漆酶预处理阻燃纤维板的制备工艺优化及阻燃性能研究

Preparation Process Optimization and Flame Retardant Performance of Laccase Pretreated Flame-retardant Fiberboard

为改善阻燃剂在纤维板中的阻燃效果,采用漆酶预先处理杨木纤维,再使用BL-环保阻燃剂浸渍杨木纤维,制备得到酶处理阻燃纤维板。以纤维板的阻燃剂负载量、氧指数和烟密度为指标,采用正交试验法确定最佳浸渍工艺,并通过氧指数、烟密度、热重(TG)分析和傅里叶变换红外光谱(FT-IR)对杨木纤维的浸渍效果进行分析。研究结果表明:在漆酶处理温度50℃、酶处理时间60 min、酶用量35 U/g、pH值4.8、阻燃剂用量50%、阻燃剂浸渍时间80 min和阻燃剂处理温度35℃的条件下,制备的纤维板阻燃效果最好。此条件下,阻燃剂负载量为20.3%,氧指数为41.5%,烟密度为10.9%,密度为0.774 g/cm~3,静曲强度为30.3 MPa,弹性模量为3 507 MPa,内结合强度为0.61 MPa,吸水厚度膨胀率为17.4%;相比于普通纤维板,BL-环保阻燃剂处理纤维板能提高其氧指数和阻燃剂含量。在干燥阶段与炭化阶段,相比于普通纤维板和仅BL-环保阻燃剂处理制备的阻燃纤维板,漆酶处理的阻燃纤维板产生相同的失重所需的温度更高,不易发生燃烧反应;漆酶处理的阻燃纤维板含氧官能团、羟基官能团明显下降,提高了纤维板的阻燃性能。

In order to improve the flame-retardant effect of flame retardants in fiberboard,laccase was used to pretreat poplar fiber and then BL-environmental friendly flame retardant was impregnated with poplar fiber to prepare laccase treated flame-retardant fiberboard.Taking the flame retardants loading,oxygen index and smoke density of fiberboard as indexes,the orthogonal experimental design was used to determine the optimal impregnation process.The impregnation effect of poplar fibers was analyzed by oxygen index,smoke density,thermogravimetric(TG) analysis and Fourier transform infrared spectroscopy(FT-IR).The results showed that the prepared fiberboard had the best flame-retardant effect under the conditions of laccase treatment temperature of 50 ℃,enzyme treatment time of 60 min,enzyme dosage of 35 U/g,pH value of 4.8,flame retardant dosage of 50%,flame retardant impregnation time of 80 min and flame retardant temperature of 35 ℃.Under these conditions,the flame retardant loading was 20.3%,the oxygen index was 41.5%,the smoke density was 10.9%,the density was 0.774 g/cm~3,the static flexural strength was 30.3 MPa,the elastic modulus was 3 507 MPa,the internal bonding strength was 0.61 MPa,and the thickness expansion rate of water absorbing was 17.4%.Compared with ordinary fiberboard,BL-environmental flame retardant treatment of fiberboard could improve its oxygen index and flame retardant content.Compared with the ordinary fiberboard and the flame-retardant fiberboard prepared by BL-environmentally friendly flame retardant treatment only,the temperature required for laccase-treated flame retardant fiberboard to produce the same weight loss was higher,and the combustion reaction was not easy to be occured in the drying and carbonization stages.The oxygen-containing functional groups and hydroxyl groups of laccase-treated flame-retardant fiberboard decreased significantly,and the flame retardancy of the fiberboard was improved.