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。     

黑荆树天然林、人工林主要树皮质量性状的差异

一、前言 黑荆树自然分布于澳大利亚东南部和塔斯马尼亚岛。它是一种速生、伐期短、单宁含量高的多用途树种。黑荆树单宁的主要组分为多类黄酮(C-C-C化合物),它与甲醛的缩合反应物是黑荆树单宁胶粘利的基础。目前,单宁胶粘剂广泛用于刨花板、胶合板和其他木制品工业。 50年代,我国南方开始引种黑荆树。种子产地不清,多数进口种子来源于非原产地国家     

微生物降解葡萄皮单宁研究

为降低葡萄皮单宁的分子量和聚合度,选取青霉(Penicillium sp.)和米曲霉(Aspergillus oryzae)为微生物菌株对葡萄皮单宁进行生物降解。以儿茶素的生成量和转化率为指标,分析碳源、氮源、时间、温度、pH和诱导培养基中单宁质量浓度对降解效果的影响。结果表明:外加碳源和氮源有利于青霉和米曲霉菌株的生长;时间为葡萄皮单宁降解得到不同中间产物的关键参数;温度、pH和葡萄皮单宁的质量浓度对菌株活性和降解能力均有不同程度影响;青霉对葡萄皮单宁的降解效果好于米曲霉。青霉最佳降解条件:培养时间24 h,温度28℃,pH6.5,单宁质量浓度12.5 g/L,儿茶素最大生成质量浓度0.32 mg/mL,转化率52.3%;米曲霉最佳降解条件:培养时间36 h,温度28℃,pH 6.5,单宁质量浓度10.0 g/L,儿茶素最大生成质量浓度0.16 mg/mL,转化率32.2%。因此,可通过生物降解法调控葡萄皮单宁的化学组成,适当降低单宁的分子量和聚合度。     

花生壳苯酚液化物-甲醛树脂胶用于集装箱底板试验

花生壳苯酚液化物-甲醛树脂胶粘剂是花生壳粉苯酚液化后的高反应活性产物与甲醛缩聚而成的高耐水性木材胶粘剂.探讨了花生壳苯酚液化物-甲醛树脂胶粘剂用于集装箱底板生产的最佳胶合工艺,检测了集装箱底板的各项物理力学性能和耐老化性能,并与传统酚醛胶及落叶松单宁胶进行了成本对比分析.结果表明,花生壳苯酚液化物-甲醛树脂胶粘剂的最佳胶合工艺为双面施胶量350 g/m2,热压时间1.2 min/mm,热压温度140℃;在此热压工艺条件下压制的集装箱底板的各项物理力学性能可以满足国家标准的要求,具有胶合强度高、耐老化性能优异、成本低廉等优点.     

CaO/MgO复合固体碱催化剂催化降解木质素的研究

在氧化镁载体上浸渍醋酸钙后烧结制备了CaO/MgO复合固体碱催化剂,所制固体碱催化剂的表面碱度与催化剂制备条件有关:当CaO/MgO比值为0.08、在700℃下煅烧时间24 h时制得的催化剂表面碱度可达到30.2 mmol/g。以该固体碱催化剂催化木质素中醚键断裂反应,测试结果表明木质素降解产物重均相对分子质量(Mw)可从3 000降低至800以下,羟值由200 mg/g增加至480 mg/g左右。FT-IR表征结果表明降解产物中醚键含量明显减少,羟基含量增多。     

固化单宁大孔吸附树脂的制备及吸附性能研究

利用Mannich反应将黑荆树单宁固定在氯甲基化聚苯乙烯树脂表面,成功地制备出一种新型固化单宁大孔吸附树脂(MARIT),并通过正交试验得出适宜的合成条件.苯酚在MARIT上的平衡吸附数据符合Freundlich吸附等温方程.利用热力学函数关系计算了等量吸附焓、吸附自由能和吸附熵,等量吸附焓在8.95～13.41 kJ/mol之间,推测吸附过程为氢键吸附.比较MARIT对苯酚的水溶液和环己烷溶液中苯酚的吸附性能,及对溶液中苯酚、间苯二酚和邻硝基苯酚的吸附性能,进一步讨论了MARIT对苯酚吸附时的氢键作用.     

