Larix gmelini tannin-based adhesive for plywood

Larix tannin-phenol-formaldehyde (TPF) adhesive, having 60% by weight of phenol being replaced, was evaluated for its utilization in plywood. The kinetic characteristic of the TPF resin was investigated through differential scanning calorimetry (DSC) and the results obtained from the DSC scans show that the resin has a little bit different thermochemical behavior from that of phenol-formaldehyde (PF) resin. Two kinds of plywood panels were produced using the TPF adhesive in laboratory. The desired test results met the Chinese GB 9846-88 and ZB B70006-88, respectively, and the long assembly time of TPF resin in preparing plywood can be improved by mixing with the filler.All the properties of plywoods bonded with the TPF adhesive were compared with those obtained with synthetic PF adhesive.     

Differential scanning calorimetry characterization of the cure of phenol-formaldehyde adhesive in the presence of copper-based preservative treated wood

The interference of copper based preservative treated southern yellow pine (SYP) on the cure of phenol-formaldehyde adhesives was investigated by using differential scanning calorimetry (DSC). Copper preservatives used in this study include copper azole (NS), alkali copper quat (ACQ)-type C (NW). Three commercial phenol-formaldehyde (PF) adhesives used for oriented strand board (OSB) face area, core area and a plywood adhesive were studied. The curing peak temperature and peak time of OSB core and face PF resin shifted to higher temperature and duration in the presence of CCA, NS, and NW-treated SYP compared to that in untreated SYP. The above treatments interfere with the cure of OSB core and face PF resin. Untreated SYP showed a curing accelerating effect on the cure of plywood adhesive, but the accelerating effect of copper-treated SYP on the cure of plywood resin was not significant.     

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。     

新型酚醛树脂改性大豆蛋白基胶黏剂的研究

以脱脂大豆粉为原料制备大豆蛋白基胶黏剂(豆胶,S),以普通甲醛制备的酚醛树脂(PF_1)和高浓度甲醛制备的酚醛树脂(PF_2)为交联剂,使用前将两者直接混合得酚醛树脂改性豆胶(PF_1/S、PF_2/S)。利用差示扫描量热(DSC)、红外光谱(FT-IR)、动态热机械性能(DMA)和核磁共振碳谱(~(13) C NMR)分析对产品性能进行了测试与表征。结果表明:等物质的量之比条件下,高浓度甲醛较之普通甲醛制备的酚醛树脂改性豆胶胶合板干、湿剪切强度分别提高4.3%和11.6%,并且强度稳定性好;动态DSC分析表明,PF_2可以降低豆胶体系的固化温度和活化能,与豆胶的交联反应较容易;~(13) C NMR分析表明,PF_2体系羟甲基达88.73%,明显高于PF_1的80.91%;FT-IR分析证实酚醛树脂与豆胶中的氨基发生反应,并且PF_2反应效率更高;DMA分析表明,PF_2/S能够改善胶合产品的力学性能和热稳定性,降低豆胶的固化反应起始温度,提高固化反应速率。     

改性MF树脂与PF树脂用于竹帘胶合板的比较

以改性三聚氰胺甲醛树脂(MF树脂)和酚醛树脂(PF树脂)为胶粘剂,设计了两组热压工艺参数,按照“冷-热-冷”工艺压制竹帘胶合板.对制品按标准JG/165-2004进行了检测,并对检测结果进行比较分析.分析结果表明,该改性MF树脂竹帘胶合板的弹性模量稍高于PF树脂竹帘胶合板,但静曲强度和保留强度不如PF树脂竹帘胶合板.如果适当增加产品的密度和降低改性MF树脂中尿素的比例,产品质量将可以进一步提高,证明该改性MF树脂可以替代PF树脂用于竹帘胶合板生产,且产品质量可以达到标准JG/165-2004的要求.     

酶解木质素改性酚醛树脂胶黏剂的研究

利用秸秆发酵制备能源酒精的残渣中提取的酶解木质素(EHL),部分代替苯酚合成改性酚醛树脂胶,并热压制得胶合板.测定了胶合板的胶合强度,改性树脂胶的黏度、固含量、水混合比、可被溴化物、游离酚、游离醛等性能指标.结果表明:木质素替代量达20%时,各项性能仍能基本达到国家标准Ⅰ类板的要求,特别是耐水性十分良好,水煮两次后胶合强度仍远大于国家标准Ⅰ类板≥0.7MPa的要求.     

