木质素基酚醛树脂泡沫的制备及性能研究

Preparation and Characterization of Lignin Based Phenolic Foam

在碱性条件下,先利用木质素部分替代苯酚与甲醛反应合成酚醛树脂,然后利用酚醛树脂经发泡工艺制备木质素基酚醛树脂泡沫,当木质素替代量为0%、10%、20%和30%时,分别记为LPF-0%、LPF-10%、LPF-20%和LPF-30%。对泡沫的性能研究结果表明:木质素可部分替代苯酚,与甲醛发生缩合反应生成酚醛树脂;当木质素替代量为20%(LPF-20%)时,泡沫热解具有最大的残炭率54.60%,其热稳定性优于其它酚醛树脂泡沫;随着木质素替代量的增加,木质素基酚醛树脂泡沫的颜色由黄色渐变为褐色,其表观密度由0.05 g/cm^3增加至0.11 g/cm^3,压缩强度从0.26 MPa增加为0.56 MPa,表面粉化程度由13.73%降低至3.48%,吸水率由3.73%降低至1.92%;木质素基酚醛树脂泡沫具有良好的阻燃性,LPF-30%的氧指数最大为33.67%。

Lignin was used to partially replaced phenol andreact with formaldehyde to form a lignin based phenolic resin under alkaline condition.Then this lignin based phenolic resin was applied to prepared a foam by foaming process.When the replacement percentages of phenol by lignin were 0%,10%,20%,and 30%,the phenolic foams were denoted as LPF-0%,LPF-10%,LPF-20%,LPF-30%,respectively.The research results on the properties of phenolic foams showed that lignin could partially replace the phenol and carry out condensed reaction with formaldehyde to form phenolic resin.Four kinds of lignin-based phenolic foam had good thermal stability.The maximum carbon residue of foam was 54.60%when the replacement percentage of phenol by lignin was 20%(LPF-20%),and the thermal stability was better than other phenolic foams.As the substitution amount of lignin increased,the color of lignin-based phenolic foam gradually changed from yellow to brown,its density increased from 0.05 g/cm 3 to 0.11 g/cm 3,and the compressive strength increased from 0.26 MPa to 0.56 MPa,the degree of surface power decreased from 13.73%to 3.48%,and the water absorption rate decreased from 3.73%to 1.92%.Lignin-based phenolic foam showed a good flame retardant property and the oxygen index of LPF-30%was as high as 33.67%.