硅橡胶／纳米铜复合材料的结构与性能研究

采用机械混炼法制备了一种新型的宫内节育器材料——硅橡胶／纳米铜（SiR／nano-Cu）复合材料。利用扫描电子显微镜（SEM）和X射线衍射仪（XRD）观察了复合材料的组织结构,系统研究了nano-Cu含量对复合材料的力学性能、热稳定性能和吸水性能的影响。结果表明,纳米铜在复合材料的分散比较均匀,呈纳米级分布,只有极少数发生团聚。nano-Cu能提高复合材料的硬度,在高添加量时,材料的拉伸强度稍稍下降,但撕裂强度得到了很好的保持。随着纳米铜含量的增大,复合材料的热稳定性和吸水性能大大提高。     

ATRP法制备纳米铜／PMMA-b-PSt复合材料及其表征

在超声辐射作用下,以α-溴代丙酸乙酯为引发剂,溴化亚铜／2,2-联吡啶为催化体系,通过原子转移自由基聚合（ATRP）制备了预聚物PMMA-Br。以此预聚物为大分子引发剂,苯乙烯为共聚单体进行ATRP反应,制得PMMA-b-PSt嵌段共聚物。通过硼氢化钠还原聚合物体系中的溴化亚铜,制得纳米铜／PMMA—b—PSt复合材料。采用红外吸收光谱（IR）、核磁共振（^1H-NMR）、凝胶渗透色谱（GPC）和透射电子显微镜（TEM）等手段对样品进行表征,并用热重分析法对样品的热性能进行了研究。实验结果表明,采用超声方法成功合成了以PMMA-b-PSt为壳和纳米铜为核的复合材料,并发现这种复合材料可以形成以PMMA-b-PSt为连续相和纳米铜为分散相的圆环状组装结构,热分析结果表明纳米铜粒子的存在降低了嵌段共聚物的分解温度。     

聚氨酯/蒙脱土纳米复合材料

综述了聚氨酯／蒙脱土纳米复合材料的制备、结构表征和热力学性能，对制备过程进行了热力学分析，并对其发展前景进行了讨论。聚氨酯／蒙脱土纳米复合材料是一种新型的有机／无机纳米复合材料。在无机材料含量远低于常规填充量的情况下复合材料就可以具有较好的力学性能、阻隔性，热稳定性能也显著提高。     

不同方法制备聚氨酯/蒙脱土纳米复合材料的力学性能研究

采用3种不同制备方法获得了聚氢酯／蒙脱土（PU／MMT）纳米复合材料。通过对材料力学性能测试，发现制备方法对纳米复合材料的拉伸强度杀Ⅱ断裂伸长率有明显影响。蒙脱土和三羟基聚氧化丙烯醚（GP03）预研磨混合制备法所得的纳米复合材料呈现出较好的力学性能。当有机蒙脱土质量分数为2％时，其拉伸强度和断裂伸长率分别比纯聚氨酯材料提高丁30％-68％。     

纳米材料在杂化聚氨酯中的效应简

近年UV固化水性聚氨酯（WPU）或聚氨酯丙烯酸酯（WPUA）纳米复合材料的特性受到众多研究者的关注,并进行了多项研究。采用的纳米材料包括SiO2、Al2O3、TiO2、ZnO、POSS、碳纳米管、碳纳米纤维等。重点综述了WPU和WPUA低聚物（预聚物）的制备、纳米材料的改性处理、WPU／纳米颗粒和WPUA／纳米颗粒杂化复合材料的制备以及所得制品的表征、性能等。     

纳米羟基磷灰石／聚氨酯复合材料的制备与表征

以模拟体液（SBF）为介质,采用仿生法制备了纳米羟基磷灰石（n-HA）,通过原位聚合法制备了纳米羟基磷灰石／聚氨酯（n-HA／PU）复合材料。利用x射线衍射（XRD）、红外光谱（FT-IR）、热重分析（TGA）、扫描电镜（SEM）研究了n—HA和复合材料的结构和热稳定性、表面形貌特征。结果表明,在SBF中用浓度为0．200mol／L硝酸钙溶液制备出具有良好结晶度的n-HA,由此制备的n—HA／PU复合材料开孔率良好,有望成为一种性能良好的医用组织支架材料。     

