木质素基酚醛树脂的制备及应用研究

发布时间：2018-12-08 09:00

【摘要】：酚醛树脂(PF)是酚类与醛类化合物在催化剂作用下缩聚而成的一类高分子化合物,由于具有优异的耐水性、耐热性及良好的化学稳定性,在工业应用中占用重要位置。但是其原料属于不可再生资源,随着经济快速发展,资源短缺与环境污染问题日益严重,开发可再生能源替代石油化工原料受到不断关注。来自木糖工业生产废渣的木质素由于含有酚羟基可以替代苯酚用于合成酚醛树脂。液态的酚醛树脂做胶黏剂可以应用到木材工业中制备高端人工合成板材,同时固化后的酚醛树脂是良好的碳源,可以应用到制备超级电容器上做储能电极材料。本论文以工业木糖生产废渣为原料,经碱催化降解提取得到碱木质素液,经苯酚酚化改性后代替部分苯酚与甲醛原位合成木质素基酚醛树脂(LPF),并在此基础上系统研究了LPF作为胶黏剂及活性炭储能材料的两个应用方向,均取得了较好的研究成果。1.玉米秸秆木质素提取条件对LPF中甲醛释放量有重要影响,在Na OH浓度为5 wt%,工业生产木糖残渣与碱液固液比为1:12,反应时间为3 h时,提取的碱木质素液与苯酚、甲醛原位参与酚醛树脂制备,在替代30%苯酚所得LPF中甲醛释放量最少,为0.115%。2.木质素的种类和提取条件对于酚醛树脂胶黏剂的胶合强度具有重要影响。在Na OH浓度为5 wt%,玉米芯生产木糖剩余残渣与水固液比为1:8,提取时间为4 h,玉米芯木质素替代20%苯酚时,得到最佳提取条件。在最佳条件下制备得到的玉米芯-LPF胶合强度达到最大值,为1.590 MPa。低于同等条件下的玉米秸秆-LPF的1.689 MPa。3.以玉米芯-LPF为前驱体,通过氢氧化钾活化制备电容炭,通过控制木质素替代率可以调节活性炭微介孔比例达到最佳比电容。当木质素替代率为20%时得到的电容炭比电容值最大,为322.65 F/g。4.对于稻草-LPF氢氧化钾活化效果优于氢氧化钠,随着木质素替代率从20%增加到40%,电化学比电容值随之增加。在相同的活化条件下,二者活化得到的炭材料比电容最大值分别为40%K-LPFC-4的302.80 F/g和40%N-LPFC-4的253.56 F/g。
[Abstract]:Phenolic resin (PF) is a kind of polymeric compounds formed by condensation of phenols and aldehydes under the action of catalyst. Because of its excellent water resistance, heat resistance and good chemical stability, it occupies an important position in industrial application. However, the raw materials are non-renewable resources. With the rapid development of economy, the problems of resource shortage and environmental pollution are becoming more and more serious, so the development of renewable energy to replace petrochemical raw materials has been paid more and more attention. Lignin from xylose industrial waste can be used instead of phenol to synthesize phenolic resin because of its phenolic hydroxyl. Liquid phenolic resin as adhesive can be applied to the wood industry to prepare high-end synthetic plate, and the cured phenolic resin is a good carbon source, and can be used as energy storage electrode material in the preparation of supercapacitors. In this paper, alkali-lignin solution was extracted from industrial xylose waste residue by alkali catalytic degradation. After phenol phenolization, lignin-based phenolic resin (LPF), was synthesized in situ instead of some phenol and formaldehyde. On this basis, two application directions of LPF as adhesive and activated carbon energy storage material have been systematically studied, and good research results have been obtained. 1. The extraction conditions of lignin from corn straw had an important effect on the formaldehyde emission in LPF. When the ratio of lignin residue to alkali solution was 1: 12 and the reaction time was 3 h, when the concentration of Na OH was 5 wt%, the alkali lignin solution and phenol were extracted. Formaldehyde in situ participated in the preparation of phenolic resin, and the formaldehyde emission of LPF was the least in the substitution of 30% phenol, which was 0.115. 2. The type and extraction conditions of lignin have an important effect on the adhesive strength of phenolic resin adhesive. The optimum extraction conditions were obtained when the Na OH concentration was 5 wt%, when the ratio of residual xylose residue to water solid liquid was 1: 8, the extraction time was 4 h, and the corncob lignin was substituted for 20% phenol. The bonding strength of corn cob LPF prepared under the optimum conditions reached the maximum value of 1.590 MPa.. Less than 1.689 MPa.3. of LPF of Corn Straw under the same condition Capacitive carbon was prepared by activation of potassium hydroxide with corncore-LPF as precursor. The optimum specific capacitance could be obtained by controlling the lignin substitution ratio. When the lignin substitution ratio is 20, the maximum specific capacitance is 322.65 F / g 路4. The activation effect of straw-LPF potassium hydroxide was better than that of sodium hydroxide. The electrochemical capacitance increased with the increase of lignin substitution rate from 20% to 40 kum. Under the same activation conditions, the maximum specific capacitance of the activated carbon was 302.80 F / g of 40%K-LPFC-4 and 253.56 F / g of 40%N-LPFC-4, respectively.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ323.1

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