无机纳米填料改性聚氨酯研究及其应用进展

无机纳米填料改性可改善聚氨酯材料的机械力学性能和耐水、耐热、选择透气性等以及引入抗菌、电磁屏蔽、形状记忆等一些功能特性,近年来,纳米无机填料改性聚氨酯成为聚氨酯改性研究的前沿热点之一。本文综述了聚氨酯纳米复合材料的最新研究进展,在扼要介绍无机纳米填料改性聚氨酯的主要制备方法基础上,着重总结了通过无机纳米填料引入功能特性并应用于多功能涂料、合成革、生物医用材料及形状记忆材料等方面的研究进展,并展望了纳米无机填料改性聚氨酯的一些主要研究方向。     

粒子-聚合物相互作用与粒子-粒子相互作用对聚合物基纳米复合物力学性能的影响

聚合物基纳米复合物(PNCs)具有比传统高分子材料更加优异的光学、力学、热力学等性能,广泛应用于各个工程领域.而纳米粒子(NPs)对材料性能提高的机理则是当前聚合物纳米复合物领域研究的重要问题,聚合物纳米复合体系相互作用的影响因素众多,至今尚未明确并完整建立复合体系相互作用与性能增强之间的关系.本文总结了近年来关于纳米粒子填充聚合物基体力学性能的研究,从粒子-聚合物相互作用和粒子-粒子相互作用角度阐述了聚合物纳米复合体系力学性能的增强机理,并根据体系中不同的结构关系分别总结了聚合物/未改性纳米粒子复合体系和聚合物/聚合物接枝纳米粒子复合体系中影响力学性能的因素.该部分内容具有重要的理论和实践意义,有助于构建复合体系微观结构与宏观性能之间的关系,进而对微观层面调控PNCs的力学性能提供指导.     

聚氨酯与乙酰丙酮铽复合物的相互作用

合成了聚氨酯、乙酰丙酮铽及其复合物. 红外光谱研究结果表明, 铽离子与聚氨酯分子链中的羰基发生了配位作用. 力学性能测试结果表明, 稀土配合物的加入提高了聚氨酯的拉伸强度和断裂伸长等力学性能. 流变性能测试结果显示, 乙酰丙酮铽的加入使聚氨酯溶液的粘度增大, 表明溶液中两者之间存在明显的相互作用.     

亲水性炭黑-天然橡胶纳米复合材料的制备及性能

利用原位球磨法制备了聚苯乙烯磺酸钠表面修饰炭黑,粒径分析和离心沉降实验结果表明,改性炭黑在水中具有十分优异的分散稳定性。利用该改性炭黑通过胶乳混合法成功制备了亲水性炭黑-天然橡胶纳米复合材料。采用万能电子拉力机、扫描电子显微镜、结合橡胶含量分析和动态热机械分析等多种手段对该复合材料进行了测试和研究。结果表明,与未改性炭黑相比,改性炭黑在橡胶基体中的分散性明显改善,与基体的相互作用显著增强,材料的力学性能大幅提高,填料网络化程度明显减弱。     

化学接枝改进ZnO-有机硅纳米复合材料的光学性能

采用N-(三甲氧基硅丙基)-4-叠氮-2,3,5,6-四氟苯甲酰胺(PFPA-silane)改性纳米氧化锌,并将PFPA-silane接枝在有机硅聚合物链上.接枝反应改变了纳米复合物的折光指数,并使ZnO纳米粒子与有机硅基体的折光指数更加匹配.这减少了纳米氧化锌粒子对光的散射作用,增加了纳米ZnO-有机硅纳米复合物的透明性.所制备的复合物通过接枝改性后透光率最多可提高50%.研究结果表明无机物和聚合物的折光指数的匹配程度可以通过偶联剂与聚合物基体的反应来进行调控.     

聚丙烯酸酯-LiNi铁氧体纳米复合物的制备和磁性研究

用流变相法制备了LiNi铁氧体纳米粒子, 通过硅烷偶联剂对纳米LiNi铁氧体表面改性, 用乳液聚合法制备了纳米LiNi铁氧体-聚丙烯酸酯复合物. 用X射线衍射(XRD)、红外光谱(IR)、透射电镜(TEM)、热重分析(TGA)、振动样品磁强计(VSM)以及阻抗-材料分析仪等表征了样品的结构、形貌和磁性能. 结果表明, 引入的纳米铁氧体被聚丙烯酸酯分子链所包覆, 明显提高了复合物的热稳定性. 在外加磁场下, 复合物表现出了较弱的亚铁磁性, 并具有一定的磁滞损耗特性.     

