【作者】 兰平；

【导师】 周定国； Nicolas BROSSE；

【作者基本信息】 南京林业大学 ， 木材科学与技术， 2013， 博士

【摘要】 葡萄渣是葡萄酒生产加工行业的剩余物，含有丰富的原花色素凝缩类单宁。到目前为止，仅有少量葡萄渣剩余物被回收利用，大部分仍用于附加值很低的肥料、饲料或直接当垃圾处理。本论文以葡萄废渣为原料提取凝缩类单宁，借助现代分析技术确定凝缩类单宁的结构特征，并用此种单宁提取物制备单宁基胶粘剂。为高效利用葡萄渣废弃物提出可行性方案，延长葡萄产业链；又能为木材工业用单宁基胶粘剂的制备与应用技术开发提供坚实的理论基础。采用碱溶液抽提法从葡萄皮渣中提取凝缩类单宁提取物，所用的提取试剂有氢氧化钠（NaOH）、碳酸钠（Na₂CO₃）、碳酸氢钠（NaHCO₃）和亚硫酸钠（Na₂SO₃）。主要讨论了两种不同的提取工艺和四个重要的提取参数（提取剂、提取剂用量、反应温度和反应时间）对单宁的得率、性能的影响。结合应用元素分析法、傅里叶变换红外光谱（FT-IR）、热重分析技术（TGA）、碳核磁共振波谱技术(¹³C-NMR)和基质辅助激光解析电离飞行时间质谱（MALDI-TOF-MS）分析技术，对不同工艺条件下提取的单宁提取物的组成、热稳定性、分子量分布和结构特点进行表征和分析。再以从葡萄皮渣中提取冻干单宁提取物为原料，配制不同的单宁基胶粘剂配方，用于压制木质刨花板，探讨葡萄皮渣单宁基胶粘剂在刨花板用胶粘剂上应用的可能性，并且研究不同的单宁提取物和不同的单宁基胶粘剂配方对板材性能的影响。在合适的提取工艺条件下，完全可以从葡萄皮渣原料中提取到单宁提取物。葡萄皮渣酸化单宁中有效活性单宁含量较高，单宁提取物的Stiasny值高于95%，但水溶性和对甲醛的反应活性较差，这主要是由于单宁在酸化过程中发生严重的单宁酸重排反应和生成红粉反应，使得单宁低聚物生成一些不溶于水和不与甲醛发生反应的单宁衍生物。葡萄皮渣冻干单宁虽然单宁提取物中的有效活性单宁含量较低，但却表现对良好的甲醛反应特性，具有制备单宁基胶粘剂的初步特征。在工艺参数的选择上，比较适合的提取温度为100°C，比较适合的提取时间为120min，当提取剂的总用量为10%时，所得到的葡萄皮渣单宁提取物中的有效活性单宁的含量最高。亚硫酸盐法是一种比较有效单宁提取法。它主要是通过凝缩类单宁类黄酮单体中的吡喃C环中引入亚硫酸离子来提高单宁的水溶性和对甲醛的反应活性。由元素分析法和傅里叶红外光谱结果表明，不同亚硫酸化试剂提取的三种葡萄皮渣亚硫酸化单宁提取物没有明显的区别，除了由于亚硫酸化程度的不一样，使得单宁类黄酮单体中吡喃—C环开环比例不同。结果显示，当提取试剂为Na₂CO₃/Na₂SO₃和NaHCO₃/Na₂SO₃时，单宁提取物的吡喃C环开环比例高于NaOH/Na₂SO₃为提取剂的单宁提取物。相比于亚硫酸化冻干单宁，葡萄皮渣酸化单宁提取物具有更明显的羰基峰（C=O）和苯环骨架振动峰；在酸化单宁提取物未检测到由亚硫酸化引起单宁类黄酮单体中的吡喃C杂环开环形成饱和C-C骨架伸缩振动峰。三种不同亚硫酸化冻干单宁提取物的TGA曲线和DTG曲线没有明显的区别。这三种单宁提取物的热分解主要分为两个阶段，第一阶段从室温到200°C，主要是单宁提取物的水分蒸发和一些低分子化合物如单糖类物质、有机酸、苯酚以及天然色素类物质分解引起。第二阶段为单宁提取物的主要分解阶段，分解温度从200°C到400°C，这一阶段主是由于单宁提取物中的聚合多酚类物质所致。¹³C-NMR结果可知，本研究所提取的单宁为粗单宁提取物，里面不但含有聚合多酚类物质同时含有非单宁类物质如碳水化合物等。聚合多酚类物质是以原花青素类凝缩类单宁为主，并含有少量的原翠雀素凝缩类单宁，单宁的类黄酮单体间以C4-C8连接为主，属于典型的原花青素类凝缩单宁的连接方式。亚硫酸化冻干单宁提取物中的非单宁类物质含量高于酸化单宁提取物，酸化单宁提取物中的羰基（C=O）吸收峰强于亚硫酸化冻干单宁。MALDI-TOF质谱结果表明，酸化单宁提取物中最大单宁低聚物由10个类黄酮单体组成的为十聚物，冻干单宁提取物的最大单宁低聚物由6个类黄酮单体组成的六聚物。葡萄皮渣单宁提取物中聚黄酮类化合物主要为原花青素类凝缩单宁，含有少量的葡萄糖基取代基和没食子酸取代基，属于原花青素—原翠雀素快速反应型凝缩类单宁。葡萄皮渣冻干单宁提取物的分子聚合度低于酸化单宁提取物。采用两种单宁基胶粘剂配方，单宁-甲醛胶粘剂和p-MDI（4，4’-二苯甲烷二异氰酸酯）-单宁-甲醛胶粘剂。提取剂及提取剂的用量对单宁基胶粘剂的弹性模量具有很大的影响。当以氢氧化钠（NaOH）为提取剂提取碱单宁时，氢氧化钠（NaOH）的用量为10%时单宁基胶粘剂的弹性模量最高。当以亚硫酸钠（Na₂SO₃）为亚硫酸化试剂提取亚硫酸化单宁时，添加不同的碱剂对单宁基胶粘剂的弹性模量具有较大的影响，以碳酸钠（Na₂CO₃）为碱剂提取的单宁基胶粘剂的弹性模量高于以氢氧化钠（NaOH）和碳酸氢钠（NaHCO₃）为碱剂提取的单宁。p-MDI对胶粘剂的弹性模量的影响不大。由不同的提取剂及用量对单宁提取物性能的影响，从而影响到木质刨花板的内结合强度。当使用碳酸钠（Na₂CO₃）加亚硫酸钠（Na₂SO₃）为提取剂的单宁提取物配制单宁基胶粘剂压制刨花板，板坯的内结合强度最好。p-MDI的加入使得板坯的内结合强度有一个明显的提高。使用单宁-甲醛胶粘剂时，最好内结合强度为0.45MPa；当使用MDI-单宁-甲醛胶粘剂时，最好内结合强度为0.68MPa。两者均达到欧洲标准EN312和国标GB-T4897.3中干燥状态下使用的家具及室内装修用刨花板内结合强度要求（IB≥0.35MPa）。此外刨花板残留甲醛释放量低于欧洲标准中要求的室内用板甲醛含量的要求（≤6.5mg/100g板重）。证实了使用葡萄皮渣单宁提取物作为刨花板用胶粘剂的可行性，可以利用葡萄皮渣单宁提取物来生产环保型的刨花板产品。更多还原