纳米TiN表面改性的研究及其在ACM胶中的应用

采用自制的大分子表面改性剂对纳米TiN进行表面改性,对改性前后的纳米TiN进行红外光谱分析（FTIR）、热重分析（TGA）、粒径分析、接触角等表征。结果表明,大分子改性剂和纳米TiN的表面发生化学键合,有效地阻止了纳米TIN的团聚,使得纳米T．N疏水性提高。用改性后的纳米TiN填充丙烯酸酯橡胶（ACM）,制备纳米TiN／ACM复合材料,透射电镜（TEM）观察到纳米TiN颗粒在ACM基体中分散良好;复合材料性能检测结果显示：材料的常规力学性能、耐油、耐热空气老化和耐磨性能均有明显提高。     

水性聚氨酯/凹凸棒土纳米复合材料的制备与研究

采用物理共混的方法制备了一系列水性聚氨酯/凹凸棒土（WPU/AT）纳米复合材料。采用扫描电镜和拉伸试验表征WPU/AT纳米复合材料的形态结构和性能。试验结果表明：AT能均匀地分散在WPU基体材料中,提高材料的拉伸强度和断裂伸长率。     

MC尼龙6/纳米SiO2复合材料的合成

用原位聚合法制备MC尼龙6／纳米SiO2复合材料。当纳米SiO2的加入量为1％时,力学综合性能最优。与纯MC尼龙相比,拉伸强度提高21％,弯曲模量提高40．3％,简支梁冲击强度提高69．1％,断裂伸长率降低43％。随着纳米SiO2含量的增加,复合材料的力学性能呈现减小趋势。采用SEM、XRD对产物进行了表征,表明采用修饰后的纳米SiO2加入到产物中,粒子分布均匀,粒径分布窄,粒子的粒径在30nm左右。随着纳米SiO2加入量的增加,MC尼龙6／纳米SiO2复合材料的结晶度下降。     

纳米二氧化钛／水性聚氨酯复合材料的研究

采用溶液共混法制备了纳米二氧化钛／水性聚氨酯复合材料,研究了纳米二氧化钛对复合材料的力学性能和热稳定性的影响,并对影响机理做出了解释。测试了复合材料的抗菌性能,结果表明复合材料对大肠杆菌和金黄色葡萄球菌的抗菌作用随着二氧化钛的含量的增加而增强。     

Polyurethane/clay nanocomposites reinforced with carbon and glass fibres: study of mechanical and thermal properties,and the effect of electron beam irradiation

Polyurethane (PU) nanocomposites with 0, 1, 3, 5, and 7?wt-% nanoclay contents were prepared. X-ray diffraction patterns, transmission electron microscopy images, tensile test, and thermogravimetric analysis were utilised to reveal the morphological, mechanical, and thermal-resistant properties of the prepared nanocomposites. The exfoliated structure was obtained for nanoclay contents up to 3?wt-%. Incorporation of nanoclay to the PU matrix prompted the thermal stability of the polymer. A nanocomposite filled with 3?wt-% nanoclay showed the best tensile strength in the prepared nanocomposites. Subsequently, the nanocomposite with the 3?wt-% nanoclay was reinforced with carbon and glass fibres. Reinforcement of the PU/nanoclay matrix with carbon and glass fibres significantly ameliorated the tensile properties. Finally, the effects of the electron beam irradiation on the nanocomposites and fibre-reinforced composites were studied. Irradiation with the doses up to 500?kGy enhanced the mechanical and thermal properties. However, further irradiation deteriorated the mechanical and thermal-resistant properties.     

A novel carbon nanotube nanopaper polyurethane coating for fiber reinforced composite substrates

High performance carbon nanotube (CNT) nanopaper (NP) reinforced polyurethane (PU) nanocomposite coating with high potential for aerospace and automotive applications was successfully fabricated and evaluated in this work. Different PU formulations were used to fabricate nanocomposites to study the effect of hard segment content on resin infiltration and nanocomposite mechanical properties. The process window of PU infiltration into the CNT NP was established by rheology measurements and thermal gravimetric analysis (TGA). The micro-structure morphology of the nanocomposite was characterized by scanning electron microscope (SEM). Uniform CNT distribution in PU matrix was observed in the high-resolution SEM images, which indicated good resin impregnation quality. Based on mechanical properties and process window, a PU formulation was selected as matrix to fabricate NP/PU nanocomposite coating for carbon fiber/epoxy composites (CFPC) substrate. The flexural strength and impact resistance of the CFPC were significantly improved by 9% and 14.7% after applying the NP/PU nanocomposite coating. Aimed at industrial applications, a continuous nanopaper fabrication process was successfully demonstrated in this work. Through the process window study, a continuous process to fabricate nanocomposite is proposed for future scale-up.     

