纳米SiO_2/聚氨酯弹性体协同增韧增强环氧树脂的研究

采用力学性能测试,扫描电子显微镜(SEM),透射电子显微(TEM)及动态力学性能分析(DMA)研究了纳米SiO2以及聚氨酯弹性体(PUR)对环氧树脂(EP)的改性效果。结果表明,纳米SiO2质量分数0.3%时可同时增韧、增强EP。纳米SiO2与PUR有协同增韧增强EP的作用,纳米SiO2质量分数0.3%,PUR质量分数20%时,纳米SiO2/PUR/EP三元复合材料的冲击强度比纯EP,纳米SiO2/EP及PUR/EP体系分别提高110%,11%和7%;弯曲强度分别相应提高21%,5%和15%。改性体系的断口形貌呈现明显的韧性断裂,表明纳米SiO2颗粒较均匀分布在基体中。三元复合材料的储能模量和玻璃化转变温度(T g)高于PUR/EP二元体系,损耗峰明显宽化。     

纳米无机填料改性酚醛树脂基防热复合材料烧蚀性能研究现状

树脂基体中共混纳米无机填料是提高酚醛树脂基复合材料烧蚀性能的一种有效途径,无机填料与酚醛树脂共混改性制备复合材料的工艺简单、成本低、改性效果明显,已成为重要的研究方向。本文对无机填料特别是纳米无机填料改性酚醛树脂基烧蚀材料的烧蚀性能研究进行了梳理,并对多种纳米填料改性复合材料的烧蚀机理研究进行总结归纳。     

聚吡咯/纳米ZnO复合材料制备及其防腐性能研究

在纳米ZnO粒子存在的情况下,以吡咯单体为原料,对甲苯磺酸为掺杂剂,三氯化铁为氧化剂,采用化学氧化法制备了聚吡咯(PPy)/纳米ZnO复合物。采用扫描电子显微镜、紫外可见分光光度计和傅立叶变换红外光谱仪对复合物进行形貌观察和结构表征。分别以PPy和PPy/纳米ZnO复合物为填料,加入到聚氨酯(PUR)涂层中,再涂覆于碳钢片表面,之后浸泡在3.5%Na Cl溶液中,通过开路电位、极化曲线和交流阻抗研究涂层的防腐性能。结果表明,含有PPy/纳米ZnO复合物的PUR涂层耐腐蚀效果优于PUR/PPy涂层。     

纳米改性碳/酚醛树脂基复合材料性能研究

针对碳/酚醛树脂基复合材料层间剪切强度低的缺点,采用纳米填料进行改性。测试了2种纳米填料(纳米碳纤维、碳纳米管)改性后酚醛树脂的热解性能,研究了纳米填料对复合材料力学性能、烧蚀性能以及高温炭化后力学性能的影响,并观察分析了复合材料测试后的微观形貌。研究结果表明,纳米填料改性后,复合材料的力学性能、烧蚀性能均有所改善。其中,纳米碳纤维改性后复合材料的常温层间剪切强度达到24.9 MPa,氧乙炔线烧蚀率为22.75μm/s,质量烧蚀率为23.58 mg/s。纳米碳纤维表面粗糙,与树脂基体的界面强度高,因此其改性后的力学性能和烧蚀性能优于碳纳米管。     

三种增强填料对交联POE强度的影响

研究了纳米碳酸钙、白炭黑、纳米高岭土作为交联POE的填料的补强效果。结果表明:白炭黑补强效果最好;纳米高岭土极易在表面改性,经含量为2%的铝酸酯偶联剂表面改性的纳米高岭土填料对交联POE有较强的补强作用,可完全取代纳米CaCO3,或部分替代白炭黑。     

PUR热熔胶研究进展

概述了湿气固化反应型聚氨酯热熔胶(PUR)的研究现状,并从PUR的合成改进、PUR的改性研究及市场应用方面,对国内外近几年的研究进展做了简述,最后对PUR的发展方向进行了展望。     