【Abstract】 Grape pomace is a by-product of winemaking industry, which retains high level ofcondensed tannins. Until now, most of the grape pomace is not exploited but only used for soilfertilizer or animal feed. Therefore, the purpose of this study is to extract condensed tannins fromgrape pomace, character its composition and structure by modern instruments analyticaltechniques, and use as tannin-based adhesive for particleboard productions in wood industry. Itnot only proposed a feasibility plan for the efficient use of grape pomace, extend the grapeindustry chain; but also provide a theoretical foundation of preparation and applicationtechnology of tannin-based adhesive in wood industry.The extraction of condensed tannins from grape pomace was examined using water mediumin the presence of different bases as catalyst （NaOH, Na₂CO₃, NaHCO₃and Na₂SO₃）. Twodifferent extraction processes and the influence of4parameters （i.e., temperature, reaction time,chemical reagents and concentration of the chemical reagents） on the tannin extracts yield andproperties were studied. The tannin fractions were characterized by Element analysis, Fouriertransform-infrared spectroscopy （FT-IR）, thermogravimetric analysis （TGA）, carbon nuclearmagnetic resonance spectroscopy (¹³C-NMR) and matrix assisted laser desorption ionization timeof flight mass spectrometry （MALDI-TOF）. Condensed tannins extracts from grape pomace wereapplied to prepare different tannins-formaldehyde formulations, which were applied to presswood particle board productions. The purpose is to investigate the possibility of using these grapepomace tannins in the formulation of wood adhesive and the influence of different tanninsextracts and formulations on the properties of particleboard productions.It was demonstrated that it is possible to extract reactive tannins from grape pomace in basicmedium. The tannin extracts obtained by precipitation in acidic conditions display a highphenolic content （Stiasny number higher95%） but low water solubility and low reactivitytoward formaldehyde because of the formation of catechinic acid phlobatannins during theacidification step. The tannins extracts obtained by lyophilization of the liquid, despite of theirlower phenolic contents, displayed promising properties for adhesive applications. The optimumtemperature of the extraction process was100°C, reaction time was120min; the bestconcentration of reagent was10%（w/w）. It was also shown that addition of sulphite ions duringthe extraction step improved the process: the introduction of a sulfonic group through sulfitationincreased both tannin solubility and reactivity as a result from the opening of the heterocyclicring during extraction.The structure of grape pomace sulfited tannin extracts did not present noticeablediscrepancy exception of the ratio of the opening pyran ring which was different as a function ofthe catalyst used. The opening of pyran ring during the tannins extraction seem to be moreimportant by using Na₂CO₃/Na₂SO₃and NaHCO₃/Na₂SO₃than when using NaOH/Na₂SO₃. TheFT-IR bands assigned to aromatic ring vibration and carbonyl groups were stronger and no bands attributed to sulfited groups were detected in acidified tannins compared to lyophilized tannins.The TG results showed that the weight