共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
氧化淀粉改性脲醛树脂胶粘剂的合成工艺研究 总被引:1,自引:0,他引:1
以氧化淀粉作为改性剂,采用正交试验法探讨了最终n(甲醛或F)∶n(尿素或U)、淀粉氧化时间、氧化淀粉加入量和交联时间等对氧化淀粉改性UF(脲醛树脂)胶粘剂的游离甲醛含量和胶接强度的影响。研究结果表明:当最终n(F)∶n(U)=1.2∶1、淀粉氧化时间为3 h、氧化淀粉加入量为10%(相对于甲醛和尿素总质量而言)和交联时间为60 min时,氧化淀粉改性UF胶粘剂的游离甲醛含量低于0.09%、胶接强度为1.48 MPa且耐水性明显提高;此时,相应胶合板的甲醛释放量(0.04 mg/L)满足GB/T 9846.3—2004标准中E0级指标要求。 相似文献
3.
环保型脲醛树脂胶粘剂的合成研究——三聚氰胺聚乙烯醇改性UF胶 总被引:2,自引:0,他引:2
介绍了三聚氰胺,聚乙烯醇(PVA)在脲醛树脂胶粘剂(UF胶)合成过程中所起的改性作用,研究了甲醛与尿素的摩尔比、PVA和三聚氰胺用量以及加料顺序、反应温度、pH值、反应时间对脲醛树脂胶性能的影响。结果表明,甲醛与尿素的摩尔比为1.4∶1,PVA和三聚氰胺的用量分别为尿素总量的1.5%和4%时,合成的脲醛树脂胶粘剂综合性能良好,游离甲醛含量低,达到了绿色环保的要求。 相似文献
4.
将不同投料比的OMMT(有机蒙脱土)引入脲醛树脂(UF)合成的3个阶段(加成、缩聚和缩聚后期)中,制备出相应的OMMT改性UF胶粘剂。研究结果表明:该改性UF胶粘剂的耐热性高于未改性UF胶粘剂,其游离甲醛含量随OMMT投料比增加而降低,粘接强度随之增大。加成阶段投入OMMT后,该改性UF胶粘剂的降醛效果明显;缩聚阶段投入OMMT后,该改性UF胶粘剂的补强效果显著。OMMT较佳的投入阶段为缩聚阶段,较佳的投料比为2%~3%(相对于尿素总质量而言)。 相似文献
5.
以MMT(蒙脱土)或OMMT(有机蒙脱土)作为改性剂,两者分别在UF(脲醛树脂)合成的不同阶段(加成阶段、缩聚阶段和缩聚后期)中以同一投料比引入体系中,制备相应的改性UF胶粘剂。研究结果表明:当n(F):n(U)=1.2:1、w(MMT或OMMT)=2%(相对于尿素总质量而言)时,MMT和OMMT的引入,能使相应改性UF胶粘剂的某些性能(如黏度、固含量、胶接强度和固化时间等)增加、游离甲醛含量降低;OMMT的改性效果优于MMT,并且OMMT在加成阶段投入时降醛效果明显,在缩聚阶段投入时补强效果明显。 相似文献
6.
多羟甲基苯酚改性脲醛树脂的研究 总被引:1,自引:1,他引:0
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%。 相似文献
7.
《中国胶粘剂》2013,(12)
利用不同硅烷偶联剂改性ATP(凹凸棒石)或SiO2-ATP,并制备了相应的UF(脲醛树脂)胶粘剂。探讨了改性ATP或SiO2-ATP的工艺条件及其对UF胶粘剂的甲醛释放量、剪切强度等影响。结果表明:含氨基的硅烷偶联剂(A-1160和KH-792)对ATP/UF或SiO2-ATP/UF胶粘剂的甲醛释放量、剪切强度的影响较大;当w(A-1160或KH-792)=15%(相对于ATP质量而言)、w(改性ATP)=10%(相对于甲醛和尿素总质量而言)时,经60℃、3 h吸附后,相应UF胶粘剂的甲醛释放量分别下降了53.27%或53.04%,剪切强度分别增加了57.27%或46.73%;当w(A-1160或KH-792)=15%、w(改性SiO2-ATP)=10%时,经60℃、2 h吸附后,相应UF胶粘剂的甲醛释放量分别下降了34.84%或48.82%,剪切强度分别增加了68.88%或55.38%。 相似文献
8.
9.
