Effects of aluminum diethylphosphinate/aluminum hypophosphite on the properties of natural rubber/butadiene rubber composites
The flame retardants aluminum diethylphosphinate(ADP)and aluminum hypophosphite(ALHP)were introduced into natural rubber(NR)and butadiene rubber(BR)to prepare the composites.In this study,we compared the effects of the two flame retardants on the processing characteristics,physical properties,flame retardancy,mechanical properties,and abrasion resistance of the composites.Results showed that both flame retardants delayed the vulcanization of the composites,increased the Mooney viscosity.ADP exhibited a more evident increase in Mooney viscosity than ALHP.When ADP and ALHP was added at 45 phr,the limiting oxygen index(LOI)of the composites increased from 22.1% to 28.7% and 24.5%,respectively.The addition of ADP and ALHP reduced the rebound resilience of the composites,but increased hardness of it.The flame retardants reduced the tensile strength,elongation at break,and tear strength of the composites.Both flame retardants had an adverse effect on the abrasion resistance,with the abrasion loss of the composites increasing by 100% and 85% at 45 phr of ADP and ALHP,respectively.When graphene is used as a carbonization agent for ADP-containing composites,it can improve the flame retardancy without affecting the abrasion resistance.ADP and ALHP have different degrees of influence on the properties of NR/BR composites.Due to the high carbon content of ADP and volatilization by heat,the flame retardancy of NR/BR composites is greatly improved.But the tensile strength and abrasion resistance of the composites are lower than that of the ALHP-containing composites.