豆渣苯酚液化物合成热固性酚醛树脂的研究

为了提高大豆豆渣的附加值,利用豆渣苯酚液化物与甲醛在碱性环境中进行反应,制取热固性酚醛树脂(PF)。考察了n(甲醛)/n(液化物)[即n(F)/n(L)]比值、n(氢氧化钠)/n(液化物)[即n(NaOH)/n(L)]比值、树脂化温度和树脂化时间对PF理化性能的影响;通过正交实验法,确定了树脂化合成的最佳工艺。研究结果表明,最佳树脂化合成的工艺条件为:n(F)/n(L)=1.8,n(NaOH)/n(L)=0.5,树脂化温度为72.5℃,树脂化时间为3h;将最佳工艺条件下制取的PF用于胶合板的压制,则所得胶合板的胶合强度符合GB/T9846-2004中Ⅱ类胶合板的标准要求。     

杉木苯酚液化物合成热固型酚醛树脂的研究

以杉木为研究树种,对比不同料液比(木材与苯酚质量比)液化物与甲醛在碱性环境中反应,进行热固酚醛树脂制备试验。考察不同甲醛与苯酚物质的量之比值(r_F/P)、氢氧化钠与苯酚物质的量之比值(r_NaOH/P)和树脂化温度对树脂理化性能的影响。结果表明,采用料液比为1:2的液化物,r_F/P1.8,r_NaOH/P0.7,树脂化温度 80℃ 条件下合成的杉木液化物树脂压制的杨木三层胶合板满足I类胶合板强度要求,各项物理力学性能与常规PF树脂压制的板材相当,板材的甲醛释放量为 0.1 mg/L,远低于GB/T 9846-2004《胶合板》中的E₀级要求。     

腰果酚改性酚醛泡沫的制备与性能研究（摘要）

首先利用多聚甲醛与苯酚为原料制备甲阶酚醛树脂,探讨了多聚甲醛／苯酚物质的量之比、缩聚反应温度、催化剂加入量对树脂性能及其可发性的影响,对合成的甲阶酚醛树脂进行物理和化学测定,结果表明：采用多聚甲醛与苯酚为原料制备甲阶酚醛树脂完全可以实现生产过程中的废水零排放;甲阶酚醛树脂的合成最佳条件为：多聚甲醛/苯酚物质的量之比1．8,缩聚反应温度90℃,催化剂加入量5g（以100g苯酚质量为基准）,     

影响高性能酚醛树脂相对分子质量的因素

本文采用两步法制备酚醛树脂，以苯酚，对叔丁基苯酚及多聚甲醛为主要原料，无水醋酸锌和草酸为催化剂，通过改变苯酚与对叔丁基苯酚物质的量比、多聚甲醛分次添加量、催化剂量以及两步法中前后的反应温度，探究影响酚醛树脂相对分子质量的因素，进而优化工业生产酚醛树脂工艺。     

多聚甲醛与苯酚物质的量比对可发性甲阶酚醛树脂性能的影响

采用多聚甲醛代替37%的甲醛溶液,在20%NaOH水溶液催化下与苯酚逐步加成聚合,合成了可发性甲阶酚醛树脂。研究了多聚甲醛与苯酚物质的量比(F/P)对合成树脂固含量、粘度、游离苯酚、游离甲醛、凝胶时间、分子结构、分子质量、树脂热性能及泡沫性能的影响。结果表明,F/P值为1.8时,可得到性能优良成本较低的可发性甲阶酚醛树脂,树脂粘度1.4 Pa.s,游离甲醛质量分数1.17%,游离苯酚质量分数6.72%,羟甲基指数1.41,树脂分子质量在240左右,耐热性较好。     

