Application Of Moleular Simulation In Bio-Based Plasticizer

Plasticizer is the largest amount of plastic products in a plastic preparation.it can reduce the Tg of the material,increase the flexibility of the polymer to improve the mechanical properties of the material.Phthalate is an environmental hormone and has a toxic effort on human and enviroment.So there are many restrictions to limit the use of the phthalate both at home and abroad.The bio-based plasticizer has low toxicity on the human body and environmental and attracts the current research focus.Traditional plasticizer research and development depends mainly on experience.This method is lack of targeted and low timeliness.The molecular simulation of the current plasticizer can only predict the compatibility of the plasticizer and PVC related thermodynamic parameters to calculate the compatibility of the plasticizer and PVC.In this paper,It was based on the Material Studio platform.The molecular simulation method of plasticizer and PVC blend system was established.The performance of the material was analyzed from the microstructure of the molecule,and then the simulation results were verified by experiment.The research content was as follows(1)The simulation method of the performance of the plasticizer and the polymer blend system was established The degree of polymerization(n)of PVC in molecular dynamics simulation was 40.The Tg of pure PVC was 340K,the Young's modulus(E)was 3.72GPa,The bulk modulus(K)was 3.27GPa,the bulk modulus(K)was 1.41GPa and the Poisson's ratio(?)was 0.301.The Tg and the mechanical properties were basically consistent with the reference.(2)The compatibility,glass transition temperature and mechanical properties of DOP/PVC,epoxy resin(EFM)/PVC and octanoic sugar ester(ISD)/PVC blends were simulated by the above method.The epoxy fatty acid ester and octanoate sugar esters are compatible with PVC is better than DOP and PVC.The molecular radial distribution function verified the compatibility of the plasticizer with PVC from a microscopic point of view.The glass transition temperature(Tg)of the plasticizer and PVC system was simulated by the specific volume-temperature curve.The Tg of the pure PVC was 340K,the Tg of the DOP/PVC,EFM/PVC and ISD/PVC system was 306K,309K,303K,respectively.the intermolecular radial distribution function and the mean displacement are explained from the molecular angle of the reason for the decrease in Tg.The mechanical properties of plasticizer/PVC system were simulated.Compared with the pure PVC system,the Young's modulus of the DOP/PVC system decreased by 22.1%,and the Young's modulus of the EFM/PVC and ISD/PVC system decreased 35.1%and 34.8%,respectively.The bulk modulus decreased by 26.2%,38.5%and 30.8%,respectively.The shear modulus decreased by 14.3%,35.0%and 34.3%,respectively.The mechanical properties of epoxy fatty acid esters and octanoic acid ester esters are better than those of DOP system.(3)The compatibility and mechanical properties of DOP/PVC and epoxy fatty acid ester/PVC system were verified by thermal stability test,thermal gravimetric analyzer,differential scanning calorimetry and tensile test.The change of color and shape of EFM system at 190 ? were less than that of DOP system.Weight loss rate of the highest temperature and weight loss rate of 10%and 50%were higher than those of DOP/PVC system.Tg were 307,312 K,respectively.Elongation at break,tensile strength,given elongation stress were 136.5%,85.6%and 83.7%of the DOP system,respectively.The experimental results showed that the thermal stability glass transition temperature and mechanical properties of epoxy fatty acid ester are better than DOP,which consisted with the simulation results.(4)The fatty acid sugar ester/PVC model with different carbon chain length was established.The compatibility of different carbon chain length fatty acid sugar esters with PVC was simulated by molecular dynamics.The molecular chain flexibility and mechanics of plasticizer/PVC system performance were studied.The compatibility of different carbon chain length fatty acid sugar alcohols with PVC,molecular chain flexibility and mechanical properties are better than DOP,in which the performance of hexadecyl sugar alcohols is most prominent.