The Decomposition Behivor Of TETA/E-51Epoxy Resin In Nearcritical Water And Re-application Of Its Product

Epoxy resin is widely used in carbon fiber reinforced materials，printed circuitboards and so on. The comsuption of epoxy materials leads to a lot of waste and causesgreat pressure on the environment. However，it is usually difficult to recycle epoxy resinand its composites because of its three-dimensional network structure and composites′heterogeneous structure. Therefore，there is an urgent need to find an efficient methodfor recycling epoxy resin.In this paper，epoxy resin E-51cured with triethylenetetramine(TETA) and the twomodel compounds are synthesised. Experiments are devised in order to identify theseveral signifcant process parameters that affect the decomposition of epoxy resin andthe two model compounds including reaction temperature，time，catalyst species andconcentration.Sodium hydroxide，sodium carbonate and phenol have been chosen as thecatalyst respectively. The results show that: the catalytic effect of sodium hydroxide isthe best, it can cause complete decomposition of TETA/E-51epoxy resin at305℃for45min; the catalytic effect of phenol on the epoxy system ranks second, thedecomposition of the epoxy system can also reach above80%; the catalytic of sodiumcarbonate is the worst, the decomposition rate is around30%.The liquid product distribution is analyzed using gas chromatography massspectroscopy (GC-MS).The GC-MS test results show that: the influence of the reactionfactors on the distributon and composition of liquid products of TETA/E-51resinsystem and the model compound1are similar, fractures of C-O and C-C are main keybreaking ways; however, the distribution of liquid products of TETA/E-51resin systemand the model compound2are different. The fracture of the C-O is the main keybreaking way of TETA/E-51resin system, while the distribution of model compound2shows that fractures of C-O and C-N are a group of competive reaction，this differencecan be attributied to the complexed structure of the resin system. At the same time, itcan be found that phenol and its derivatives are the main components in the liquiddecomposition product from GC-MS results. Phenolic resol resin is synthesized bydecomposition products and its properties are tested.