木材加工用耐水性苯酚液化树皮-甲醛胶粘剂的研制

树皮是一种来源丰富可再生的天然高分子材料。本文采用高温苯酚液化的方法,在复合酸存在下将落叶松全树皮液化成为木材胶粘剂的原料。研究了树皮液化产物制备木材胶粘剂的合成工艺,特别是碱用量对苯酚液化落叶松全树皮一甲醛胶粘剂各主要性能的影响。结果表明,增加碱用量会缩短树皮胶的贮存期,但可降低胶中的游离甲醛;通过降低树皮胶合成时的终点黏度,并在合成末期用水稀释,可有效提高树皮胶的适用期,并可确保树皮胶具有很好的胶接强度和耐水性、较快的固化速率以及很低的游离甲醛释放量。     

低游离甲醛含量酚醛树脂胶粘剂的合成

采用两次加碱一次回流法合成工艺代替一次法和两次碱法制备了酚醛树脂胶粘剂。对产物粘度,游离甲醛含量及固化物拉伸剪切强度测试,研究了酚醛比、催化剂加入量、反应温度、回流时间等对产物性能的影响。结果表明:苯酚与甲醛物质的量比1∶2,催化剂加入量为苯酚质量分数的25%,回流反应45 min可得到具有交联结构的酚醛树脂胶粘剂,产品分子质量及粘度适中,拉伸剪切强度可达到5 MPa以上,游离甲醛质量分数<0.03%,稳定性较好。     

环保型高剪切强度脲醛树脂胶黏剂的制备

采用碱-酸-碱合成工艺,分段控制温度,分批加入尿素,加PVA改性,制备脲醛树脂胶黏剂。研究了n(F)/n(U)、反应温度、反应时间和PVA加入量对胶液甲醛含量和试样剪切强度的影响。结果表明:当n(F)/n(U)为1.4:1,反应温度为95℃,反应时间为70min,PVA加入1.0%时,制备的胶黏剂游离甲醛的含量降至0.1%以下,试样的剪切强度可达3.0MPa以上。     

多羟甲基苯酚改性脲醛树脂的研究

脲醛树脂(UF)是木材工业的主要胶种,为了提高UF的胶接性能和耐水性,同时实现低n(甲醛)∶n(尿素)比例UF中尿素的作用,采用自制的多羟甲基苯酚对UF进行改性,并通过胶合板的压制试验和差示扫描量热(DSC)法来研究改性UF的使用性能。结果表明:多羟甲基苯酚加入时间对UF诸多性能产生明显的影响;当质量分数为10%的多羟甲基苯酚在UF合成末期投入时,所得UF的综合性能相对最佳;与未改性UF胶粘剂压制的胶合板相比,由改性UF胶粘剂压制的胶合板具有相对较高的干强度(1.86 MPa)和湿强度(1.82 MPa),其甲醛释放量降低了30.8%。     

茭白废弃生物质苯酚液化及其产物树脂化制备胶黏剂

采用正交试验,考察了苯酚用量、催化剂用量、反应时间及反应温度对茭白废弃生物质液化效果的影响,并研究了该液化产物制备胶黏剂的影响因素。结果表明:茭白废弃生物质液化过程中,苯酚用量的影响最大,反应温度和反应时间次之,而催化剂用量的影响相对较弱,优化参数是苯酚用量为1∶5,催化剂用量为7%,反应时间为90 min,反应温度为140℃,在此优化条件下,液化率为95.83%。胶黏剂制备过程中,茭白液化物与甲醛的质量比为1∶1.8,高温缩聚反应温度为92℃较为合适。     

