MDF甲醛释放量评价新方法的研究

研究了MDF甲醛释放量两种评价方法（干燥器法和穿孔法）的关系，通过对不同测试条件下用干燥器法对MDF甲醛释放量进行检测，其结果用穿孔法的检测结果进行对比和检验。用穿孔法的ms／100g为单位表达检测数据，能结合两种梭测方法的结果，建立了一种统一的模型。通过对影响甲醛释放量评价准确性的几个因素（表面积，质量，厚度等）进行研究，表明新的结合模塑比原有的两种方法更具有可行性和科学性。     

Microcracks in MDF Cement

The relationspip between the microcracks and the mechanical behaviors and the characteristics of fracture of MDF cement have been studied. The results show that most of the microcracks lie and propagate in the matrix or along the boundary of the clinkers. The microcracks improve the toughness of MDF cement. The Griffith's equation is invalid to describe the fracture of MDF cement.     

Research on Very Volatile Organic Compounds and Odors from Veneered Medium Density Fiberboard Coated with Water-Based Lacquers

Very volatile organic compounds (VVOCs) are a group of important odor pollutants affecting indoor air quality that have been shown to be harmful to human health. A 15 L environmental chamber, combined with multi-bed tube was used to collect gases. Fifteen very volatile organic compounds (VVOCs), including 12 odor compounds, were identified from veneered medium density fiberboard coated with water-based lacquer (WB-MDF) using gas chromatography–mass spectrometry/olfactometry (GC-MS/O). The total very volatile organic compound (TVVOC) and total odor intensity (TOI) showed a decreasing trend over time, reaching equilibrium on day 28. TVVOC showed an overall slow-fast-slow emission profile, from day 3 to day 7, with a maximum decay rate of 29.7%. TOI showed the greatest rate of decline from day 1 to day 3, at approximately 12%. Alkane and alcohol VVOCs were the more abundant compounds, accounting for at least 60% and even up to 80% of the total. The major odor impression was fruity, with a highest odor rating of 6.6, followed by sweet, with an odor rating of 6.1. Although the odor impression changed from sweet to fruity over time, it seemed pleasant overall. The odor contributors were mainly alkanes, alcohols, esters, and ethers, which had relatively high odor intensities. The main odor-contributing substances were dichloromethane, ethanol, ethyl acetate, 2-methylacrylic acid methyl ester, and tetrahydrofuran. When WB-MDF is used for furniture or other decorative materials, it is strongly recommended that it be stored under ventilation for at least 28 days and the adoption of substitute solvents of lacquers, modified adhesives, and low-odor wood raw materials is recommended. These possible initiatives would contribute to the aim of building an environmentally friendly indoor environment.     

MDF甲醛释放流变性的研究

在MDF甲醛释放蠕变过程中，MDF甲醛释放驱动力保持不变时，MDF甲醛释放量随时间延长而变化。马克斯韦模型可在甲醛释放驱动力为恒定条件下，较好地模拟MDF的甲醛释放流变性的规律；凯尔文模型较好地模拟了MDF甲醛延时释放特征；勃格模型是描述MDF甲醛释放蠕变的重要公式，它较好地模拟了MDF甲醛常规释放蠕变特征，换算得到的公式可较好地描述锯切后试件放置时间对MDF甲醛释放量的影响规律，是描述和预测MDF甲醛释放松弛特性的有价值模型；也可较好地描述干燥器测试时间对MDF甲醛释放量的影响规律，是描述和预测MDF甲醛释放蠕变特性的有价值模型。     

Synthesis,moisture resistance,thermal, chemical and SEM analysis of macro-defect-free (MDF) cements

The results, presented here discusses the Macro-Defect-Free (MDF) cements prepared from the blends of sulfoaluminate ferrite belite (SAFB) clinkers, ordinary Portland cement (OPC), Al₂O₃ and poly(butyl acrylate) (PBA), styrene/acrylonitrile co-polymer (SACP) or sodium polyphosphate (poly-P). Though MDF cements have several attractive properties, their utilization has been limited due to the insufficient moisture resistance. It is a very challenging task for scientists and technologist to improve the moisture resistance of MDF cements. Therefore, the new MDF cements were subjected to various moist atmospheres to investigate their moisture resistance. The most significance of this work is the improvement of moisture resistance of the studied MDF cements. The aim of this work was to understand the effects of polymers, Al₂O₃, OPC and SAFB clinkers in the raw mix and delayed drying on MDF cements and also on their subsequent moisture resistance and thermal stability as well as to discover the new properties of these materials. Their chemical, thermal and scanning electron microscopic (SEM) analysis was also carried out before and after exposure to moisture. PBA was found to be the most suitable polymer for MDF cement synthesis, since the samples containing PBA showed the highest resistance to moisture. There are three main temperature regions on TG curves of both series of MDF cement samples. The significant differences in SEM of MDF cements before and after moisture attack and with different polymers were observed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Standardization on stanag test methods for ease of compatibility and thermal studies

MDF cements using the blends of sulfoaluminate ferrite belite (SAFB) clinkers and ordinary Portland cement (OPC) in mass ratio 85:15 with Al₂O₃, and starch, polyphosphate (poly-P) or butylacrylate/acrylonitrile were subjected to moist atmospheres (ambient, 52 and 100% relative humidity (RH)) to investigate their moisture resistance. Their chemical, thermal, electron microscopic and magnetic properties were also studied before and after moisture attack. Butylacrylate/acrylonitrile (BA/AN) copolymer was found to be the most suitable for MDF cement synthesis since the sample containing BA/AN showed the best moisture resistant. There are significant differences in scanning electron microscopy (SEM) of MDF cements before and after moisture attack and with different polymers. New data on the paramagnetic nonhysteresis magnetization curves for all the samples are observed. The MDF cements synthesized from SAFB clinker with dissolved poly-P give the best signal/noise (S/N) ratio. Three main temperature regions on TG curves of both series of MDF cements are observed. In the inter-phase section of MDF cements, the content of classical cement hydrates decomposing by 250°C is increased. Combustion of organic material took place by 550°C. In the temperature range 550-800°C, the decomposition of CaCO₃ occurs.     

弯曲木成型技术及其在家具制作中的应用研究

介绍了弯曲木成型技术及其在家具制造中的历史与发展 ,详细论述了实木弯曲成型技术、多层胶合板弯曲成型技术以及MDF纤维板弯曲成型技术的技术工艺 ,并介绍其在家具制造中的具体应用。     

MDF老化过程中甲醛释放量的研究

将MDF放在气候箱中按设定的条件进行快速老化,同时在室内环境中作对比试验,比较两种条件下MDF甲醛释放量与力学性能的变化。MDF甲醛释放量随着加速老化周期增加而不断减少,与循环周期呈显著指数关系。加速老化对木材纤维与树脂之间的结合有较大的影响,UF在高温高湿下体形结构受到破坏。MDF加速老化后甲醛释放量与放置室内每10d的MDF的甲醛释放量具有显著的指数关系。