间苯二酚-苯酚-甲醛树脂胶的快速老化性能试验

通过10、15、30和50次煮佛-干燥循坏人工快速老化处埋对间笨二酚-苯酚-甲醛(RPE)、酚醛(PF)树脂胶胶合试件以及实木(solid wood)试件的木块顺纹剪切强度进行比较。试验结果表明:RPF胶的耐候性优于PF胶的耐候性,研制的RPF胶是一种性能优良的耐候性结构用胶。     

间苯酚—苯酚—甲醛树脂胶的快速老化性能试验

通过１０，１５，３０和５０次煮沸－干燥循环人工快速老化处理对间苯二酚－苯酚－甲醛，酚醛树脂胶胶合试件以及实木试件的木块顺纹剪切强度进行比较。试验结果表明：ＲＰＦ胶的耐候性优于ＰＦ胶的耐候性，研制的ＰＲＦ胶是一种性能优良的耐候性结构用胶。     

间苯二酚—苯酚—甲醛树脂制备及性能研究

主要研究催化剂、反应时间、摩尔比等反应条件对间苯二酚－苯酚－甲醛（ＲＰＦ）树脂性能的影响，当甲醛／苯酚摩尔比为１￣１．５：１、间苯二酚／苯酚摩尔比为０．６：１时可制得室外级冷固型胶粘剂。通过ＤＳＣ和ＩＲ分析固化行为表明，低温下的放热量主要受多聚甲醛的影响，固化后的树脂中存在着大量的亚甲基醚键。     

PF与UF树脂混合比对竹帘板胶合性能的影响

以酚醛（PF）胶为基础，通过与不同加量的脲醛（UF）胶相混合，形成一系列混合胶粘剂。在不同的热压条件下，用混合胶粘剂压制竹帘胶合板，经对各组分制品的耐沸水和耐老化性检验，确认当热压温度为140℃时，脲醛胶的最大加量可以达到酚醛胶量的40％，制品的胶合状态不会受到破坏。     

苯酚－尿素－甲醛共缩聚树脂与酚醛树脂胶合性能对比研究

利用自制PUF树脂,采用不同固体含量PUF树脂压制竹建筑模板,对PUF和PF压板进行对比试验,并对PUF树脂和PF树脂进行热重分析.结果表明:用PUF树脂压制的竹建筑模板胶合性能与目前企业所用PF树脂压制板材的胶合性能相当,浸胶固体含量以30%为宜,生产成本比相同固体含量的PF树脂降低约13.5%,热重分析显示两者的热固化行为相似.     

DFK树脂与胶合性能

本文较为详细地介绍了烷基间苯二酚的提取及精制方法,并阐述了烷基间苯二酚的化学特性及DFK树脂的合成原理,同时概要地介绍了DFK树脂在木材工业中的应用状况。     

日本胶合木的制造与应用

日本胶合木的制造与应用陆继圣（福建林学院福建南平３５３００１）现今大径优质木材资源日益短缺，代之而起的是人工速生树种材，而利用速生树种材的有效途径之一是应用指接和胶合技术制造胶合木，这样可做到小材大用，次材优用，可获得人造板不可替代的板材，提高了木材...     

浅议胶合木与胶粘剂

概括地介绍了生产胶合木的多种胶粘剂,以较多篇幅说及苯酚－间苯二酚－甲醛树脂和水性高分子－异氰酸酯胶粘剂,还顺便提到胶合木的特点和发展。     

填充剂对间苯二酚—苯酚—甲醛树脂性能的影响

以间苯二酚—苯酚—甲醛树脂胶粘剂压制的落叶松板材为研究对象,通过均匀设计的方法,对树脂填充剂中的面粉、核桃壳粉、飞灰按不同比例混合,考察各因子及因子之间的交互作用对板材剪切强度和剥离率的影响。结果表明,混合填充剂中核桃壳粉和飞灰对落叶松板材性能的影响较大。     

