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1.
以N,N-二甲基甲酰胺(DMF)为溶剂、辛酸亚锡为催化剂,采用4,4’-亚甲基双(异氰酸苯酯)/γ-氨丙基三乙氧基硅烷(MDI/KH550)对杨木粉(PWP)表面接枝化学改性。研究了反应物料比、反应温度、反应时间及催化剂用量对杨木粉改性反应的影响,并通过接触角测量、元素分析、红外光谱(FT-IR)、13C固体核磁共振光谱(13C CP-MAS NMR)及扫描电子显微镜(SEM)表征了改性杨木粉的结构与表面性能。研究结果表明,以MDI与PWP活性羟基物质的量比2∶1,MDI与KH550物质的量比1∶1,120℃反应2 h,制备的MDI/KH550改性杨木粉质量增加率为40%~60%,催化剂对改性反应无明显影响;改性后杨木粉疏水性增强。  相似文献   

2.
桐马酸酐酯多元醇的合成研究   总被引:5,自引:4,他引:1  
以酮油为原料,合成了桐酸甲酯和桐马甲酯(桐酸甲酯和马来酐的加成物)等中间产物,再用过量的小分子二元醇与桐马甲酯进行酯化反应,制备了桐马酸酐酯多元醇。重点了不同反应条件对合成反应的影响,并对产物 红外光谱进行了解析。  相似文献   

3.
由腰果酚与烯丙基缩水甘油醚反应合成烯丙基醚腰果酚(AGE-C),再与甲基丙烯酸酐酯化反应制备含醚、酯键烯丙基腰果酚单体(MAA-AGE-C),并采用FT-IR、~1H NMR及~(13)C NMR表征了产物化学结构。实验结果表明:在烯丙基缩水甘油醚与腰果酚物质的量比1.2∶1,催化剂氢氧化钾用量为腰果酚质量的1%,100℃反应2 h的最佳合成反应条件下,腰果酚转化率95%。MAA-AGE-C的最佳合成反应条件为:甲基丙烯酸酐(MAA)与AGE-C羟基物质的量比1.2∶1,催化剂4-二甲氨基吡啶用量为AGE-C质量的2%,90℃反应3 h,AGE-C转化率93.5%。AGE-C的羟值154 mg/g,碘值2.4 g/g;MAA-AGE-C的羟值10 mg/g,碘值2.1 g/g。  相似文献   

4.
以桐马酸酐甲酯改性杨木纤维(MEMA-PWF)为增强体、双酚A缩水甘油醚型环氧树脂(E51)/甲基四氢邻苯二甲酸酐(MeTHPA)为基体树脂,经热压成型制备杨木纤维增强环氧树脂复合材料.通过接触角测量、扫描电镜(SEM)分析表征了复合材料表面及断裂面结构形貌,并测试了复合材料的冲击强度、弯曲强度.实验结果表明,改性后的杨木纤维表面疏水性及其与环氧树脂基体界面相容性得到明显提高;以MEMA-PWF/环氧树脂体系制备的复合材料力学性能提高,冲击强度、弯曲强度分别达到7.95 kJ/m2、55.42 MPa,并具有较好的疏水性.  相似文献   

5.
马来松香对木粉/HDPE复合材料流变性质的影响   总被引:2,自引:1,他引:1  
用马来松香对木粉进行流动性能改善处理,与高密度聚乙烯(HDPE)熔融复合,挤出成型制备木粉/HDPE复合材料(WF-HDPE).利用傅里叶变换红外光谱(FTIR)和X-射线光电子能谱(XPS)技术,分析经马来松香改性前后木粉表面官能团的变化和元素的变化,采用旋转流变仪研究.WF-HDPE的流变行为.FrIR与XPS分析表明,马来松香分子中的酸酐基团与木粉表面的羟基发生了酯化反应,并且马来松香是以单酯的形式接枝到木粉表面,同时产生一游离羧基.WF-HDPE流变学研究表明:复合材料的复合黏度(η*)、储能模量(G′)和损耗模量(G″)随马来松香用量的增加先减小后增大最后减小,但体系的黏度和模量总体呈下降趋势,木粉经马来松香改性后复合熔体的流变性能显著改善,这不仅有利于提高复合材料的成型加工效率,而且适当的马来松香处理也能够提高复合材料的拉伸强度和弯曲强度,后者被静态力学试验结果所证实.  相似文献   

