【作者】 王辉；

【导师】 杜官本；

【作者基本信息】 南京林业大学 ， 木材科学与技术， 2013， 博士

【摘要】 本文研究了不同合成工艺路线对三聚氰胺-尿素-甲醛（MUF）共缩聚树脂性能的影响，以及在最佳合成工艺条件基础上，详细探讨了特定工艺条件下MUF共缩聚树脂的结构形成、分子组分的分布，以及借助现代仪器分析手段对其固化特征、耐热性能等进行了表征，为MUF共缩聚树脂的应用提供了有力的理论指导。主要研究内容如下：（1） MUF共缩聚树脂合成工艺的探讨。不同合成工艺与MUF树脂性能有着密切的联系，重点比较了三种MUF共缩聚树脂合成工艺路线对树脂性能的影响。不同合成工艺条件下的树脂分别命名为：MUF1、MUF2、MUF3。性能测试主要包括树脂的基本性能、结构分布、以及固化性能。（2） MUF共缩聚树脂的结构形成及分布的研究。在最佳合成工艺基础上，借助傅立叶红外光谱（FT-IR）和基质辅助激光解析电离飞行时间质谱仪（MALDI-TOF MS）对MUF共缩聚树脂合成过程中结构的形成及组分分布进行了追踪，同时辅助模型化合物之间的反应，对MUF共缩聚树脂的形成机理进行了剖析。（3） MUF共缩聚树脂固化性能的表征。固化是热固性树脂应用过程当中非常重要的一个过程，借助热分析方法，如差示扫描量热法（DSC）、动态热机械分析法（DMA），对不同条件下MUF共缩聚树脂的固化特征进行了表征。利用FT-IR对树脂固化过程中结构及基团的变化进行了分析，讨论了不同固化条件下MUF共缩聚树脂的固化机理。（4）耐热性能是评价MUF共缩聚树脂性能的另一重要指标。采用热重分析法（TG）对MUF共缩聚树脂的耐热性能进行评价，重点比较了固化剂、贮存时间、样品状态等条件对MUF树脂耐热性能的影响。（5）最后，通过实验室制备小型胶合木试件，对MUF共缩聚树脂的胶接及耐久性能进行了评价。比较了不同耐老化处理条件下树脂的胶接性能，评估了处理条件对耐久性的影响。对MUF共缩聚树脂的研究，得出的主要结论为：（1）在终摩尔比（即F:（U+M））一致的条件下，不同合成工艺路线对MUF共缩聚树脂的性能有显著影响。基本性能测试结果表明，不同合成工艺路线对树脂中游离甲醛含量、贮存稳定性有非常显著的影响，游离甲醛含量最低达到0.15%，而最高达0.54%。伴随着游离甲醛含量的不同，树脂的贮存时间亦有明显差异，从一周到一个月不等。FT-IR、¹³C-NMR、1H-NMR对MUF1、MUF2、MUF3三种不同树脂的结构组成及基团分布进行表征发现，三种树脂中所含基团的类型极度相似，但组成比例存在差异。尤其是羟甲基（-CH₂OH）、亚甲基桥键（-CH₂-）、亚甲基醚键（-CH₂-O-CH₂-）的比例各不相同。而且，DMA测试结果显示，在固化剂作用条件下，所能获得的最大模量亦不尽相同。综合多方性能认为，MUF3的合成工艺路线最优。（2）以MUF3的合成工艺路线为基础，在合成过程中的不同反应阶段进行取样，对其中结构的形成和分布进行表征认为，MUF树脂合成过程中包含了三种主要反应类型，即羟甲基化、树脂化、共缩聚反应，并且彼此之间没有严格的划分界限。事实上，无论是羟甲基化阶段还是树脂化阶段，都存在着三聚氰胺与尿素之间的共缩聚反应，也就是说，共缩聚反应贯穿于整个反应过程当中。尤其是当二次三聚氰胺加入以后，对整个树脂的结构及性能有很重要的作用。从反应现象看，二次三聚氰胺加入后，在较短时间内即可变为清液，意味着反应速度很快。由此时样品的MALDI-TOF MS分析也证实了三聚氰胺主要参与了羟甲基化反应，随着反应时间的延长，高分子量物质所占丰度的上升，表明了缩聚反应的发生。根据相关分子量推断，此阶段共缩聚反应的连接方式以亚甲基桥键（U-CH₂-M）为主。利用模型化合物之间的反应，对二次三聚氰胺的作用进行了进一步的分析，结果发现三聚氰胺的加入对基体树脂中的羟甲基化合物，尤其是羟甲基脲，具有非常强的凝聚作用，对树脂分子量的增加具有重要影响。而且，共缩聚反应主要以羟甲基化合物中的羟甲基与剩余活性氢之间的缩合反应。（3）采用DSC表征MUF共缩聚树脂的固化特征，结果表明测试方式、固化剂等对MUF共缩聚树脂的固化过程有不同程度的影响。其中，开放式测试条件下，树脂的固化发生在较低温度（40¹000C）和较高温度（100²000C）两个区域。而在封闭式测试条件下，树脂的固化发生在相对较高温度区域（100²000C），仅有一个固化峰，类似于干燥样品的固化过程。对不同升温速率条件下的固化峰值温度进行线性拟合可知，测试方式并不影响树脂的固化峰值温度（约1000C）。固化剂的使用可以有效降低树脂的固化起始温度、加速固化反应的发生。FT-IR对不同固化条件下树脂中的基团变化进行分析结果也显示，固化剂的加入并不会改变树脂的固化机理，但可有效促进树脂中活性基团的缩合反应，尤其是羟甲基基团的消耗。DMA热分析结果显示，氯化铵作为MUF共缩聚树脂固化反应的固化剂时，使用量控制在0.5¹%之间时，可获得性能优异的固化胶层。（4） TG热分析结果表明，在氮气保护条件下，未加固化剂时液态树脂样品的残炭率均高于固态样品的残炭率，但并未影响树脂热分解的温度及达到最大分解状态的速率。加入1%固化剂后，液态样品的热分解分为三个区域，而固态样品的分解主要发生在一个大的区域。无论是液态样品还是固态样品，1%固化剂的加入，可以有效提高树脂的残炭率。不同贮存时间，并不会对MUF树脂的耐热分解性能造成影响，但对最终的残炭率略有影响。空气条件下，将树脂置于8000C的高温条件下，灼烧7min后，残炭率保留在6⁹%之间，与氮气保护条件下的热分解强度和历程大不相同。（5）对MUF共缩聚树脂应用于胶合木制备的可行性试验表明，MUF树脂具有较强的胶接强度及耐久性能，均可满足结构用材标准中的相关规定。更多还原

【Abstract】 The effect of different synthetic process on the MUF co-condensation resin performance wasstudied, and based on the best synthetic process, to investigate in detail the structure formation,molecular distribution of MUF resin. With the help of modern apparatus, the curing and thermalproperties of MUF resin were studied, which provide powerful theoretical basis for theapplication of MUF resin.The main content were as follows:（1） The investigation on the synthetic process of MUF co-condensation resin。