苯酚-三聚氰胺-尿素-甲醛胶粘剂的合成及其应用

通过共缩聚的方法,制备了具有良好的耐水性能和胶合性能的苯酚-三聚氰胺-尿素-甲醛树脂。着重讨论了该树 脂的制备方法以及在压制室外型中密度纤维板中的应用情况。     

苯酚-尿素-甲醛共缩聚树脂研制Ⅰ.合成与分析

以苯酚、尿素和甲醛为起点合成了一种苯酚—尿素—甲醛共缩聚 ,并对树脂性能和结构进行了全面分析评估。结果表明所合成的共缩聚树脂贮存稳定 ,固化速度快 ;差热分析和热重分析表明苯酚—尿素—甲醛共缩聚树脂的热行为与酚醛树脂十分相似而与脲醛树脂显著不同 ;13 CNMR结构分析中分别观测到源于共缩聚结构单元o -Ph -CH2 -NHCO -(δ =4 1 .5)和 p -Ph -CH2 -NHCO -(δ =4 4.8)的吸收 ;使用PUF共缩聚树脂压制的竹木复合中密度纤维板和竹大片刨花板 ,其板材的物理力学性能明显高于脲醛树脂而与常规酚醛树脂相近。     

PMUF树脂胶黏剂的制备与性能

以尿素和三聚氰胺作为酚醛树脂改性单体制备苯酚-三聚氰胺-尿素-甲醛(PMUF)树脂胶黏剂,研究甲醛、苯酚、尿素、三聚氰胺及氢氧化钠用量对PMUF树脂胶黏剂性能的影响,并采用DSC和13C-NMR对其进行表征.结果表明:PMUF树脂游离甲醛含量低,能满足耐水、耐候性能要求较高的人造板产品的生产.当甲醛、苯酚、尿素、三聚氰胺、NaOH的摩尔比为3.1∶1∶0.7∶0.3∶0.5时胶黏剂性能最佳,其最佳固化温度为135.5℃.     

蔗糖-三聚氰胺-甲醛共缩聚树脂胶黏剂的合成研究

以蔗糖、三聚氰胺、甲醛为原料,在碱性条件下合成了外观为黄色、透明、均一、无沉淀且水溶性好的蔗糖-三聚氰胺-甲醛(SMF)共缩聚树脂木材胶黏剂。采用均匀试验设计对合成反应体系的蔗糖、交联剂用量和甲醛与三聚氰胺的摩尔比进行了优化,通过正交试验设计对桉树胶合板热压工艺参数进行了优化。结果表明:最佳合成条件为:蔗糖与三聚氰胺的摩尔比为0.7,甲醛与三聚氰胺的摩尔比为2.7,交联剂用量为树脂的0.33%;桉树胶合板最佳胶合工艺参数为:双面施胶量为340g/m~2、热压压力为0.9MPa、热压温度为150℃、热压时间为60s/mm。     

苯酚-尿素-甲醛共缩聚树脂结构形成比较

用13C NMR 定量分析跟踪研究了两种不同合成路线中苯酚-尿素-甲醛共缩聚树脂(PUF)结构形成过程,比较了3种PUF树脂的结构构成.研究发现树脂制备过程中的酸性环境导致脲醛树脂初聚物含量增加以及尿素与苯酚之间的共缩聚增加;合成反应初期的介质环境对羟甲基酚的形成有着决定性的影响;合成过程中酸性环境所处阶段不同,最终树脂结构出现差异.     