6.
以KOH和Al_2O_3联合桐壳灰制备了固体碱催化剂(KOH-TSA-Al_2O_3),并将其用于催化桐油甲酯化。采用单因素及正交试验,以桐油甲酯化过程中桐油的转化率为指标,考察了催化剂KOH用量、烧结温度及桐壳灰添加量对甲酯化的影响,结果表明:当KOH用量为6 g、Al_2O_3用量为4 g、桐壳灰分添加量为3 g,烧结温度700℃下煅烧10 h制备的固体碱催化剂催化桐油甲酯化效率最高,为76.34%。对得到的固体碱催化剂进行碱量、SEM及XRD分析,结果显示该固体碱催化剂表面为树状多枝结构;加入桐壳灰后,该催化剂产生CaO、MgO和SiO_2等新相。与0~#柴油相比,该催化剂催化下制备的生物柴油具有更优良的性能。  相似文献   

7.
为提高木质素的反应活性,采用微波辅助加热方式,在HBr/十六烷基三正丁基溴化磷(HBr/TBHDPB)体系下对木质素进行脱甲基化改性。考察了HBr用量、反应温度、反应时间和催化剂用量对木质素改性反应的影响。通过紫外光谱(UV)、核磁共振氢谱(1H NMR)、傅里叶变换红外光谱(FT-IR)、凝胶渗透色谱(GPC)和元素分析等手段研究了木质素改性前后的官能团及分子质量变化,并由羟甲基化反应和曼尼希反应分析了木质素改性前后的活性变化。结果表明:木质素在微波辅助加热条件下,HBr用量为20 mmol/g,催化剂TBHDPB用量为木质素质量的2%,95℃反应1 h,制备的改性木质素含酚羟基为4.95%,相比原料木质素提高了32.71%,甲氧基为6.11%,相比原料木质素降低了20.44%。与甲醛反应的活性提高了18.15%,胺基侧链增加了7.54%。UV、1H NMR和FT-IR分析也表明,改性木质素的酚羟基含量增加,甲氧基含量降低。  相似文献   

8.
分别以十六烷基三甲氧基硅烷(HDS)和1H,1H,2H,2H-全氟十七烷三甲基氧硅烷(FDS)为改性剂、乙醇/水溶液为分散介质,采用浸渍法和喷雾法对杨木纤维(PWF)表面改性,制得HDS浸渍改性杨木纤维(HPWF)、FDS浸渍改性杨木纤维(FPWF1)和FDS喷雾改性杨木纤维(FPWF2)。考察了溶剂配比、硅烷用量、硅烷水解温度和时间、反应温度及反应时间等因素对PWF表面改性效果的影响,并通过红外光谱(FT-IR)、接触角测量、X射线衍射(XRD)、X射线能谱(EDS)及扫描电镜(SEM)等方法表征了改性前后PWF的结构与表面性能,结果表明:在乙醇质量分数60%乙醇/水溶液中以HDS与PWF活性羟基物质的量比0.4∶1、HDS于60℃水解1 h,再与PWF于60℃反应1 h,所得HPWF的表面接触角达139°;在乙醇质量分数50%乙醇/水溶液中以FDS与PWF活性羟基物质的量比0.16∶1、FDS于60℃水解1 h,再与PWF于60℃反应1 h,所得FPWF1的表面接触角达141°;FDS与PWF活性羟基物质的量比0.008∶1,经喷雾搅拌使纤维表面润湿后于120℃活化反应1.5 h,所得FPWF2的表面接触角达138°。与浸渍法相比,喷雾法具有硅烷用量小、工艺简单、清洁高效等特点。此外,改性后杨木纤维的结晶度提高(由62.1%提高到67.7%~69.7%),表面变得粗糙,比表面积增加,表面极性降低,疏水性能显著提高,有利于改善与疏水性基体树脂的界面相容性与粘结作用。  相似文献   

9.
以丁二酸酐和邻苯二甲酸酐两种酸酐按一定配比混合后作为酯化剂,4-二甲氨基吡啶为催化剂,二甲亚砜为分散介质,对胡桑枝条木粉进行改性,成功制备了具有较好热塑性和良好力学性能的注塑级生物基塑料。探讨了丁二酸酐占总酸酐物质的量百分比(简称酸酐配比)、反应温度、反应时间对生物基塑料力学性能的影响。采用三因素三水平的Box-Behnken设计方法,利用Design Expert软件得到回归方程的预测模型,并通过响应面分析,优化木粉酯化改性的工艺条件。最佳条件下混合酸酐改性制备的材料,其拉伸(酸酐配比18.79%,反应时间3.03 h,反应温度69.06℃)和弯曲(酸酐配比17.85%,反应时间3.12 h,反应温度68.11℃)强度分别达到30.13和41.32 MPa。  相似文献   

