紫外光固化丙烯酸酯胶粘剂的研制

用甲基丙烯酸甲酯、丙烯酸丁酯、丙烯酸-β羟丙酯等单体共聚成光敏树脂（预聚物），加入适量甲基丙烯酸丙酯和光敏剂即得紫外光固化胶粘剂。当加入适量多官能丙烯酸酯（如季戊四醇三丙烯酸酯）时，可大大缩短胶的光固化时间。该胶对诸多基材粘接良好。     

UV固化丙烯酸酯胶粘剂的合成及性能研究

以甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)、甲基丙烯酸缩水甘油酯(GMA)和丙烯酸羟乙酯(HEA)为共聚单体,并以二缩三丙二醇二丙烯酸酯(TPGDA)为交联剂、十二烷基硫醇(NDM)为链转移剂和乙酸乙酯为极性溶剂,采用核/壳溶液聚合法合成了侧链含C=C的丙烯酸酯预聚体;然后以此为基体树脂、丙烯酸异冰片酯(IBOA)和三羟甲基丙烷二丙烯酸酯(TMPTA)为活性稀释剂、651为自由基光引发剂和碘鎓盐为阳离子光引发剂,制备了UV固化胶粘剂。研究结果表明:合成丙烯酸酯预聚体的最佳工艺条件是m(BA)∶m(MMA)∶m(GMA)∶m(TPGDA)∶m(HEA)=20∶60∶10∶4∶6、n(TPGDA)∶n(NDM)=2∶2、w(热引发剂)=3%和w(乙酸乙酯)≥70%(均相对于共聚单体总质量而言);自由基/阳离子混杂双重UV固化胶粘剂比单一自由基UV固化胶粘剂具有更大的附着力和耐酸碱性,此时前者的最佳配方中w(预聚体)=55%、w(651或碘鎓盐)=5%、w(IBOA)=15%、w(TMPTA)=12%和w(GMA)=8%(均相对于胶粘剂总物料质量而言)。     

耐高温热固化胶粘剂问世

由北京航空材料研究院研制出一种耐高温热固化胶粘剂。该研究采用向硅橡中加入乙烯基三特丁基过氧化硅　和金属氧化物等混合配成胶粘剂,这种方法可提高胶粘剂的粘接强度和耐热性能,解决了硅橡胶和金属的粘接技术　困难。粘接件在室温下的粘接扯离强度达2 5MPa ,在30 0℃达0 83～1 4 5MPa,最高使用温度可达35 0℃,该胶的研　制成功,拓宽了硅橡胶及其胶粘剂的应用范围。耐高温热固化胶粘剂问世     

FPC用改性丙烯酸酯胶粘剂的固化研究

改性丙烯酸酯类胶粘剂应用于挠性印制电路板(FPC)及其基材时,其固化程度对性能有着决定性的影响。本文以自制的环氧树脂改性的丙烯酸酯类胶粘剂为例,通过动态差示扫描量热仪(DSC)从理论上分析其非等温固化的动力学行为,以研究其在室温时的储存稳定性和高温固化的工艺条件。然后通过傅里叶变换红外光谱仪(FT-IR)研究其在室温以及125～300℃温度范围内的固化反应历程,以保证该胶粘剂应用于FPC的热固性胶膜/片的固化性能或效果。研究结果表明：(1)通过非等温DSC测试,确定了改性丙烯酸酯胶粘剂的固化动力学方程,由此推算其在10～50℃的常规储存温度下的反应速率常数K值低至10^-5 min^-1级别及以下,具有优异的B阶稳定性;同时在180℃及以上的K值达到10^-1 min^-1级别,可以满足其高温烘烤迅速固化的使用要求。(2)由动态DSC测试得到的三种特征温度,进而推算本胶膜的理论固化温度为182℃,且在此温度下实现100%固化需时约100 min,并通过DSC测试进行了验证。(3)通过FT-IR对比验证了以上...     

