【作者】 傅深渊；

【导师】 赵广杰；

【作者基本信息】 北京林业大学 ， 木材科学与技术， 2011， 博士

【摘要】 生物质材料液化是近年来能源和林业领域重点研究的一项技术,竹材作为生长快、生物量的生物质材料,对其进行液化研究具有明显特色,它通过化学转化可以形成反应性的液化物,用作合成高分子树脂化原料,可来替代化石原料合成的苯酚等化工原料。本论文从竹材的竹种、化学成分、结构特点出发,在苯酚介质进行液化比较,得出优选的竹材液化原料-毛竹,运用新的液化催化技术,选择碳酸钾经过对竹粉的处理,分析催化剂、反应温度、反应时间、苯酚与竹材的投料液比,对液化效果影响。利用IR、13C-NMR、1H-NMR等分析技术比较了竹粉碳酸钾处理前后的化学变化；研究了竹材液化反应动力学,竹材液化物的流变学,竹材的液化及成胶机理,竹材液化物酚醛树脂胶固化特征及其动力学；研究了竹材液化胶纸塑复合材料燃烧动力学和燃烧性能,复合材料热降解行为。得出如下结论：1、比较三种竹材的木素含量,毛竹(Phyllostachys edulis)最多,雷竹(Phyllostachys praecox)其次,孝顺竹(Bambusa multiplex)最少；结晶度分析,毛竹最小；比较三种竹子的灰分含量,毛竹最低,孝顺竹最高,灰分含量高,液化成胶后会使树脂胶产生团聚。毛竹是一种适合液化的材质。2、毛竹材在苯酚液中的液化受酸催化剂添加量、液化温度及其酚竹比的影响,实验表明,催化剂添加量5%,液化温度115-125℃,酚竹质量比(2：1-1：1)之间可实现液化,并能得到流动度较好的液化液。3、毛竹材液化产物红外IR分析表明：用碳酸钾作催化剂,随着液化温度的升高波数在2935 cm-1处饱和亚甲基吸收峰,明显增强,吸收带变宽,说明液化过程中饱和键增多。4、毛竹材液化产物13C-NMR、1H-NMR图的特征分析表明,不论是否加入碳酸钾催化剂,它们的13C-NMR图的特征基本一致,温度越高,则液化程度越剧烈。有碳酸钾催化剂时,100℃下的液化的其产物的质子数明显的多,反应剧烈。5、毛竹材液化反应属1级反应。随着升温速率的增加,特征液化温度峰值温度Tp向高温方向移动。不同催化剂(碳酸钾、氯化钾、无催化剂)条件毛竹材液化的表观活化能依次是：45.95 KJ/mol、59.99 KJ/mol、58.0 KJ/mol。结合外推法,得出竹材液化反应的最佳工艺为：碳酸钾为催化剂,初始液化温度为69.1℃,液化峰高温度为97.25℃,液化峰终温度111.85℃。6、在苯酚和竹粉重量比为3：1情况下,对不同液化温度下,未添加碳酸钾催化剂与添加碳酸钾催化剂的液化竹材的稳态与动态流变行为分析表明,碳酸钾催化剂的加入有利于高分子组分的降解与体系内结合酚的生成。液化温度的升高,体系中的结合酚含量会达到饱和,对于未添加碳酸钾催化剂体系,饱和液化温度为150℃,添加催化剂体系的饱和液化温度在130℃左右。动态流变测试表明,随着液化温度的上升,体系内的复杂网络结构逐渐被破坏,但在实验所选用的液化温度范围,液化物中仍存在网络结构。7、通过对毛竹材在苯酚液中酚竹比、酸催化剂、液化温度等因素对液化的系统研究得出,当用HCl或BF3作催化剂、添加量5%、酚竹比2-1：1、115℃下达到竹材完全液化。用IR对BL、BLF和PF树脂分析,BL和BLF存在大量的羟基和芳香族醚键,分析表明是竹材中木质素和纤维素在酚液中裂解成大量碎片,并与苯酚结合所致；BLF在IR出现的几个特征峰与PF基本相似。8、竹材液化物(liquefied bamboo即LB)与甲醛的树脂化反应,当液化物中苯酚与甲醛摩尔比1：1.6～2.0条件下,制得室外级竹材液化物树脂胶(liquefied bamboo formaldehyde adhesive即BLF)。通过TG-DSC分析固化行为表明,竹材液化物树脂胶比酚醛树脂胶(PF)有更低的固化温度；竹材液化树脂胶与酚醛树脂胶出现基本一致的IR特征峰。9、运用DSC对竹材液化物树脂胶的固化动力学分析得到：随着F/P摩尔比的提高(P/F=1：1.3、1：1.6、1：1.8),竹材液化胶的固化过程表观活化能逐渐减小,分别为64.60KJ/mol、58.36 KJ/mol、57.12 KJ/mol。竹材液化胶固化反应吸收的热量逐渐降低。并且随着F/P的摩尔比的提高,利用外推法得出的静态(β=0℃/min)的特征固化温度Ti、Tp和Tf均逐渐降低,与竹材液化胶固化反应的表观活化能的大小顺序一致。10、通过对竹材液化物树脂纸塑复合材料MLBPF-PPC,三聚氰胺-苯酚-甲醛树脂纸塑复合材料MPF-PPC与酚醛树脂纸塑复合材料PF-PPC,在锥形量热仪上其质量损失率a(0-60%)和时间t的单方程模型与g(a)=[-1n(1-a)]1/2]化学动力学方程拟合。燃烧反应表观活化能Ea是MLBPF-PPC材料为14.18 kJ/mol, PF-PPC材料为27.10kJ/mol和MPF-PPC材料为26.47 kJ/mol,对液化竹材MLBPF-PPC材料相对小。MPF树脂PPC与PF树脂PPC材料表观活化能相当,为竹材液化树脂PPC材料表观活化能2倍左右多,阻燃性能竹材液化树脂PPC材料相对要弱。燃烧动力学活化能的理论推导和对不同PPC材料的各项燃烧性能测定,得到相同结论,当热辐射功率为50kW·m-2燃烧温度733℃时。三种材料的阻燃效果是：MLBPF-PPC<PF-PPC<MPF-PPC。11、三种MLBPF-PPC, MPF-PPC与PF-PPC浸渍纸塑复合材料,经过热降解动力学行为考察。发现不同的浸渍树脂胶黏剂没有改变纸塑复合材料的第一个失重阶段,热失重曲线基本重合。但是,不同的酚醛浸渍树脂胶黏剂对于热失重的第二个阶段有明显的影响,三聚氰胺的加入提高了纸塑复合材料第二阶段的热失重温度与燃烧活化能,MLBPF-PPC具有最高的热失重温度与燃烧活化能,表明竹材液化物树脂胶能提高纸塑复合材料阻燃性。更多还原

【Abstract】 Biomass liquefaction has attracted a lot of interests in the area of energy and wood products. The liquefied products derived by chemical-conversion method could be used in the production of resins, such as, replacing petroleum based phenol in the production of phenolic resins. In this work, the bamboo species selection were first studied through liquefaction in phenol according to their chemical compositions and structure. The Moso bamboo(Phyllostachys edulis) was found to be the best species for liquefaction. In order to obtain better liquefaction conditions of moso bamboo, the effect of catalysts, reaction temperatures, reaction times, and ratios of phenol to bamboo on moso bamboo liquefaction were investigated. And the difference before and after treatment of potassium carbonate were characterized with techniques of IR,13C-NMR, and 1H-NMR. This paper also studied the kinetics of bamboo liquefaction, the rheology of bamboo liquefied products, the mechanisms of bamboo liquefaction and resinification of bamboo liquefied