麦芽糖-三聚氰胺-甲醛共缩聚树脂合成及表征

以麦芽糖、三聚氰胺和甲醛为主要原料在碱性条件下合成麦芽糖-三聚氰胺-甲醛共缩聚树脂(MMF树脂),对MMF树脂合成工艺进行探讨并研究了麦芽糖与三聚氰胺的摩尔比(M_(mal)/M_(mel))对MMF树脂的储存稳定性、胶合强度、分子结构以及分子量的影响。结果表明:MMF树脂优化合成工艺的缩聚温度为88~90℃、pH值为9.0~9.5、麦芽糖与三聚氰胺的摩尔比(M_(mal)/M_(mel))为0.1~0.3;MMF树脂的储存期比MF树脂的储存期延长20d左右;当麦芽糖与三聚氰胺的摩尔比低于0.3时,胶合板强度达到国家标准Ⅰ类胶合板要求;FT-IR表明MMF树脂分子结构连接方式主要以醚键和亚甲基键为主;GPC表明MMF树脂数均分子量为1600~1750。     

麦芽糖-三聚氰胺-甲醛共缩聚树脂合成及表征北大核心

以麦芽糖、三聚氰胺和甲醛为主要原料在碱性条件下合成麦芽糖-三聚氰胺-甲醛共缩聚树脂（MMF树脂）,对MMF树脂合成工艺进行探讨并研究了麦芽糖与三聚氰胺的摩尔比（M_（mal）/M_（mel））对MMF树脂的储存稳定性、胶合强度、分子结构以及分子量的影响。结果表明：MMF树脂优化合成工艺的缩聚温度为88~90℃、pH值为9.0~9.5、麦芽糖与三聚氰胺的摩尔比（M_（mal）/M_（mel））为0.1~0.3;MMF树脂的储存期比MF树脂的储存期延长20d左右;当麦芽糖与三聚氰胺的摩尔比低于0.3时,胶合板强度达到国家标准Ⅰ类胶合板要求;FT-IR表明MMF树脂分子结构连接方式主要以醚键和亚甲基键为主;GPC表明MMF树脂数均分子量为1600~1750。     

尿素—三聚氰胺甲醛共缩合浸渍树脂生产与使用

<正> 我们研制成功一种新型树脂;尿素--三聚氰胺甲醛共缩合浸渍付脂,并已投入使用,采用这种树脂代替原使用的乙醇改性三聚氰胺树脂浸渍装饰纸生产塑料贴面板,既保证了优良的耐磨、耐水和耐热性,又降低了成本,克服了改性不好时韧性差的缺点。产品质量完全符合 Ly218-219-80的要求,某些性能超出使用原胶的产品。     

碱性环境下苯酚-尿素-甲醛共缩聚树脂结构形成研究

为了了解碱性环境中苯酚-尿素-甲醛(PUF)共缩聚树脂结构形成规律,为PUF树脂结构控制提供依据,使用13CNMR表征,采用分次加入苯酚、甲醛和尿素的技术路线.定量分析了PUF树脂合成过程中各种官能团的变化和聚合物分子链的构成.结果表明,碱性环境中各种加料方式合成的PUF树脂初聚物具有十分相近的化学结构,PUF树脂也具有十分相近的化学结构,但结构组分存在差异,在原料物质的量之比一定的条件下,最终反应进程基本接近.甲醛分次加入,减少了醚类的生成,有利于简化反应进程.初聚物的热机械性能分析表明不同加料方式对酚醛树脂固化性能无显著影响.     

PF和PUF树脂分子结构对比研究

为了判断苯酚-尿素-甲醛(PUF)树脂中原料共缩聚反应是否发生,并确认共缩聚分子形成特点,借助13C核磁共振(13C NMR)和基质辅助激光解析电离飞行时间质谱(MALDI-TOF-MS)两种主要分析仪器,对比研究了苯酚-甲醛(PF)树脂和PUF树脂的结构特点,结果证实了PUF树脂中苯酚、尿素和甲醛3种原料之间共缩聚反应的存在,认为PUF树脂结构以PF树脂为主体,且共缩聚结构主要形成于合成反应初期。     

高脂马尾松优良家系的多性状综合选择

以１３年生高产脂马尾松４９个优良家系的子代测定林资料,采用稳健主分量方法,对以产脂力为主的１１个性状因子进行综合分析,结果表明;参试家系可分为４种类型,即第Ｉ类：高产脂稳定型,共１０个家系,产脂力增益２０．５９：第Ⅱ类：中产脂变动型,共１４个家系,产脂力增益３．４５％;第Ⅲ类：中产脂高材积稳定型,共１０个家系,其材积增益可达１２．７１％,产脂力增益５．４１％,第Ⅳ类其它家类型。     

