Study on properties of modified ammonium polyphosphate coated with polysiloxane and its flame retardancy on polyethylene
The microencapsulation modification of ammonium polyphosphate(APP)was performed to prepare the modi-fied APP/DMDES,APP/MTES,and APP/PTMS for enhancing their flame retardancy,thermal stability and hydro-phobicity through a sol-gel process using tetraethylorthosilicate(TEOS)as a main precursor and dimethylldiethoxysilane(DMDES),methyltriethoxysilane(MTES),and phenyltrimethoxysilane(PTMS)as co-precursors.The structures and performance of the resulting APP coated with polysiloxane was investigated by using Fourier-transformation infrared spectroscopy,water contact angle,scanning electron microscope,energy dispersive spectrometer,and thermogravimet-ric analysis.The effects of modified APP on the flame retardancy,mechanical and thermal properties of low-density poly-ethylene(PE-LD)were also studied.The results showed that polysiloxane-coated modified APP could be prepared un-der suitable processing conditions,and its hydrophobicity and thermal stability of the modified ammonium polyphosphate were significantly improved compared to pristine APP.As a PE-LD/APP/PTMS/pentaeritritol/melamin mass ratio of 65/18.7/11.7/4.6,the PE-LD composite exhibited the best overall performance with a limiting oxygen index of 26.6 vol%,which is 23.3%higher than that of pristine APP.The composite also reached a UL 94 V-0 level in the vertical burning test and obtain the highest tensile strength of 12.84 MPa.
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维普
