Study On The Application Of Polyamide-Amine Dendrimers In Rubber

Polyamidoamine(PAMAM) dendrimers, including hyperbranched polyamidoamine and dendritic polyamidoamine, have a multi-branched structure with much primary amine groups in the surface, numerous amide bonds inside and abundant intermolecular hydrogen bonds. They are widely used in drug transport, sewage treatment, nanoparticle catalysis, resin curing and other fields. The thesis studied the application of polyamidoamine in rubber from two aspects: using it as rubber additives to postpone the effects of rubber aging; using it as raw materials to synthesize a new-style rubber material by chemical reaction.First we used MA and EDA as the raw material to prepare hyperbranched PAMAM through one pot method; then we synthesized 1.0G, 2.0G and 3.0G dendritic PAMAM by converged Method. These products were characterized by FT-IR, 1HNMR and other means. In addition, the amino value of hyperbranched and dendritic PAMAM were also determined by back titration method.We researched the influences of hyperbranched and dendritic PAMAM as antioxidants on the multiple performance of NBR. And antioxidants 4010 NA,4020,MB and ODA were used to compare wth PAMAM. Through the thermo-oxidative aging, ultraviolet aging and ozone aging testes, it was turned out that the retention tensile strength and enlongation of hyperbranched PAMAM and dendritic PAMAM were comparatively higher. UV and ozone aging surface topography images showed NBR with addition of hyperbranched PAMAM and dendritic PAMAM have less crack. On the one hand, PAMAM play the role of chain transfer agent through capturing free rdical; on the other hand, the dehydration of PAMAM by high temperature result in the forming of imidazole derivative, which was very stable after losing hydrogen. The results showed the maximum service temperature of NBR with addition of hyperbranched PAMAM and 3.0G dendritic PAMAM was 14℃ and 16℃ higher than antioxidant 4010 NA.Finally, using different age dendritic polyamidoamines as raw materials and react with dimer acid and urea, we prepared 1.0G-SP、2.0G-SP、3.0G-SP Self-healing elastomers. The structure of elastomers was characterized using IR and coupling technique of Pyrolysis gas chromatography with mass spectrometry. The result of DSC test indicated that the Tg of 1.0G-SP、2.0G-SP and 3.0G-SP were-13.5℃,-18.1℃ and-41.6 ℃, respectively, all far below the room temperature. Mechanical property test showed that the self-healing efficiency of the three elastomers all decrease with the increase of time the section was parked. And the highest self-healing efficiency reached 81%. Through the simulation of self-healing process and study of the mechanism, it was found that the self-healing ability was depended on the association and disassociation of reversible hydrogen bond. The opinion can be varified by variable temperature infrared test.