In this research,molecular dynamics(MD)simulations were used to study the transport properties of small gas molecules in the butadiene-styrene copolymer(SBR).The condensed-phase optimized molecular potentials for atom...In this research,molecular dynamics(MD)simulations were used to study the transport properties of small gas molecules in the butadiene-styrene copolymer(SBR).The condensed-phase optimized molecular potentials for atomistic simulation studies(COMPASS)force field was applied.The diffusion coefficients were obtained from MD(NVT ensemble)and the relationship between gas permeability;the chemical structure and free volume of butadiene-styrene copolymer were investigated.The results indicated that the diffusion coefficient of oxygen declined with increasing styrene content.The fraction of free volume(FFV)in butadiene-styrene copolymer was calculated.It was concluded that diffusion coefficient increased as the FFV increases,which is in accordance with the analysis of the small molecular hop through the free volume in polymer matrix.Subsequently,the glass transition temperatures of these copolymers were calculated by MD.The result showed that the glass transition temperature increased with increasing styrene content in polymer.展开更多
基金the financial support from the National Natural Science Foundation of China(Grant No.50973007)Project 08-04-01-07 from the PetroChina Company Ltd.
文摘In this research,molecular dynamics(MD)simulations were used to study the transport properties of small gas molecules in the butadiene-styrene copolymer(SBR).The condensed-phase optimized molecular potentials for atomistic simulation studies(COMPASS)force field was applied.The diffusion coefficients were obtained from MD(NVT ensemble)and the relationship between gas permeability;the chemical structure and free volume of butadiene-styrene copolymer were investigated.The results indicated that the diffusion coefficient of oxygen declined with increasing styrene content.The fraction of free volume(FFV)in butadiene-styrene copolymer was calculated.It was concluded that diffusion coefficient increased as the FFV increases,which is in accordance with the analysis of the small molecular hop through the free volume in polymer matrix.Subsequently,the glass transition temperatures of these copolymers were calculated by MD.The result showed that the glass transition temperature increased with increasing styrene content in polymer.
