【作者】 蔡晓红；

【导师】 屠幼英；

【作者基本信息】 浙江大学 ， 茶学， 2010， 硕士

【摘要】 本论文研究了不同温度、时间条件下茶多酚(TP)、茶黄素(TF)、茶氨酸(TA)和咖啡因(CA)与甲醛溶液的反应体系中各主要成分对甲醛的吸附特性。甲醛吸附动力学研究表明,上述四种成分对甲醛吸附能力效果为茶黄素＞茶多酚＞茶氨酸＞咖啡因。通过吸附曲线研究了不同温度、反应时间下各成分与甲醛吸附的相关性。结果表明,高温有利于吸附反应,低温与常温条件下,反应体系几乎无显著差异;各成分对反应体系的pH值无显著影响。论文还探讨了儿茶素、茶黄素、茶氨酸和咖啡因吸附甲醛的活性官能团及反应机理。研究以刨花板为例,将红茶渣、绿茶渣、乌龙茶梗、陈绿茶和茶树修剪枝这五种茶下脚料及茶制品废弃物应用于脲醛树脂胶粘剂和人造板生产,并对脲醛树脂胶粘剂配方和茶及茶制品废弃物的添加形式进行筛选。结果表明脲醛树脂中添加2%的200目(0.074mm)茶制品废弃物颗粒,能有效降低脲醛树脂的游离甲醛释放量,且不影响胶的其他重要指标。在刨花板中,以茶树修剪枝组和陈绿茶组的添加效果最好,其游离甲醛释放量分别降至对照组的51.3%和35.5%;添加量对游离甲醛释放量的吸收效果为:15%＞10%＞5%。同时,添加陈绿茶、茶树修剪枝和绿茶渣对刨花板的静曲强度有显著增强作用。并且,在刨花板的后期存放过程中,茶及茶制品废弃物可以降低刨花板甲醛的长期稳定释放,陈绿茶和修剪枝刨花板的后期甲醛稳定释放量,分别只有空白组的37.60%和51.87%。通过对添加的茶及茶制品废弃物主要内含成分与甲醛释放降低值之间的关系,我们发现TP、TA和TF的含量均与游离甲醛释放量的降低具有正相关性。本研究成果证明茶下脚料及茶制品废弃物可用于环保型人造板的生产,获得高性能环保刨花板。本论文的成果为解决目前人造板游离甲醛引发的环境和健康问题以及解决茶产业链中的茶及茶制品废弃物综合利用问题提供了实践依据和理论基础;同时也为长期低醛释放的板材研发提供借鉴。更多还原

【Abstract】 In this study, the solutions of four tea components including tea polyphenols(TP), theaflavins (TF), L-theanine (TA), and caffeine ( TC ) were designed to react with formaldehyde under different temperatures and reaction times. The reaction characteristics and sorption kinetics of formaldehyde were analyzed and discussed. Results showed that all of four tea main components had the abilities on free formaldehyde absorption, the formaldehyde reducing effects were TF > TP > TA > CA. TF was the most effective one on free absorbing formaldehyde. After 3 hours, it reached the maximum of formaldehyde absorption. TP had a slower speed on adsorption of formaldehyde, but didn’t reach the maximum after 4 hours. TA and CA had a little effect on adsorption of formaldehyde with fluctuant. The relationship between temperature, reactive time of four tea components and formaldehyde were analyzed through adsorption curve. It showed that high temperature promoted formaldehyde absorption, low and normal temperature had no significant difference; the pH of reaction systems were stable through the procedure. The active functional groups and the reaction mechanisms of tea catechins, theafiavins, L-theanine, and caffeine on formaldehyde adsorption were discussed.The tea and waste tea products (black tea residue, green tea residue, oolong tea stalk, pruned tea branch, and stale green tea) were applied to prepare urea-formaldehyde resin and the produce of flakeboards. The formula of resin and the additional proportions with tea and waste tea products on flakeboards were analyzed. The results showed that 200mu (0.074mm) powder of tea and waste tea products to resin at 2% level could effectively reduce the FFE and didn’t reduce the properties of resin. The addition of tea and waste tea products in flakeboards could significantly reduce formaldehyde-emission. Compared with blank group, the free formaldehyde emission from pruned tea branch group and stale green tea samples were reduced to 51.3% and 35.5%, respectively. The effects of different additional proportion of tea and waste tea product on the formaldehyde absorbency of flakeboards were 15% > 10% > 5%. And the flakeboards added with green tea residue, pruned tea branch, and stale green tea all had a better static bending strength than blank group. During the post-storage of flakeboards, released formaldehyde from improved flakeboards become stable, the free formaldehyde emission in pruned tea branch group and stale green tea group reduced to 51.87% and 37.60%. Furthermore, the analysis between the reducing amounts of free formaldehyde emission and the contents of main compounds suggested that tea polyphenols, amino acids and theaflavins were correlated with the reduced amounts of formaldehyde.From this study the functions of tea and waste tea products for reducing the formaldehyde in flakeboards was proved. which showed that low quality tea and residue will be very useful in preparation of man-made boards with high quality and low formaldehyde.更多还原