香蕉假茎苯酚液化及其产物树脂化制备胶黏剂

以苯酚为液化试剂、硫酸为催化剂对香蕉假茎进行液化,探讨液化条件对液化反应的影响,并结合傅里叶红外光谱(FT-IR)、热重分析(TGA)和成分分析研究了不同液化时间的液化物性质差别,同时以液化产物制备环氧树脂胶黏剂,并对其性能进行表征。单因素试验结果表明:优化条件为催化剂用量(占原料的质量分数)30%、反应温度150℃、液固比4:1和液化时间90 min; FT-IR分析表明:40 min和90 min液化产物官能团相似且具有芳香衍生物和酚羟基特性;成分分析和TGA分析表明:40 min残渣中纤维素保留量比90 min高;性能测试表明,90 min液化产物环氧树脂胶黏剂的剪切强度可达7.26 MPa,玻璃化温度(T_g)可达78℃。在优化的反应温度、催化剂用量和液固比的条件下,液化时间对残渣率和液化产物官能团的影响较小,但对残渣中纤维素含量的影响较大,液化产物适合制备生物质环氧树脂胶黏剂。     

香蕉假茎苯酚液化及其产物树脂化制备胶黏剂北大核心

以苯酚为液化试剂、硫酸为催化剂对香蕉假茎进行液化,探讨液化条件对液化反应的影响,并结合傅里叶红外光谱(FT-IR)、热重分析(TGA)和成分分析研究了不同液化时间的液化物性质差别,同时以液化产物制备环氧树脂胶黏剂,并对其性能进行表征。单因素试验结果表明:优化条件为催化剂用量(占原料的质量分数)30%、反应温度150℃、液固比4∶1和液化时间90 min;FT-IR分析表明:40 min和90 min液化产物官能团相似且具有芳香衍生物和酚羟基特性;成分分析和TGA分析表明:40 min残渣中纤维素保留量比90 min高;性能测试表明,90 min液化产物环氧树脂胶黏剂的剪切强度可达7.26 MPa,玻璃化温度(T_g)可达78℃。在优化的反应温度、催化剂用量和液固比的条件下,液化时间对残渣率和液化产物官能团的影响较小,但对残渣中纤维素含量的影响较大,液化产物适合制备生物质环氧树脂胶黏剂。     

茭白废弃生物质苯酚液化及其产物树脂化制备胶黏剂

采用正交试验,考察了苯酚用量、催化剂用量、反应时间及反应温度对茭白废弃生物质液化效果的影响,并研究了该液化产物制备胶黏剂的影响因素。结果表明：茭白废弃生物质液化过程中,苯酚用量的影响最大,反应温度和反应时间次之,而催化剂用量的影响相对较弱,优化参数是苯酚用量为1：5,催化剂用量为7％,反应时间为90 min,反应温度为140℃,在此优化条件下,液化率为95．83％。胶黏剂制备过程中,茭白液化物与甲醛的质量比为1：1．8,高温缩聚反应温度为92℃较为合适。     

苯酚-尿素-乙二醛树脂的合成工艺研究

为从根本上消除木材胶合制品的甲醛释放对环境和人体健康的危害及改善尿素-乙二醛(UG)树脂的性能,选择无毒、低挥发的乙二醛代替甲醛,与尿素、苯酚反应制备苯酚-尿素-乙二醛(PUG)共缩聚树脂木材胶黏剂。研究了在反应的不同阶段加入苯酚以及苯酚的加入量对树脂性能的影响,并通过傅里叶变换红外光谱法(FTIR)对树脂的结构进行了表征。结果表明:在所研究的合成条件下,PUG树脂的pH和状态受苯酚加入量和加入时间的影响不大,苯酚的加入量为尿素总量的10%为宜;树脂中主要含有氮氢(N—H)、氧氢(O—H)、羰基(C=O)、饱和碳氢(C—H)、醚键(C—O—C)及碳氮(C—N)键等主要官能团。     

木质素碱催化苯酚液化物纤维固化工艺

以木质素碱催化苯酚液化物为原料,加入六次甲基四胺后熔融纺丝,将熔纺纤维置于甲醛和盐酸混合溶液中固化处理制得固化纤维,研究了碱存在条件下木质素苯酚液化物的成纤性及初生纤维固化条件。结果表明:木质素碱催化苯酚液化物具有很好的成纤性;所得纤维性能与纺丝条件和固化工艺相关。在收丝辊转速450r/min、压力0.02 MPa、固化液盐酸质量分数15%、甲醛质量分数18.5%、固化温度95℃、升温速率10℃/h、固化时间4 h条件下,所得纤维性能较好,适于制备碳纤维。     

