【作者】 时君友；

【导师】 顾继友；

【作者基本信息】 东北林业大学 ， 生物材料工程， 2007， 博士

【摘要】 利用廉价的玉米淀粉开发绿色高性能木材胶粘剂是人类不懈追求的目标，论文针对传统的淀粉胶粘剂因耐水性差不能满足木材胶接需要的难题，将淀粉进行复合变性处理后作为水性高分子-异氰酸酯（API）木材胶粘剂主要原料进行应用，研制出淀粉基API木材胶粘剂。用于胶接不同剪切强度要求的木（竹）材胶合制品获得成功；对胶膜的老化机理进行了研究；揭示出主要成分淀粉与聚合异氰酸酯（P-MDI）动力学反应机理；对淀粉基API固化反应机理进行了探索。论文主要是以玉米淀粉为原料，通过对淀粉进行酸解、氧化、接枝共聚等多重变性，制成一种复合变性淀粉；以复合变性淀粉、乙二酸、聚乙烯醇和P-MDI为主要因素，通过正交试验优化出满足不同需要的最佳淀粉基API，采用此种胶粘剂的不同的配方胶接木材时，可实现JIS K6806标准中不同耐水胶接强度的要求，较好地解决了木材胶接制品耐水性与胶接制品的绿色化的要求相矛盾的问题。通过常规化学分析及仪器分析对胶粘剂理化性能进行了表征；揭示了淀粉基API采用不同封闭的P-MDI为交联剂室温下活性期长的原因；对玉米淀粉及复合变性淀粉与P-MDI之间的反应进行差式扫描量热法（DSC）、傅立叶红外（FTIR）、X-射线光电子能谱（ESCA）等分析，试图揭示淀粉基API的固化机理；通过傅立叶拉曼（FT-Raman）、激光拉曼光谱、¹³C-CP／MAS-NMR、凝胶色谱GPC等方法分析淀粉基API胶膜的老化机理。论文首先对玉米淀粉采用氧化酸解后，与丙烯酰胺接枝共聚的方法制得复合变性淀粉进行了较为全面的研究。①对酸解氧化淀粉的制备及其性质进行了研究：采用盐酸为酸解催化剂、过硫酸铵为氧化剂在较短时间里得到一种粘度较低并具有一定氧化程度的酸解氧化淀粉。②以过硫酸铵为引发剂，合成了酸解氧化淀粉接枝丙烯酰胺共聚物并进行了表征。研究发现：引发剂对淀粉接枝共聚反应的影响非常显著；引发剂采取分两次加入的方式有利于接枝共聚反应的进行；通过单因素试验，初步确定了较优的接枝工艺；通过红外光谱、X-射线衍射、电子扫描显微镜等分析手段，证明了接枝共聚反应的发生。其次，以复合变性玉米淀粉、乙二酸、聚乙烯醇、P-MDI为影响因素，按照日本JIS K6806标准中关于水性高分子-异氰酸酯木材胶粘剂胶接木材时的不同耐水性要求，通过正交试验，分别优化出Ⅰ型、Ⅱ型中Ⅰ、Ⅱ类的常态胶接、热水浸渍、反复煮沸胶接强度的六种淀粉基API的配方，并在对实验结果进行了验证性试验的基础上，进行了工业化生产试验。结果表明：采用优化出的六种淀粉基API的最佳配方制得的胶粘剂，所胶接的木材胶合制品的剪切强度完全满足JIS K6806的要求，胶粘剂的各项性能指标满足实际生产工艺需要。第三，采用FTIR、DSC和ESCA等仪器分析的方法，对不同含水率的淀粉、复合变性淀粉与P-MDI动力学反应机理；淀粉基API的固化反应机理及其与木材之间的胶接反应机理进行了较为系统的研究。①采用化学分析法，系统地研究室温下淀粉基API主剂与交联剂按比例混合后，—NCO含量随时间的变化规律，确定胶粘剂的活性期。②通过对不同含水率的玉米原淀粉、复合变性淀粉与P-MDI混合物的等速升温及等温扫描的DSC试验分析，得出反应机理及其函数、反应活化能及有关反应动力学参数。从本质上揭示出相同含水率条件下，复合变性淀粉比原淀粉更易与P-MDI进行化学反应。③为揭示固化反应生成物的化学结构，通过等温扫描的DSC试样的FTIR分析，定性得出生成物的官能团；通过X-射线光电子能谱（ESCA）的分析，进一步证实不同含水率的玉米原淀粉、复合变性淀粉与P-MDI的化学反应规律。④为揭示淀粉基API与木材之间的胶接机理，论文通过对淀粉基API、桦木及淀粉基API与桦木胶接界面的DSC、FTIR及等温扫描DSC试样的ESCA分析，以及对胶接界面的ESCA分析，揭示出淀粉基API与桦木胶接机理。最后，对Ⅰ型Ⅰ类反复水煮用淀粉基API的耐老化性，通过对常温固化胶膜多次反复煮沸后的激光拉曼光谱、FT-Raman光谱、¹³C-CP／MAS-NMR、凝胶色谱GPC分析，揭示出淀粉基API的加速老化机理；为准确探明内部发生的化学变化，在对使用的淀粉基API完整的知晓的情况下，通过对Ⅰ型Ⅰ类淀粉基API的胶膜进行多次反复煮沸—干燥加速老化处理，使胶粘剂的老化引起化学变化，采用激光拉曼光谱、FT-Raman、¹³C-CP／MAS-NMR、凝胶渗透色谱（GPC）分析其胶膜的理化特性，分析煮沸时水可溶份及胶膜残渣化学结构变化，研究胶膜的老化机理。结果表明，通过Raman分光分析，认为加速老化处理胶膜出现的化学变化是由异氰酸酯基的反应、胺的生成与分解、PVA溶于水所引起的；水可溶份的¹³C-CP／MAS-NMR分析，确认加速老化处理后溶于水的物质，是来源于水溶性的PVA，PVA在反复煮沸加速老化之前就有溶于水的情况，但加速老化的化学变化之一，是由PVA的溶出形成的；由GPC对加速老化水可溶份分析表明，加速老化后的胶粘剂中PVA的高分子链被切断，形成低分子后溶于水中。更多还原

【Abstract】 Unremitting pursuit goal is to deVelop high-performance wood adhesive by utilizing lowcost corn starch. The starch treated by composite modifier is used for the main raw materials of wood adhesive API which has been used and starch-based API has been deVeloped because poor water-resistance of traditional starch adhesive didn’t meet requirement of wood bonding. Using for wood glued-product with the different requirement of shearing strength has been successful. Retrogression mechanism of glue-film is studied. Dynamic reaction mechanism of the main ingredient of starch to P-MDI is revealed. Curing reaction mechanism of starch-based API is searched.Corn starch as the main raw material produces composite modifier