PRODUCTION AND CHARACTERISATION OF RIGID BIOBASED FOAM FROM PLANT-DERIVED CHEMICALS

Abstract

Bio-based foams are promising materials for replacing foams of petrochemical origin, due to availability of the raw materials, low cost, good thermal insulation performance, and excellent fire retardance. The aim of this study is to synthesize rigid bio-based foams, replacing noisome synthetic chemicals with chemicals that have green credentials, and derived from plant biomass, synthesis conditions were varied. The effects of variation of the synthesis parameters were evaluated, using various analytical techniques. Lignin was isolated, optimized, liquefied and characterized from five agrarian wastes. Similarly, furfural was obtained from three agrarian wastes alongside with corn cob. Corn cob gave the highest yield (7.2%).Furfural yield was optimized by varying concentrations of sulfuric acid, solidto-liquid ratio, time, and temperature. The furfural obtained was subsequently transformed to furfuryl alcohol by a simple hydrogenation process. Fifteen different bio-based foams were produced from furfuryl alcohol liquefied lignin and other additives. The following parameters; lignin to furfuryl alcohol ratio, catalyst concentration, blowing agent concentration, hardener concentration, and bentonite concentrations were varied. The produced foams were characterize using various analytical techniques such as; FTIR, TGA, SEM-EDX, molecular weight determination, solvent solubility index, water absorption capacity, compressive strength and density. Lignin yield was optimized by varying concentration of Sodium hydroxide, solid to liquid ratio, time and temperature. The results showed that palm kernel shell (PKS) have the highest yield of lignin in all the samples, this highest value was obtained when volume of NaOH was varied with weight of biomass. The highest yield obtained was quantitavely high at ratio 1:40 weight of biomass to the volume 25%NaOH at 160 minutes and 160oC. The isolated lignin from the wastes were characterized using GC MS and FTIR, the results indicate aromatic of lignin derivatives were present in all the sacharacterize. Hydroxyl number, liquefaction yield and residue content were 409.53 mg KOH/g 3.39% and 93.22% respectively. The results furfural yield revealed that increasing the concentration of sulphuric acid, time, and temperature at constant biomass weight favoured furfural production. The highest yield of furfural (7.2%) was obtained at a ratio of 1:30 sulphuric acid (20%) to biomass weight at 160 oC and 160 minutes. The production of furfuryl alcohol was favored by increasing the concentration of NaOH, time of reaction, and temperature at 20 oC. More FA was obtained at 20 oC, above which less FA was recovered. The produced furfural and FA were characterized using gas chromatography-massspectrometry (GC-MS) and Fourier transforms infrared spectrometry (FTIR). The mass to charge ratio using GC-MS and FTIR data confirmed synthesis of furfuryl alcohol. The results obtained from rigid bio-based foam characterization are as follows; SEM morphological studies showed, a close cell, Thermo-gravimetric analysis TGA, Tmax (o C) ranges between 443.58 to 586.09, water absorption capacity ranges between 21.81 % to 332.14%,, compressive strength ranges from 35.050 KN to 50.968 KN, density ranges from 0.076 to 1.016 g/cm3. Tetrahydrofuran (THF) has the highest solubility index of 90% and water has the least (0.1%). These results are akin to that of rigid foams which are suitable for thermal insulation and acoustic applications with packaging material applications as well.mples. The bio-polyols were obtained by liquefaction of lignin obtained from PKS and