Preparation of liquefied bark‐based resol resin and its application to particle board

Barks of Taiwan acacia (Acacia confusa) and China fir (Cunninghamia lanceolata) were liquefied in the presence of phenol with sulfuric acid (H₂SO₄) and hydrochloric acid (HCl) as catalyst. The properties of resins prepared from liquefied bark and the feasibility of liquefied bark‐based resol resins in particle board manufacturing were investigated. The viscosity and thermosetting property of liquefied bark‐based resol resins were affected by the kind of bark species and the catalyst used. Liquefied bark‐based resol resins using China fir bark as raw material had higher viscosity than the ones using Taiwan acacia bark. In the course of thermosetting, liquefied bark‐based resol resins using Taiwan acacia bark as raw material had a higher maximum temperature of exothermic peak and onset temperature as well as a larger quantity of exothermic heat than those using China fir bark. Resol resins prepared from bark liquefied with H₂SO₄ as catalyst had higher viscosity, while resins with HCl as catalyst had a higher maximum temperature and height of exothermic peak and a larger quantity of exothermic heat at thermosetting. Particle board made with A‐S adhesive that was prepared from liquefied Taiwan acacia bark with H₂SO₄ as catalyst had the best particle board properties than those made with other adhesives. For the particle board made with A‐S adhesive, its static bending strength and internal bonding strength would be increased as the hot‐pressing time extended. The particle board made with hot‐pressing temperature of 150°C and hot‐pressing time of 10 min had the maximum normal and wet static bending strength and internal bonding strength. Its normal static bending strength was 170.8 kgf/cm² and the particle board showed satisfactory wet static bending strength and internal bonding strength. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1837–1841, 2003     

落叶松树皮化学改性及其对铜离子吸附性能的研究

以落叶松树皮为原料,经甲醛改性、盐酸催化处理后制备生物基吸附材料Ⅰ;经环氧氯丙烷改性、氢氧化钠催化处理后制备生物基吸附材料Ⅱ.通过正交实验法得到最佳改性条件：生物基吸附材料Ⅰ最佳改性条件为树皮粒径60～80目,甲醛20mL,盐酸催化剂的浓度0.5mol/L,改性温度50℃,反应时间2h;生物基吸附材料Ⅱ最佳改性条件为树皮粒径60～80目,环氧氯丙烷30mL,氢氧化钠催化剂的浓度0.7mol/L,改性温度70℃,反应时间2h时.实验结果表明：经过改性得到的生物基吸附材料Ⅰ和Ⅱ对铜离子的吸附量分别增加了65％和69％.     

Eucalyptus bark lignin substituted phenol formaldehyde adhesives: A study on optimization of reaction parameters and characterization

The major adhesive resin worldwide used in the manufacture of plywood is phenol formaldehyde resole (PF) resin. The raw material for this kind of adhesive is derived from petroleum oil. Because of rising prices of crude oil and the scarcity of petroleum products, their replacement by natural resource–based raw material has become a necessity. In the present work, the possibility of replacing phenol in PF resin with lignin was explored. The parameters for preparation of bark lignin substituted PF (LPF) adhesive, such as lignin concentration, formaldehyde to phenol molar ratio, catalyst concentration, reaction time, and reaction temperature, were optimized. It was found that up to 50 wt % of phenol can be substituted by lignin to give an LPF adhesive with better bonding strength compared to that of control PF resin. Prepared resins were characterized using IR, DSC, and TGA. IR spectra of LPF adhesive showed structural similarity with that of PF adhesives. Thermal stability of LPF adhesive was found to be lower compared to that of control PF (CPF) adhesive. DSC studies revealed a lower curing temperature for LPF resin than that for CPF resin. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3514–3523, 2004     

