Four Studies Like Zinc Oxide Whisker Surface Modification And Its Effect On The Mechanical Properties Of NBR

Tetrapod-shaped ZnO (T-ZnOw) whisker is inorganic crystal material with three-dimensional space structure.The angle between every two needles is109o28’.As a result of random orientation of T-ZnOw in the matrix,the composites modified by T-ZnOw show the isotropic properities.Moreover,the whiskers posses many superior properties sueh as high strength,wear resistance and antibacterial effect,therefore,it has been considered as an ideal inorganic filler.It has a wide-spread applications in many different activities such as adhesives,rubber,platics and so on.But the nanoparticles are more difficult to disperse in the rubber than the thermoplastics due to their high specific surface and the high surface free energy.So the research of rubber nanocomposites is focused on nanomaterials’ surface modification and strengthening mechanism of nanomaterials.Surface modification of T-ZnOw and the performance of the rubber nanocomposites are in deep investigation.The work could be summarized as follows:1.Wet surface modification and dry surface modification of T-ZnOw with silane coupling agent KH570was carried out. The factors of the modification were discussed and orthogonal experiments were made. The optimum conditions were deterimined by activation index.For wet surface modification,the optimum conditions:hydrochloric acid acts as catalyst; hydrolysis time is1h; mass fraction of silane coupling agent is4%;coupling temperature is70℃;coupling time is3h.For dry surface modification, the optimum conditions:mass fraction of silane coupling agent is4%, coupling temperature is70℃,time is70min. The effect of modification with KH570on dispersibility, lipophilicity and measuring the contact angle of T-ZnOw were investigated. Those test results indicated that the dispersivity,lipophilicity and contact angle of modified T-ZnOw are improved..It was shown by FT-IR that the whiskers was modified by KH570molecular compounded with the O-H of whiskers.2.The influences of modified T-ZnOw contents,modification methods,coupling agent type and dosage on the T-ZnOw/NBR composite properties were studied,when the modified T-ZnOw were used as the filler of NBR.The results showed that wet surface modification is best.With increase of silane coupling agents,the ultimate elongation decreased,resulting in better tensile strength at small loading but decreased strength at large loading.The optimum dosage of silane coupling agents was found at4phr (per hundred of rubber),and it could be concluded KH570gave better outcome of modification that KH560.The quantity of modified T-ZnOw had more effect on the properties of rubber,when filled with50phr modified T-ZnOw,the tensile strength of vulcanizates increased84.8%.Meanwhile,in this paper,the combined effects of T-ZnOw and carbon black on the properties of NBR nanocomposites was investigated.The results showed that two fillers were uniformly dispersed in the NBR matrix,at the same total filling amount,combining T-ZnOw and carbon black could increase the mechanical properties of the nanocomposites.