Wei Gao 《Iranian Polymer Journal》2012,21(5):283-288
The effect of typical wood composite preservatives, ammonium pentaborate (APB), nanosize copper oxide and basic copper carbonate, on the cure characteristics of phenol formaldehyde (PF) resin in the presence of wood was evaluated by solid-state 13C nuclear magnetic resonance with cross-polarization and magic angle spinning (CP/MAS). With the introduction of APB the absorption intensity and peak area of PF resin at 129.5?ppm was reduced, and the carbons in methylene bridges shifted from 65.8 to 73.5?ppm, which were the result of hydrogen bond formation between ammonium in APB and oxygen of phenolic hydroxyl, as well as coordination bond between the boron in APB and oxygen in phenolic hydroxyl and/or unreacted hydroxymethyl. In addition, the peak area at 152.7?ppm increased with the addition of poplar powder for the overlap of cellulose, hemicellulose, and lignin chemical shifts with the active groups in PF resin. However, the connection status of critically active chemical groups of condensed polymer structure in cured PF resin such as the existence of phenolic ring, phenolic hydroxyl, methylene bridges, and hydroxymethyl linkage are unchanged. Combined with relative increase in the amount of carbon in methylene bridges from 2.42 to 2.56, drop in number of carbons of unreacted hydroxyls from 1.19 to 1.07, and the reported increase in physical and mechanical properties, the nanosize copper oxide improved the curing degree of PF. Furthermore, the similar analysis indicated that basic copper carbonate delayed the curing degree of PF. 相似文献
10.
将腐植酸(HA)进行羟甲基化改性,然后按照m(HA羟甲基化溶液)∶m[脲醛树脂(UF)]=1∶4比例将两者混合均匀,制得腐植酸-脲醛树脂(HUF)。采用红外光谱(FT-IR)、热重分析(TGA)及差示扫描量热(DSC)法等对UF和HUF的结构、热稳定性及玻璃化转变温度(Tg)等进行表征。结果表明:HUF与UF的FT-IR曲线基本相同,前者的FT-IR特征峰均有不同程度增强,热失重峰向高温区移动,说明HUF既保留了UF的原有结构,又具有较强的耐热性;当w(改性HA)=5%~30%时,HUF胶粘剂的胶接强度相对较大;与未改性UF相比,HUF价格更低(节约350元/t)、更环保(甲醛释放量达到GB 18 580-2001标准中E1级指标要求),故HUF具有较强的市场竞争力和良好的应用前景。 相似文献
11.
脲醛树脂中游离甲醛气相色谱的分析 总被引:2,自引:0,他引:2
建立了脲醛树脂中游离甲醛含量的2,4-二硝基苯肼衍生化的气相色谱分析方法。用HP-5弹性石英毛细管柱(30m×0.25mm×0.25μm)分离,以苯甲酸萘酯为内标,线性范围0.2~1.0g/L,线性相关系数R=0.9973,检测限可达0.1g/kg,该法简便快速,分离完全,变异系数CV=2.10%,平均回收率为100.11%,结果满意。 相似文献
12.
13.
14.
介绍了脲醛树脂包膜尿素的制备方法,研究了脲醛树脂及植物油用量对脲醛树脂包膜尿素氮初期溶出率的影响。结果表明,包膜量越多,包膜尿素氮的溶出率越低,但使用脲醛树脂直接包膜尿素的方法并不理想;先使用植物油在尿素颗粒的表面包一层油膜,再使用脲醛树脂包膜,可大幅度降低包膜尿素氮的溶出率,在使用1.0%的植物油后,树脂包膜量为15%时,氮的初期溶出率即可低于40%,大大降低包膜材料的使用量。 相似文献
15.
