Microstructure Analysis And Molecular Simulation Of Hydrogenated Nitrile Butadiene Terpolymer And Ethylene Propylene Rubber

In this paper,the structure characteristics of butadiene-acrylonitrile-isoprene(NBIR),butadiene-acrylonitrile-butyl acrylate(NBBR)copolymer,and their hydrogenated structure were quantitatively analyzed by nuclear magnetic resonance spectroscopy(1H-NMR)and Fourier transform infrared(FTIR)spectra.Molecular weights and glass transition temperatures(Tg)of these copolymers were measured by gel permeation chromatography(GPC)and differential scanning calorimetry(DSC).The peak positions of NMR spectra were analyzed in detail.In addition,the composed structures and corresponded contents of NBIR,NBBR and hydrides were determined by the quantitative calculation of the peak area.Based on these data,molecular models of these copolymers were built by Materials Studio software.Tg was used to verify the reliability of molecular simulation.The experimental data and molecular simulation results showed a good agreement.Molecular simulation method could provide basic data and guidance for the preparation and processing of copolymerized materials.In order to investigate the influence of different copolymer composition on the low temperature resistance,thermal stability,and oil resistance,the solubility parameters,Tg,and half decomposition temperatures of different structures were obtained by molecular dynamics simulation.The results showed that mass fraction of acrylonitrile was the main factor affecting Tg and solubility parameters of two kinds of polymers.Moreover,it is also the key factor affecting the low temperature resistance and oil resistance.The effect of hydrogenation on the copolymer is similar to that on HNBR.The high hydrogenation degree increases the thermal stability,but is unfavorable to the low temperature performance.Two kinds of third monomers both can improve the low temperature resistance,in which the acrylate can maintain the oil resistance.The increase of 1,2-butadiene increasing fraction is unfavorable to low temperature resistance and oil resistance,but hydrogenation on the side group leads to the derease of Tg.FFV and RDF calculations prove that it is due to the increase of free volume fraction,which offseted rigidity of molecular chians.At present,there are many kinds of EPDM rubber in the domestic independent production and application,but comparing with some foreign development and improvement products,there are still some gaps.In this paper we compared microstructures of several different kinds of EPDMs from foreign companies and Jilin Chemical Group Company by FT-IR,1H-NMR and 13C-NMR.Molecular weights and glass transition temperatures of EPDMs were measured by GPC and DSC.Their molecular models were built based on NMR dates.The Tg which was calculated by dynamic simulation method was compared with the results of DSC.The relative error is less than 10%and is mainly due to crystal of EPDMs.These results prove the feasibility of predicting the parameter of different EPDMs by molecular simulations.The types and contents of three groups in EPDM were analyzed by 13C-NMR,and the influence of sequence arrangement on crystallinity was discussed by comparing the results of molecular simulation and experiment.On one hand,it provides the basic data for the domestic development of EPDM database;on the other hand,it provides the improved ideas for the development of domestic EPDM from the aspect of copolymer microstructure.