Preparation And Properties Of Rubber Antioxidant Grafted With Halloysite Nanotubes

Rubber products are widely used in the modern world.However,in the course of use,due to the influence of internal and external factors in the environment,the rubber aging phenomenon will occur and the mechanical performance will be reduced.It will affect the service life and cause hidden dangers seriously.In rubber processing,traditional formulas usually add small-molecule antioxidants to protect the aging of rubber,but improper use of small-molecule antioxidants can easily form a "blooming" phenomenon on the rubber surface,affecting the appearance of rubber products,and making the antioxidants invalid in advance to the antioxidant.Natural one-dimensional inorganic—halloysite nanotubes is a kind of natural nano-clay materials in nature.Halloysite has active hydroxyl structures on both the inner and outer surfaces.Due to its special structure,it is easy to modify and functionalize,becoming a research hot spot.The route of chemically grafting the antioxidant with the active hydroxyl groups on the surface to make the halloysite nanotubes have the function of anti-aging is prepared,and a new type of halloysite nanotubes grafting antioxidant product is prepared.The details are as follows:(1)The chemical grafting method was used to study the reaction route of the hallowite nanotube-grafted anti-aging agent intermediate,and a new type of halloysite nanotubes grafted with antioxidant product(HNTs-M)was prepared and explored the most suitable reaction conditions.Under the most suitable conditions,the highest grafting efficiency of the graft antioxidant can be measured by TGA thermal analysis to reach about 2%.(2)After the halloysite is treated by the modification method,the grafting reaction is carried out.After the modification and activation,the halloysite surface has more hydroxyl active group sites,which can effectively further improve the grafting rate.After the short-term acid treatment of nanotubes at 60?,the grafting rate can be increased to about 7%,and the short-term base treatment can greatly increase the grafting rate to about 21%,which improves the grafting efficiency of halloysite nanotubes and the possibility of application in rubber formulations.(3)The effect of HNTs-M on the aging properties of styrene-butadiene rubber was studied.Comparison with the original formula using small molecule antioxidants alone shows that not only the processing performance of the grafted antioxidants has been improved,but also that the mechanical properties of the rubber composites are better maintained with higher tensile strength and elongation at break retention rate,dispersion performance decreased slightly.After aging at 100? for 7 days under hot oxygen aging conditions,the rubber has excellent resistance to "blooming" compared with the equivalent content of small molecule antioxidants,and the content of the antioxidant migration surface is less.