Particleboards from Acetylated Wood Flakes

Particleboards from acetylated wood flakes with various resins were pressed and compared with untreated control boards with respect to their weathering resistance and mechanical strength. The industrially used melamine, urea, and phenol resins showed a poor adhesion behavior to the acetylated flakes resulting in a high decrease of the mechanical strength of the particleboards. A novel type of apolar resin based on methylmelamines was developed and characterized. Using this resin particleboards with good mechanical strength and weathering stability could be produced.     

Investigations on the Crosslinking Reactions of Melamine Resins in the Presence of Wood

Summary. The crosslinking behavior of MFRs (melamine formaldehyde resins) in the presence of wood was investigated. The influence of various factors (wood content, resin structure, etc.) on the crosslinking temperature of the resins was examined using DMTA and DSC/TGA. Fully methylated MFRs turned out to be more stable in the presence of wood than partially methylated MFRs. A dependence of the crosslinking temperature on the wood content was found. Model reactions with wood components demonstrated, that cellulose, hemicelluloses, and lignin affect the crosslinking temperature to different extends, whereas hemicelluloses (xylan) showed the strongest effect. Solvents, especially water, led to a further decrease of the crosslinking temperature of wood/MFR compounds.     

New Acetylated Flavonol Glycosides from Knoxia corymbosa

Two new diacetylated flavonol glycosides, kampferol-3-O-β-3“, 6“-diacetylglucopyrano-side and quercetin-3-O-β-3“, 6“-diacetylglucopyranoside were isolated from knoxia corymbosa. Their structures were elucidated by spectroscopic evidents.     

K33位乙酰化修饰SUMO蛋白的化学合成

采用高温辅助固相合成技术及基于多肽酰肼的自然化学连接技术,高效获得了小泛素相关修饰物(SUMO)蛋白及33位赖氨酸(K33)乙酰化SUMO蛋白.聚丙烯酰胺凝胶电泳(SDS-PAGE)和圆二色光谱分析结果表明,与生物表达蛋白相比,化学合成蛋白具有较好的纯度和类似的二级结构.     

酸性染料用于木材染色的研究

选择酸性染料对低质阔叶材单板进行染色研究，发现此类染料对滇杨木，滇桤木，西南桦有较好的易染性，通过试验得到几例常见木材颜色的染料配比，并对染色工艺进行了初步探讨，结果表明温度在70-80℃，pH=4及助染剂量1.5(wt)%时，染色效果最佳。     

Processing of Thermal Sensitive Materials – a Case Study for Wood Plastic Composites

Summary. The influence of processing parameters, e.g. throughput and temperature, of the compounding step of wood plastic composites was investigated in this work. The effects on the mechanical properties as well as the influence on the colour of the produced composites were correlated with the different processing parameters. The composites showed a wide range of good processability, only at high temperature and low throughput strong darkening occurred, as well as a loss of tensile strength was found for these samples.     

阔叶树皮木醋液与木焦油有机成分的气相色谱分析

运用气相色谱对阔叶树皮木醋液及木焦油水提取液的有机成分,如醇类、羧酸类、酮类、酚类等进行了定量分析.结果表明,木醋液随着蒸馏处理,甲醇、乙醇、丙酮等低沸点物质主要分布在前馏液中,2,6-二甲氧基苯酚、甲基环戊烯醇酮、2-甲基-3-羟基-4-吡喃酮等高沸点物质主要分布在残馏液中.通过阔叶树皮木醋液及木焦油水提取液的两种主馏分所含有机成分的定量分析比较,表明除甲醇、乙酸、丙酸、2-呋喃醛等成分以外,二者具有相似的化学成分组成.     

Wastes from Wood Extraction Used in Composite Materials: Behavior after Accelerated Weathering

New materials were obtained by incorporating in polypropylene (PP) matrix 60% wood wastes resulting after extraction with supercritical carbon dioxide, water, and ethanol. Structural, mechanical, thermal, and rheological characterizations, as well as moisture uptake of the composites, were evaluated before and after accelerated weathering. It was found that the extraction method influenced the composite properties due to the hydrophilic-hydrophobic balance. The addition of extracted fibers results in an increase in hardness and tensile properties and a decrease of impact strength as compared to PP.     

Wood plastic composites weathering: Visual appearance and chemical changes

The effects of outside and accelerated (xenon-arc and UVA) weathering on the visual appearance and chemical changes of wood plastic composite (WPC) formulations based on high density polyethylene (HDPE) and polypropylene (PP) were investigated. Colorimetry, scanning electron microscopy, Fourier transform infrared spectroscopy (FT-IR), and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) were employed in this study. The study showed that for both outside and accelerated weathering, longer exposure time increased the degree of color change (and lightness), carbonyl concentrations, and wood loss on weathered WPC surfaces. HDPE-based WPC exhibited decreased lightening, carbonyl concentrations, and wood content loss when compared to PP-based WPC. From this study, relationships between chemical and color changes that occurred during exterior weathering of HDPE-based WPC were established. Oxidation and degradation of wood lignin influenced WPC color changes (lightening) during weathering.     