starch by multi-ply modifier such as acid-thinned, oxidized, graft-copolymerized starch. The optimal starch-based API is optimized in the orthogonal test by adopting composite modifier starch, second diacids, polyvinyl alcohol and P-MDI as the main elements in the paper. Adopting the different formulation of the adhesive bonds wood which can implement demand of the different water resistant bonding strength in the JIS K6806 standard and resolves paradoxical problem between water-resistance of wood glue-product and greenzation request. Physical and chemical properties are symbolized by conventional chemistry analysis and apparatus analysis. The cause for long pot lift of starch-based API by adopting the different blocking out P-MDI as cross-linking at room temperature. The reaction of corn starch and composite modifier starch to P-MDI are analyzed by DSC、FTIR、ESCA to try to reveal curing mechanism of starchbased API. Retrogression mechanism of glue-film of starch-based API is analyzed by laser Raman, ¹³C-NMR, GPC.Firstly, composite modifier starch made by grafting copolymer corn starch oxidized and acid-thinned into acrylamide is comprehensively studied.①Preparation and properties of the acid-thinned and oxidized starch are studied. The acid-thinned and oxidized starch of a low viscosity and some oxidization degree is prepared in a short time with hydrochloric acid as acid-thinned catalyzer and ammonium persulfate as oxidant.②Reaction of grafting copolymerization of acrylamide to acid-thinned and oxidized starch by using ammonium persulfate as initiator is synthesized and investigated. The results show initiator is a very remarkable effect on the reaction of graft copolymer of starch. By single-factor tests, the optimum graft technology is determined primarily. The occurrence of grafting copolymerization reaction is testified by analytical means such as infrared spectrum, X-ray diffraction and SEM. Secondly, composite modifier corn starch, second diacids, polyvinyl alcohol, P-MDI as influencing elements by orthogonal test, formulations ofⅠⅡtype six starch-based API with request for bonding strength ofⅠⅡkind of normal bonding, hot-water soakage, boiling are optimized respectively according to the different water-resistance request of aqueous polymer isocyanate wood adhesive glued wood and base on validated experiment of test results it is manufactured industrially. The results show sheafing strength of wood glued-product produced by adhesive prepared with the optimal formulation of six starch-based API wood adhesive can completely meet requirement of JIS K6806 and each property indices of adhesive satisfy demand for the practical process technology.Thirdly, dynamic reaction mechanism of starch with the different moisture content, composite modifier starch to P-MDI and curing reaction mechanism of starch-based API and bonding reaction mechanism between them and wood are studied systemically by adopting apparatus analysis methods such as FTIR, DSC and ESCA.