The Study On Toughening Of Radar Absorbing Coating Adhesive

The excellent mechanical properties of radar absorbing coating were the premise that radar absorbing coating get practical. A kind of high filler and excellent properties adhesive needed to be looked for urgently to satisfy requirement. The paper contrasted several system of adhesive and chosen epoxy resin with the high filler as matrix. Hydroxy-Terminated Butadiene Nitrite Liquid Rubber (HTBN)-Epoxy Resin(EP), Carboxy-Terminated Butadiene Nitrile Liquid Rubber(CTBN)-EP and Polyurethane(PU)-Epoxy Resin 1PN were studied systematically.First, the system of HTBN-EP was studied. The toughening mechanism and the influence factor of toughening effect were discussed. The results indicate that HTBN had the effect of toughening. The curing time would be reduced and the toughness would decrease with temperature increasing. The higher temperature didn't influence the adhesive attraction of the HTBN-EP. The toughening mechanism was drawn from the above research. The -OHofEP and HTBN turned into -NCO. The curing reaction proceeded between -NCO and amine curing agent synchronously. Then the rubber soft segment of PU was introduced to the interpenetrating networks of EP. The toughened EP was obtained.Secondly, the two different systems I and II of CTBN-EP were synthesized by different mixed method. The mixed methods influence the toughness. The reasons of influencing toughness were discussed from the dynamics and thermodynamics. The CTBN-EP II was chosen to experimentize. The toughening factors of CTBN-EP II were studied. The toughening mechanisms were discussed. The toughness of CTBN-EP curing on high temperature is lower than that of on low temperature. The curing effect of triethylene tetra-amine was better than that of trifluoride single ethylamine. The change of mechanical properties is related to microstructure of the toughened system.Finally, PU was used to modify EP. The two different EP/PU Interpenetrating PolymerNetworks (IPN) I and II were synthesized with different -NCO content. The mechanical properties of IPN I were better than that of IPN II. The Infrared Spectroscopic of the EP-PU IPN I were analyzed. The group of epoxy didn't attend the reaction basically and the reaction proceeded between -NCO of PU and -OH of epoxy resin. At the same time, characteristic peak overlapped partly after forming IPN and the integer of PU/EP was IPN system through the Infrared Spectroscopic. The microstructure of the EP-PU IPN was observed by Scanning Electron Microscopy (SEM). When the quality ratio of EP / PU was 90/10, the PU-EP IPN system formed the higher interpenetrating network and the adhesive attraction and toughening of PU-EP IPN was the best.The three modify system were considered synthetically at the end of the paper. The toughening effect of CTBN-EP system is the best. But the toughness and adhesive attraction don't get the highest synchronously in the CTBN-EP system. The effect of HTBN modifying EP is worse than that of the CTBN-EP system, but the price of HTBN is lower than that of CTBN. The toughness of EP-PU IPN system is better than that of HTBN-EP system and lower than the CTBN-EP system. When the quality ratio of EP/PU is 90/10, the toughness and adhesive attraction get the highest synchronously. So the different systems are chosen according to application.