10.
以磷钨酸、30%H_2O_2和十二烷基氯化吡啶为原料制备了磷钨酸季铵盐相转移催化剂(C_(12)H_(25)C_6H_5N)_3[PW_4O_(16)],并将该催化剂用于催化桐油甲酯(TOME)合成环氧桐油甲酯(ETOME),考察了不同反应条件对TOME环氧化反应的影响。研究发现:该相转移催化剂与H_2O_2和TOME相互作用的体系可以视为均相反应,且反应速率快,当n(C=C)∶n(H_2O)为1∶1.6,TOME和催化剂的质量比1∶0.03,反应温度为50℃,反应时间为3 h时,制得的ETOME的环氧值达到4.9%;热重(TG)分析表明桐油(TO)、TOME和ETOME的热稳定性顺序为ETOMETOTOME。  相似文献   

11.
研究了杨木线性振动摩擦焊接的干剪切强度、湿剪切强度和木破率。为提高杨木摩擦焊接的湿剪切强度与木破率,采用表面氧化、表面磺化以及表面涂覆的方式处理杨木板材,再经线性振动摩擦焊接进行黏合,使用万能力学试验机测得其剪切强度,对比表面处理前后剪切强度的变化,并利用傅里叶红外光谱分析了其表面处理前后基材和摩擦焊接层的化学基团变化情况,对胶合性能的变化做出解释。研究结果表明:杨木经过表面氧化磺化涂覆醋酸锌处理后,摩擦焊接层的干剪切强度为5.41 MPa,木破率为63%,与未处理的杨木相比,分别提高了48.22%和96.88%;湿剪切强度从0提高到1.34 MPa;摩擦焊接时厚度损失减少了46.4%。杨木分别经过表面氧化和表面磺化处理后,摩擦焊接层的干剪切强度仅为3.45和4.10 MPa,木破率为28%和42%,湿剪切强度为0.76和0.96 MPa。摩擦焊接层的红外光谱分析表明,经表面氧化磺化涂覆醋酸锌处理后,杨木中的纤维素和半纤维素分解,使木质素的相对含量有所增加,且活化了杨木中的—OH,与醋酸锌生成多醚,消耗了亲水性的—OH。  相似文献   

12.
To clarify the influencing factors of liquefaction of wood in phenol using phosphoric acid as a catalyst and get its liquefaction technology, a study on the liquefaction technology of Chinese fir (Cunninghamia lanceolata) and poplar (triploid Populus tomentosa Carr) under different conditions was conducted. The results indicate that the residue rate decreases with the increase of liquefaction temperature, liquefaction time, catalyst content or liquid ratio. It is also found that the optimum condition of liquefaction for poplar is estimated as: the reaction temperature of 180 ℃, the reaction time of 2.5 h, liquid ratio (phenol/wood ratio)of 4.5 and catalyst content of 8%, and 4.2% residue rate could be obtained. Under the processing parameters of temperature 180 ℃, the reaction time of 2.5 h, liquid ratio (phenol/wood ratio) of 4 and catalyst content of 10%, the residue rate of Chinese fir can reach 5.6%.  相似文献   

13.
Chinese fir (Cunninghamia lanceolata) and poplar (Populus spp.) wood meal were phenolated in the presence of sulfuric acid used as a catalyst. The effects of reaction time and reaction temperature on the wood liquefaction were investigated. The results showed that the reaction temperature had the greater influence on the residue content than reaction time. Additionally, the liquefaction curve for the Chinese fir and Poplar were similar in general.  相似文献   

14.
研究了速生杨木单元经过纤维素酶和半纤维素酶处理后的表面润湿性能、化学基团和胶合强度的变化。结果表明:随着纤维素酶和半纤维素酶用量的增加,杨木的表面自由能和胶合强度逐渐上升。在试验区间内,酶处理时间越长,杨木的胶合性能改善效果越明显。  相似文献   

15.
INTRODUCTION Wood is far from a stable material. One of the biggest challenges for woodworking is learning to work within the constraints of wood properties. Discoloration of wood directly influences the decorative performance of wood products. Therefore, the degree of color change is a critical factor that determines the utilization area of dyed wood (Sakuragawa Satoshi, 1996). Discoloration has occurred because the wood components and dye molecules are degraded by UV-ray (Kaneko Shin…  相似文献   

