In situ growth of ZIF-67 nanocrystals on layered double hydroxides for flame⁃retardant epoxy composites

doi:10.19491/j.issn.1001-9278.2025.04.006

Abstract

Abstract:

In this study， Co⁃LDH@ZIF⁃67 composite structure was constructed in situ using Co⁃LDH as a carrier， which effectively improves the defects of low catalytic activity and low specific surface area of Co⁃LDH. The flame retardancy tests showed that the Co⁃LDH@ZIF⁃67 modified epoxy （EP） composites had significant advantages in suppressing heat， smoke， and toxic gases compared to Co⁃LDH. Specifically， the LOI value of the composites increased from 24.5 % to 28.2 % when Co⁃LDH@ZIF⁃67 was added at 2 wt%. The peak heat release rate， the total heat release， and the total smoke release of the EP/Co⁃LDH@ZIF⁃67 composites were reduced by 35.1 %， 16.3 %， and 15.8 %， respectively， compared with pure EP. And it has more obvious flame retardant and smoke suppression ability compared with Co⁃LDH.

Key words: metal-organic frameworks, layered double hydroxides, epoxy resin, flame retardancy

CLC Number:

TQ323.5

SONG Kunpeng, BAI Wei, XIE Meina, HE Jiyu, YANG Rongjie. In situ growth of ZIF-67 nanocrystals on layered double hydroxides for flame⁃retardant epoxy composites[J]. China Plastics, 2025, 39(4): 31-36.

Figures/Tables 17

Fig.1. Schematic diagram of samples preparation process

Fig.2. TEM， SEM and element mapping images of the samples

Fig.3. XRD pattern of the samples

Fig.4. FTIR spectra of samples

Fig.5. XPS spectra of the samples

信号	键能/eV	含量/%
信号	键能/eV	Co⁃LDH	Co⁃LDH@ZIF
C 1s	285.5	12.0	30.5
N 1s	398.6	0.7	7.9
O 1s	529.5	64.2	30.4
Co 2p	779.5	23.1	31.2

Tab.1. XPS data of the products

Fig.6. Nitrogen adsorption/desorption curves of the samples

Fig.7. Pore diameter distribution curves of the samples

样品	S_BET/m²·g^-1	平均孔径分布/nm
Co⁃LDH	582.3	6.7
Co⁃LDH@ZIF	58.2	2.4

Tab.2. BET surface area and average pore diameter data of the products.

Fig.8. TG curves of the samples

样品	T_{5 %}/℃	T_max/℃	800 ℃下的残炭率/%
Co⁃LDH	229.5	241.2	62.2
Co⁃LDH@ZIF	221.3	487.1	48.9

Tab.3. TG and DTG data of the products under nitrogen.

Fig.9. SEM of brittle surfaces of EP and its composites

Fig.10. TG curves of EP and its composites

样品	T_{5 %}/℃	T_max/℃	800 ℃下的残炭率/%
EP	355.6	399.6	5.6
EP/Co⁃LDH	338.5	365.1	12.4
EP/Co⁃LDH@ZIF	339.6	366.8	16.8

Tab.4. TG and DTG data of EP and its composites under nitrogen

参数	EP	EP/Co⁃LDH	EP/Co⁃LDH@ZIF
LOI/%	24.5	26.1	28.2
PHRR/kW·m^-2	1 200.1	1 005.9	778.6
THR/MJ·m^-2 （500 s）	88.7	82.6	74.2
TSP/m²（500 s）	23.4	22.3	19.7
av⁃COY/kg·kg^-1	0.094 0	0.089 8	0.084 5
av⁃CO₂Y/kg·kg^-1	1.913 5	1.862 6	1.725 0
残炭率/%	3.4	5.9	8.2