There was aclose relationship between different synthetic process and MUF resin properties, so the effect ofthree synthetic processes of MUF resin on the MUF resin performance, which was mainlystudied. The resin was separately named MUF1, MUF2, MUF3by synthetic process. The resinperformance evaluation mainly included basic performance, the structure distribution of MUFresin and the curing performance.（2） Study on the structure formation and distribution of MUF co-condensation resin. On thebase of best synthetic route, the structure formation and component distribution of MUFco-condensation resin were tracked with the help of FT-IR and MALDI-TOF MS, moreover, theformation mechanism of MUF co-condensation resin was also further analyzed by reaction ofmodel compound.（3） The characterization of MUF co-condensation resin curing performance. Curing was anvery important process for application of thermoset resin, and the curing characteristics of MUFco-condensation resin were studied by DSC, DMA. The structure and group change of MUFco-condensation resin during curing process were studied using FT-IR, and the curing mechanismwas analyzed.（4） Heat-resistant quality was another important index for appreciating MUFco-condensation resin performance. Use TG to investigate heat-resistant quality of MUF resin,and the effect of curing agent, storage time, sample state on that was mainly studied.（5） At last, the bonding strength and durability performance of MUF co-condensation resinwere studied by glulam preparation in laboratory. And the durability performance was evaluatedby comparing bonding strength after treated by different condition.The main results were as follows:（1） With the same F:（U+M） mola ratio, it was remarkable that effect of synthetic process onMUF co-condensation resin performance. The basic property results showed that syntheticprocess focally impacted the formaldehyde-free content and storage time of MUF co-condensation resin, and the minimum content was0.15%, the highest content was0.54%.Simultaneously, the storage time was different changed from one week to one month due tochange of formaldehyde-free content. The FT-IR,¹³C-NMR,1H-NMR characteristics results ofMUF1, MUF2, MUF3revealed that three resins included same group category, but its ratio wasdifferent, especially, the hydroxy-methyl group（-CH₂OH）, methylene bridge（-CH₂-）, methyleneether link（-CH₂-O-CH₂-）. Furthermore, DMA results showed that the maximum modulus ofMUF resin was different under the curing agent condition. Many performance showed thatsynthetic process of MUF3resin was best.（2） On the bases of synthetic process of MUF3resin, samples were taken in differentreaction time during synthetic process, the characteristic results of samples revealed thatformation of MUF resin included three key types of reaction, that was hydroxy-methyl reaction,resinification, co-condensation reaction, in fact, there was no obvious boundary for three reactiontypes. The co-condensation reaction not only existed in hydroxy-methyl reaction phase but inresinification phase, in other words, there was always co-condensation reaction of melamine andurea though the whole reaction. Especially, seconde melamine addition had an important role inthe resin structure formation and its