胶合木及其在工程中的应用

木材是唯一可再生的四大建筑材料之一。在工程中应用的胶合木对木材的生长周期要求不高。在应用中,可将不同强度的干燥木材进行组合,达到最优强度,提高木材的使用效率。胶合木结构构件的设计不但要满足强度以及稳定性的要求,尤其还要对构造要求加以重视。胶合木在公共建筑以及公路桥梁上的应用在我国有一定的发展空间,需要政府、企业的大力支持。     

UF-G低毒脲醛树脂在胶合板上的应用研究

UF-G低毒脲醛树脂在胶合板上的应用研究结果表明,最佳调胶参数为面粉添加量25%,固化剂添加量1.2%;最佳热压工艺参数为热压温度110℃、热压压力1.2 MPa、热压时间60 s·mm-1、涂胶量300 g·m-2。在此条件下压制出的胶合板甲醛释放量达到E1级,且胶合强度满足国家标准的要求。     

角蛋白改性脲醛树脂胶的研究

角蛋白改性脲醛树脂胶的试验结果表明,利用角蛋白与脲醛树脂进行共聚反应,可以得到环保型的改性脲醛树脂胶;最佳工艺条件为:摩尔比为1.31.0;角蛋白加入时间在第3次尿素投料后,角蛋白加入量为尿素的5%。采用角蛋白改性脲醛胶压制的胶合板,胶合强度达到了国家标准GB/T9846—2004Ⅱ类板胶合要求,其甲醛释放量也达到了国家标准E1级胶合板用胶标准。     

Property of nano-SiO2/urea formaldehyde resin

In this paper, we discuss the effects of a nanometer silicon dioxide (nano-SiO₂) coupling agent, dispersal methods and the amount of nano-SiO₂/urea formaldehyde resin. The results of our study indicate that when nano-SiO₂, using KH-550 silane as a coupling agent, was added to UF resin by discontinuous ultrasonic vibration, its properties improved effectively. When the content of nano-SiO₂ was below 1.5%, the amount of free formaldehyde decreased, and the viscosity and bonding strength of resin increased with an increase in the added nano-SiO₂, which did not prolong the curing time. The performance indices of plywood, particleboard and medium density fiberboard (MDF), hot-pressed by nano-SiO2 (1%)/UF resin (F/U molar ratio=1.2), exceeded the requirements of the National Standard. Their free formaldehyde emission reached E1 grade. Finally, we analyzed the mechanism of the strengthening effects of nano-SiO₂ on UF resin by means of infrared spectrum analysis and X-ray photoelectronic spectrum (XPS). __________ Translated from Scientia Silvae Sinicae, 2005, 41(2) [译自: 林业科学, 2005, 41(2)]     

含LT型裂纹木梁起裂载荷确定方法的试验研究

木材裂纹萌生的准确判定对木材损伤断裂的评估具有重要的意义,起裂载荷是标定裂纹萌生的关键参数。本试验以杉木为研究对象,利用声发射技术(AE)、数字图像相关法(DIC)和电测法(EM),对含LT型裂纹木梁的损伤断裂特性进行了试验研究。通过研究木梁在加载过程中声发射参数变化规律以及裂尖区域的表面应变信息的演变,分析木梁裂纹萌生规律并确定起裂载荷Pini。结果表明:声发射累计振铃计数、幅度可有效反映木梁内部损伤的产生和演化,利用声发射参数的变化规律能准确确定含LT型裂纹木梁的起裂载荷Pini;数字图像相关法、电测法可以实时监测木梁表面裂缝尖端区域的应变变化,根据应变演变特征可以有效监测木梁表面裂纹的萌生和扩展。声发射技术、数字图像相关法、电测法在确定木梁起裂载荷Pini方面有较好的适用性,所确定的起裂载荷大小为:电测法>数字图像相关法>声发射。试验结果为研究监测含LT型裂纹木材裂纹萌生的试验方法提供了依据,应用时可结合实际工况选择合适的测量方法。     

