| Polyester ranks the first in the synthetic fiber.It owns high strength,high temperature resistance,abrasion resistance,corrosion resistance,light resistance and other properties.Therefore,it is widely used in military,agricultural,industrial,the textile industry and other fields.However,the limit oxygen index(LOI)value of polyester fabric is only about 21%,which is a flammable material.And a large number of droplets and black smoke will produce during the combustion process,which easily caused secondary damage.The flame retardants used in polyester are mainly classified into four categories: halogen,phosphorus,inorganic and intumescent.Since the intumescent flame retardant(IFR)is one of composite flame retardant formed mainly of phosphorus and nitrogen.Moreover,it has the advantage of environmental protection,low smoke,low toxicity and high efficiency.As a new type of flame retardant,IFR has received much attention in recent years.Carbon microspheres(CMSs)is emerging carbon material and has been studied in the field of flame retardant,and mainly played in the condensed phase.So it can act as a new carbon source in the IFR.Ammonium polyphosphate(APP)has the advantages of good thermal stability,high phosphorus content,no pollution,and low price.In the field of flame retardant,APP belongs to gas phase flame retardant and owns smoke suppressing property,so it is the preferred material for acting as an acid source and gas source in the expanded flame retardant.The combination of CMSs and APP can build a new IFR system,which is expected to achieve the dual effects of flame retardant and smoke suppression,by the synergistic flame retardant effect.In view of this,this topic firstly explored the synergistic flame retardant effect between CMSs and APP by using the compounding method.Secondly,in order to improve the compatibility between the flame retardant compositions and the matrix,the microcapsule composite flame retardant(CMSs-APP)with the structure of CMSs as core materied and APP as shell materied was designed.And the CMSs-APP/PET composites were prepared by melt blending.The flame retardant properties and mechanical properties were studied.And the mechanism was initially explored.Finally,the composite flame retardant was directly applied in the polyester fabric by post-finishing method.The thermal stability,mechanical properties,flame retardancy of the polyester fabric were studied.Through the above research,the main conclusions are as follows:(1)When the compounding ratio of CMSs and APP was 1:2 and the total content of CMSs/APP flame retardant was 2%,the synergistic flame retardant effect was the best.The LOI value of CMSs/APP/PET composite can reach 27.5%.The peak heat realese rate(PHRR)value decreased by 45.4%,the amount of carbon residue increased from 13.2% to 17.3%,and the total smoke production(TSP)value decreased by 13.9%.The dual effects of flame retardant and smoke suppression were achieved.But the tensile strength of PET composites decreased from 47.56 MPa to 18.97 MPa,which was 60.1% lower than that of pure PET.(2)A series of encapsulated flame retardants CMSs-APP(CA)were prepared by coating technology.The results showed that,when the total content of CMSs-APP flame retardant was 2% and the coating ratio of CMSs and APP was 1:2(CA2),the synergistic effect was the best.The LOI value of the CA2/PET composites reached 28.6%,and the V-0 rating of the UL-94 test was passed.Compared with pure PET,the PHRR value of CA2/PET composites decreased by 71.4%,the fire performance index(FPI)value increased by 177.0%,the TSP value decreased by 18.7%,and the tensile strength reached 36.13 Mpa.(3)The polyester fabric was immersed by twice in the coating liquid with 1.3% flame retardant content.And the flame retardant effect has reached the required requirements.The LOI value reached 28.1%,which was 33.8% higher than that of the uncoated polyester fabric,and the B1 level was reached in the vertical burning test.And the PHRR value reduced by 51.0% compared to the pure polyester fabric. |
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