Study On Preparation And Application Of Flame Retardant Plhragmites Communis

Due to easy burning and inferior compatibility with matrix of phragmites communis fiber(PF),its application areas are limited.Based on this,flame retardance modification and surface modification on PF were examed and PVC/PF composites were also prepared.The effects of modifications on properties of PF and its composites were investigated.Firstly,physical impregnation flame retardant PF was prepared using intumescent flame retardant APP,PER and MEL.At the same time,autonomous synthesized halogen free flame retardant PPP which contained P and N element as reactive monomer,chemical grafting flame retardant PF(PF-PPP)was obtained by esterfication.The optimum reaction conditions were achieved through orthogonal test,that was 1g PF being infiltrated by 30% NaOH for 10 min and then reacted with 1.5g PPP,0.05 g quaternary ammonium salt at 50℃ for 4 hours.The effects of modification on flame retardancy and thermal stability were contrasted and analyzed through measures of vertical burning,oxygen index,thermal degradation and thermal weight loss.It was found that flame retardant modifications on PF could improve the flame retardancy and thermal stability effectively,which PF-PPP had better flame retardancy with V-0 grade and 55.4% LOI and exhibited a outstanding property compared with physical impregnation flame retardant PF.It also indicated that the chemical treatment was the most efficient way to improve the thermal stability of PF.Secondly,effects of PF dosage on composites’ mechanical properties were studied and the effects of flame retardant on mechanical property,flame retardancy,thermal stability,water absorption and microstructure of composites were analyzed.The results showed that flame retardant modification was beneficial to improve flame retardency,water absorbency,thermal stability and interfacial compatibility of composites and the tensile strength was also improved.Because the content of polar group-OH in chemical grafting flame retardant PF decreased,leading to better interfacial properties between PF and PVC,the mechanical property increased considerably.Further more,effects of reaction conditions on growth rate of benzylated phragmitesaustralis fiber(PF-BIAN)had been discussed.The optimum reaction conditions were determined through orthogonal test,that was the amounts of NaOH and benzyl chloride were respectively 10 ml and 7ml,the reaction temperature and time were 110℃ and 4h.The impact strength,flexural strength,flexural modulus,processing flowability,water absorption performance and thermal stability of composite were improved after benzylation while the tensile strength increased 18.64 MPa.At last,analysis of the flame retardance modification and surface modification on the properties of composites was conducted.It found that two kinds of modification methods could both improve the thermal stability and water absorption property of composites and flame retardance modification performed better thermal stability while surface modification had superior water absorption property.