国内木材工业中低毒脲醛树脂研究进展

介绍了当前通过降低摩尔比、改进工艺条件或使用改性剂等方法降低木材工业用脲醛树脂胶中游离甲醛含量或其生产的人造板甲醛释放量的最新进展情况。     

树脂型甲醛捕捉剂对脲醛树脂性能的影响

在实验室制备得到树脂型甲醛捕捉剂,考察了甲醛捕捉剂与不同F/U摩尔比脲醛树脂混合使用后制备得到的刨花板力学性能及甲醛释放量。研究结果表明,甲醛捕捉剂的添加能有效降低刨花板的甲醛释放量,但对混合树脂的最终力学强度性能不利。混合树脂的摩尔比F/U是决定相关刨花板力学性能及甲醛释放量的主要因素。当与摩尔比F/U=1的脲醛树脂混合使用时,添加占总施胶量5%甲醛捕捉剂的刨花板甲醛释放量可达到E1级,同时,内结合强度值满足室内级国家标准要求。与摩尔比F/U=1.2的脲醛树脂混合使用,当甲醛捕捉剂的添加量为20%时,刨花板性能达标。     

Compressive deformation of wood impregnated with low molecular weight phenol formaldehyde (PF) resin III: effects of sodium chlorite treatment

To obtain high-strength phenol–formaldehyde (PF) resin-impregnated compressed wood at low pressing pressure, we investigated the effects of sodium chlorite (NaClO₂) treatment on wood prior to low molecular weight PF resin impregnation. Sawn veneers of Japanese cedar (Cryptomeria japonica) were treated with 2% aqueous NaClO₂ solution at 45°C for 12 h to remove lignin, and the process was repeated up to four times, resulting in weight loss of 21%. NaClO₂ treatment has shown considerable potential for high compression of PF resin-impregnated wood at low pressing pressure, especially after adding moisture to a content of 10%–11%. This deformation is further enhanced during pressure holding by creep deformation. The density, Young’s modulus, and bending strength of PF resin-impregnated veneer laminated composites that were treated with NaClO₂ four times and compressed at 1 MPa, reached 1.15 g/cm³, 27 GPa, and 280 MPa, respectively. The values in untreated PF resin-impregnated wood reached 0.8 g/cm³, 16 GPa, and 165 MPa, respectively.     

脲醛树脂中游离甲醛含量测定不确定度评定

本文依据国家标准GB/T14074—2006,用滴定法测量脲醛树脂中游离甲醛含量,详细分析了测量过程中的各个影响因素,对检测结果的不确定度进行了评定,在测量过程中,重复性对不确定度贡献比较大。     

The effect of urea pretreatment on the formaldehyde emission and properties of straw particleboard

For manufacturing low-formaldehyde emission particleboard from wheat straw and urea-formaldehyde (UF) resins using urea treatment for indoor environments, we investigated the influence of urea treatment on the formaldehyde emission, physical and mechanical properties of the manufactured particleboard. Wheat straws were treated at three levels of urea concentration (5%, 10%, 15%) and 95℃as holding temperature. Wheat straw particleboards were manufactured using hotpress at 180℃and 3 MPa with two types of UF adhesive (UF-45,UF-91). Then the formaldehyde emission values, physical properties and mechanical properties were considered. The results show that the formaldehyde emission value was decreased by increasing urea concentration. Furthermore, the results indicate that the specimens under urea treatment have better mechanical and physical properties compared with control specimens. Also specimens under urea treatment at 10% concentration and UF-91 type adhesive have the most optimum physical and mechanical strength.     

Preparation of phenol formaldehyde resin from phenolated wood

The technique for preparing phenol formaldehyde resin from phenolated wood (PWF) and its characters were studied and analyzed. Poplar (Populus spp) wood meal was liquefied by phenol in the presence of sulfuric acid as a catalyst. After the liquefied products were cooled, alkaline catalyst and formaldehyde were added. The mixture was kept at (60±2)°C for 1h and then was heated to (85±2)°C for 1h. The influence of molar ratio of formaldehyde to phenol (F/P) was investigated. The results showed when the molar ratio of formaldehyde to phenol was over 1.8, the PWF adhesives had high bond quality, bond durability and extremely low aldehydes emissions. Foundation item: The research was supported by Sino-Japanese Technical Cooperation Project (2-1-b) and the key technologies R & D Program for the 10th Five-Year Plan (325-11). Biography: LI Gai-yun (1974-), female, Assistant professor in Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, P. R. China Responsible editor: Zhu Hong