稻草中密度纤维板用改性脲醛树脂的研究

对比三聚氰胺、二甲基硅油、硅树脂和偶联剂KH-550四种改性剂改性的脲醛(UF)树脂性能的差别及其对稻草中密度纤维板性能的影响,并进行经济评价,最终确定适用于稻草纤维板的改性UF树脂的工艺条件,同时借助于红外光谱(FT-IR)和差热扫描分析(DSC)研究最佳改性UF树脂的结构和固化特性.结果表明,三聚氰胺改性脲醛(MUF)树脂不论是对树脂性能、板性能改善还是从成本分析方面均为稻草纤维板最佳的胶黏剂,FT-IR显示出与未加三聚氰胺相比,加入三聚氰胺后树脂的羟甲基含量降低了10 %,DSC分析则表明其峰值温度有较大幅度的提高,但放出的热量较少.加入三聚氰胺改性的UF树脂其表面张力变小.     

三聚氰胺甲醛浸渍树脂的改性研究

为提高三聚氰胺甲醛（MF）浸渍树脂的储存稳定性和柔韧性,联合二甘醇和己内酰胺,对MF树脂进行改性。分析甲醛与三聚氰胺的量比,水、二甘醇和己内酰胺的加量等因素,对改性树脂性能的影响。结果表明,二甘醇和己内酰胺联合改性的方法,可同时提高MF树脂的储存稳定性和柔韧性;并提出最优化工艺参数。     

枫香采脂试验研究

采用V字形下降法对枫香树进行采脂试验研究,主要考察了采脂季节、枫香树胸径、树龄、采割高度、割沟频率等因素对产脂量的影响。结果表明,7、8、9三个月为产脂量较高月份;30cm以上胸径的树产脂量更高;树皮黑色、有裂纹、30年以上的枫香树产指率更高;第一对割沟高度在1．5m的树产脂量更高;15天割一次沟的产脂量更高等。采用V字形下降法进行枫香树采脂是可行的。     

三聚氰胺脲醛树脂改性酚醛树脂胶粘剂的研究

采用常规合成的脲醛(UF)或酚醛(PF)树脂胶对多层胶合板贴面时，很容易出现开胶或透胶现象。本研究采用三聚氰胺脲醛(MUF)树脂对PF树脂进行改性，生产浅色改性PF胶粘剂，探讨了MUF与PF树脂摩尔比、混合比、热压条件等对胶液的粘度、缩合度、稳定性、胶层颜色及胶合质量的影响。结果表明，改性后的浅色酚醛树脂胶粘剂筘存性好、固化后胶层近似木材本色、高强耐水、耐候，用来压制的多层实木复合地板可达到GB9846．1～12-88Ⅰ类胶合板要求。     

Curing kinetics of phenol formaldehyde resin and wood-resin interactions in the presence of wood substrates

The curing kinetics of resol PF resin and resin–wood interactions in the presence of wood substrates have been studied by differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy. The activation energy of cure of PF resin generally increases when PF resin is mixed with wood, mainly due to the decrease of the pH values resulting from the presence of wood. However, wood decreases the curing enthalpy of PF resin through diffusion and the change in the phase of the curing system, which suggests that the curing reactions reached a lower final degree of conversion for the mixtures of PF resin with wood than for the PF resin alone. Moreover, DSC curves and the variation of activation energy with conversion indicate that wood accelerates the addition reactions and retards condensation ones during the curing process of PF resin with wood. The study also revealed that almost no chemical reactions occur between PF resin and wood, but the secondary force interactions of hydroxyl groups between PF resin and wood have been detected. These most significant secondary forces can catalyze the self-condensation reactions of PF resin, although their effect is not vital on the curing kinetics of PF resin.     

