间苯二酚—苯酚—甲醛树脂的研制与在胶合木梁上的应用

本文介绍了室温固化的间苯二酚-苯酚-甲醛树脂胶粘剂的制备及性能,以及用它粘合成的大断面胶合木梁的情况。通过加速老化试验表明间苯二酚-苯酚-甲醛树脂胶粘剂的耐候性比酸固化酚醛树脂胶好。间苯二醛-苯酚-甲醛树脂胶粘剂的研制成功,为胶合木结构和承重指接材提供了一种性能优异的木工用胶粘剂。     

低成本酚醛树脂压制家具用胶合板的研究

酚醛树脂是一类性能优良的结构胶黏剂,但价格昂贵。在保证胶合强度的条件下,试验引入价廉的尿素替代部分苯酚,以降低酚醛树脂生产成本。试验表明,对酚醛树脂性能影响的主次依次为:尿素含量聚乙烯醇用量NaOH用量。通过正交试验确定出尿素改性酚胶试验的最佳工艺条件:甲醛(37%)的加入量为272s,苯酚的质量为120s,尿素含量为30%,摩尔比1:0.65(P/NaOH),聚乙烯醇的加人量为6g,所制得的改性酚醛树脂的胶合强度优异,且成本降低。     

思茅松的苯酚液化及树脂化研究

研究了硫酸催化条件下,将恩茅松在苯酚中液化用于制备酚醛树脂的技术工艺,分析了各工艺参数对思茅松液化效率的影响,测定了由液化产物制备的液化木基酚醛树脂的物理化学性质和胶合强度。结论如下：1）．液比、反应温度、时间和木粉目数是影响液化反应效率的重要因素,液化产物的残渣率均随上述工艺参数值的升高而降低。2）．残渣含量对树脂物化性质和胶合强度均有影响,残渣含量降低,树脂粘度减小,聚合时间缩短,游离酚含量降低,胶合强度升高。3）．甲醛／苯酚摩尔比对树脂的物化性质和胶合强度也有影响,甲醛／苯酚摩尔比增加,树脂粘度增加,聚合时间减少,游离酚含量减低,胶合强度升高。     

液化木质素磺酸钙基环保酚醛胶黏剂的合成

探讨了加料方式对传统酚醛树脂(PF)胶黏剂游离酚、醛的影响因素.在此基础上,采用热化学酚化技术活化木质素磺酸钙得到木质素磺酸钙酚化产物,将酚化产物代替苯酚制备低成本的木质素基酚醛胶黏剂(LPF).实验结果表明,当甲醛分3次加入、碱液分2次加入时,制备的PF胶黏剂具有较低的游离酚、醛,且以苯酚为液化试剂,液化温度140℃、液化时间15min、苯酚与木质素磺酸钙的质量比(酚木比)为2∶1,酚化工业木质素磺酸钙,将得到的酚化液代替苯酚在酚醛物质的量之比为1∶1.7时,制得的LPF具有更低的游离酚、醛含量、较长的储存期和优异的胶合性能.     

焦油酚—苯酚甲醛（PCF）共缩聚树脂的合成

本文采用正交试验法,主要探讨了焦油酚－苯酚－甲醛共缩聚树脂的原料配比及合成工艺,并借助凝胶色谱（ＧＰＣ）仪测定了焦油酚的平均分子量。研究结果表明：用焦油酚替代３０％的苯酚合成胶合性能优异的酚胶是可行的。通过合理地调整原料配比及合成工艺参数,其胶合性能满足ＧＢ９８４６－８８Ⅰ类合板和ＪＡＳ特类合板的要求,其平均胶合强度分别为１．２６ＭＰａ和１．２２ＭＰａ,平均木材破坏率分别为５０％和６５％。     

油茶饼粕苯酚液化物的树脂化研究

以油茶饼粕苯酚液化物为原料制备酚醛树脂,测定树脂的理化性能,评价树脂的胶合性能.考察了甲醛与苯酚的摩尔比(F/P)、氢氧化钠与苯酚的摩尔比(NaOH/P)和树脂化时间对树脂理化性能和胶合性能的影响.结果显示,在F/P 1.8、NaOH/P 0.6、树脂化时间70 min的条件下合成的酚醛树脂压制的胶合板能满足Ⅰ类胶合板强度要求.FTIR分析显示液化物树脂具有常规酚醛树脂典型的官能团特征,树脂中含有较多的羟甲基等活性官能团.     