Morphologies and properties of nanocomposite films based on a biodegradable poly(ester)urethane elastomer

Biodegradable poly(ester)urethane (PU) elastomer‐based nanocomposite films incorporated with organically modified nanoclay were prepared with melt‐extrusion compounding followed by a casting film process. These films were intended for application as biodegradable food packaging films, with their enhanced gas barrier, mechanical, and thermal properties and good flexibility. From both X‐ray diffraction measurements and transmission electron microscopy observations, the coexistence of intercalated tactoids and exfoliated silicate layers in the compounded PU/clay nanocomposite films was confirmed. In addition, the morphology exhibited a clay dispersion state in the matrix and was influenced by the incorporated nanoclay content. The effects of the nanoclay loading level on the thermal, mechanical, and barrier properties of the compounded nanocomposites were also investigated. As a result, it was revealed that the addition of nanoclay up to a certain level resulted in a remarkable improvement in the thermal properties in terms of thermal stability and the degree of thermal shrinkage; mechanical properties, including dynamic storage modulus and tensile modulus; and oxygen/water‐vapor barrier properties of the nanocomposite films. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation and properties of polyurethane/multiwalled carbon nanotube nanocomposites by a spray drying process

A spray drying approach has been used to prepare polyurethane/multiwalled carbon nanotube (PU/MWCNT) composites. By using this method, the MWCNTs can be dispersed homogeneously in the PU matrix in an attempt to improve the mechanical properties of the nanocomposites. The morphology of the resulting PU/MWCNT composites was investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SEM and TEM observations illustrate that the MWCNTs are dispersed finely and uniformly in the PU matrix. X‐ray diffraction results indicate that the microphase separation structure of the PU is slightly affected by the presence of the MWCNTs. The mechanical properties such as tensile strength, tensile modulus, elongation at break, and hardness of the nanocomposites were studied. The electrical and the thermal conductivity of the nanocomposites were also evaluated. The results show that both the electrical and the thermal conductivity increase with the increase of MWCNT loading. In addition, the percolation threshold value of the PU composites is significantly reduced to about 5 wt % because of the high aspect ratio of carbon nanotubes and exclusive effect of latex particles of PU emulsion in dispersion. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Subsurface mechanical properties of polyurethane/organoclay nanocomposite thin films studied by nanoindentation

A series of the exfoliated or intercalated PU/organoclay nanocomposite thin films were prepared by in situ polymerization of polyol/organoclay mixture, chain extender and diisocyanate. The surface mechanical properties of the PU/organoclay nanocomposite films were investigated by means of nanoindentation. The results show that the hardness, elastic modulus and scratch resistant of the nanocomposites dramatically improved with the incorporation of organoclay. This improvement was dependent on the clay content as well as the formation structure of clay in the PU matrix. At 3% clay content, the hardness and elastic modulus of intercalated nanocomposites increased by approximately 16% and 44%, respectively, compare to pure PU. For exfoliated nanocomposite, the improvements in these properties were about 3.5 and 1.6 times higher than the intercalated ones. The exfoliated PU nanocomposites also had greater hardness and showed better scratch resistance compared to the intercalated ones.     

Efficient Dispersion of Magnetite Nanoparticles in the Polyurethane Matrix Through Solution Mixing and Investigation of the Nanocomposite Properties

Recent studies on inorganic/polymer nanocomposites have shown enhancements in thermal, mechanical, and chemical properties over the neat polymer without compromising density, toughness, and processibility. When nanoparticles are incorporated into the polymer matrix, significant enhancements in thermal and mechanical properties of the nanocomposite are observed. The present study is focused on the preparation and characterization of nanosize magnetite-reinforced PU composites, which induces magnetic properties to a specific thermoplastic polyurethane elastomer. The nanocomposites are prepared and the effects of magnetite content on thermal, mechanical, and magnetic properties of the nanocomposites are evaluated. Ultrasonication was used to disperse the nanoparticles and break up any large clumps and aggregates and followed by mechanical mixing. The magnetic nanocomposites were characterized by FT-IR spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and vibrating sample magnetometry (VSM). Characterization of the magnetic nanocomposite by FT-IR showed a successful incorporation of magnetite nanoparticles into the polymeric matrix. TGA and magnetometry of the magnetic nanocomposites revealed the amount of magnetite that was incorporated into the polymeric phase. Finally, the corresponding magnetization behavior of the nanocomposites was studied.     

