Preparation Of Flame Retardant Graphite Polystyrene Foam And Its Polymerization Mechanism

With the intensification of the energy crisis and the greenhouse effect and the implementation of domestic energy-saving emission reduction policies,as well as the domestic higher demand for housing comfort in the winter time,here is a growing demand for organic foamed materials represented by Expandable Polystyrene(EPS).However,due to EPS material is extremely easy to burn,its application in high-rise buildings are greatly limited.Adding graphite as filler to EPS not only can reflect infrared rays to further reduce its thermal conductivity,but also as inorganic filler as its nucleation point,but also because of its high carbon content can improve EPS flame retardant properties.In this paper,the mechanism of aerosol-polystyrene(G-EPS)pellet suspension polymerization was explored.And provide a theoretical basis for further industrial synthesis of G-EPS.As the flake graphite has the characteristics of low surface energy and poor compatibility with the monomer.It is subjected to surface treatment prior to in situ polymerization to improve its dispersibility in the monomer.In this paper,a double aromatic diazomethane compound with epoxy group was synthesized and the graphite was modified by carbene addition reaction to improv e the dispersion stability of graphite in styrene monomer.The two intermediates were synthesized by FT-IR,1H NMR,13 C NMR and mass spectrometry.The modified graphite was characterized by FT-IR,XPS and solid-state NMR.The dispersion of graphite after modification was confirmed by the comparison of the graphite in the styrene monomer before and after modification.In this paper,the mechanism of suspension polymerization of graphite-styrene system was investigated by exploring the effect of modified grap hite addition,graphite purity,initiator system,nucleating agent type and dosage,crosslinking agent on suspension polymerization.The addition of the modified graphite was more uniform than that of the sample without the addition of the modified graphit e after foaming.The increase of the amount of modified graphite will destroy the stability of the system,increase the demand of the initiator dosage,reduce the molecular weight of the polymer,and reduce the particle size.The use of high purity graphit e will increase the stability of the system,Ethylene molecular weight.The use of low-medium-high temperature compound initiation system can effectively improve the monomer conversion efficiency and increase the molecular weight of the polymer.The reduction of the nucleating agent can significantly increase the glass transition temperature and the molecular weight distribution width of the polymer.Tests by cone calorimeter show that the addition of graphite can significantly improve the flame retardancy of the material.The research of this paper solves the problems brought by the addition of graphite,and also provides theoretical guidance for the industrial production of G-EPS pellets.