人工林木材的苯酚液化及树脂化研究Ⅱ.液化木基酚醛树脂的制备和性能表征

研究液化产物树脂化合成工艺,表征液化木基酚醛树脂的物化性质,评价树脂的胶合强度和木破率.结果表明,采用一次缩聚的投料方式能简化操作工艺,缩短合成时间.木材液化产物中残渣的过滤与否,对树脂性能有一定程度的影响:残渣含量高时,影响较大;残渣含量低时,影响较小.当甲醛与苯酚的量比为1.5和1.8时,利用含11.0%残渣的杉木液化产物和含16.5%残渣的杨木液化产物,制备了性能优良的酚醛树脂.     

木材液化产物制备热塑性树脂的研究

在酸性催化剂作用下,用木材的苯酚液化产物和甲醛进一步树脂化制备了液化木基热塑性酚醛树脂(PWF).用正交试验方法研究了各影响因素对树脂产率和软化点的影响,结果表明,pH值和反应温度对PWF树脂产率的影响最大,而甲醛与苯酚的投料比对PWF树脂软化点的影响最大.当木材液化产物中残留的苯酚与甲醛的物质的量之比为1∶0.75,pH值为木材液化产物的实际值,在105℃反应150min时,液化木基热塑性酚醛树脂的产率达到124%,软化点为110℃左右.用凝胶渗透色谱(GPC)、傅立叶红外光谱(FT-IR)和核磁共振(NMR)对比研究了PWF和传统热塑性酚醛树脂(PF)的结构特征.结果显示PWF和PF的结构基本相似,酚单元之间的连接形式主要是邻-对位和对-对位连接.PWF中含有木材组分的液化碎片,且相对分子质量较低,分布较窄.     

落叶松树皮热解油替代部分苯酚合成酚醛树脂胶的研究北大核心

为降低酚醛树脂胶(PF)生产成本,提高木材废弃物利用率,利用落叶松树皮热解油部分替代苯酚合成PF胶,探讨其用量对PF树脂胶性能的影响,并进行成本分析。结果表明:落叶松树皮热解油-PF胶具有良好的胶合性能,制备的胶合板可满足GB/T 9846.3-2004中I类胶合板的强度要求,且生产成本降低。     

落叶松树皮热解油替代部分苯酚合成酚醛树脂胶的研究

为降低酚醛树脂胶(PF)生产成本,提高木材废弃物利用率,利用落叶松树皮热解油部分替代苯酚合成PF胶,探讨其用量对PF树脂胶性能的影响,并进行成本分析.结果表明:落叶松树皮热解油-PF胶具有良好的胶合性能,制备的胶合板可满足GB/T 9846.3-2004中Ⅰ类胶合板的强度要求,且生产成本降低.     

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     

Factors affecting the resinification of liquefied phenolated wood

Wood of Chinese fir and poplar were liquefied in phenol at 150℃ and atmospheric pressure. The liquefied wood were reacted with formaldehyde to synthesize the liquefied wood-based resin. The factors affecting the resinification and the properties of new resin were investigated. The results show that the formaldehyde/liquefied wood molar ratio, reaction temperature, reaction time and sodium hydroxide/liquefied wood molar ratio have important influence on the resin characteristics. With the increase of formaldehyde/liquefied wood molar ratio, the yield of resin increases, and the flee phenol content of resins decreases, showing that the resinification of liquefied wood is more complete at higher formaldehyde/liquefied wood molar ratios. The reaction temperature on the viscosity of the liquefied resin has considerable effect; the viscosity of resin increased with increasing reaction temperature, and the amount of liquefied poplar resin increased more quickly than that of liquefied Chinese fir resin. The resinification time also has obvious influence on the viscosity of resin; the viscosity of liquefied poplar resin is more sensitive to resinification time compared with that of liquefied Chinese fir. The amount of sodium hydroxide can improve the water miscibility of liquefied wood resin. The optimum sodium hydroxide/liquefied wood molar ratio for preparation of liquefied wood-based resins exceeds 0.4.     

C NMR 定量分析

按酚醛(PF)树脂的制备工艺,采用CaO和NaOH为复合催化剂,在碱性条件下制备了95%～200%的系列尿素改性酚醛(PUF)树脂,贮存期达30 d以上。该系列PUF树脂压制的杨木三合板,胶合强度符合Ⅱ类胶合板要求,甲醛释放量<0.5 mg/L,符合E0级。其中选用尿素/苯酚(U/P)质量比为1.5∶1,甲醛与尿素-苯酚(F/(U+P))物质的量的比值为0.97的配方制胶,结合13C NMR分析手段,监控投料甲醛在反应过程中形成的亚甲基、羟甲基和亚甲基醚键的含量变化,以及最终PUF树脂的亚甲基(32.4%)、羟甲基(57%)和亚甲基醚键(10%)的结构比例。     

Preparation of liquefied wood-based resins and their application in molding material

