本文選題：木質(zhì)素　切入點(diǎn)：減水劑　出處：《青島科技大學(xué)》2017年碩士論文　論文類(lèi)型：學(xué)位論文

【摘要】：自然界中,木質(zhì)素作為僅次于纖維素的第二大生物質(zhì)資源,其具有含量豐富,環(huán)保,可再生的優(yōu)點(diǎn)。但是,由于其結(jié)構(gòu)復(fù)雜,分子量分布不均勻的特點(diǎn),高值利用率低。所以,對(duì)木質(zhì)素進(jìn)行分級(jí)純化改性,不僅能提高其利用率,還能降低石油等不可再生資源的消耗,對(duì)人類(lèi)社會(huì)的可持續(xù)發(fā)展具有重要意義。本文采用甲酸提取針葉木中的木質(zhì)素,再通過(guò)有機(jī)溶劑對(duì)木質(zhì)素進(jìn)行分子量分級(jí),并進(jìn)行化學(xué)改性,制備木質(zhì)素基高效混凝土減水劑。將甲酸提取木質(zhì)素實(shí)驗(yàn)條件優(yōu)化后,將松木在140℃、L/S=6:1、H_2O_2溶液用量為5%(以絕干松木質(zhì)量為基準(zhǔn))與88%甲酸反應(yīng)40min可得甲酸木質(zhì)素(FAL)。再利用有機(jī)溶劑溶解FAL進(jìn)行分級(jí)處理可得到可溶木質(zhì)素(S-FAL)和不溶木質(zhì)素(I-FAL)。經(jīng)元素分析,液相色譜、GPC、FT-IR、~1H-NMR測(cè)定分析可得:1、松木原料的最高脫木素率達(dá)到87.2%,所得纖維素純度為89.3%、纖維素收率88.7%、半纖維素收率76.6%;2、分級(jí)的木質(zhì)素具有更多的反應(yīng)活性點(diǎn)(更多的亞甲基和羥基,和較少的甲氧基),更容易被改性(如磺化或磺甲基化),從而提高其工作性能。將改性實(shí)驗(yàn)條件優(yōu)化后,將所得木質(zhì)素與50%的H_2O_2溶液(以絕干FAL質(zhì)量為基準(zhǔn))在100℃下反應(yīng)1h進(jìn)行氧化反應(yīng),然后,與100%HCHO溶液和50%的Na_2SO_3固體在150℃下反應(yīng)2h進(jìn)行磺甲基化反應(yīng)制得分級(jí)改性木質(zhì)素(MS-FAL、MI-FAL)。采用元素分析,液相色譜、GPC、FT-IR、~1H-NMR、水泥凈漿流動(dòng)度、磺化度和減水率測(cè)試對(duì)所有產(chǎn)品進(jìn)行表征分析可得:經(jīng)丙酮溶劑(分析純)溶解分級(jí)的木質(zhì)素改性后,當(dāng)摻量為0.3%時(shí),其水泥凈漿流動(dòng)度可達(dá)到178±2 mm,減水率可達(dá)21%,與商品萘系減水劑效果相當(dāng),達(dá)到高效減水劑的要求。實(shí)驗(yàn)所用的甲酸溶液和有機(jī)溶劑均可回收再利用,可減少污染,并降低生產(chǎn)成本。
[Abstract]:In nature, lignin, as the second largest biomass resource after cellulose, has the advantages of rich content, environmental protection and renewable. However, because of its complex structure, uneven molecular weight distribution, low utilization ratio of high value, The classification and purification modification of lignin can not only improve its utilization rate, but also reduce the consumption of non-renewable resources such as petroleum, which is of great significance to the sustainable development of human society. In this paper, formic acid was used to extract lignin from coniferous wood. Then the molecular weight of lignin was classified by organic solvent, and the lignin based high efficiency concrete water reducer was prepared by chemical modification. The experimental conditions of extraction of lignin by formic acid were optimized. After 40 minutes of reaction of pine wood with 88% formic acid for 40 minutes, soluble lignin S-FAL and insoluble lignin I-FALL can be obtained when the amount of solution is 5 (based on the mass of absolutely dried pine) and 88% formic acid, and the soluble lignin S-FAL and insoluble lignin I-FALL can be obtained by using organic solvent to dissolve FAL for 40 minutes. The highest delignification rate of pine wood was 87.2, the purity of cellulose was 89.33p, the yield of cellulose was 88.7%, the yield of hemicellulose was 76.6%, and the graded lignin had more reactive activity points (more methylene and hydroxyl). And less methoxy, it is easier to be modified (such as sulfonation or sulfomethylation), so as to improve its performance. The lignin was oxidized with 50% H _ S _ 2O _ 2 solution (based on the dry FAL mass) at 100 鈩，

本文編號(hào)：1599715