Study On Structure And Properties Of Hydrogenated Nitrile Butadiene Rubber

In this paper,hydrogenated nitrile rubber latex?HNBR?was prepared by in situ hydro-genation of nitrile latex using hydrazine hydrate/hydrogen peroxide catalyst system.Preparation of hydrogenated nitrile rubber/reduced graphene oxide nanocomposites?HNBR/RGO?by one-step reduction using emulsion method,The active chain diimide produced by the molecular chain carbon-carbon double bond in the NBR emulsion and the GO hydrated hydrazine/hydrogen peroxide/copper sulfate catalytic system is simultaneously hydrogenated and reduced.The effects of different amounts of hydrazine hydrate,the amount of hydrogen peroxide,different reaction time and reaction temperature on the synthesis of HNBR were discussed.The optimum reaction system is determined.The reaction temperature is 5°C,the molar ratio of hydrazine hydrate to carbon-carbon double bond is 9,the molar ratio of hydrogen peroxide to carbon-carbon double bond is 6,and the reaction time is selected for1 hour.In order to ensure that GO can be uniformly dispersed in the latex environment,it was treated by adding a surfactant in advance,and at the same time,it is selected to be added before the in-situ hydrogenation of the NBR latex,which ensures the uniform dispersion of GO.The microstructure of HNBR and HNBR/RGO was analyzed by Fourier transform infrared spectroscopy,and the hydrogenation success is determined by the absorption peak at 725 cm^-1 in the spectrum.The morphology of HNBR was analyzed by TEM and Malvern particle size analyzer.The latex particles were intact and the particle size was uniform.The sample is subjected to thermogravimetric analysis and DSC analysis,and it is found that the rate of weight loss slowed down and the Tg moved toward the low temperature,indicating that the thermal stability of the material is improved.According to the dynamic performance analysis of the material,the storage modulus G'of HNBR decreases rapidly with the increase of the applied strain amplitude.Because the specific surface area of the sheet of GO and RGO is large,the filler network is formed and the storage modulus is high.The tan?increases with the increase of the applied strain,because the cross-linking network acts together with the filler network to greatly weaken the chain's ability to move,and the internal friction increases.After the thermal oxygen aging of the sample,the mechanical properties test results show that the addition of GO and RGO makes the tensile strength of the HNBR material significantly improved and the thermal stability increases.At the same time,the method of total atomic dynamics simulation is combined with the experimental results to quantitatively analyze the microstructure of NBR and HNBR from the molecular layer.The NBR and HNBR molecular chain models were established.The amorphous three-dimensional periodic boxes of NBR and HNBR were established by Amorphous cell module,and the relaxation process such as structural optimization and annealing was carried out to obtain the energy balance system.At the same time,the hard sphere probe is used to measure and analyze the free volume and occupied volume of the system.Molecular dynamics simulation calculations using NVT and NPT ensembles,using NBR and HNBR in different properties in glass and viscoelastic states,The curve inflection point is selected to determine the glass transition temperature range,and the obtained parameters were subjected to piecewise linear curve fitting.The glass transition temperatures?Tg?of NBR and HNBR were 255K and 252.42K,respectively.And compared with the experimentally measured data,it is determined that the results obtained by this MD simulation are basically consistent with the experimental values.