Preparation And Properties Of Reactive Si-p-n Flame Retardant

The harm of fire is not to be underestimated,often causing damage to people and property.Many common polymer materials have serious fire hazards due to high flammability.A good flame retardant can effectively improve the flammability of polymer.Generally speaking,additive flame retardants will make the use or processing performance of matrix materials worse,while reactive flame retardants have good compatibility with matrix materials,which can better solve this problem.In addition,the environmental friendliness of flame retardants should also be considered.Halogen flame retardants will release toxic and harmful gases in the combustion process,causing secondary damage to human body and environment.Organosilicon is an ideal source of flame retardant because it has no harmful substances,less heat release,no dripping,and easy to migrate to the surface to form a protective layer.In order to achieve better flame retardant effect and ensure environmental friendliness.Three kinds of flame retardants were designed and prepared.The organosilicon was grafted with phosphorus and nitrogen groups through the reaction,and the active groups were retained to participate in the curing process of the resin.In order to achieve a better unity of environmental friendliness,compatibility with matrix and flame retardancy.The main contents are as follows:1.Using phytic acid,?-glycidyl ether oxypropyl trimethoxysilane and side methoxymethyl polysiloxane as raw materials to prepare flame retardant PKP.The active hydroxyl group in PKP was used to cure epoxy resin E51 to obtain intrinsic flame retardant epoxy resin.Under the action of PKP,the tensile strength of intrinsic flame retardant epoxy resin reaches 33 MPa.Compared with the epoxy resin cured by poly ether amine D230,the residual weight of epoxy resin in nitrogen atmosphere increased from 7.92 wt%to 39.49 wt%,and the maximum thermogravimetric rate decreased by 57.25%,which effectively inhibited the thermal decomposition process of epoxy resin.The LOI increased to 25.9%,the vertical combustion reached V-1 grade,and the flame retardancy was improved.The maximum smoke density decreased from 72.17%to 7.85%,and the time of smoking was delayed from 92.3 s to 159.1 s.2.The flame retardant PKE was prepared by using phenyl dichloride phosphate,?-aminopropyltriethoxysilane and ethylenediamine.PKE and PMOS were added into epoxy resin E51 cured by polyether amine D230 to improve the flame retardancy of epoxy resin.The limiting oxygen index of PKE flame retardant epoxy resin reaches 26.5%,the vertical combustion reaches V1 grade,no droplet is produced,and the maximum smoke density is reduced to 10.57%.It can be seen from the optical microscope that PKE has good compatibility with epoxy resin without obvious phase separation.The mechanical properties were improved obviously,and the tensile strength could reach 61.59 MPa at 22.2 wt%.The results show that the residual weight is increased to 20.72%in nitrogen atmosphere,and more residual carbon is helpful to improve the flame retardant effect of condensed phase.3.The flame retardant PKM was synthesized from phytic acid,melamine and y-aminopropyltriethoxysilane.Flame retardant epoxy resin was prepared by adding PKM to epoxy resin E51 cured by polyether amine D230.The compatibility between PKM and matrix is good and the cross section is smooth.The tensile strength of PKM flame retardant epoxy resin reached 49.09 MPa,and the glass transition temperature increased from 80.33? to 82.81?.The residual weight increased to 20.92 wt%in nitrogen atmosphere.The LOI increased from 22.0%to 29.5%,the maximum smoke density decreased to 62.68%,and the vertical combustion reached V-0 level at 13.3 wt%.