橡胶籽壳/苯酚液化物酚醛树脂的合成及表征

采用液化技术和树脂化技术,制备了橡胶籽壳/苯酚液化物(简称液化物);然后以此为原料,制备了胶合板用液化物PF(酚醛树脂)胶粘剂,并采用单因素试验法和正交试验法优选出制备液化物PF的最佳工艺条件。研究结果表明:当反应温度为90℃、n(甲醛)∶n(液化物)=2.0∶1.0、反应时间为2.0 h和n(氢氧化钠):n(液化物)=0.7∶1.0时,由液化物PF胶粘剂压制而成的胶合板,其湿态胶接强度(为1.36 MPa)相对最大,并且达到GB/T 9846—2004标准中I类胶合板的指标要求;液化物PF与纯PF的结构基本相似,但前者的固化温度略高于后者、热稳定性低于后者。     

EDTA改性无水酚醛树脂的合成

对用EDTA改性酚醛树脂进行了研究。通过研究确定了最佳的反应条件为n(苯酚):n(多聚甲醛):n(EDTA):n(Na OH)=1:1.3:0.01:0.05,反应时间为5h,树脂的固含量为88.5%,残炭量为46.2%,开始热分解温度为386℃,红外光谱显示该树脂为高邻位酚醛树脂。     

多聚甲醛合成热塑性酚醛树脂过程中游离酚含量的研究

在热塑性酚醛树脂合成过程中,由于苯酚过量,部分苯酚没有参与反应而是进入废液中,不仅导致苯酚的浪费,同时也使废液中的酚含量过高。研究反应体系中酚含量的变化,对提高苯酚的转化率以及减少树脂中游离酚的含量有重要的意义。在酚/醛物质的量比为1∶0. 75的条件下,用草酸做催化剂,催化苯酚与多聚甲醛合成热塑性酚醛树脂。研究了催化剂用量、反应温度和时间、后处理工艺等因素对游离酚的影响。结果表明,草酸用量为苯酚质量1%时,催化效果较好。同时延长低温反应阶段时间,可以提高苯酚的转化率。后处理工艺对最终树脂游离酚含量的影响较大,要保证树脂中的低游离酚含量,后处理的温度和时间是关键。     

竹材液化物酚醛树脂胶固化及固化动力学研究

采用非等温差示热量扫描DSC曲线方法探讨了竹材液化物酚醛树脂胶不同物质的量之比时的固化反应过程。在25～300℃温度范围内,运用Kissinger方程对不同的升温速率下竹材液化物酚醛树脂胶的DSC曲线进行了固化动力学研究。结果表明:随着甲醛配比的提高(苯酚与甲醛物质的量之比分别为1:1.3、1:1.6、1:1.8),竹材液化物酚醛胶的固化过程表观活化能逐渐减小,分别为64.60、58.36、57.12 kJ/mol;3种配比的竹材液化物酚醛胶的固化反应模型分别为:da/dt=1.30×10⁵e^-64600/RT(1-a)^0.9054,da/dt=1.37×10⁵e^-58360/RT(1-a)^0.8971和da/dt=1.44×10⁵e^-57120/RT(1-a)^0.8959;随着甲醛配比的提高,利用外推法得出的静态(β=0 K/min)的特征固化温度T_i、T_p和T_f均逐渐降低,结果与竹材液化物酚醛胶固化反应的表观活化能的大小顺序一致。     

可发性生物油-酚醛树脂制备工艺研究

以生物油、苯酚及多聚甲醛为原料制备出可发性生物油-酚醛树脂,通过正交实验法优选出最佳合成工艺,采用FTIR表征了其产物结构,并测定了由此树脂制备出的生物油-酚醛泡沫材料的性能。结果表明,适宜制作泡沫材料的生物油-酚醛树脂的最佳合成反应条件如下:多聚甲醛与苯酚物质的量比为2.2∶1,生物油添加质量分数20%,NaOH与苯酚物质的量比为0.35∶1,反应时间20 min。该树脂具有较高活性和更多醚键。以其制备的生物油-酚醛泡沫综合性能良好,可用于建筑保温材料。     

