Study On The Structure And Properties Of The Seal Material With Low Compression Set And High Obstruction

The blend of Epichlorohydrin-co-epoxyethane rubber (ECO) and nitrile rubber (NBR) with low compression set and good dynamic properties was prepared by dynamical vulcanization technique. The study was concentrated on decreasing the compression set of the blend. The work included the following three parts:Firstly,The fitting vulcanizing systems for ECO and NBR were investigated. The results showed that the best recipe was TCY/TT for ECO and S/TT/CZ for NBR. This recipe provided the blend with low compression set,good dynamic properties and oil resistance . Secondly, the influence of micro morphology structure of the blend on compression set was studied and the dynamical vulcanization technique, which made ECO with low compression set form continuous phase and NBR with outstanding oil resistance form disperse phase. The dynamical vulcanization technique let properties of oil resistance, low temperature resistance and compression set of the blend turn into comprehensive equilibrium. So the dynamical vulcanization technique was investigated .The best technique was the following: At 150℃, dynamic curing time was t90 of NBR.Thirdly,The difference of properties of the blend prepared by static vulcanization and the blend prepared by dynamical vulcanization ,such as rheological properties,oil resistance,compression set were systemically studied.The results showed that the system of TCY/ TT could dramatically decrease the compression set of ECO. What is more,it could not only endow the blend with good mechanical properties but also avoid toxicity of NA-22/Pb3O4 for compounding operators. The S /TT /CZ system could also decrease the compression set of NBR and endowed the NBR/ECO blend with good comprehensive properties. Micro morphology structure of NBR/ECO blend (20/80) made by static vulcanization showed ECO could not become continuous phase because of its high density of cohesion energy .The fitting dynamical vulcanization technique made the micro morphology structure of NBR/ECO reverse. The difference of CN content of NBR and rate of the blend on properties was studied.　When the rate of NBR and ECO was 30/70, the blend of NBR-41/ECO made by dynamic vulcanization was provided with low compression ,good oil resistance,aging resistance and excellent mechanical properties. Dynamical vulcanized blend of NBR/ECO filled with carbon black in both continuous phase and dispersed phase behaved well processing properties, smooth appearance of extrusion, low compression set, excellent gas barrier and oil resistance, which was a excellent sealing material.