Tab.5. Combustion properties of the samples

Fig.11. HRR， THR， TSP， av⁃COY， and av⁃CO2Y curves of the samples

Fig.12. Photos and SEM images of residual char

References 18

1	Zou Y， Xiong Z， Li Y， et al. Phosphoric acid⁃based hydrogen⁃bonded organic framework offer both photoluminescence⁃functionalized and excellent flame retardancy for epoxy composite ［J］. Chemical Engineering Journal， 2023， 476： 146651.
2	Zhang A， Zhang J， Liu L， et al. Engineering phosphorus⁃containing lignin for epoxy biocomposites with enhanced thermal stability， fire retardancy and mechanical properties ［J］. Journal of Materials Science & Technology， 2023， 167： 82⁃93.
3	Liu X， Zhou J， Zhao J， et al. Design and synthesis of polyetherimides as a flame⁃retarded thermolatent hardener for high⁃performance epoxy thermosets ［J］. Composites Part B： Engineering， 2023， 259： 110754.
4	Deng C， Liu Y， Jian H， et al. Study on the preparation of flame retardant plywood by intercalation of phosphorus and nitrogen flame retardants modified with Mg/Al⁃LDH ［J］. Construction and Building Materials， 2023， 374： 130939.
5	Kim M， Kim J. Enhancement of the flame retardant properties of PPS⁃based composites via the addition of melamine⁃coated CaAl⁃LDH fire⁃retardant filler ［J］. European Polymer Journal， 2023， 201： 112584.
6	Yu J， Wang Q， O'Hare D， et al. Preparation of two dimensional layered double hydroxide nanosheets and their applications ［J］. Chemical Society Reviews， 2017， 46： 5 950⁃5 974.
7	Song K， Zhang H， Pan Y T， et al. Metal⁃organic framework⁃derived bird's nest⁃like capsules for phosphorous small molecules towards flame retardant polyurea composites ［J］. Journal of Colloid and Interface Science， 2023， 643： 489⁃501.
8	Wang T J， Liu X， Li Y， et al. Ultrasonication⁃assisted and gram⁃scale synthesis of Co⁃LDH nanosheet aggregates for oxygen evolution reaction ［J］. Nano Research， 2020， 13： 79⁃85.
9	Song K， Li X， Pan Y T， et al. The influence on flame retardant epoxy composites by a bird's nest⁃like structure of Co⁃based isomers evolved from zeolitic imidazolate framework-67 ［J］. Polymer Degradation and Stability， 2023， 211： 110318.
10	Song K， Bi X， Yu C， et al. A Gas⁃steamed route to mesoporous open metal⁃organic framework cages enhancing flame retardancy and smoke suppression of polyurea ［J］. ACS Applied Materials & Interfaces， 2024， 16： 7 617⁃7 630.
11	Wang X， Wu T， Hong J， et al. Organophosphorus modified hollow bimetallic organic frameworks： Effective adsorption and catalytic charring of pyrolytic volatiles ［J］. Chemical Engineering Journal， 2021， 421： 129697.
12	Bi X， Song K， Zhang H， et al. Dimensional change of red phosphorus into nanosheets by metal–organic frameworks with enhanced dispersion in flame retardant polyurea composites ［J］. Chemical Engineering Journal， 2024， 482： 148997.
13	Han Z， Zhang W， Song X， et al. Fast char formation induced by POSS confining Co⁃MOF hollow prisms in epoxy composites with mitigated heat and smoke hazards ［J］. Chemical Engineering Journal， 2023， 474： 145682.
14	Sun Y， Yu B， Liu Y， et al. Bio⁃inspired surface manipulation of halloysite nanotubes for high⁃performance flame retardant polylactic acid nanocomposites ［J］. Nano Research， 2024， 17： 1 595⁃1 606.
15	Wang R， Chen Y， Liu Y， et al. Synthesis of sugar gourd⁃like metal organic framework⁃derived hollow nanocages nickel molybdate@cobalt⁃nickel layered double hydroxide for flame retardant polyurea ［J］. Journal of Colloid and Interface Science， 2022， 616： 234⁃245.
16	Sun Y， Yu B， Liu Y， et al. Design of 2D charring⁃foaming agent for highly efficient intumescent flame retardant polylactic acid composites ［J］. Composites Communications， 2023， 43： 101720.
17	Song K， Pan Y T， Zhang J， et al. Metal⁃organic frameworks⁃based flame⁃retardant system for epoxy resin： a review and prospect ［J］. Chemical Engineering Journal， 2023， 468： 143653.
18	Zhang J， Li Z， Qi X L， et al. Recent progress on metal⁃organic framework and its derivatives as novel fire retardants to polymeric materials ［J］. Nano⁃Micro Letters， 2020， 12： 173.