原位聚合PUR/纳米TiO_2复合材料及其光催化性能

以聚氨酯(PUR)泡沫作为载体,利用纳米TiO_2表面丰富的羟基与二苯基甲烷二异氰酸酯中的异氰酸根反应,通过原位聚合制备了PUR/纳米TiO_2复合材料。以亚甲基蓝(MB)为模拟污染物,研究了PUR孔径、纳米TiO_2的添加量对PUR/纳米TiO_2复合材料光催化性能的影响。FTIR分析结果显示,PUR/纳米TiO_2复合材料在653 cm-1附近出现Ti—O的吸收峰,说明TiO_2成功连接到了PUR的分子链段上。SEM分析结果显示,负载了纳米TiO_2的PUR表面粗糙度增加,有利于MB的吸附,且TiO_2无脱落现象。TG/DTG分析结果显示,纳米TiO_2的加入有利于提高PUR的热稳定性。当纳米TiO_2用量为其它试剂总质量的2.00%时,PUR/纳米TiO_2复合材料最大失重速率温度从纯PUR的324.97℃升高至333.97℃。当PUR泡沫的孔径为4.2 mm、纳米TiO_2用量为其它试剂总质量的2%时,PUR/纳米TiO_2复合材料光催化降解MB的效果较优,降解120 min时的降解率为52.29%,且易于从溶液中回收,表现出较纳米TiO_2粉体不可比拟的易回收性。     

增韧改性聚氯乙烯的研究进展

综述了近年来国内外对聚氯乙烯(PVC)增韧改性的方法,重点介绍了弹性体共混、纳米粒子填充、纤维增强、弹性体/纳米粒子复合材料增韧改性以及绿色填料在PVC增韧改性中的研究进展,指出了改性PVC复合材料具有广阔的应用前景。但开发价格低廉的纳米材料,简化生产工艺,降低产品成本,纳米复合材料增韧PVC的机理、多相协同增韧PVC的机理、不同填料的混杂效应及其协同机理、不同品种木粉改性PVC等尚需进一步研究。     

不同无机填料在聚氨酯弹性体中的性能对比

以聚醚N-204、甲苯二异氰酸酯为原料,用1,4-丁二醇为扩链剂,填充经超声波分散、偶联处理的不同无机填料,分别合成填充型聚氨酯(PUR)弹性体。研究了填充型PUR弹性体的耐磨性、力学性能以及填料在弹性体中的分布状况。结果表明,不同无机填料在PUR弹性体中所表现出的性质不同,碳化硅主要提高了弹性体的耐磨性,而陶瓷微珠、玻璃微珠在增强增韧方面发挥了作用。     

离子液体在合成橡胶中的应用研究进展

综述了离子液体在合成橡胶的加氢反应、硫化和填料改性等方面的应用,着重总结了其在碳纳米颗粒和无机纳米颗粒填料改性中的应用。     

聚酰亚胺树脂改性研究进展

总结了近年来聚酰亚胺树脂(PI)的改性研究进展。重点介绍了PI的结构与功能改性、共聚改性、共混改性(共混树脂包括环氧树脂、热塑性聚氨酯和聚四氟乙烯等)和填充改性(填料包括无机填料、杂化填料、金属和金属氧化物)等方面的研究内容,并对PI未来的研究方向进行了展望。     

Mechanical characteristics of sealants based on polyurethane-lignin polyblends

Previously, different characteristics such as curing, morphology, miscibility and swelling have been evaluated in studies of polyurethane-lignin polyblends. In the present paper the mechanical properties of the same polyblends are investigated and compared with those of polyurethane filled with some mineral fillers. The effect of these fillers and lignin on the polyurethane sealant curing kinetics and the effect of their packing characteristics on the mechanical properties are considered and discussed. The research showed that the addition of mineral fillers or different kinds of lignins increases the Young modulus. The enhancement of the mechanical characteristics is more evident for Sillitin/Titanox (clay/TiO₂) filled polyurethane than for lignin filled polyurethane. This mineral filler combination increases both stress and strain, which is attributed to its finer average particle size.     

本征型自愈合聚氨酯及其相关复合材料的研究进展

综述了近年来本征型自愈合聚氨酯材料的研究进展,包括共价和非共价化学自愈合聚氨酯,以及负载有纳米填充物的相关复合材料的应用.归纳了这些先进材料的发展进程以及赋予其自愈合特性的不同方法,介绍了自愈合聚氨酯领域的潜在应用、挑战和未来的发展前景.     

