China Plastics ›› 2018, Vol. 32 ›› Issue (05): 41-47.DOI: 10.19491/j.issn.1001-9278.2018.05.006

Previous Articles     Next Articles

Preparation and Properties of Silane-crosslinked EVA/PP/Magnesium Hydroxide Compounds

  

  • Received:2017-12-12 Revised:2017-12-22 Online:2018-05-26 Published:2018-05-25

Abstract: Halogen-free flame-retardant compounds based on silane-crosslinked PP and EVA were prepared through a two-step melt blending method using magnesium hydroxide (MH) as a flame retardant, and the crosslinking efficiency of silane grafted onto EVA/PP compounds were investigated in terms of block-copolymerized PP (PP-B) and homo-PP(PP-H). The mechanical properties, hot elongation performance and flame-retardant properties of compounds were investigated by using universal testing machine, hot-set elongateion tester, limiting oxygen index and vertical burning experiments. The results indicated that the silane-crosslinked EVA/PP-B compounds achieved a higher crosslinking degree than the EVA/PP-H ones. The EVA/PP-B crosslinked compound could reach the crosslinking level required when the content of MH was lower than 120 phr. With increasing the MH content from 80 to 160 phr, the limiting oxygen index values of compounds increased from 25.0 to 32.2 vol %, which were improved by 0.5 %~1.5 % compared to the un-crosslinked ones. The flame retardancy of compounds was improved up to the V-0 grade of GB/T 2408—2008 when the MH content exceeded 120 phr. The compounds were found to undergo a two-stage thermal degradation, in which the first stage involved the dehydration of MH and decarboxylic reaction of EVA and the second one involved the thermal pyrolysis of polymer main chain and volatilization of residues.