三氟化硼微胶囊热固化环氧树脂胶粘剂研究

介绍了三氟化硼微胶囊制备工艺与微囊性能。探讨了单组分三氟化硼微囊热固化环氧树脂胶粘剂的配比与制备工艺。研究了这种胶粘剂在常温下贮存稳定性和在固化温度下对不同材料的粘接工艺和效果。实验表明,该胶粘剂在常温下可稳定贮存３个月,对２５号碳钢的拉伸剪切强度达１６ＭＰａ。     

固化物透明的双组份丙烯酸酯胶粘剂的研制

研究了不同丙烯腈含量的丁腈橡胶(NBR)对双组份丙烯酸酯胶粘剂进行改性,结果表明随着丙烯腈含量提高,固化物透明度增加。     

水溶性丙烯酸酯树脂热固化反应研究

用动力学扭辫分析(TBA)法研究了水溶性丙烯酸酯树脂与六甲氧基甲基三聚氰胺的固化反应。实验证明,仅含羧基或羟基的树脂,其固化反应是一步完成的,所得力学阻尼-温度曲线中只出现一个内耗峰;而既含羧基又含羟基的树脂,其固化反应分二步进行,在该曲线中出现两个对应的峰。同时,也用DSC法研究了丙烯酸树脂的热固化反应,得到与TBA法一致的结论。     

高温固化结构胶粘剂底胶的研究

研制了一种高温固化结构胶粘剂底胶。介绍底胶的配方、工艺、与主体胶粘剂的匹配性及耐介质、耐老化性能。讨论了树脂、固化剂、成膜剂、粘附促进剂、溶剂载体对胶接性能的影响。     

车用胶粘剂热辐射固化CFD分析

以不锈钢受热球体及半球体反射镜(不锈钢)、半球体玻璃罩、不锈钢挡板为分析对象,运用CFD(计算流体力学)技术预测在一定热源的作用下,电子元件的辐射特性对温度场的影响。SolidWorksFlow Simulation可以很好模拟电子元件的辐射传热情况,通过后处理可以直观获得挡板的温度分布云图、所有电子元件的表面温度分布,预测辐射传热的好坏,可为电子元件设计及材质选择提供一定的参考。     

WD3102室温固化耐高温胶粘剂的研制

通过对环氧树脂、液体橡胶、固化剂的选择,研制了一种可以室温固化、耐高温性能好的双组份环氧胶粘剂。     

Thermal decomposition of polyurethane pressure-sensitive adhesives dispersions

The thermal degradation of polyurethane pressure-sensitive adhesives (PSAs) at temperature 600 °C was investigated by the application of pyrolysis-gas chromatography technique. The present study was undertaken in order to determine the key thermal degradation products of polyurethane PSA based on isophorone diisocyanate (IPDI), polypropylene glycol (PPG), hydroxylated polybutadiene (HTPB), dimethylolpropionic acid (DMPA) and to elucidate the mechanism of the polyurethane PSAs pyrolysis.     

Residual monomer release from orthodontic adhesives cured with different light sources

Introduction: The aim of this study was to evaluate the residual monomer release from orthodontic adhesives cured with light-emitting diode (LED) and halogen light sources.

Methods: Seven hundred and twenty stainless steel brackets were divided into 3 groups according to the adhesive system used (Transbond XT light-cure adhesive [TXT], Transbond LR capsule [LR], and Light Bond light-cure adhesive paste [LB]), and each group was divided into 2 subgroups according to light-curing procedure (LED or halogen). Brackets were bonded with adhesives onto tooth buccal surfaces and polymerized. Each specimen contained 24 brackets that simulated the oral environment (n = 5). The specimens were immersed in a 75% ethanol/water solution at 37 °C for 10 min, 1 h, 1 d, 7 d, 14 d, and 30 d, respectively. Eluted monomers (Bis-GMA, UDMA, and TEGDMA) were detected using HPLC.

Results: There was residual monomer release at all time periods, and the highest amount of release was observed cumulatively on the 30th day. The cumulative Bis-GMA released from adhesives was not different (p > 0.05). The cumulative TEGDMA released from adhesives was statistically different (p < 0.05). There was no statistical difference between QTH and LED light-curing units for each adhesive (p > 0.05).

