聚氨酯/闭孔珍珠岩复合改性酚醛泡沫的制备及性能研究

Preparation and the Research of Properties of Modified Phenolic Foam with Polyurethane and Obturator Perlite

酚醛泡沫(PF)是一种新型保温材料,具有低毒、低烟、轻质、难燃、隔热、耐高低温等优点,针对其质脆、易粉化的缺陷,本文首先利用蓖麻油和甲苯二异氰酸酯(TDI)制备端异氰酸酯基聚氨酯预聚体(IPUP),再利用其对PF进行增韧改性,通过正交试验考察了异氰酸酯基(-NCO)与羟基(-OH)的摩尔比、IPUP的加入量、发泡温度(T)对PF质量的影响,确定当n-NCO/n-OH=5∶1、wIPUP=7%(wt)、T=75℃时密度最小,为0.0501 g/cm3,IPUP改性泡沫(IPUP/PF)与未改性泡沫(PF)相比,粉化率由2.25%降低到1.40%,吸水率由72.26%降低到58.12%,表明IPUP可以提高PF的韧性。在此基础上结合闭孔珍珠岩(OP)复合改性PF,利用压缩强度结合TGA、垂直燃烧实验及极限氧指数(LOI)对性能进行表征,当wIPUP=7%(wt),wOP=5%(wt)时,IPUP/OP/PF的压缩强度最大为650.26 k Pa,粉化率最低为1.20%,吸水率最低为55.38%,表观密度增大为0.0699 g/cm3;TGA分析结果显示:在700℃时,IPUP/OP/PF的残留质量分数虽然比PF下降了4.26%,但是比IPUP/PF增大了5.93%,表明OP在高温环境下保持了IPUP/OP/PF的热稳定性;垂直燃烧实验结果显示:IPUP/OP/PF较IPUP/PF平均质量百分数增加了2.63%,平均燃烧时间减少了4 s,同时由LOI可以发现IPUP/OP/PF的氧指数为35%,大于32%,说明IPUP/OP/PF仍属于难燃性材料。可见,IPUP/OP在对PF韧性改性的基础上保持了PF的热学性能。

Phenolic foam（PF） is a new type of insulated material.It has many advantages such as low toxicity,low smoke,light,flame retardant,insulation,high and low temperature resistance,etc.But it is brittleness and easy pulverization.For this defect,in this work, firstly,isocyanate groups-terminated polyurethane prepolymer（IPUP） was prepared via the chemical reaction between castor oil and TDI.Then PF was toughened by IPUP through orthogonal experiment to examine the influence of the molar ratio of -NCO to -OH,the amount of the IPUP,the foaming temperature on the contents of PF quality.It was found that the apparent density of IPUP/PF had the minimum of 0.0501 g/cm^3 when n_NCO/n-OH=5：1 ,wIPUP=7 %（wt）,T=75℃. The chalking rate of IPUPfPF reduced from 2.25% to 1.40%,and the water absorption ratio declined from 72：26% to 58.12% by comparing with PF which indicated that the IPUP could improve the toughness of PF.On this basis,this paper used obturator perlite （OP） combine with IPUP to modify PF.The compression strength,TGA,vertical firing test and limiting oxygen index （LOI） were used to characterize the properties of the IPUP/OP/PF.It was found that the compression strength of IPUP/OP/PF had the maximum of 650.26 kPa,the chalking rate had the minimum of 1.20%,the water absorption ratio had the minimum of 55.38%,and the apparent density rised to the 0.0699g/cm^3.Meanwhile,the results of TGA showed that the residual mass fraction increased 5.93% compared with IPUP/PF but declined 4.26% compared with PF at 700℃ for IPUP/OP/PF,which indicated that the OP maintained the excellent thermal stability of IPUP/OP/PF in high temperature environments.The vertical flame test found that the percentage of average quality for the IPUP/OP/PF increased 2.63%,and the average burning time reduced 4 s compared with the IPUP/PF.Meanwhile, the results of LOI for IPUP/OP/PF was 35% that was higher than 32.0%,indicated the IPUP/OP/PF were still flame retardant material.It can be seen that IPUP/OP maintain the thermal performance of the PF.