lost of these tannin extracts mainly composed of two steps.The first step starts from room temperature to200°C. It is attributed to the mass loss of waterand some easy-degraded small low molecules. The secondly steps which is the mainlydegradation step of tannin extract samples from200to400°C. It is attributed to the mass loss ofpolyphenol materials in the tannin extracts.The results from¹³C-NMR showed that condensed tannin extracts from grape pomace wereconsistent with dominant procyanidin units with a minor amount of prodelphinidin units that arelinked together by a C4-C8bond; Relatively low carbonhydrate and high catechinc acid contentwas obeserved in acidified tannins compared to lyophilized tannins. It was shown by MADI-TOFexperiments that grape pomace tannin extracts are mainly composed of flavoinoid oligomers upto6repeating units in lyophilized tannins and10repeating units in acidified tannins respectively,with dominant procyanidin units. A small proportion of substitution with glucose and gallic acidwas detected in procyanidin units of polyflavonoid oligomers. The degree of polymerization ofacidified tannins is higher than lyophilized tannins.Two different formulations （nonfortified tannin–formaldehyde adhesive and fortified withaddition of20%of polymeric4,4’-diphenyl methane diisocyanate （p-MDI） tannin–formaldehyde adhesive） were used to press one layer wood particle board. It was shown that thenature and concentration of the extraction reagents greatly impact the properties of the tanninresins MOE value. When the tannin was extracted by sodium hydroxide （NaOH）, the highestMOE value was reached for the concentration of NaOH is10%. When the tannin was extractedby sulfitaion reagents, the nature of the extraction reagents greatly impact the MOE value, thetannin extracted by Na₂CO₃/Na₂SO₃is higher than the tannin extracted by NaOH/Na₂SO₃andNaHCO₃/Na₂SO₃. The addition of p-MDI did not yield an important increase in the MOE value.The tannin properties were affected by the nature and concentration of the extractionreagents, then directly impacted the IB value of the wood particleboard which press by tanninbased adhesive. The addition of p-MDI yielded an obviously improved the IB strength. Whenused the nonfortified tannin adhesive, the best IB values is0.45MPa, used the p-MDI fortifiedtannin adhesive, the best IB value is0.68MPa. The wood particleboards bonded by the tanninsextracted using Na₂CO₃/Na₂SO₃as catalyst give the best performance and were good enough topass relevant international standard specifications for interior grade panels according to EN312and China National Standard GB-T4897.3（IB≥0.35MPa）. Formaldehyde emission of thesepanels was below the European Norm requirements （≤6.5mg/100g panel）. It proves that thetannin extracted from grape pomace can be used as a kind of environmentally friendly naturaladhesive in wood industry.更多还原