超声波法活化麦草碱木素及用于PF胶黏剂的研究

麦草碱木素是我国造纸工业重要的剩余物,但是麦草碱木素的结构决定了其反应活性较低,从而使其应用受到较大的限制。笔者根据麦草碱木素的特点分别对比超声破碎仪不同的超声条件(时间:10、20、30、40min;振幅:60、80、100)和不同的溶液质量比(100:0,60:1,20:1)对麦草碱木素的活化效果,并探索用活化后的木素代替部分苯酚(10%、20%、30%、40%)制备酚醛树脂胶黏剂的可行性。研究结果表明:超声波作用可显著提高酚羟基的含量。超声波作用时间在20min、振幅80、溶液质量比20:1时效果相对较好。经过超声波活化的木素按20%的量替代苯酚制备LPF,压制的胶合板的胶合强度都达到国家Ⅰ类胶合板的要求,并能与未改性的酚醛树脂(PF)胶黏剂相媲美。     

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.     

落叶松树皮碱抽出物胶粘剂的研究

研究了落叶松树皮碱抽出物制造胶粘剂的生产工艺。碱抽出物胶粘剂压制的桦木，杨木三合板的检测结果，符合国家标准Ⅰ类板的质量要求，并对胶粘剂的经济效益进行了分析。     

基于UFC和葡萄糖改性脲醛树脂的合成与性能

在碱性条件下用尿素和甲醛合成脲醛预缩液(UFC),然后用UFC与尿素制备脲醛树脂(UFC/U),并添加葡萄糖对UFC/U改性得到G/UFC/U树脂,采用DSC和FT-IR等对树脂进行分析。结果表明:与普通脲醛树脂(UF)相比,UFC/U树脂胶合强度提高5.83%,游离甲醛含量降低3.70%,G/UFC/U树脂贮存期大于30 d,综合性能较好,G_1-25/UFC/U树脂游离甲醛含量降低44.44%,胶合板湿胶合强度为1.11 MPa,优于国家II类胶合板标准;DSC结果表明:UFC/U、G_1-25/UFC/U比UF树脂的固化特征温度高;FT-IR分析表明:G_1-25/UFC/U和UF树脂相比,羟基及亚甲基醚键的峰强度增强,改性树脂的羟甲基优先和葡萄糖分子C(6)的羟基发生反应生成亚甲基醚键。     

生物乙醇木质素-PAE改性大豆蛋白胶黏剂合成工艺研究

将生物乙醇木质素与自合成的聚酰胺多胺环氧氯丙烷(PAE)树脂进行接枝共聚改性大豆蛋白,制备环保型胶合板用胶黏剂,并通过单因素试验确定了木质素种类、木质素与PAE质量比、木质素与PAE树脂反应时间、大豆蛋白添加量等工艺条件对大豆蛋白胶黏剂胶合强度的影响。结果表明:当选用生物乙醇木质素与PAE进行接枝共聚、木质素与PAE质量配比为1∶4、反应时间为30 min、大豆蛋白添加量为50%(以木质素-PAE总质量而言)时,制得的三层胶合板湿胶合强度(1.03 MPa)可达到GB/T 9846—2015Ι类杨木胶合板的指标要求。     

等离子体改性热塑性树脂薄膜制备环保胶合板试验

为获得无甲醛释放的环保胶合板,将热塑性树脂薄膜(低密度聚乙烯(LLDPE)、聚丙烯(PP)、聚氯乙烯(PVC))用作胶黏剂,并利用空气介质阻挡等离子体对热塑性树脂薄膜进行表面改性处理以提高薄膜与杨木单板的界面相容性,从而获得性能良好的环保胶合板。研究了等离子体处理对胶合板胶合性能的影响,并从等离子体处理对热塑性树脂薄膜表面化学组分及其对胶合板界面形貌的影响分析其胶合机理。结果表明:在等离子体处理功率为4.5 kW、处理时间为8 m/min的条件下处理热塑性树脂薄膜,胶合板的胶合强度得到显著提高,LLDPE/杨木胶合板的胶合强度从0.49 MPa增至0.81 MPa,PP/杨木胶合板的胶合强度从0.65 MPa提高到0.84 MPa,均达到Ⅱ类胶合板标准要求。其中用等离子体处理后PVC与杨木制备的胶合板能满足Ⅰ类胶合板的标准要求,胶合强度达到0.79 MPa。XPS分析表明,等离子体改性热塑性树脂薄膜的表面发生了氧化反应,引入了含氧官能团,提高了薄膜表面极性,有利于提高薄膜与杨木单板之间的相互作用,从而使得胶合板的界面胶合更为紧密,说明等离子体处理后树脂与杨木单板的相容性提高,树脂能在单板表面更好地附着。热塑性树脂薄膜与杨木单板制备的胶合板仅有极微量甲醛释放,其主要源于木材自身,远低于国家标准对人造板甲醛释放限量的要求。研究证明等离子体处理能明显改善热塑性树脂薄膜与杨木单板的界面相容性。     