Polyurethane foams derived from liquefied mountain pine beetle‐infested barks

In this study, lodgepole pine (Pinus contorta Dougl.) bark infested by the mountain pine beetles (Dendroctonus ponderosae hopkins) was liquefied using either polyethylene glycol (PEG) or polyethylene glycol/glycerol (PEG/G) as the solvent. It was found that the addition of glycerol to PEG reduced the residue ratio during bark liquefaction. The liquefied bark fraction obtained by using PEG/G had a slightly higher hydroxyl number than that obtained by using PEG. The residue from PEG/G liquefaction contained less lignin and more cellulose than the residue from PEG liquefaction. Various polyurethane foams containing liquefied bark fractions were made, and it was found that the weight ratios of liquefied bark to pMDI used in foam formulation and bark liquefaction solvents affected the density, gel content, thermal stability, mechanical properties, and the cell structure of the resulting foams. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

落叶松生物油改性脲醛树脂胶粘剂的制备与性能研究

以自制落叶松热解生物油为原料,采用萃取法制备富酚油;然后以此作为UF(脲醛树脂)的改性剂,考察了富酚油含量对改性UF胶粘剂性能的影响。结果表明:富酚油组分复杂,其中酚类物质含量为53.87%;当w(富酚油)=10%(相对于尿素质量而言)时,改性UF胶粘剂的综合性能较好,由其压制而成的3层杨木胶合板的胶接强度(1.23 MPa)和甲醛释放量(1.05 mg/L)均优于未改性UF胶粘剂。     

Performances of larch (larix gmelini) tannin modified urea–formaldehyde (TUF) resin and plywood bonded by TUF resin

Tannin from larch (Larix gmelini) bark extracts, as a natural renewable resource, was used to prepare tannin–urea–formaldehyde (TUF) resin. The chemical structures of larch tannin and TUF resin were characterized by matrix‐assisted laser desorption/ionization‐time of flight mass spectrometry and ¹³C nuclear magnetic resonance. The thermal behaviors of TUF resin were evaluated by differential scanning calorimetry (DSC) and thermomechanical analysis (TMA). The performances of TUF resin were investigated by measuring the bond strength and formaldehyde emission of its bonded plywood. It was clearly shown that larch tannin is mainly composed of prodelphinidin repeating units. Phenolic groups were introduced into TUF resin mainly linked by methylene bond. Larch tannin has an adverse effect on the resin curing. However, it promoted the rigidity and flexibility of the glued system and upgraded the properties of plywood. Therefore, larch tannin could be applied in the modification of urea–formaldehyde resin. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41064.     

落叶松栲胶的改性及其溶液的性质表征

通过对落叶松栲胶进行亚硫酸盐和氢氧化钠的改性,测定其溶液黏度,用不同溶剂进行分级和薄层色谱。结果表明改性栲胶溶液黏度下降,相对分子质量降低且分布集中。高度亚硫酸化的改性落叶松栲胶相比碱处理的改性落叶松栲胶更有效地降低其黏度和相对分子质量。可应用于酚醛树脂绝缘板的黏合剂生产。     

四种原料生物油-酚醛树脂胶粘剂特性研究

利用生物质快速热解液化产物制备燃料或化工产品已成为国内外的研究热点。将四种生物质原料(落叶松、杨木、棉秸秆和玉米秸秆)快速热解液化产物作为苯酚替代物,由此制备出不同种类的热解生物油-PF(酚醛树脂)胶粘剂,并探讨了胶粘剂胶接强度与热解生物油组成的关系。结果表明:落叶松热解生物油-PF胶粘剂的胶接强度最大(1.277 MPa),玉米秸秆热解生物油-PF胶粘剂的胶接强度最小(1.021 MPa);胶粘剂的胶接强度主要与热解生物油中酚类物质含量有关。     

落叶松树皮栲胶废渣各组分及其磺化产物的表面活性对比研究

分析了兴安落叶松树皮栲胶废渣的主要化学组分及各组分的磺化产物对木质素磺酸盐的表面活性的作用,发现树皮栲胶废渣制备的木质素磺酸盐表面活性、分散性能和净浆流动度较木材木质素磺酸盐高。表面活性和分散性能好的主要原因是栲胶废渣中可溶单宁和红粉的存在,而具有更好的净浆流动度是因为可溶单宁和酚酸的存在。