The synthesis and characterization of polyurethane/clay nanocomposites

The water absorption of montmorillonite was studied using TGA and FTIR, and a removal method through boiling with toluene was investigated. PU/MMT was synthesized and its morphology, thermal dynamic mechanical properties and tensile behaviour were investigated by WAXD, FTIR, DMTA and Instron techniques. We find that, compared with the PU matrix, the intercalated PU/MMT nanocomposite was reinforced and toughened by the addition of nanometer‐size MMT layers. Copyright © 2003 Society of Chemical Industry     

Preparation of Cu/Dickite/LLDPE nanocomposites and synergistic effect of exfoliated dickite and nano‐Cu in LLDPE matrix

A novel anticorrosion packaging nanocomposite composed of LLDPE (linear low‐density polyethylene), nano‐sized Cu, and exfoliated dickite was prepared via melt mixing combined with melt extruding process. X‐ray diffraction and transmission electron microscopy (TEM) were employed to characterize the resultant nanocomposite. The results showed that most dickite layers were exfoliated and the nano‐Cu particles were distributed uniformly in the polymer matrix. The characteristic properties of the Cu/dickite/LLDPE nanocomposite were investigated using salt spray test, thermogravimetry analysis, mechanical test, and antibacterial test. The salt spray test results showed that exfoliated dickite and nano‐Cu improved the anticorrosion properties of the Cu/dickite/LLDPE nanocomposite in simulated ocean environment, respectively. Furthermore, the coexistence of exfoliated dickite and nano‐Cu in Cu/dickite/LLDPE nanocomposite produced a synergistic effect on enhancing the anticorrosion properties. Additionally, the co‐incorporation of exfoliated dickite and nano‐Cu in LLDPE matrix also improved the thermal‐oxidative stability and mechanical properties of the polymer matrix. The bactericidal properties evaluation showed that the Cu/dickite/LLDPE nanocomposite had better bactericidal ability because of the presence of nano‐Cu in LLDPE matrix. POLYM. COMPOS., 34:1061–1070, 2013. © 2013 Society of Plastics Engineers     

Soy Oil-Based Rigid Polyurethane Biofoams Obtained by a Facile One-Pot Process and Reinforced with Hydroxyl-Functionalized Multiwalled Carbon Nanotube

Highly conductive, thermally insulating, and three-dimensional (3D) macromolecular network-structured nanocomposite biofoams with very low density were designed from soy oil-based polyurethane (PU) and hydroxyl-functionalized multiwalled carbon nanotubes (MWCNT-OH) using a facile one-pot process with water as the sole blowing agent. Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM) and Fourier Transform Infrared spectroscopy (FTIR) analyses revealed homogeneous dispersion as well as interaction or reaction of MWCNT-OH with the PU biofoam matrix or a polymeric methylene diphenyl diisocyanate (MDI) to form a 3D macromolecular network structure. Mechanical properties and electrical conductivity were remarkably enhanced with the increase of MWCNT-OH. Dynamic mechanical analysis and thermogravimetric analysis results showed that all the nanocomposite PU biofoam products had good thermal stability properties. Hence, the prepared nanocomposites hold promise as rigid biopolyurethane (BioPU) foams, serving the needs of the conductive composite material fields.     

Self-sacrificial templating synthesis of flower-like nickel phyllosilicates and its application as high-performance reinforcements in epoxy nanocomposites

The nanocomposites of flower-like nickel phyllosilicate particles incorporated into epoxy resin were fabricated via an in-situ mixing process. The flower-like nickel phyllosilicate particles were firstly synthesized using a mild self-sacrificial templating method, and the morphology and lamellar structure were examined carefully. Several properties of mechanical, thermal and tribological responses of epoxy nanocomposites were performed. It was demonstrated that adequate flower-like nickel phyllosilicate particles dispersed well in the matrix, and the nanocomposites displayed enhanced tensile strength and elastic modulus but decreased elongation at break as expected. In addition, friction coefficient and wear rate were increased first and then decreased along with the particle content, and showed the lowest values at a mass fraction of 5%. Nevertheless, the incorporated flower-like nickel phyllosilicate particles resulted in the continuously increasing thermal stability of epoxy resin (EP) nanocomposites. This study revealed the giant potential of flower-like particles in preparing high-quality EP nanocomposites.