多胺基聚合物改性室温固化型MUF树脂胶黏剂

为解决三聚氰胺-尿素-甲醛(MUF)树脂作为室外级结构集成材胶黏剂时存在的脆性大、易开裂的问题,得到韧性优秀且综合性能满足室外级结构集成材标准的室温固化型MUF树脂胶黏剂,本研究在MUF树脂合成中使用两种改性剂尿素-乙二胺(UE)、尿素-三(2-氨基乙基)胺(UD)分别替代部分三聚氰胺合成了 MUF-UE、MUF-UD...     

Durability of isocyanate resin adhesives for wood I: Thermal properties of isocyanate resin cured with water

The thermal properties of isocyanate (IC) resin cured with water were studied using dynamic mechanical analysis (DMA) and Fourier transform infrared spectroscopy. The thermal properties of cured phenol formaldehyde (PF) resin were also studied for comparison purposes. The DMA specimens were prepared using a unique technique. The relation between the mechanical and chemical changes of the resin during DMA was clarified. The cured PF resin had better thermal stability than the IC resin cured with water. The improvement of thermal stability in cured IC resin by heat treatment was considered to be less effective. The effect of the heating rate on the mechanical properties was also investigated. The apparent activation energy in the thermal degradation of cured IC resin was calculated based on the results obtained.Part of this paper was presented at the 47th Annual Meeting of the Japan Wood Research Society, Kochi, April 1997     

Resin flow responses to fertilization, wounding and fungal inoculation in loblolly pine (Pinus taeda) in North Carolina

Resin flow is the primary means of natural defense against southern pine beetle (Dendroctonus frontalis Zimm.), the most important insect pest of Pinus spp. in the southern United States. As a result, factors affecting resin flow are of interest to researchers and forest managers. We examined the influence of fertilization, artificial wounding and fungal inoculation on resin flow in 6- and 12-year-old stands of loblolly pine (Pinus taeda L.) and determined the extent of that influence within and above the wounded stem area and through time. Fertilization increased constitutive resin flow, but only the younger trees sustained increased resin flow after wounding and inoculation treatments. An induced resin flow response occurred between 1 and 30 days after wounding and inoculation treatments. Wounding with inoculation resulted in greater resin flow than wounding alone, but increasing amounts of inoculum did not increase resin flow. Increased resin flow (relative to controls) lasted for at least 90 days after wounding and inoculation. This increase appeared to be limited to the area of treatment, at least in younger trees. The long-lasting effects of fungal inoculation on resin flow, as well as the response to fertilization, suggest that acquired resistance through induced resin flow aids in decreasing susceptibility of loblolly pine to southern pine beetle.     

Migration of pine wood nematodes in the tissues of <Emphasis Type="Italic">Pinus thunbergii</Emphasis>

The distribution of pine wood nematodes (Bursaphelenchus xylophilus, PWNs) in Japanese black pine (Pinus thunbergii) tissues was investigated by staining with fluorescein isothiocyanate-conjugated wheat germ agglutinin. After PWNs were inoculated to current-year stems of pine seedlings, their distribution at about 5 cm below the inoculation site was confined only to cortical resin canals 1 day after inoculation, and then spread to other tissues, including resin canals of short branches. When PWNs were inoculated onto cross or tangentially cut surfaces of stem segments, maximal PWN migration speed was estimated to be faster through cortical resin canals and xylem axial resin canals vertically (>6.7 and <2.3 mm/h, respectively) than through cortical tissues both vertically and horizontally (<1.2 and <0.2 mm/h). To examine whether PWNs in cortical resin canals could invade surrounding tissues, segments in which PWNs resided only in cortical resin canals were prepared by removing the top portion 6 h after inoculation. Additional incubation of such segments caused extended PWN distribution to xylem axial resin canals and then to other tissues. A similar experiment with top portions of girdled segments removed 12 h after inoculation also showed extended PWN distribution from xylem axial resin canals and pith to cortical resin canals and then to other tissues. These results provided direct evidence that PWNs have the ability to migrate from cortical resin canals and xylem axial resin canals to other tissues.