products, curing characteristics and curing kinetics of bamboo-based phenolic resol resins, the combustion kinetics, combustion properties, and behavior of thermal decomposition of paper-plastic composites (PPC) prepared with bio-based phenolic resol resins. The results mentioned above are summarized as follows.1. Moso bamboo contained the highest amount of lignin compared to Phyllostachys praecox and Bambusa multiplex. Bambusa multiplex, and included the lowest content of lignin. According to the crystallinity of moso bamboo was the lowest among these three kinds of bamboo. Meanwhile, there was the lowest content of ash in moso bamboo, and Bambusa multiplex had the highest content of ash. The high content of ash in liquefied products could lead to the clustering phenomenon during the process of resin synthesis. The above results indicated that moso bamboo is most suitable for liquefaction.2. The moso bamboo could be liquefied completely with 5% of acid catalyst. Meanwhile, the results also showed that moso bamboo could be easily liquefied at temperature in the range of 115 to 125℃with weight ratio of phenol to bamboo between 2:1 and 1:1. And the liquefied liquid products presented good fluidity. 3. The IR profiles of liquefied products from the liquefaction of moso bamboo with catalyst of potassium carbonate presented a marked absorption peak at 2935 cm-1. Moreover, with temperature increasing, the absorption peak of methylene group became stronger and wider. These results suggested that the saturated bond increased during the process of liquefaction.4. The addition of potassium carbonate did not produce a significant effect on the chemical structure of liquefied products from different temperatures (100,120 and 150℃) according to their analyses of 13C-NMR and 1H-NMR. And the liquefaction temperature had a marked effect on bamboo liquefaction. High temperature could help the liquefaction of bamboo. However, there were more protons in the liquefied products from liquefaction under 100℃using potassium carbonate compared to that from liquefaction above 100℃without using potassium carbonate. These results showed that the addition of potassium carbonate could accelerate the liquefaction of bamboo.5. The liquefaction reaction of moso bamboo is one-order reaction. The temperature of curing peak (Tp) was transferred to higher temperature with heating flow increasing. The activation energies of liquefaction reaction using different catalysts (potassium carbonate, potassium chloride and blank reference) were 45.95,59.99, and 58.00 KJ/mol, respectively. The curing characteristic temperatures (Ti, Tp and Tf, at 0℃/min) which were calculated based on linear regression were 69.1,97.25 and 111.85℃, respectively.6. The effects of catalyst of potassium carbonate on the steady-state and dynamic rheology behavior of bamboo liquefaction under different temperatures with weight ratio of phenol to bamboo of 3:1 were also investigated. The results showed that the addition of potassium carbonate could help the depolymerization of bamboo and the forming of combined phenol. The amount of combined phenol would become saturated with liquefaction temperature increasing. The saturation state required the liquefaction temperature of 150℃without using any catalyst. However, the saturation temperature can be decreased to 130℃with catalyst. According to the analysis of dynamic rheology, the complex network of bamboo was decomposed gradually with temperature increasing. But the network structure could still be observed