Effect Of Flame Retardant On UV-Aging Of PP And Research On Flame Retardancy And UV-Aging Resistence

Polypropylene（PP）has excellent properties,so it is widely used in various fields,such as home appliances,construction,etc.However,PP is easily ignited companied with amount of molten droplets,which brings safety hazards.Moreover,PP is also vulnerable to ultraviolet（uv）light,contributing the photo-oxidative degradation.Therefore,it is critical to improve its flame retardancy and UV resistance.In this paper,the effects of flame retardants and hindered amine light stabilizers（HALS）on the flame retardancy,mechanical and photoaging properties of PP were explored,and the photoaging properties of PP were studied.The flame retardant and anti-light aging mechanism of different flame retardant systems in PP matrix were discussed and analyzed.It is important to the preparation of high-performance flame retardant and anti-photoaging PP composites.The main results of this paper are as follows:（1）The influence of two widely used flame retardants including ammonium polyphosphate（APP）and decabromodiphenylethane（DBDPE）on photoaging properties of PP was explored,the interaction between flame retardants and HALS under UV irradiation was also studied.It showed that the surface cracks and carbonyl index increased after adding DBDPE and APP,the photoaging property of PP was accelerated,bromine flame retardant DBDPE showed the more sever acceleration degree.After adding light stabilizer,both APP and DBDPE showed antagonistic effect with HALS,and the antagonistic effect of DBDPE was also more obvious.（2）In order to eliminate the negative effect of APP on the anti-photoaging properties of PP,polysiloxane-coated ammonium polyphosphate（SiAPP）was designed and synthesized,and it was combined with melamine（MEL）and phytic acid（PA）through supramolecular self-association to prepare supramolecular aggregates SiAPP-MEL-PA and added to PP to prepare flame retardant and anti photoaging composites.PP/25%SiAPP-MEL-PA sample showed excellent anti-UV aging performance.After aging,the surface cracks,carbonyl index,and the decrease rate of mechanical properties are less than that of control PP.At the same time,after adding 25%SiAPP-MEL-PA,the peak heat release rate（pHRR）of PP decreased by 34%,the CO₂production also decreased by 43.9%,and the obvious expanded carbon layer was observed with 11%char residue.（3）Modified sodium lignosulfonate（SLS）was grafted by hindered amine monomer（Temp）to prepare the flame retardant synergist and light stabilizer,and used together with SiAPP and CFA to prepare multifunctional intumescent flame retardant PP.The LOI of PP/19%SiAPP/CFA/2%SLS-Temp reached to33.5 and the pHRR decreased by 76%,and the smoke suppression performance was also greatly improved.Compared with pure PP,the p SPR and TSR decreased by 81%and 53.7%,respectively.Moreover,PP/19%SiAPP/CFA/2%SLS-Temp showed the excellent anti-UV performance with the lowest carbonyl index and the decrease rate of mechanical properties after aging.Importantly,it still maintained good flame retardant performance after 100 h UV aging,the sever dripping cannot be observed and passed the UL-94 V-0 rating.The preparation and introduction of flame retardant and anti-UV synergists improved the safety and service life of PP.