To investigate value in use of liquefied wood-based resin applications in molding material, Chinese fir （Cunninghamia lanceolata） and poplar （Populus tomentosa） wood meal were liquefied in phenol. The reactant was co-condensed with formaldehyde to obtain liquefied wood-based resin. For this paper, we investigated the characterization of the resin and its application in molding material. The result shows that the basic properties of liquefied wood-based resin were satisfactory; the bonding strength of plywood prepared with liquefied Chinese fir and liquefied poplar resin can reach 1.54 and 1.00 MPa, respectively. The compression strengths of the molding material prepared with two kinds of liquefied wood resin were 73.01 and 73.58 MPa, almost the same as that of PF resin molding material. The limiting volume swelling of molding material made with liquefied Chinese resin and liquefied poplar resin were 8.5% and 8.3%, thickness swelling rates of water absorption were 3.3% and 4.2%, and the maximum weight ratios of water absorption were 25.9% and 26.2%, respectively. The soil burial test result shows that the weight loss rate of the molding materials made with liquefied Chinese resin and liquefied poplar resin were 8.3% and 9.1% and that of the PF resin molding material was 7.9%. After the soil internment test, the reduction ratio of compression strength of the two kinds of molding material achieved 16.9% and 17.7%, while that of the PF resin molding material was 15.4%. The test results of wood fungi inoculation on the three surfaces of the molding material indicate the breeding rate of molding material prepared with liquefied Chinese resin and liquefied poplar resin were at level 4 and that of PF resin molding material was at level 1 of the ISO standard.     

杉木粉液化与液化产物树脂化的研究

以硫酸为催化剂、苯酚为液化剂采用溶剂热法对杉木粉进行液化,用杉木粉液化产物制备出酚醛树脂;考察了反应温度、反应时间、液比(苯酚-木粉的质量比)和催化剂用量对杉木粉液化效率的影响,并初步探讨了液化产物残渣率对所制酚醛树脂性能的影响。实验结果表明,杉木粉液化的最佳工艺条件是:反应温度160℃,液化时间12 h,液比值3,催化剂用量3%,在此条件下残渣率约为10%。液化产物残渣率的测定表明,升高反应温度、延长反应时间、增加液比和催化剂用量可以降低残渣率,提高液化效率;液比值为0.5~1.5时残渣率随液比增加而显著降低,催化剂用量为0.5%~2%时液化效率的变化明显。红外光谱结果表明,由液化产物所合成的酚醛树脂中羟甲基含量较高。液化产物残渣率低时制备的酚醛树脂残碳率较高。     

Characterisation of the curing of liquefied wood by rheometry, DEA and DSC

Liquefied wood is a naturally based product which has the potential to be used as an adhesive. The bonding of wood with liquefied wood requires a high enough temperature to cure the liquid polymers and achieve bond strength. Dielectric analysis, rheometry and differential scanning calorimetry were used to analyse the curing process of low solvent liquefied wood. For the liquefaction, ethylene glycol was used as a solvent and sulphuric acid was used as a catalyst. The dielectric analysis was used for in situ measurements of the curing of liquefied wood during the bonding of wood. It was found that curing started after a temperature of 100 °C had been reached in the bond. This is correlated with the water evaporation and the diffusion of water and ethylene glycol from the liquefied wood into the wood substrate. Rheological measurements proved the influence of the substrate on the curing of the liquefied wood during bonding. Differential scanning calorimetry showed that the curing of liquefied wood occurs in two parts: first, the initial elimination of water and ethylene glycol from the liquefied wood, and then the chemical reaction of the liquefied wood at higher temperatures.     

Dynamic wettability and curing characteristics of liquefied bark-modified phenol formaldehyde resin (BPF) on rice straw surfaces

Larch bark was liquefied in the presence of phenol and the obtained liquefied resultant was reacted with formaldehyde to prepare the liquefied bark-modified phenol formaldehyde resin (BPF) in an attempt to apply for preparing straw boards. The dynamic wettability of the BPF resin was evaluated on the surfaces of rice straw; either on the alkali solution treated or untreated rice straw surfaces. A new wetting model was employed to quantify the resins’ penetration performances using the spreading–penetration parameters (K value) as a constant to characterize penetration rate. The bigger the K value was, the stronger the penetration and spreading capacity was. Moreover, the curing kinetics of the BPF resin was also investigated with dynamic differential scanning calorimetry. The results showed that the K value of BPF resin was the highest, followed by those of BPF mixed with polymethylene diphenyl diisocyanate PMDI resin and conventional phenol formaldehyde (PF) resin, indicating that the BPF resin had the best wettability. The activation energy of BPF was close to that reported for wood/phenol/formaldehyde resins, but was higher than that of PF resin. The curing reaction was almost complete at 40 % conversion.