in liquefied products for all the liquefaction temperatures used in this research.7. The effects of weight ratio of phenol to moso bamboo, acid catalysts and liquefaction temperatures on bamboo liquefaction were also detected. The results displayed that the bamboo could be completely liquefied using 5 wt% of HC1 or BF3 with weight ratio of phenol to bamboo of 2～1:1 under 115℃. According to the IR profiles of LB (liquefied bamboo products), BLF (liquefied bamboo products formaldehyde adhesive) and PF (phenol formaldehyde resin), there was a large amount of hydroxyl groups and aryl-ether bonds in BL and BLF. It could be caused by the combination of phenol with the small fragments derived from the decomposition of lignin and cellulose in bamboo. The IR spectrum of BLF performed several similar characteristic peaks with that of PF resin.8. The BLFs were synthesized using LB and formaldehyde with molar ratio of phenol to formaldehyde betweenl:1.6～2.0. In accordance with the TG-DSC analyses of BLF and PF resins, BLF showed lower curing temperatures than those of PF resin. Moreover, BLF displayed similar IR profile with that of PF resin.9. The curing kinetics of BLFs was obtained according to the DSC analyses of BLFs. The results showed that the activation energy of curing reactions of BLFs decreased with the increasing of molar ratio of F/P (1.3:1,1.6:1, and 1.8:1). The activation energies of them were 64.60,58.36 and 57.12 kJ/mol, respectively. These results indicated that the energy for curing reaction of BLF decreased gradually with the increasing of molar ratio of F/P. Meanwhile, similarly, the characteristic curing temperatures (Ti, Tp and Tf) at heating flow of 0℃/min also decreased with the increasing of molar ratio of F/P.10. The combustion behavior of three kinds of paper-plastic composite materials MLBPF-PPC (Melamine modified bamboo Phenol Formaldehyde-Paper Plastic Composite), MPF-PPC (Melamine modified Phenol Formaldehyde-Paper Plastic Composite) and PF-PPC (Phenol Formaldehyde-Paper Plastic Composite) were studied by using a cone calorimeter. The single equation rate model of mass loss rate (0～60%) and time was simulated by using a chemical kinetic method (g(a)=[-ln(1-a)]1/2]). The average activation energy Ea calculated based on the above equation of MLBPF-PPC, MPF-PPC and PF-PPC were 14.18,27.1 and 26.47 kJ/mol, respectively. The Ea of MPF-PPC and PF-PPC were almost two times than that of MLBPF-PPC. The similar results were also obtained from the analyses of combustion properties under temperature of 733℃(radiation power of 50 kW-m-2), such as mass loss rate, total heat released, heat release rate, total smoke released and yields of CO and CO2. In summary, the flame-retardant properties of three kinds of materials were MLBPF-PPC< PF-PPC< MPF-PPC.11. According to the analyses of TG-DTG of MLBPF-PPC, MPF-PPC and PF-PPC, all PPCs represented two major thermal events. For the first thermal event, all PPCs showed similar thermal decomposition profiles. The second thermal event of all PPCs, however, wasmarkedly different. The possible reason could be that the addition of melamine into phenolic resins transferred the decomposition temperature of PPCs to higher temperature, and improved the combustion activation energy. Both of the decomposition temperatures and activation energies of MLBPF-PPC were the highest compared to those of MPF-PPC and PF-PPC. These results suggested that the utilization of MLBPF in PPC materials could improve the flame-retardant properties of PPC materials.更多还原