高效液相色谱法检测木材产品中8-羟基喹啉铜

采用高效液相色谱法测定木材产品中8-羟基喹啉铜。木材样品经甲醇超声提取两次,以反相C18柱为分离柱、甲醇与乙酸铵-乙酸缓冲溶液作为流动相进行洗脱,采用光电二极管阵列检测器在257nm处进行检测。8-羟基喹啉铜的质量浓度在0.1~10.0mg·L-1范围内与峰面积呈线性关系,检出限(3S/N)为0.06mg·kg-1。对空白样品进行加标回收试验,回收率在76.4%~94.2%之间,测定值的相对标准偏差(n=5)在3.2%~7.5%之间。     

Investigations of the Rheology and Reactivity of Extrudable Wood-Resin Compounds

Summary. The extrusion of wood composites based on thermosetting resins is a new application in the field of wood plastic composites. To enable the extrusion of wood thermosetting compounds, it is necessary to know their reactivity and rheology well beforehand, to prevent the system curing inside the extruder. This study shows the different techniques that were adapted to allow in combination an estimation of the processing behaviour of wood-resin compounds in extrusion.     

功能化离子液体液化木粉及其酚醛复合材料

合成了氯代1-(2-羟乙基)-3-甲基咪唑离子液体[He MIM]Cl、溴代1-乙胺基-3-甲基咪唑离子液体[Ae MIM]Br和氯代1-羧乙基-3-甲基咪唑离子液体[Ce MIM]Cl 3种功能化咪唑离子液体,并分别进行了红外与氢核磁结构表征.然后用3种离子液体液化木粉,液化3 h后向体系直接加入苯酚、甲醛和氢氧化钠,制备酚醛复合材料,并采用FTIR、XRD、DSC和SEM对酚醛复合材料进行结构、性能与形貌测试,研究离子液体种类对木粉液化率及酚醛树脂性能的影响.结果表明,离子液体及其液化木粉产物制备的酚醛复合材料性能得到明显改善.[Ce MIM]Cl液化效果最好,90℃液化率高达24.6%,当[Ce MIM]Cl与木粉质量比为10∶1时,制备的酚醛复合材料的游离醛释放量由原来的3.64%降低到0.92%.离子液体[Ae MIM]Br能将酚醛复合材料的冲击强度由原来的0.93 k J/m2提高到6.96 k J/m2,而[Ae MIM]Br及其液化的木粉产物制备的酚醛复合材料拉伸强度从原来的3.28 MPa提高到9.70 MPa.     

In-line rheometry of polypropylene based Wood Polymer Composites

A completely satisfactory off-line rheological investigation of Wood Polymer Composites (WPCs) is very challenging at processing temperatures: when using rotational rheometry in oscillatory mode, the linear viscoelastic region is often too small, while in capillary rheometry the sieving effect of the fibres may invalidate the results. Moreover, all off-line tests present the risk of wood degradation.To this aim, an in-line extrusion rheometer (slit die) has been developed. The major advantages are that the measurements are made in real processing conditions and degradation problems are less severe thanks to reduced oxygen level inside the extruder barrel.In order to verify the methodology, tests have been conducted on a commercial polypropylene based WPC with 30 wt.% white fir fibres and compared with off-line measurements performed at a lower temperature on the same material. For comparison, a temperature shift factor has been used, that has been estimated by characterizing the polypropylene matrix alone.     

Characterization of Five Kinds of Wood Vinegar Obtained from Agricultural and Forestry Wastes and Identification of Major Antioxidants in Wood Vinegar

Wood vinegar(WV)has a powerful antioxidant activity,but it is unclear which components are responsible for the antioxidant activity.In the present study,the double-column retention index qualitative method was used for the identification of the major components in five kinds of W7 And the major antioxidants of wood vinegar were accurately identified with the aid of Pearson product-moment correlation coefficients and authentic standard samples. Our results demonstrate that phenolic compounds are mainly responsible for the powerful antioxidant activity. 2,6-Dimethoxyphenol is the most powerful antioxidant in WV.2-Methoxyphenol and 3-methyl-1,2-cyclopentanedioue also have an important influence on the antioxidant activity of WV.Our results suggest that the contents of 2-methoxyphenol,2,6-dimethoxyphenol and 3-methyl-1,2-cyclopentanedione should act as the criteria for evaluating the antioxidant activity of WV.Our work will provide useful information for WV's application in the fields of food and medicine as antioxidants.     