The flammability of expandable polystyrene foams coated with melamine modified urea formaldehyde resin
下载免费PDF全文
![点击此处可从《应用聚合物科学杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Bo Cao Xiaoyu Gu Xiaohui Song Xiaodong Jin Xinyu Liu Xiaodong Liu Jun Sun Sheng Zhang 《应用聚合物科学杂志》2017,134(5)
Urea formaldehyde resin (UF) was modified by introducing melamine during the condensation in order to reduce the amount of free formaldehyde and increase the solid content. The melamine modified UF (MUF) was firstly mixed with intumescent flame retardant (IFR) and then coated on the surface of pre‐expanded polystyrene (PS) particles to prepare flame retardant expandable PS (EPS) foams. The flammability of EPS foam samples was characterized by limiting oxygen index (LOI), UL‐94 vertical burning and cone calorimeter tests, and the results indicated that the peak heat release rate was significantly reduced from 406 to 49 kW/m2 and LOI value could reach 36.3 with V‐0 rating in UL‐94 test after coated with IFR. The smoke density test indicated that the maximum smoke density was decreased by the addition of IFR. Thermal analysis suggested that the thermal stability and char formation were significantly improved by the presence of coated flame retardants. The residual char observation revealed that MUF and IFR were beneficial to form integrated char layers with hollow stents, which could be the main reason for the improvement of flame retardant properties. The mechanical properties of flame retardant EPS foams can still meet the standard requirements for industrial applications. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44423. 相似文献
16.
Hao Zhang Ying She Shuping Song Qian Lang 《Journal of Adhesion Science and Technology》2013,27(9):1023-1031
In this study, nanocrystalline cellulose (NCC) was used for reinforcement and formaldehyde (HCHO) adsorption of urea-formaldehyde (UF) resin adhesive in fiberboard. The original NCC was modified by 3-aminopropyltriethoxysilane for improving the wetting property with UF resin adhesive. The UF resin adhesive with modified NCC was analyzed by X-ray powder diffraction, thermogravimetric analysis, and Fourier transform infrared. The HCHO emission and bending and bonding strength of the UF resin adhesive with modified NCC were tested according to Chinese National Standard GB/T 17657-1999. Compared with the original UF resin adhesive, modified NCC led to limited effects on the crystal structure, thermal stability, and characteristic absorption peaks of UF resin adhesive. The HCHO emission of the UF resin adhesive with 1.0% modified NCC decreased by 13.0%, while the bending and bonding strength increased by 40.5 and 158.3%, respectively. The improvements of modified UF resin adhesive were destroyed by the reunion of NCC when the content was more than 1.5%. 相似文献
17.
磺化三聚氰胺脲醛树脂的三步法合成工艺研究 总被引:7,自引:1,他引:7
采用三步法代替以往的四步法并以廉价的尿素代替部分价格昂贵的三聚氰胺,合成了具有高减水分散性能的磺化三聚氰胺脲醛树脂(SMUF),简化反应工艺,使羟甲基化和磺化同时进行。研究了磺甲基化反应、缩聚反应和重整反应工艺参数对SMUF分散性能的影响,适宜的反应条件为:原料比n(甲醛):n(三聚氰胺):n(尿素):n(磺化剂)=6:1:1:2时,磺甲基化反应(pH值11.0-11.5,60 min)、酸性缩聚反应(pH值4.5,60-75 min)及碱性重整反应(pH值7-8)温度均在80℃下进行。初步探索了三步法中磺甲基化反应机理。 相似文献
18.
Amorn Petsom Sophon Roengsumran Supattra Hanphichanchai Polkit Sangvanich 《应用聚合物科学杂志》2003,89(7):1918-1924
A brominated phenol–formaldehyde resin was investigated as a plywood adhesive to study the effect of bromine on the physical and flammability properties of this resin. The results of these studies showed that brominated phenol–formaldehyde resin of 10% bromine content by weight of the phenol–formaldehyde resin was suitable to be used as a plywood adhesive. The optimal compressing temperature and compressing time were 110°C and 30 min, respectively. The prepared plywood obtained from the optimal condition gave a high shear strength, good flame retardancy, and good resistance to both hot and cold water. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1918–1924, 2003 相似文献
19.
20.
脲醛树脂(UF树脂)胶黏剂具有胶合强度高、制作简单、成本低廉、原料来源丰富等一系列特点,成为我国人造板生产的主要胶种,是市场上需求量最大的胶黏剂之一。但由于在固化时会放出刺激性的甲醛,游离甲醛高,在使用时严重危害人的健康。近年来,随着人们环保意识的提高,生产和使用低毒UF树脂胶势在必行。本文介绍了稀土氧化镧对脲醛树脂的改性过程并对改性后脲醛树脂胶的各项性能进行了测试。本实验通过在不同反应阶段加入稀土氧化镧,分别探讨它们对脲醛树脂胶黏剂性能影响。实验表明:在脲醛树脂胶中加入稀土氧化镧可以增加黏度、固化时间、固含量,并可以减少游离甲醛释放量。 相似文献