①Change regularity of—NCO content with time is systemically studied by adopting chemical analysis after the main agent of starch-based API is blended with cross-linking in proportion at room temperature and pot life of adhesive is determined.②Reaction mechanism and function, reaction activity energy and relevant reaction dynamics parameters are elicited by DSC experimental analysis on mixture of corn starch and composite modifier starch with the different moisture content, and P-MDI at the same heating rate and the constant temperature scanning.③To reveal chemical structure of curing reaction product, function-group of reaction product is qualitatively elicited, reaction regularity of corn starch of the different moisture content, composite modifier starch to P-MDI is further testified by ESCA analysis. Composite modifier starch is easier to reaction to P-MDI than corn starch under the same moisture content, which is revealed in essence.④DSC, FTIR of starch-based API, birch, bonding interface between starch-based API and birch, sample with the constant temperature DSC scanning and bonding interface are analyzed by ESCA in order to reveal bonding mechanism between starch-based API and wood in the thesis. Bonding mechanism between starch-based API and birch is revealed.on retrogression-resistance of I type and I kind of starch-based API used boiling, acceleration retrogression mechanism of starch-based is revealed by laser Raman, ¹³C-NMR, GPC analysis on boiling repeatedly of glue-film cured in the normal temperature. To prove precisely chemical change of internal occurrence, under the condition that starch-based API is completely known, glue-film of I type and I kind of starch-based API which makes retrogression of adhesive cause chemical change accelerates retrogression treatment by boiling-drying repeatedly. Physical and chemical properties of glue-film and change on chemical structure of water soluble fraction or residual are analyzed by adopting Laser Raman Spectrum, ¹³C-NMR, GPC and retrogression mechanism of glue-film is studied based on these analyses.Finally, the results show Raman analysis considers chemical change of glue-film of acceleration retrogression treatment is caused by isocyanate’s reaction, creation and decomposition of amine, water-solvable PVA. ¹³C-CP/MAS-NMR analysis of water soluble fraction determines that water-solvable material derives from water-solvable PVA and PVA dissolves water before boiling acceleration retrogression, but one of the chemical changes of the acceleration retrogression is formed by PVA dissolving out. GPC analysis of water soluble fraction on acceleration retrogression shows PVA macromoleeule chain of adhesive after acceleration retrogression is cut off and forming low-molecule dissolves water.更多还原