Degradation Behaviors of Lignin Catalyzed by CaO/MgO Composite as Solid Base Catalyst

在氧化镁载体上浸渍醋酸钙后烧结制备了CaO/MgO复合固体碱催化剂,所制固体碱催化剂的表面碱度与催化剂制备条件有关:当CaO/MgO比值为0.08、在700℃下煅烧时间24 h时制得的催化剂表面碱度可达到30.2 mmol/g.以该固体碱催化剂催化木质素中醚键断裂反应,测试结果表明木质素降解产物重均相对分子质量(Mw)可从3000降低至800以下,羟值由200 mg/g增加至480 mg/g左右.FT-IR表征结果表明降解产物中醚键含量明显减少,羟基含量增多.     

改性松香-缩合单宁酯的制备及性质

在微波辐照下,以吡啶作催化剂,通过缩合单宁与改性松香酰氯的O-酰化反应,以改性松香和不同级分或树种的缩合单宁为原料,合成了一系列改性松香-缩合单宁酯.利用UV、IR、TG-DTA和元素分析等方法对目标产物进行了分析和表征,并测试了它们的抗氧化性及其钠盐的表面活性.结果表明,改性松香-缩合单宁酯的油溶性普遍好于缩合单宁,在花生油中表现出良好的抗氧化性,且去氢枞酸-毛杨梅树皮缩合单宁酯的抗氧化性能最佳.改性松香-缩合单宁酯的钠盐比缩合单宁的钠盐具有更优良的表面活性,其降低表面张力能力强弱顺序为:HR-WT钠盐＞HR-ET钠盐＞DR-ET钠盐＞DR-WT钠盐＞DHA-WT钠盐≈DHA-MET钠盐＞DHA-ET钠盐＞ET钠盐;不同松香改性产物钠盐的表面张力和临界胶束浓度有一定差异,但差别不大,其中氢化松香改性产物钠盐的表面活性最好,歧化松香改性产物钠盐的表面活性次之,去氢枞酸改性产物钠盐的表面活性最差.改性松香-缩合单宁酯钠盐对苯的乳化力都超过了60min,具有很好的乳化能力.改性松香-缩合单宁酯钠盐起泡比顺序为:氢化松香-黑荆树树皮缩合单宁酯钠盐＞歧化松香-黑荆树树皮缩合单宁酯钠盐＞去氢枞酸-黑荆树树皮缩合单宁酯钠盐＞去氢枞酸-毛杨梅树皮缩合单宁酯钠盐＞毛杨梅树皮缩合单宁钠盐.     

TiO2/核桃壳炭复合材料的制备及光催化降解苯酚研究

为提高TiO2的回收性能,促进农林废弃物的资源化利用,以核桃壳为炭源,采用溶胶 凝胶法制备TiO2/核桃壳炭复合材料。通过傅里叶红外光谱、X射线衍射、比表面积和电镜扫描等手段对复合材料的化学和晶相结构、比表面积和微观形貌进行表征,并测试其对苯酚的吸附 光催化性能。物相表征结果显示,TiO2/核桃壳炭(400℃,2 h)中TiO2以锐钛矿相颗粒分散在核桃壳炭表面,炭的固载提高了TiO2的分散性能,使其晶粒尺寸由15.7 nm降低至11.6 nm,增强了可见光吸收能力。活性分析结果表明:当TiO2含量为80%,催化剂用量为2 g/L,苯酚初始质量浓度为10 mg/L,紫外光照射240 min时,TiO2/核桃壳炭(400℃,2 h)对苯酚的降解率为97.7%,化学需氧量降解率为92.36%,优于TiO2(分别为71.55%和63.34%)和商业购买的平均粒径为25 nm的锐钛矿晶和金红石晶混合相的TiO2(降解率88.56%),且几乎完全矿化,符合一级反应动力学方程。TiO2和TiO2/核桃壳炭光催化降解苯酚的主要活性中心分别为·OH和·O-2,核桃壳炭的负载提高了TiO2吸附 光催化苯酚性能和回收效率。     

