type.…”