TY - JOUR
T1 - Enhancing char formation of flame retardant epoxy composites
T2 - Onigiri-like ZIF-67 modification with carboxymethyl β-cyclodextrin crosslinking
AU - Li, Qianlong
AU - Han, Zhengde
AU - Song, Xiaoning
AU - Pan, Ye Tang
AU - Geng, Zhishuai
AU - Vahabi, Henri
AU - Realinho, Vera
AU - Yang, Rongjie
N1 - Publisher Copyright:
© 2024 Elsevier Ltd
PY - 2024/6/1
Y1 - 2024/6/1
N2 - To enhance char formation of flame retardant epoxy (EP) composites, carboxymethyl β-cyclodextrin (CM-β-CD) is employed as an etchant for or ZIF-67 derivatives. In the early stage, etching plays a dominant role. The mismatch in size between CM-β-CD opening and ZIF-67 pore leads to the stacking of carboxyl cobalt complexes on the shell. When the reaction time is prolonged, crosslinking occurs between carboxyl and hydroxyl groups. Crosslinked CM-β-CD weakens and eventually stops the etching process. Triethyl phosphate (TEP), an additive to improve flame retardancy, is also absorbed on the shell in this one-pot synthesis. Herin, the synthesis of metal-organic framework (MOF) derivatives can impart multiple functions to MOF. This novel nanohybrid significantly improved flame retardancy of EP composites with only 2.0 wt% loading. The peak heat release rate (pHRR) and total smoke production (TSP) were reduced by 54.8 and 46.9%, respectively. The integrated multi-element system resulted in an expanded and reinforced char layer. This study proposes a simple and precise method for controlling the structure of MOF-carbohydrate hybrids through competition between chemical reactions.
AB - To enhance char formation of flame retardant epoxy (EP) composites, carboxymethyl β-cyclodextrin (CM-β-CD) is employed as an etchant for or ZIF-67 derivatives. In the early stage, etching plays a dominant role. The mismatch in size between CM-β-CD opening and ZIF-67 pore leads to the stacking of carboxyl cobalt complexes on the shell. When the reaction time is prolonged, crosslinking occurs between carboxyl and hydroxyl groups. Crosslinked CM-β-CD weakens and eventually stops the etching process. Triethyl phosphate (TEP), an additive to improve flame retardancy, is also absorbed on the shell in this one-pot synthesis. Herin, the synthesis of metal-organic framework (MOF) derivatives can impart multiple functions to MOF. This novel nanohybrid significantly improved flame retardancy of EP composites with only 2.0 wt% loading. The peak heat release rate (pHRR) and total smoke production (TSP) were reduced by 54.8 and 46.9%, respectively. The integrated multi-element system resulted in an expanded and reinforced char layer. This study proposes a simple and precise method for controlling the structure of MOF-carbohydrate hybrids through competition between chemical reactions.
KW - Carboxymethyl β-cyclodextrin
KW - Crosslinking
KW - Epoxy composites
KW - Flame retardant
KW - Metal-organic framework
UR - http://www.scopus.com/inward/record.url?scp=85185888398&partnerID=8YFLogxK
U2 - 10.1016/j.carbpol.2024.121980
DO - 10.1016/j.carbpol.2024.121980
M3 - Article
C2 - 38494206
AN - SCOPUS:85185888398
SN - 0144-8617
VL - 333
JO - Carbohydrate Polymers
JF - Carbohydrate Polymers
M1 - 121980
ER -