封闭异氰酸酯改性脲醛树脂制备胶合板

采用亚硫酸氢钠封闭异氰酸酯改性UF树脂制备胶合板,研究了制板用混合胶液的比例、热压时间、热压温度等热压工艺对胶合板性能的影响,结果表明,在UF/PAPI=100/10、热压温度为110℃、热压时间为4min时,所制备胶合板的甲醛释放量达到国家标准,并且具有较高的胶合性能.     

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.     

玉米淀粉改性UF树脂胶合高含水率单板

采用半酯化的玉米淀粉与脲醛树脂(UF)共聚改性,探讨加入量、脲醛树脂的量比、混合比、热压条件等对胶液的黏度、稳定性、固化时间及胶合质量的影响.结果表明:当单板含水率提高到16%～18%时,用改性UF树脂生产的多层胶合板,其物理力学性能指标达到GB/T 9846.1～12-88中Ⅱ类胶合板的要求,并大幅度地降低了胶合板的制造成本.     

室外木结构用胶粘剂胶合制品抗剪切性能评价

分别利用酚醛树脂胶粘剂和间苯二酚胶粘剂,对落叶松、桦木、红松、杉木4种树种进行胶合,测定制品在经过干状试验、真空-压力试验和蒸煮-干燥-冰冻试验之后的剪切强度。试验结果表明,经过干状试验、真空-压力试验后,间苯二酚胶粘剂的总体性能较好;而经过蒸煮-干燥-冰冻试验后,酚醛树脂胶粘剂较好。     

Susceptibility of thermo-hydro-treated birch plywood to mould and blue stain fungi

In this study, mould and blue stain susceptibility, capillary water uptake (CWU) and microstructural properties of two thermo-hydro-treated (THT) birch plywood products A and B were investigated. Plywood A represented a THT industrial plywood glued with a phenol formaldehyde (PF) adhesive. Plywood B represented panels from THT veneers glued with a PF film. The THT regimes were (temperature, °C/time, min): 150/10, 150/50, 160/10 and 160/50. Both THT plywood products and untreated samples were resistant to mould and blue stain growth in 1 month of exposure in laboratory and outdoor conditions. A statistically significant correlation between fungal growth in laboratory and outdoor conditions for plywood products A and B was not found (P?>?.05). Artificial weathering of both plywood products provided adverse fungal growth results compared to the natural weathering test outdoors. The fungal growth on plywood A and B samples mutually strongly correlated (P?相似文献   

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.     

微纳纤丝改性豆胶制造染色杨木胶合板

将不同微纳纤丝添加量的三聚氰胺树脂涂饰在杨木单板表面,并以添加微纳纤丝的豆胶作为胶黏剂,制造杨木胶合板,检测微纳纤丝添加量对染色杨木单板表面色牢度、胶合板表面耐磨性能、胶合强度的影响。结果表明:微纳纤丝可明显改善单板表面色牢度及表面耐磨性能;在豆胶中加入微纳纤丝,可提高胶合板的胶合强度。     

电磁屏蔽功能胶合板的研究

以镍粉、石墨粉、不锈钢纤维和铜纤维作为导电单元,脲醛树脂为胶黏剂,制备3层落叶松胶合板,研究不同导电单元和涂胶量对板材电磁屏蔽效能(ESE)及胶合强度的影响.结果表明,纯镍粉填充的胶合板的ESE几乎为零;后3种导电单元填充的胶合板ESE分别达到5～10 dB,17～21 dB和6～17 dB;试板的胶合强度除不锈钢纤维添加量为80 g/m2时低于国家标准外,其余条件下均达到或超过国家相关标准要求.