Study on cross-linking agent of a novel one-component API adhesive

The high reactivity and toxicity of isocyanates do not allow their storage and use in one-component system aqueous polymer isocyanate adhesives. Blocked isocyanates are a solution to protect the isocyanate groups by blocking with suitable blocking agent. In order to obtain eco-friendly systems and eliminate the effect of the organic solvents on environment, the blocked isocyanates can be dispersed in water by using external emulsifier by incorporating hydrophilic groups into the backbone. In this work, a series of waterborne blocked polyisocyanate dispersions were prepared by anionic modified process, using polyaryl polyisocyanate (PAPI), 2,4,6-trichlorophenol (TCP), and dimethylol propionic acid. Particle sizes were measured and compared by laser particle sizer and scanning electron microscopy. The structures of aqueous dispersions were characterized by FTIR, ¹H NMR, and ¹³C NMR, and results confirmed that the –NCO groups are effectively blocked by –OH groups. Thermal property was investigated using differential scanning calorimetry; then, kinetic parameters, ΔE, and n were deduced. It was found that the deblocking temperature of aqueous dispersion is about 55?°C. Hydrophilicity was characterized by measuring the water contact angles. The experimental results showed that the contact angle of solvent-borne solution is 68.6°, while that of aqueous dispersion is only 25.2°, which indicated that the hydrophilicity of waterborne TCP-blocked PAPI increases for the introduced hydrophilic group compared with solvent-borne TCP-blocked PAPI. The compressive shear strength was tested to evaluate wood bonding performance of the adhesive.     

熔纺氨纶的流变性能

研究了聚氨酯(TPU)切片、氨纶无油丝和不同混合比例的TPU与交联剂的混合物的流变性能,发现4种样品在熔融状态下均为切力变稀流体,熔体的剪切黏度随剪切速率的增大而减小;交联剂加入越多,熔体剪切黏度越大,在同样剪切速率下其熔融温度越高;随着熔融温度提高,熔体的剪切黏度减小。目前纺丝生产的经验值是TPU切片的熔融温度约为210℃,熔体管路及纺丝箱的温度约在200℃左右。     

水溶性超高分子量聚丙烯酰胺/丙烯酸的研制及竞聚

以丙烯酰胺(AM)和丙烯酸(AA)为原料,采用水溶液自由基共聚法制备超高分子量聚丙烯酰胺/丙烯酸(PAM/AA)共聚物。由正交实验研究了单体浓度、引发剂用量、助剂尿素用量、单体配比、反应温度对聚合物相对分子质量的影响。结果表明,最佳条件为:m(AM)∶m(H2O)=30%,m(AM)∶m(AA)=3,m(I)∶m(AM)=0.3%,m(尿素)∶m(AM)=0.3%,温度20℃,在此条件下,产物分子量高达5 120万,AM和AA的竞聚率为r AM=0.684、r AA=0.278,其中单体残余量由紫外分光光度法测得。     

一种熔融纺防脱散氨纶丝的工艺研究

介绍了一种防脱散氨纶丝的使用原理,并对其生产工艺进行研究。在干燥、组件过滤、冷却、上油等条件优良的前提下,调整了交联剂的添加比例和纺丝温度。试验结果表明:在交联剂质量分数9%、纺丝温度196¹97℃时,生产的防脱散氨纶丝性能优异,防脱散效果好。     

聚氨酯丙烯酸酯大单体及共聚物合成与表征

通过甲苯二异氰酸酯（TDI）和异佛尔酮二异氰酸酯（IPDI）分别与聚乙二醇（PEG）和甲基丙烯酸β-羟乙酯（HEMA）反应，合成了一种聚氨酯丙烯酸酯大分子单体。在引发剂偶氮二异丁氰（AIBN）作用下使大分子单体与苯乙烯（St）交联固化得到一种透明度高、尺寸稳定性好的高分子材料；讨论了温度、时间、催化剂对大分子单体制备的影响；并对材料的机械性能、热性能、光学性能进行了测试。结果表明：材料的透光率达87％以上，热变形温度为180℃以上，硬度为105以上。     

β晶型聚丙烯混杂复合体系的结构和性能

为了了解β晶型聚丙烯混杂复合体系的结构和性能,研究了β晶型聚丙烯在化学交联、添加纳米填料和热处理后的力学性能变化规律。结果表明5％～10％(wt)纳米CaCO3填料或2％(wt)交联剂与0．5％(wt)β晶型成核剂TMB共用时对聚丙烯有优良的增强、增韧效果;在80～150℃热处理温度范围内,加有05％(wt)TMB的聚丙烯在130℃时有最小的抗拉强度。经X衍射分析、差热分析证明在0.4％～0.8％(wt)TMB的用量范围内,对聚丙烯的β晶体的有序性和结晶效率影响不大,在0．5％(wt)成核剂TMB用量时,聚丙烯有最大的结晶度,130℃热处理可进一步提高聚丙烯β晶的结晶效率和总结晶度,结晶温度和熔融温度;加入纳米填料对β晶型聚丙烯的总结晶度和结晶效率影响不大,对有序性有较大的影响：而加入2％(wt)交联剂大大增加了总结晶度,同时大幅降低了β晶的有序度。偏光显微测试发现,纳米填料加入可降低球晶的尺寸和诱导纤维状的β晶形成。     

鞋用水性聚氨酯胶粘剂的研究进展

介绍了水性聚氨酯鞋用胶粘剂制备方法、性能,以及用于提高水性聚氨酯耐水性、耐溶剂性和耐热性能的交联改性技术,综述了水性聚氨酯的国内外研究进展及其在制鞋领域中的应用情况。     

Combined monte carlo/thermodynamic model of formation of microporous aggregate structure like silica from quaternary ammonium silicate solutions

Quaternary ammonium silicate is a surfactant with very high content of silica that allows its use for preparation of protective coatings. The problem of silica aggregation from quaternary ammonium solution in limited volume is the focus of this paper. The system is described by a model based on a Monte Carbo approach with thermodynamic limitations. Thermodynamic characteristics are estimated by statistical polymer method. The model is employed for estimation of such properties as monomer concentration and tortuosity. The results of computer simulation are used for forecasting properties of coatings and for practical preparation of samples coated with quaternary ammonium silicate-based composition.     

水性聚氨酯胶粘剂改性研究进展

综述了水性聚氨酯胶粘剂改性的方法,其中包括交联改性、共混改性、共聚改性及复合改性;并展望了水性聚氨酯胶粘剂改性的发展方向.     

可再生原料为交联剂制备水性聚氨酯脲

以二苯基甲烷二异氰酸酯(IPDI)、二羟甲基丙酸(DMPA)为硬段,聚氧化丙烯二元醇(GE210)为软段,乙二胺(EDA)为扩链剂,制备了具有良好分散性的阴离子水性聚氨酯脲(PUU)分散液。并用可再生的氧化玉米淀粉对其进行了交联改性。测试结果表明,加入氧化交联淀粉后,水性PUU分散液的表面张力增加,成膜后的力学性能得到改善。同时随氧化淀粉用量的增大,水性PUU膜的拉伸强度也逐渐增大。