Conclusions: The release of residual monomers stays at a high level for a long time after polymerization. The total leaching of residual monomers from the Light Bond light-cure sealant resin plus Light Bond light-cure adhesive paste was higher than that of other materials for both curing units. Different curing units (LED or QTH) did not affect the monomer release from the orthodontic adhesives.     

Liquid-rubber-modified epoxy adhesives cured with dicyandiamide. I. Preparation and characterization

n-Butylacrylate/acrylic acid (nBA/AA) copolymers were synthesized and used to modify epoxy resin (DGEBA) cured with dicyandiamide (DICY). The precuring reaction between nBA/AA copolymer and DGEBA, the curing cycle of DGEBA, and the effects of DICY and aluminum powder upon the adhesive strengths of modified DGEBA were studied. It was found that the optimum DICY/DGEBA ratio was 6 g/100 g, and lap shear strength and T-peel strength increased with increasing amount of aluminum powder. The curing cycle for modified DGEBA was determined to be 1 h at 177°C.     

Thermal behavior and cured products of fluorine-containing bismaleimides

Thermal behavior of fluorine-containing bismaleimides was investigated by differential scanning calorimetry and the effects of introducing fluorine groups on thermal behavior and properties of cured products were discussed. The melting point was lower and the polymerization temperature was higher with increasing fluorine content. This decrease in polymerization reactity of fluorine-containing bismaleimide was explained by the stabilization energy of the double bond or the bismaleimide molecule itself as calculated by the MNDO or MM method. Thermal polymerization of the double bond was interpreted by an autocatalytic reaction mechanism in which the activated biradical product accelerated the radical propagation. It was found that the fluorine-containing cured product had good thermal stability and a low dielectric constant.     

Quantification of hydrolytic degradation of cured urea-formaldehyde resin adhesives using confocal laser scanning microscopy

This study reports a method of measuring the extent of hydrolytic degradation of cured urea-formaldehyde (UF) resins trapped in the lumen of softwood tracheids, using confocal laser scanning microscopy (CLSM) which enables quantitative determination of the area of a cured UF resin in the lumen as a function of acid etching time. Two formaldehyde/urea (F/U) mole ratios (1.6 and 1.0) and two hardener levels were employed to compare the extent of hydrolytic degradation of cured UF resins. For comparison, we also measured the mass loss of cured UF resin films after acid etching. Cured UF resins with a 1.6 F/U mole ratio resulted in greater hydrolytic degradation than those with a 1.0 F/U mole ratio. The hardener level also showed a clear influence on the extent of degradation with a limited consistency. These results indicate that cured UF resins with higher F/U mole ratios are more easily hydrolyzed than those with low F/U mole ratios, which could be ascribed to a more branched network structure of cured UF resins with a high F/U mole ratio.     

Hydrolytic stability and crystallinity of cured urea-formaldehyde resin adhesives with different formaldehyde/urea mole ratios

This study investigated the relationship between the hydrolytic stability and the crystalline regions of cured UF resins with different formaldehyde/urea (F/U) mole ratios to better understand the hydrolysis of cured urea-formaldehyde (UF) resin adhesives responsible for its formaldehyde emission in service. As the F/U mole ratio decreased, the hydrolytic stability of cured UF resins improved, but decreased when the particle size of the resin was reduced. To further understand the improved hydrolytic stability of cured UF resin with lower F/U mole ratios, X-ray diffraction (XRD) was extensively used to examine the crystalline part of cured UF resins, depending on F/U mole ratios, cure temperature and time, hardener type and level. Cured UF resins with higher F/U mole ratios (1.6 and 1.4) showed amorphous structure, while those with lower F/U mole ratios (1.2 and 1.0) showed crystalline regions, which could partially explain the improved hydrolytic stability of the cured UF resin. The crystalline part intensity increased as cure temperature, cure time and hardener content increased. But the 2θ angles of these crystalline regions did not change, depending on cure temperature and time, hardener type and level, suggesting that the crystalline regions of the cured UF resin were inherent. This study indicates that the crystalline regions of cured UF resins with lower F/U mole ratio contribute partially to the improved hydrolytic stability of the cured resin.