桐油改性酚醛树脂的研究（I）：合成,机理与结构表征

通过桐油和苯酚在催化剂存在下的反应，然后再在碱性催化剂存在下与甲醛反应制得一种桐油改性甲阶酚醛树脂，探讨了反应的机理。利用化学分析、无素分析和凝胶渗透色谱分析对第一步反应进行了研究，发现１摩尔桐油大体上可与６摩尔苯酚发生反应，反应过程中同时存在桐油自聚和降解现象，随着初始苯酚／桐油摩尔比的降低，该现象更为明显。利用紫外光谱、红外光谱和＾１ＨＮＭＲ等分析手段对桐油－苯酚反应产物和桐油改性酚醛树脂的结     

Corn flour-mimosa tannin-based adhesives without formaldehyde for interior particleboard production

A formaldehyde-free adhesive consisting of a corn flour/NaOH adhesive mixture and a mimosa tannin/hexamine intermediate component was developed and evaluated for application to wood panels such as particleboards. The main ingredients of this adhesive include corn flour, NaOH, mimosa tannin and hexamine. This study investigated the physical properties (rheological and thermal analysis) of corn flour/NaOH and mimosa tannin/hexamine adhesives as well as mechanical properties of particleboards produced with these adhesives. Thermomechanical (TMA) experiments indicate the best performance of the adhesives to be around the relative mass proportions of 50:50 between corn flour/NaOH and mimosa tannin/hexamine. Former NMR measurements on corn starch and mimosa tannin proved that the two components behave as a polymer blend rather than co-reacting. The laboratory results show that particleboards bonded with the adhesive at this optimal ratio show good mechanical properties. Moreover, the formaldehyde emission levels obtained from boards bonded with the optimal adhesive were considerably lower to those obtained from boards made with control urea formaldehyde.     

黑荆树皮单宁降解产物的抑菌性能

通过对黑荆树皮单宁化学降解改性,制备了具有优良抑菌性能的降解产物。用滤纸圆片法研究了降解产物对６种细菌、２种霉菌和１种酵母菌三大类微生物的抑制作用,发现降解产物的抑菌作用与其分子量及分布有关。在一定的分子量及分布条件下,降解产物对大肠杆菌、金黄色葡萄球菌、蜡状芽孢杆菌、铜绿假单胞菌、志贺氏痢疾杆菌等５种菌有明显的抑制作用,其最低抑制浓度（ＭＩＣ）分别为００５％、００３％,００５％,００３％、００５％,均比茶多酚对相应微生物的最低抑制浓度低约一个数量级,表明了其在医药等领域具有重要应用前景     

核桃壳苯酚液化及其产物树脂化制备木材胶黏剂的研究

采用硫酸催化剂,考察了苯酚与核桃壳质量比等条件对核桃壳液化的影响。结果表明相同液化条件下,随着苯酚与核桃壳质量比从2∶1升至5∶1,残渣率从26.49%降至6.60%;随着浓硫酸加入量从2%增至4%、反应时间从5 min延至120 min、反应温度从100℃增至150℃,残渣率则分别从20.79%降至10.48%、48.84%降至15.62%、28.86%降至9.39%,游离酚含量分别从17.32%降至12.67%、41.71%降至10.25%、21.94%降至14.33%。同时,液化产物重均相对分子质量(MW)可降至706~1 030、分散度可降至1.04~1.25;液化产物中高相对分子质量部分随着苯酚与核桃壳质量比的增加有所降低,但随着浓硫酸加入量、液化反应时间和温度的增加而有所增加;核桃壳液化产物/苯酚/甲醛共缩聚树脂胶黏剂(WPF)与传统酚醛树脂胶黏剂(PF)的对比表明,WPF的胶接强度可达1.33 MPa,可作为胶合板用胶黏剂。     

木结构用胶黏剂蠕变性能的评价

以红松、落叶松、杉木和桦木为试验材料,采用苯酚-间苯二酚-甲醛树脂胶(RPF)和酚醛树脂胶(PF)进行胶合,使用专用卡具,在长期、恒定的荷栽作用下,研究胶合试件在各种使用条件下的蠕变性能.结果表明:RPF树脂的抗蠕变性能优于PF树脂,落叶松、红松试件的抗蠕变性能优于桦木和杉木.     