[1]	WU Qimin, WANG Weimin, LE Deliang, LIN Zhonghua, PEI Kemei. Research progress in epoxy resin cement mortar repair materials [J]. China Plastics, 2025, 39(3): 109-113.
[2]	. Research Progress of Epoxy Resin cement mortar repair materials [J]. , 2025, 39(3): 109-113.
[3]	WANG Bo, ZHANG Qian, GAO Yan, WU Longkun, LEI Ying, LIU Nianjie. Research progress in silicone⁃modified epoxy resin [J]. China Plastics, 2025, 39(1): 126-131.
[4]	JI Jiajun, ZHANG Zengping, LI Junhui, SHI En, LI Qingxu. Research and application progress of epoxy resin sealant used in highway engineering [J]. China Plastics, 2025, 39(1): 63-74.
[5]	WEI Shenzhi, CHEN Juan, RAO Jie, ZHANG Yinghao, ZHOU Minjie, ZHANG Qi. Preparation of new phosphorus⁃nitrogen composite flame retardant and its application in TPU [J]. China Plastics, 2024, 38(9): 88-93.
[6]	WU Weihong, ZHANG Jing, ZHANG Ge, GENG Rongrong, QU Hongqiang. Preparation of piperazine pyrophosphate @COF flame retardant and its flame retardant effect on epoxy resin [J]. China Plastics, 2024, 38(8): 88-93.
[7]	DU Rong, LIN Tong, XIAO Hang, YIN Lyu, ZHANG Jin. Research progress in preparation， properties and applications of nano⁃Fe₃O₄ modified epoxy resin [J]. China Plastics, 2024, 38(6): 132-138.
[8]	WANG Han, LIANG Jinhua, GAO Zhenguo, JIANG Wei, ZHOU Hao. Mechanical properties and repair efficiency of self⁃repairing microencapsulated epoxy resin [J]. China Plastics, 2024, 38(5): 40-46.
[9]	ZHANG Qingsong, LI Liangyong, CAO Weiqiang, CHENG Yanwen, PENG Tianxiang, WANG Juntong, LI Houyang. Effect of alkali⁃treated coir⁃geotextile on the tensile properties of epoxy resin⁃based materials [J]. China Plastics, 2024, 38(4): 26-31.
[10]	WANG Dong. Research progress in metal⁃organic framework⁃based flame retardants in flame⁃retardant polymers [J]. China Plastics, 2024, 38(2): 118-125.
[11]	LIU Gang, JIANG Xiong, LANG Tao, WANG Yi, ZHANG Lu, HU Songchao, CHANG Yijun, ZHANG Qilu. A comparative study on water resistance of polyurethane and epoxy resin coatings [J]. China Plastics, 2024, 38(2): 39-44.
[12]	TONG Yaxuan, GAO Hainan, CHEN Liping, WENG Yunxuan. Research progress in modification and functionalization of bio⁃based aerogels [J]. China Plastics, 2024, 38(2): 87-94.
[13]	HU Peng, XU Hao, CAI Shaojun. Preparation and properties of waste epoxy resin/polyamide composite materials [J]. China Plastics, 2024, 38(12): 138-142.
[14]	ZHANG Caili, ZHANG Chongxi, YU Yanlong, YANG Fenglei, MENG Qingying. Road performance of waterborne epoxy color coating [J]. China Plastics, 2024, 38(12): 97-104.
[15]	JI Meiyu, ZHAO Yizhe, ZHANG Wenchao, GUO Xiaoyan, YANG Rongjie. Synergistic effect of 1⁃oxo-4⁃hydroxymethyl-2，6，7⁃trioxa-1⁃phosphabicyclo ［2.2.2］ octane and ammonium polyphosphate on flame retardancy and smoke suppression of epoxy composites [J]. China Plastics, 2024, 38(11): 1-7.