02347nas a2200241   4500008004100000022001400041245013800055210006900193260000800262300001200270490000700282520146200289653003301751653001801784653002301802653002501825653001601850653003801866100002001904700001501924700003401939856013201973       2019                        eng d  a1022-134400aImpact of plasticizer addition on molecular properties of polybutadiene rubber and its manifestations to glass transition temperature0 aImpact of plasticizer addition on molecular properties of polybu  cJUL  a19000030 v283 a<p>Effect of blending low and high T-g polymer on the structural, spatial, and temporal properties of the polybutadiene rubber are investigated using molecular dynamics simulations. It is elucidated that smaller chain length counterpart of polybutadiene (5mer-OB) acts as plasticizer for the polybutadiene rubber matrix (32mer-PB). Observed flexibility at macroscopic level by plasticizer addition is corroborated at the molecular level in the form of lower conformational rigidity and faster diffusion of polybutadiene chains in the mixtures. It is inferred that plasticizers decreases T-g of the matrix, due to cooperative influence of decreased chain packing and rigidity. Opposite effect is observed in mixtures with high T-g polymer, polystyrene. T-g of the mixtures showed substantial dependence on the type, concentration, chain length as well as miscibility of plasticizers in the matrix. However, the effect of increasing chain length is more pronounced but counter-controlled by the spatially heterogeneous distribution of the plasticizer. Clustering of polystyrene chains induced significant dynamic heterogeneity in the homogeneous polybutadiene matrix, which apparently lead to reduced plasticization effect. Addition of plasticizers in rubber induce discernible changes in the structural and dynamic properties of the rubber matrix, which manifest as the variation in glass transition and explains the real-life activity of plasticizers.</p>
10aGlass transition temperature10aMD Simulation10aplasticizer action10apolybutadiene rubber10aPolystyrene10aspatial and dynamic heterogeneity1 aSharma, Pragati1 aRoy, Sudip1 aKarimi-Varzaneh, Hossein, Ali  uhttps://library.ncl.res.in/content/impact-plasticizer-addition-molecular-properties-polybutadiene-rubber-and-its-manifestations02204nas a2200205   4500008004100000022001400041245014700055210006900202260000900271300001200280490000700292520144700299653003301746653003401779653001301813653001101826100002001837700001501857856012601872       2020                        eng d  a1539-445X00aGlass transition temperature of polybutadiene and polyisoprene from high temperature segmental relaxation correlation using molecular dynamics0 aGlass transition temperature of polybutadiene and polyisoprene f  cJUL   a290-2960 v183 a<p>Predicting glass transition temperature for rubber and rubber composites is immensely important for tire industry for the development of products and fine-tune process conditions. Molecular dynamics simulation is been used to predict glass transition temperature as a function of molecular-level structural changes, e.g., composition (functional groups), topology, and polymerization. However, prediction of glass transition temperature within experimental error bar from molecular dynamics simulation is only possible from all atomistic description (model) of the system as united atom and coarse-grained models under-predict the values. Conventional way of calculation of glass transition temperature from density (or any other properties which show sharp transition)-temperature plots are computationally very demanding because of atomistic simulations and simulations below the glass transition point, i.e., in glassy state. Here we report a novel method for calculation of glass transition temperature using only segmental relaxation correlation functions calculated at higher temperatures, i.e., above glass transition temperature. We have presented a protocol here and shown for two polymeric systems polybutadiene and polyisoprene. We believe this method cuts the computational cost of predicting glass transition temperature by one-third and will be applicable for industrial applications for structure-property validations.</p>
10aGlass transition temperature10amolecular dynamics simulation10aPolymers10arubber1 aSharma, Pragati1 aRoy, Sudip  uhttps://library.ncl.res.in/content/glass-transition-temperature-polybutadiene-and-polyisoprene-high-temperature-segmental