16.
To clarify liquefaction ratios and their construction variations of the main chemical compositions of wood in phenol using phosphoric acid as a catalyst, the chemical ingredients of wood such as holocellulose, cellulose and lignin, were measured and extracted according to GB methods. With Fourier transform infrared (FTIR), the product identification of reactant before and after liquefaction in phenol was investigated. The molecular weights and their distributions of the liquefaction results (acetone soluble parts) were studied by gel permeation chromatography (GPC). Results show that the molecular weights and their distributions of poplar and Chinese fir are almost the same. In poplar, the distribution of cellulose is the largest, and that ofholocellulose the smallest after liquefaction. For Chinese fir, the distribution of holocellulose is the largest, and that of cellulose the smallest. After liquefaction of poplar cellulose, the change bands of FTIR spectrum observed below 1 600 cm^-1, can be attributed to new substitute groups. The same is true for poplar lignin. For Chinese fir, the spectra of liquefaction results of all chemical compositions differ from that of wood meal. This reveals the more activity groups were produced because of the reactions between Chinese fir and phenol. The research shows that the liquefaction ratios of poplar decrease in the following order: holocellulose 〉 lignin 〉 cellulose, and those of Chinese fir in the order: lignin 〉 cellulose 〉 holocellulose.  相似文献   

17.
研究了一种用含有少量硫酸的乙酸溶液分离杨木成分的方法。考察了反应时间、乙酸浓度、液比和催化剂浓度对木材成分分离的影响。对分离出的木材三种成分进行了表征。结果表明,分离杨木成分的较佳条件为:硫酸浓度0.3%,液比6,反应时间3h和乙酸浓度90%。残渣的主要成分是α-纤维素和半纤维素。水不溶沉淀物(乙酰化木质素)的重均分子量分布在341到253之间,分散性系数分布在1.1到1.2这一窄范围内。糖分析结果表明,可溶性成分主要来源于半纤维素,以单糖形式存在。  相似文献   

18.
杨木应拉木微区结构可视化及化学成分分析   总被引:1,自引:0,他引:1  
木材微区结构与木材宏观性质密切相关,杨木应拉木与对应木宏观性质存在较大差别,探究杨木应拉木和对应木微区结构和化学成分,可为了解杨木应力木的宏观性质提供理论根据。借助光学显微镜、荧光显微镜、显微拉曼成像光谱仪、透射电镜对杨木应拉木微区结构进行可视化研究,并借助X射线衍射技术和美国可再生能源实验室方法,分析杨木应拉木的微晶尺寸、结晶度以及化学成分。结果表明:杨木应拉木中应拉区和对应区纤维细胞微区结构差异显著。光学显微镜下显示应拉区木纤维中胶质层清晰可见,荧光显微镜和拉曼显微镜下显示胶质层的木质素浓度比对应区低。透射电镜下显示应拉区木纤维细胞壁结构由初生壁、次生壁和胶质层组成,未见次生壁外层,各层的平均厚度分别为0.61,1.22和2.53μm。对应区木纤维为典型的初生壁和次生壁结构,次生壁各层平均厚度分别为0.33,2.28和0.14μm。杨木应拉区纤维素含量(58.91%)比对应区(41.53%)高,木质素含量和半纤维素含量均比对应区的低,应拉区木质素和半纤维素含量分别为21.99%和12.01%,对应区分别为28.10%和17.08%。杨木应拉区结晶度(48.06%)比对应区(41.01%)高,应拉区晶区宽度为2.66 nm,长度为8.84 nm;对应区晶区宽度为2.65 nm,长度为9.87 nm。  相似文献   

19.
20.
The effects of high temperature, moisture, and mechanical action during the thermo-hydro-mechanical (THM) processing, on the changes in surface properties of poplar, namely, surface color, roughness, wettability, and microstructure, were investigated in this study. The correlation between observed changes in surface properties and chemical characteristics was also analyzed. Poplar woods with high moisture content were compressed using different pressures at temperature of 160 °C for four different periods. The wood surfaces became darker and smoother, and their surface free energy decreased significantly after the THM process. THM process markedly reduced surface hygroscopicity compared to the control wood. The cell lumens of THM wood became narrow with increasing compression ratio due to the enhancing high pressure. Collapse and fractures of cell walls developed during THM treatment. Furthermore, results indicated that a series of chemical reactions in different components of wood took place during THM process, such as degradation of hemicelluloses, condensation of lignin, and decomposition of extractives. In turn, these chemical modifications contributed to the darkening of color as well as the reduction of wettability and surface free energy of THM wood.  相似文献   

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