Effect of Micro- and Nano-Particle Fillers at Low Percolation Threshold on the Dielectric and Mechanical Properties of Polyurethane/Copper Composites

Polymeric composites based on polyurethane (PU) as the matrix and copper (Cu) particles as the filler were prepared by using solution casting. The effects of micro- and nano-particles size and content on the dielectric and mechanical properties depend upon the interface between metal filler and polymeric matrix. The dispersion of the fillers within the polymeric matrix was investigated by scanning electron microscopy (SEM). The SEM results showed a relatively homogeneous dispersion for the micro-particle size and the existence of the aggregation and poor compatibility for the nano-particle size. Differential scanning calorimetric measurements showed that the glass transition temperature (Tg) in case of micro-particles is quite similar to that of the neat PU, but the increase in Tg was observed when nano-particles were used. The dielectric properties of the composites as a function of the filler concentration and filler size was investigated in the frequency range of 100?Hz–10?kHz, showing an increase in dielectric constant with increasing filler content. This increase was more significant when using the nano-particles. The mechanical properties of the composites were obtained by using a tensile tester (ASTM D412). The tensile modulus generally increased with increasing Cu content, but the extent of increase was lower in case of micro-particles. The tensile strength of composite filled with nano-particle slowly decreased when filler content increased, while there was a significant in case of micro-particle as fillers. In addition, the elongation at break decreased with increasing Cu content, but the effect was more significant when micro-particle were employed. AFM image was used to investigate a topology of the tensile fractured surface, showing the mechanism of failure of the composites.     

耐热型聚氨酯弹性体研究进展

综述了聚氨酯弹性体耐热性能的影响因素和提高聚氨酯弹性体耐热性能的一些方法,重点从调整链段结构,选择填料、原料、交联剂等方面介绍了聚氨酯弹性体耐热性能改进的研究成果和发展趋势。     

High strength continuous glass strand—polyurethane composites by the reaction injection molding process

Considerable work has been published on the subject of filling reaction injection molded (RIM) polyurethane elastomers with discontinuous particulate fillers such as milled glass fibers, flake glass and wollastonite, RIM polyurethane elastomers are filled for three reasons: (1) to increase stiffness, (2) to decrease the linear coefficient of thermal expansion, and (3) to improve thermal dimensional stability. Discontinuous particulate fillers either do not appreciably change strength properties, e.g., tensile strength or they cause dramatic reduction in strength properties, e.g., impact resistance. To overcome these deficiencies, new fillers are necessary. Once such material is continuous glass strand mat. In order to make continuous glass strand-polyurethane composites by the RIM process, a particular balance of ingredients to produce the RIM polyurethane must be used. We will discuss the properties of these composites and suggest possible applications and future directions in which this research might proceed.     

Melt mixing of carbon fibers and carbon nanotubes incorporated polyurethanes

Polyurethane composites filled with carbon fibers (CF) and carbon nanotubes (CNT) were prepared by mixing and injection molding, and its mechanical as well as their thermal properties were investigated. Dynamic mechanical analysis (DMA), thermogravimetry analysis (TGA), and thermal conductivity tests were done, and the properties were evaluated as a function of the filler concentration. The storage modulus of the composites increased with fillers concentration, which also mean the increase of the stiffness, suggest a good adhesion between the polyurethane matrix and the fillers. Addition of more CF and CNT to the composites broadened and lowered the peak of tan δ specifies that the polyurethane composite became more elastic because there is a good adhesion between the fillers and the matrix. The addition of carbon fillers improves the thermal stability of the polyurethane. The inclusions of CNT show a better thermal stability when compared with CF. The addition of carbon fillers also increased the thermal conductivity of the polyurethane composites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

双液型遇水膨胀聚氨酯密封胶的研制

介绍了双液型遇水膨胀聚氨酯密封胶的研究。该密封胶以水溶性聚氨酯预聚体为A组分,复合固化剂、填料和增塑剂为B组分,具有遇水膨胀的特殊功能。重点讨论了填料用量、增塑剂用量、固化剂形态对密封胶性能的影响。     

环氧树脂-有机硅复合改性水性聚氨酯耐温防腐涂料的研究

以异氟尔酮二异氰酸酯(IPDI),聚丙二醇(PPG),二甲基硅油及环氧树脂等为主要原料合成了环氧树脂-有机硅复合改性水性聚氨酯,通过添加无机填料和助剂制备了水性聚氨酯涂料。利用红外光谱和热分析仪对乳液、涂料的结构和性能进行表征。探讨了乳液、镇水粉和铁红的用量对涂膜力学性能、耐水性能和防腐性能的影响。当乳液含量为65%,镇水粉含量为10%,铁粉含量为6%时,其热稳定性能提高了50℃,吸水率降低了3倍,冲击强度增加到80 kg/cm,附着力达到0级,自腐蚀电位提高至450 mV。结果表明,无机填料的加入,可极大改善水性聚氨酯涂层的综合性能。