高替代率竹焦油酚醛树脂的合成工艺研究

竹焦油是竹炭产业的副产物之一,富含酚类物质,可部分替代昂贵苯酚合成竹焦油酚醛树脂(BPF)。以n(苯酚)/n(甲醛)、竹焦油替代率、n(NaOH)/n(苯酚)和反应时间为试验因素,以BPF的黏度和游离酚含量、相应胶合板的胶接强度和甲醛释放量为考核指标,采用正交试验法优选合成高替代率环保型BPF的最佳工艺条件。结果表明:当n(苯酚)/n(甲醛)=2.0、竹焦油替代率为50%、n(NaOH)/n(苯酚)=0.35和反应时间为60 min时,由BPF胶粘剂压制而成的胶合板,其胶接强度和甲醛释放量分别达到GB/T 9846.3—2004标准中Ⅰ类胶合板和E0级的指标要求。     

Phenolic resol resin adhesives prepared from alkali-catalyzed liquefied phenolated wood and used to bond hardwood

Wood-based resol resins were prepared from both water- and sodium hydroxide (NaOH)-catalyzed liquefied phenolated wood. The effects of various reaction parameters, e.g. the concentrations of phenol and formaldehyde, temperature, and time, on the extent of yield, free phenol content, molecular weight as well as the gluability of the resol resins have been evaluated. As far as the yield, free phenol content, and molecular weight are concerned, the optimum conditions of resol resin preparation were found to be a phenol : wood weight ratio of 4 : 6, a formaldehyde : phenol mole ratio of 1.5 : 1, a temperature of 82.5°C, and time 3 h. However, these optimum conditions changed when the performance of the adhesives was considered in terms of the adhesive bond strengths for plywood joints. The yield, molecular weights, polydispersity, and gluability of resol resins prepared from water-catalyzed liquefied wood were lower compared with those prepared from NaOH-catalyzed ones. In most cases, the dry-bond strengths of the experimental plywood joints exceeded the minimum Japan Agricultural Standard (JAS) values. On the other hand, except at a higher formaldehyde: phenol ratio (i.e. 2.0 : 1 mole ratio), the plywood joints of all samples delaminated during 'boil-dry-boil' cyclic treatments. However, both dry- and wet-bond strengths of the plywood joints could be improved to exceed standard values by using an additional crosslinking agent, e.g. poly(methylene (polyphenyl isocyanate)) (polymeric MDI). The adhesive perfomance of the wood-based resol resins was explained on the basis of the adhesion between wood veneers and resol resin adhesives.     

改善模塑料性能的苯酚改性蜜胺树脂的制备

采用苯酚对三聚氰胺-甲醛树脂(MF)进行改性,研究了3种原料(苯酚、三聚氰胺和甲醛)不同配比下的合成产物的模塑料性能,优选出低酚摩尔分数(8%)的用于模塑料加工的苯酚改性蜜胺树脂(PMF)。该树脂中甲醛与三聚氰胺的物质的量比(F1/M)为1.75∶1,甲醛与苯酚的物质的量比(F2/P)为1.7∶1,甲醛和苯酚的物质的量之和与三聚氰胺物质的量比((F1+F2+P)/M)为2.5∶1。该树脂可提高模塑料的加工性能,降低加工能量损耗,改善制品的模塑性和耐冲击性。     

Effect of synthesis parameters on thermal behavior of phenol–formaldehyde resol resin

Differential scanning calorimetry (DSC) was used to investigate the influence of resin synthesis parameters on the thermal behavior of low molecular weight phenol–formaldehyde (PF) resol resins prepared with different formaldehyde/phenol (F/P) molar ratios, different sodium hydroxide/phenol (NaOH/P) molar ratios, and different catalysts. As the F/P molar ratio increased, the molecular weight and activation energy increased while the gel time, peak temperature, resin pH, and nonvolatile solids content decreased. By contrast, the molecular weight, gel time, resin pH, resin solids content, and peak temperature increased with an increasing NaOH/P molar ratio. However, the activation energy decreased with an increasing NaOH/P molar ratio. The polydispersity increased with both F/P and NaOH/P ratios. Calcium hydroxide gave a faster curing resin compared to sodium and potassium hydroxides. All DSC thermograms of this study showed just a single exothermic peak for the resins that were used. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1415–1424, 2002     

