TY - JOUR
T1 - Multielement Flame-Retardant System Constructed with Metal POSS-Organic Frameworks for Epoxy Resin
AU - Hou, Boyou
AU - Zhang, Wenyuan
AU - Lu, Hongyu
AU - Song, Kunpeng
AU - Geng, Zhishuai
AU - Ye, Xinming
AU - Pan, Ye Tang
AU - Zhang, Wenchao
AU - Yang, Rongjie
N1 - Publisher Copyright:
© 2022 Authors. All rights reserved.
PY - 2022/11/2
Y1 - 2022/11/2
N2 - The direct coordination between polyhedral oligomeric silsesquioxane (POSS) and Co forms an assembly of nanoparticles with low specific surface area and leads to a poor dispersion state in the epoxy resin matrix, resulting in unsatisfactory flame-retardant efficiency. Metal-organic frameworks (MOFs), for instance, ZIF-67, provide not only the cobalt element but also the porous framework that endows the nanocomposite of MOFs and POSS with high specific surface area and abundant Co sites in the silica skeleton. Herein, ZIF-67 is hybridized with octacarboxyl POSS, resulting in the removal of the alkaline ligand to form novel metal POSS-organic frameworks (MPOFs). The size differences for organic groups and silica nanocages of POSS vs. micropores of ZIF-67 gave rise to a reverse click reaction, reforming octavinyl POSS isolated on the outer surface of the Co complex, which could be further modified by a phosphorous flame retardant using an addition reaction. The obtained MPOFs-P with 2 wt % loading in epoxy resin could improve the limiting oxygen index value of the composites to 27.0% and pass the V-0 rating in the UL-94 test. Meanwhile, the peaks of the heat release rate and especially the total smoke production were reduced by 46.6 and 25.2%, respectively. The robust char layer reduces the emission of toxic gas CO by 39.8%. The above epoxy product with promising flame retardancy also improved mechanical properties, thanks to the filler with a unique nanostructure. The ingenious work offers enlightenment for the hybridization method of MOFs and POSS to fabricate a multielement flame-retardant system for epoxy resin with high efficacy.
AB - The direct coordination between polyhedral oligomeric silsesquioxane (POSS) and Co forms an assembly of nanoparticles with low specific surface area and leads to a poor dispersion state in the epoxy resin matrix, resulting in unsatisfactory flame-retardant efficiency. Metal-organic frameworks (MOFs), for instance, ZIF-67, provide not only the cobalt element but also the porous framework that endows the nanocomposite of MOFs and POSS with high specific surface area and abundant Co sites in the silica skeleton. Herein, ZIF-67 is hybridized with octacarboxyl POSS, resulting in the removal of the alkaline ligand to form novel metal POSS-organic frameworks (MPOFs). The size differences for organic groups and silica nanocages of POSS vs. micropores of ZIF-67 gave rise to a reverse click reaction, reforming octavinyl POSS isolated on the outer surface of the Co complex, which could be further modified by a phosphorous flame retardant using an addition reaction. The obtained MPOFs-P with 2 wt % loading in epoxy resin could improve the limiting oxygen index value of the composites to 27.0% and pass the V-0 rating in the UL-94 test. Meanwhile, the peaks of the heat release rate and especially the total smoke production were reduced by 46.6 and 25.2%, respectively. The robust char layer reduces the emission of toxic gas CO by 39.8%. The above epoxy product with promising flame retardancy also improved mechanical properties, thanks to the filler with a unique nanostructure. The ingenious work offers enlightenment for the hybridization method of MOFs and POSS to fabricate a multielement flame-retardant system for epoxy resin with high efficacy.
KW - POSS
KW - ZIF-67
KW - epoxy nanocomposites
KW - fire safety
KW - metal-organic framework
UR - http://www.scopus.com/inward/record.url?scp=85140890369&partnerID=8YFLogxK
U2 - 10.1021/acsami.2c14740
DO - 10.1021/acsami.2c14740
M3 - Article
C2 - 36270017
AN - SCOPUS:85140890369
SN - 1944-8244
VL - 14
SP - 49326
EP - 49337
JO - ACS applied materials & interfaces
JF - ACS applied materials & interfaces
IS - 43
ER -