performance. Reaction phenomena revealed that reactionspeed of melamine and basic resin was very fast, because solution could change clear in veryshort time. MALDI-TOF MS analysis of sample also confirmed that melamine mainly takenhydroxy-methyl reaction, as the extension of reaction time, abundance rise of high molecularmeaned that condensation reaction taken place. According to distribution of molecular weight, itcould be deduced that formation of methylene bridges between melamine and urea wasdominant.Using model compound reaction, seconde melamine action on matrix resin was furtheranalyzed, the results showed that melamine had an strong cohesion effect on hydroxy-methylcompounds, especially methylolurea, and had important effects on the resin molecular weightincrease. Moreover, condensation reaction between hydroxy-methyl of hydroxy-methylcompounds and residual active hydrogen was major condensation reaction type.（3） Curing characteristic of MUF co-condensation resin was characterized by DSC, resultsrevealed that test method, curing agent had different degree impact on the curing process of MUFco-condensation resin. Among them, under open testing condition, curing of MUF resin took intwo areas, lower temperature area（40¹000C） and higher temperature area（100²000C）. Butunder the close testing condition, curing mainly took place in higher temperaturearea（100²000C）, which was similar to the dried sample curing process. By linear fitting of peaktemperature at different heating rate, it was found that testing method did not affect peaktemperature of MUF resin curing（about1000C）. Curing agent could effectively reduced initialcuring temperature, and accelerated curing reaction. By FT-IR analyzing groups change of resinin different curing condition, it was found that curing agent did not change resin curingmechanism, but could effectively promote condensation reaction of active groups, especially consume the hydroxy-methyl group. DMA results showed when curing agent（NH4Cl） contentwas0.5¹%, the glue-line performance could achieve excellent.（4） TG thermal analysis results showed that under nitrogen protection, char residue rate ofliquid sample without curing agent was higher than solid sample’s char residue rate, but did notaffect resin thermal decomposition temperature and maximum decomposing rate. After adding1%curing agent, liquid thermal decomposition of the sample was divided into three regions, andthe decomposition of the solid sample mainly happened in a large area. Either liquid or solidsamples,1%curing agent addition, char residue rate of the resin could be effectively improved.Different storage time did not affect thermal decomposition properties of MUF resin, butslightly affect char residue rate of MUF resin. Under air condition, burned for7min at8000C, thechar residue rate of MUF resin was between6⁹%, so the decomposition degree and processwere different from the nitrogen atmosphere.（5） The results of glulam performance showed that MUF co-condensation resin had strongbonding strength and durability, which can satisfy the standards of timber performance.更多还原