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A facile approach to prepare cage‐ladder‐structure phosphorus‐containing amino‐functionalized POSS for enhancing flame retardancy of epoxy resins
Author(s) -
Li Shengnan,
Zhao Xiaojuan,
Zhang Yu,
Yang Xin,
Yu Ran,
Zhang Ying,
Deng Kuilin,
Huang Wei
Publication year - 2021
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.49870
Subject(s) - limiting oxygen index , materials science , curing (chemistry) , silsesquioxane , epoxy , fourier transform infrared spectroscopy , fire retardant , polymer chemistry , char , chemical engineering , pyrolysis , polymer , composite material , organic chemistry , chemistry , engineering
The cage‐ladder‐structure phosphorus‐containing amino‐functionalized polyhedral oligomeric silsesquinoxanes (CLNH 2 ‐POSS) have been synthesized through a facile catalyst‐free hydrolytic condensation of 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide‐vinyltrimethoxysilane (DOPO‐VTMS) with 3‐aminopropyl trimethoxysilane (KH540). The successful preparation of CLNH 2 ‐POSS has been proven by the characterization of Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy ( 1 H‐NMR, 29 Si‐NMR), matrix‐assisted laser desorption ionization time of flight (MALDI‐TOF), and X‐ray diffraction (XRD). Then flame retardant (FR) epoxy resins (EPs) were prepared by the addition of different content of CLNH 2 ‐POSS into EPs with thermal curing technology. The CLNH 2 ‐POSS showed good solubility in EP matrix. The well‐dispersed CLNH 2 ‐POSS contributed to thermal, mechanical, and FR properties of EP. Dynamic scanning calorimetry nonisothermal curing scans showed that CLNH 2 ‐POSS had accelerating effect on the curing of EP. With the addition of only 3 wt% CLNH 2 ‐POSS (0.30% phosphorus loading), the limiting oxygen index value of the EP composite increased from 25.5 of pure EP to 31.8, and vertical burning (UL‐94) V‐0 ratings was achieved. In addition, the EP composites showed improved thermal and mechanical properties. The investigations on char residue and pyrolysis volatiles of cured EP further revealed that CLNH 2 ‐POSS exerted FR effects in condensed and gas phase simultaneously.