Rapid wood liquefaction by supercritical phenol

Wood was rapidly liquefied at the supercritical temperature of phenol. Under these conditions, wood was liquefied by over 90% for 0.5 min, and the combined phenol content of the obtained liquefied wood reached about 75%. The effects of various reaction conditions on liquefaction were investigated. With increases in reaction temperature, phenol/wood weight ratio, and the charged mass-to-reactor capacity (w/v) ratio, the amount of methanol-insoluble residue decreased and combined phenol content increased. The range of molecular weights and polydispersity of the products obtained after the time at which sufficient liquefaction was achieved were from 400 to 600 and from 1.5 to 2.5, respectively. Wood showed a marked decomposition to low molecular weight components early in the reaction, and then the molecular weight increased slightly with increasing reaction time. The properties of liquefied wood were investigated and compared with those obtained with conventional liquefaction methods. Combined phenol content was similar to that obtained by other liquefaction methods, except the sulfuric acid–catalyzed method, which resulted in flow properties comparable to those of other liquefaction methods. The flexural strength of moldings prepared using liquefied wood was also comparable to those prepared by other liquefaction methods.     

Kraft lignin utilization in adhesives

Summary The utilization of lignin from Pinus radiata black liquor, as a copolymer in ligninphenol-formaldehyde resin binders was studied. Methylolation, demethylation and ultrafiltration separation of high molecular-weight fractions were carried out in order to increase lignin reactivity. The different modified lignins were tested in preparation of lignin-phenolformaldehyde resin binders. Mechanical properties and water resistance were evaluated through testing particleboard panels manufactured with the resins obtained. The best resin was composed of 18,8% ultrafiltrated high molecular weight lignin, 22,9% phenol and 58,3% formaldehyde and had comparable properties with typical commercial resins prepared only with phenol and formaldehyde. An economic analysis was made in order to compare possible benefits obtained through the replacement of phenol by lignin products. The ultrafiltrated lignin copolymer was significantly less costly than a phenol-formaldehyde resin and had comparable physical and chemical properties.The authors acknowledge financial support from the Office of Research, Catholic University of Chile (DIUC) and the National Science Foundation of Chile (CONICYT)     

Predicting the hydroxymethylation rate of phenols with formaldehyde by molecular orbital calculation

The rates (k) of hydroxymethylation of phenol, resorcinol, phloroglucinol, and several methylphenols in diluted 10% dimethylformamide aqueous alkaline solution were calculated based on the consumption of phenols and formaldehyde. Thek values of phloroglucinol and resorcinol relative to that of phenol were about 62000 and 1200 times, respectively. The phenols that have methyl or hydroxyl groups at the C-3 or C-5 position (or both) have larger rate constants than phenols with substituents at other positions. Several kinds of atomic charge of the carbons on the aromatic ring of phenols were calculated using the semiempirical orab initio method. The correlations between the averagek (Ave.k) and average electrostatic charges (Ave.q) at the carbons were fairly good. Highest occupied molecular orbitals (HOMO) were observed. The best correlation between Ave.k and Ave.q was obtained when diphenols and triphenols were assumed to exist in solution as their respective di-anion.     

落叶松栲胶高度亚硫酸化改性及其产物应用性质的研究

落叶松栲胶经过高度亚硫酸化反应，小分子部分增多，产物平均分子量降低，Ｎａ２ＳＯ３ 和ＮａＨＳＯ３ 总用量为３０ ％ 时，分子量低于７１３ 的组分由３０ ％ 增加到６０ ％ ，其分布变得更均匀，色度值、粘度值、盐析值均下降，耐酸性增强，用于制革时，渗透速率增加，具有比传统方法生产的栲胶更优良的结合鞣、复鞣及填充性能。     

中国黑荆单宁与羟甲基反应动力学的研究

用动态ＤＳＣ研究中国黑荆单宁与活性酚醛树脂中羟甲基的反应动力学过程，分别测定了不同升温速率和不同摩尔比的活性酚醛树脂的反应动力学常数，发现上述两种因素对反应动力学常数均有一定的影响。