NaOH用量对PUF共缩聚树脂结构和性能的影响

以13^C核磁共振分析（13^C NMR）和基质辅助激光解析电离飞行时间质谱（matrix-assisted laser desorption／ionization time-of-flight mass spectrometry．MALDI—TOF—MS）为手段．研究了不同的NaOH／P物质的量比（nNaOH／nP）条件下合成的苯酚-尿素-甲醛（PUF）共缩聚树脂的结构特征,通过压制胶合板,进一步评价了nNaOH／nP变化对PUF共缩聚树脂的影响。13^C核磁共振和MALDI—TOF—MS结构分析结果显示,在本研究范围内改变碱性条件对PUF共缩聚树脂的结构构成无显著影响;合成的PUF共缩聚树脂结构仍是以酚醛树脂为主体,特别是聚合物的链接方式;胶合性能研究结果表明,在尿素／甲醛／苯酚物质的量比不变的条件下,在一定范围内增加NaOH的用量,PUF树脂干状和湿状胶合强度增加显著,这一合理的范围应小于nNaOH／nP=0．53,超出这一范围后,随着nNaOH／nP的增加,树脂的胶合性能快速下降,但仍在可以接受的范围内。     

中温固化高邻位酚醛树脂胶粘剂制备与性能研究

以Ba(OH)2/NaOH为复合催化剂,采用两步加入甲醛法合成了高邻位PF(酚醛树脂)胶粘剂;然后以间苯二酚为改性剂,比较了不同n(甲醛)∶n(苯酚)配比、催化剂用量和反应时间等对PF胶粘剂性能的影响。结果表明:当反应时间为2.0 h、n(甲醛)∶n(苯酚)=1.7∶1.0,w(NaOH)=2.0%、w(Ba(OH)2)=3.0%和w(间苯二酚)=10.0%(均相对于苯酚质量而言)时,所得产物的性能相对较优;催化剂Ba(OH)2的引入,能有效提高邻位羟甲基含量、降低固化温度和加快固化速率;间苯二酚的引入,可有效加快PF胶粘剂的固化反应。     

Phenolic resol resin from phenolated corn bran and its characteristics

To prepare phenolic resol resin, corn bran (CB) was liquefied in the presence of phenol and the liquefied CB was condensed with formaldehyde under alkaline condition. From NMR spectra of phenolated CB and phenolated CB–based resol resin, it was found that phenol was reacted with depolymerized CB components and the phenolated CB was methylolated by condensation with formaldehyde. Molecular weight distribution was divided into a high molecular weight zone, attributed mainly to phenolated CB, and a low molecular weight zone, which was attributed to the condensation reactants of formaldehyde and the unreacted phenol of liquefied CB. When reaction conditions became severe, a high molecular weight zone was increased. Formaldehyde/unreacted phenol of liquefied CB molar ratio most affected the change of a low molecular weight zone. To reduce the viscosity of the phenolated CB–based resol resin, a milder condensation condition was required compared with that for preparing the conventional resol resin. Properties of the resol resin were comparable to those of conventional resol resin for plywood manufacture. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1365–1370, 2003     

Synthesis and cure kinetics of liquefied wood/phenol/formaldehyde resins

Wood liquefaction was conducted at a 2/1 phenol/wood ratio in two different reactors: (1) an atmospheric three‐necked flask reactor and (2) a sealed Parr reactor. The liquefied wood mixture (liquefied wood, unreacted phenol, and wood residue) was further condensed with formaldehyde under acidic conditions to synthesize two novolac‐type liquefied wood/phenol/formaldehyde (LWPF) resins: LWPF1 (the atmospheric reactor) and LWPF2 (the sealed reactor). The LWPF1 resin had a higher solid content and higher molecular weight than the LWPF2 resin. The cure kinetic mechanisms of the LWPF resins were investigated with dynamic and isothermal differential scanning calorimetry (DSC). The isothermal DSC data indicated that the cure reactions of both resins followed an autocatalytic mechanism. The activation energies of the liquefied wood resins were close to that of a reported lignin–phenol–formaldehyde resin but were higher than that of a typical phenol formaldehyde resin. The two liquefied wood resins followed similar cure kinetics; however, the LWPF1 resin had a higher activation energy for rate constant k₁ and a lower activation energy for rate constant k₂ than LWPF2. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008