Experimental And Molecular Dynamics Simulation Stud Yon The Damping Mechanism Of C5 Petroleum Resin/chlorinated Butyl Rubber Composites

Noise pollution has been plaguing the normal life of human beings.How to effectively reduce noise pollution is a hot issue in materials research.Viscoelastic polymers convert vibration and noise energy into heat,but ordinary pure rubber is difficult to meet the actual application needs.In recent years,the addition of petroleum resin to rubber matrix has become a method for preparing novel high damping rubber composite material.The petroleum resin molecules and the rubber matrix will form strong van der Waals interaction force,and the acoustic energy or mechanical energy absorbed during the interaction between the two will be converted into heat energy,thereby achieving the purpose of shock absorption and noise reduction.In this paper,the C5 petroleum resin/chlorinated butyl rubber composite system was studied by means of experiment,molecular dynamics simulation and statistical analysis.The damping mechanism of the composite system was explained in detail from macroscopic and microscopic level.The quantitative relationship between the damping performance parameters(glass transition temperature,effective damping temperature range)and intermolecular interaction parameters(binding energy,free volume fraction)is obtained by using linear regression analysis,the research content includes the following three aspects:(1)The C5 petroleum resin/chlorinated rubber cell was constructed by full atomic molecular dynamics simulation,and the simulation parameters were calculated.The binding energy of the composite system increases with the increase of C5 petroleum resin content,indicating the increasing interaction force between C5 petroleum resin and chlorobutyl rubber molecules.The binding energy is positive,indicating good compatibility between C5 petroleum resin and chlorobutyl rubber matrix.The statistical results of van der Waals interaction and electrostatic interaction force show that with the increase of C5 petroleum resin content,van der Waals interaction and electrostatic interaction force are gradually increasing,but the influence of van der Waals interaction force is far greater than the electrostatic interaction force,the damping property of the composite is mainly determined by the effect of van der Waals force.Free volume fraction calculation indicates as the content of C5 petroleum resin increases,the free volume fraction decreases gradually,the accumulation of molecular chains is more compact,which can increase the friction force between molecular chains and improve the damping properties of the composite.From the results of calculating the mean square displacement,it is known that as the content of C5 petroleum resin increases,the mean square displacement of CIIR gradually decreases,the movement of the CIIR molecular chain is difficult,it is speculated that the glass transition temperature will move toward the high temperature.As the content of C5 petroleum resin increases,the mean square radius of gyration gradually increases,and the CIIR chain becomes more stretched.The reason is that the compatibility between the C5 petroleum resin molecule and the chlorinated butyl molecular chain is increased.(2)According to the ratio designed by molecular simulation,C5 petroleum resin/chlorinated butyl rubber composites were prepared and characterized.The contact angle test found that the van der Waals force part Ysd of C5 petroleum resin and chlorobutyl rubber was about 6 and 14 times that of its electrostatic force part Ysp,therefore,the interaction force between C5 petroleum resin and chlorobutyl rubber is mainly provided by Van der Waals force,which complies with the simulation calculation result.According to the analysis results of the dielectric spectrum,it is found that the spectrum shows two dielectric loss peaks,respectively corresponding to the local segment mode(high frequency,short relaxation time)and Rouse mode(low frequency,long relaxation time).With the addition of C5 petroleum resin,the relaxation time corresponding to the local segment mode and the Rouse mode are shifted to high temperature in different degrees,and the influence of C5 petroleum resin on the Rouse mode is greater than local segment mode,finally damping temperature region widening.Thermodynamic and dynamic mechanical analysis results show that the damping performance of the composite system increases with the increase of C5 petroleum resin content.(3)Linear regression analysis was used to quantify the relationship between damping performance parameters(glass transition temperature,effective damping temperature range)and intermolecular interaction parameters(binding energy,free volume fraction).There is a significant linear relationship(R2>0.95)between the intermolecular interaction parameters(binding energy and free volume fraction)and the damping performance parameters(glass transition temperature and effective damping temperature domain)of the composite system,therefore,the damping properties of the composite system can be further predicted by calculating the intermolecular interaction parameters of the composite system,thereby improving the experimental efficiency and reducing the cost.