Effect Of Manganese,Iron And Their Ions On Thermal Stability Of Polyarylethers

For polymer materials,thermal stability refers to the thermal degradation or aging properties of polymer materials.The thermal stability of the polymer determines the difficulty of the deformation of the material in the case of heat.The better the thermal stability,the less possibility to change,which makes the material have a more relaxed processing range and longer service life.While the thermal stability of the material is poor,which is a negative impact to its processing and use.Polyarylether is a kind of high-performance plastic,whose molecular structure contains strong rigid,high heat-resistant phenylene,while containing flexible,heat-resistant oxygen ether bond or thioether bond.It has heat resistance,high strength,creep resistance,strength and toughness,high rigidity and other excellent performance.Polyarylethers as a special polymer engineering plastics and high-performance fiber reinforced composite material substrate,has important application value.Polyether ether ketone(PEEK)and polyphenylene sulfone(PPSU),as the outstanding representatives of polyarylethers,have been playing an important role in aerospace and other fields.However,in the synthesis of two polymers and later processing,we often ignore the effects of metal ions,including synthetic raw materials,washing,melt processing and injection molding,will be the introduction of metal ions,such as manganese ions and Iron ions,which leading to performance deterioration of the material.Therefore,we selected two representative metal ions of manganese and iron to study their effects on the thermal stability of polyether ether ketone and polyphenylene sulfone.In this study,two kinds of polymers including polyether ether ketone and polyphenylene sulfone were used as the substrate,and different amounts of manganese and iron ions were added respectively.The effects of metal ions on the thermal stability of the two substrates were characterized by means of melt index,capillary rheology and parallel plate rheology from the viewpoint of melt fluidity.The effects of metal ions on the thermal stability of the two substrates were characterized by means of melt flow rate,capillary rheology and parallel plate rheology from the viewpoint of melt mobility.At the same time,the samples were further studied from the aspects of thermal properties(TGA),dynamic mechanical properties(DMA),crystallinity(DSC),molecular weight(GPC)and free radical(ESR)to prove the conjecture.The results show that Mn(?),Fe(?)and Fe(?)have effects on the PEEK and PPSU,which affect the melt viscosity and thermal stability.Moreover,we suspect that these three metal ions degrade and crosslink PEEK and PPSU in varying degrees depending on the flow state of the melt and the color and surface changes of the extrudate,which in turn affects the melt flow properties.The results of TGA showed that the thermal stability of the matrix was deteriorated.The DMA results indicated that the glass transition temperature of the sample was increased.The DSC results showed that the crystallinity of the sample was increased.The GPC results showed that the molecular weight distribution of the sample was broadened.ESR curves demonstrate the presence of free radicals in the matrix.These representations further confirm that the three metal ions cause PEEK and PPSU to undergo degradation and cross-linking.