聚芳基乙炔树脂/杉木粉木材陶瓷的制备与表征

用聚芳基乙炔树脂浸渍杉木粉,固化制得聚芳基乙炔/杉木粉复合材料,经高温炭化得到了一种新型木材陶瓷。 用DTG分析了聚芳基乙炔树脂和复合材料的热稳定性,用XRD、LRS和SEM研究了炭化温度和树脂用量对木材陶瓷物相构成、断面微孔形态和抗压强度的影响。 结果表明,木材陶瓷呈三维多孔结构,孔分布比较均匀;复合材料保持了很高的热分解温度(325 ℃)和残碳率(70%)。 随着炭化温度升高,d002晶面间距由0.3895 nm减小至0.3530 nm,而微晶尺寸Lc和La有不同程度增加。 木材陶瓷的开孔率随炭化温度的升高由31.5%减小至20.1%,而抗压强度由3.0 MPa增大至6.2 MPa。 树脂/杉木粉质量比对木材陶瓷的微孔尺寸和形状有较大影响,但对石墨微晶尺寸影响不明显。     

Composites of Wood and Biodegradable Thermoplastics: A Review

This paper is an overview of current understanding in the areas of composites made from biodegradable thermoplastics and wood fillers. The review finds that the composite properties depend on the type of wood filler, the choice of polymer matrix, the wood filler content, the compatibilization technique used and the processing parameters. The extent of interfacial adhesion and the filler morphology are identified as the underlying factors that control the composite properties. Future research needs are identified, including establishment of fundamental relationships between quantified interfacial adhesion and end-use properties and advanced modelling of biodegradation processes.     

Characteristics and Bond Performance of Wood Adhesive Made from Natural Rubber Latex and Alkaline Pretreatment Lignin

The aim of this study was to characterize an aqueous polymer isocyanate (API) type adhesive made from natural rubber latex (NRL) and lignin as base polymers, and to evaluate bond performance of the adhesive as laminated wood adhesive. The base polymers of the adhesive were prepared by blending NRL, polyvinyl alcohol (PVA), and lignin isolated from black liquor of alkaline pretreatment of oil palm empty fruit bunch (OPEFB) and sugarcane bagasse (SB) with compositions of 25/25/0, 25/20/5, 25/15/10, 25/10/15, 25/5/20, and 25/0/25 (w/w/w). The isocyanate crosslinker was added at the level of 15% of the weight of base polymer. The glass transition temperature (Tg), heat degradation, and the homogenity of the adhesive blend were analyzed. The adhesive was used for producing laminated wood (20×8 cm²). Results showed that the addition of lignin in the base polymer blends of API adhesive did not significantly affect the Tg of the adhesives. However, it affected the thermal decomposition and bond performance of the adhesives. There were more residues and less homogenous adhesive solution due to the addition of lignin in the base polyemr blends of API adhesives. The addition of lignin in the base polymer blends caused significant decrease in bond performance of the adhesive applied in glue laminated wood.     

Determination of Phenolic Compounds and Coumarins in Sugar Cane Spirit Aged in Different Species of Wood

The identities and quantities of the phenolic compounds and coumarins in twelve samples of sugar cane spirit aged in Quercus sp., Amburana cearensis, Cariniana legalis, Castanea sativa Mill, Ocotea sp., Cotyledon orbiculata L., and Hymenaea sp. casks were determined. These compounds have a direct influence on the sensory characteristics of aged beverages; some of them are considered to be markers for the aging process. The analysis of phenolic compounds was performed by HPLC. Solid phase extraction (SPE) was also used for the determination of coumarins. The concentrations of the principal compounds extracted varied according to the species of wood. The concentrations of total phenolic compounds ranged from 0.08 for a sample stored in a 4000-L jatobá barrel for a period of six months to 40.9 mg · L^?1 for a sample aged in a 50000-L oak barrel for a period of 48 months. The use of the SPE technique removed interfering compounds from the samples, thereby improving the detection of coumarin.     

木材表面改性的XPS分析

利用微波等离子体对木材表面进行处理，并诱导引发接枝甲基丙烯酸甲酯；达到表面改性的效果以提高木质材料的性能，利用X射线光电子能谱(XPS)对木材表面改性前后的表面化学结构进行分析；结果表明：木材经微波等离子体处理，表面氧与碳的原子浓度比(no／nc)增加，产生大量的含氧官能团或过氧化物，从而引发木材与甲基丙烯甲酯单体产生接枝共聚反应。