Fe_3O_4/CdTe/聚氨酯纳米复合物的制备及其性能研究

由共沉淀法和Stober法制备了伯胺基功能化SiO2稳定的Fe3O4磁性纳米粒子Fe3O4@SiO2-NH2;Fe3O4@SiO2-NH2与二异氰酸酯及咪唑阳离子二醇、聚乙二醇的反应使其表面形成阳离子型聚氨酯稳定层;通过阳离子型聚氨酯与CdTe量子点表面修饰的巯基乙酸间的电荷相互作用,制备得到了Fe3O4/CdTe/聚氨酯纳米复合物.用X射线衍射(XRD)、红外吸收光谱(FTIR)、热重分析(TGA)、透射电子显微镜(TEM)、磁强计(VSM)、紫外吸收光谱(UV)、荧光发射光谱(PL)表征了该纳米复合物的结构与性能.结果表明,CdTe量子点均匀地分散在Fe3O4@SiO2磁性纳米粒子周围,所得纳米复合物在溶剂中分散均匀,不团聚,且具有超顺磁性,并保持了CdTe量子点的荧光性能.     

天然橡胶原位接枝炭黑的分散性研究

采用原位固相接枝方法,使在高温和强剪切作用下降解的天然橡胶接枝到炭黑表面.采用透射电镜(TEM)、原子力显微镜(AFM)等方法观察了接枝前后的炭黑粒子形貌变化,发现未接枝炭黑以微米级的附聚体形式存在,而由于炭黑聚集体被强剪切力部分破坏,接枝炭黑的聚集程度明显减弱,粒子的尺寸减小.采用激光光散射粒度仪对接枝前后炭黑的粒度进行分析,接枝炭黑的体积平均粒径为164 nm,远小于测得的原炭黑的粒径797 nm.采用沉降法、透光率法及zeta电位测量研究了接枝改性对炭黑在溶剂中的分散性及分散稳定性的影响,结果表明,接枝炭黑在接枝分子的溶剂中的分散性变好,分散稳定性提高.     

有机硅/蒙脱土复合改性聚氨酯弹性体的制备和性能

采用先将聚醚三元醇N330与有机蒙脱土(OMMT)研磨,制得N330/OMMT复合物,再将其与有机硅改性聚氨酯的预聚体混合的方法,以二甲硫基甲苯二胺(DMTDA)为固化剂,制备了有机硅/蒙脱土复合改性聚氨酯弹性体,并用FTIR对产物结构进行了表征.XRD和TEM表明,蒙脱土片层被撑开,并分散在基体中;SEM显示,加入蒙脱土后,有机硅与聚氨酯之间的相容性提高;TGA表明,有机硅和OMMT共同改性聚氨酯后,其耐热性比有机硅单一改性聚氨酯有所提高,并在OMMT含量为5 wt％时提高最大;DSC数据表明,在OMMT含量为5 wt％时,有机硅/蒙脱土复合改性聚氨酯弹性体的Tg明显升高.复合改性材料具有良好的表面性能和力学性能,其拉伸强度、断裂伸长率和硬度在OMMT含量为3 wt％时达到最大值.     

基于碳纳米管/钯纳米粒子复合材料的电化学传感平台

在碳纳米管存在下合成了直径2~10nm的钯纳米粒子,利用全氟磺酸盐聚合物Nafion溶解碳纳米管/钯纳米粒子复合物,构建了检测H2O2的电化学传感平台.循环伏安法证实所合成的钯纳米粒子在复合材料中保持了其电化学活性,该纳米复合物对H2O2具有催化能力.将葡萄糖氧化酶固定在碳纳米管/钯纳米粒子复合物修饰的玻碳电极上,制备...     

Synergistic effects on polyurethane/lead zirconate titanate/carbon black three-phase composites

Synergistic processes in hybrid composites have frequently been described in the literature over the past few years, opening doors to new studies and applications for this type of material. In this study, three-phase composites were obtained using polyurethane (PU) as the matrix, lead zirconate titanate (PZT) as the ferroelectric ceramic and carbon black (CB) as the conductive phase. The discussion is primarily focused on a comparison of the electrical, thermal and dielectric properties of three-phase composites with those of PU_CB and PU_PZT biphasic composites. The study describes a synergistic effect between the PU/PZT/CB phases involved in the generation of charges between the particles, implying better homogeneity of the composites as well as influence over the PU crystallization. The PU_CB conductivity profile showed a phenomenon of multi-step percolation thresholds attributed to the molecular structure and repulsive surface charge of CB particles. The surface charge phenomenon restricted the percolation curve analysis of the three-phase composites by means of classic percolation theory, shown by distortion of the critical exponents. The dielectric constant three-phase composites increased gradually as a function of CB in accordance with the percolation profile.     

Development of electrochemical performances of carbon black obtained by the surface organosilicon-modified method

Carbon black (CB) was simply modified by tert-butylchlorodimethylsilane (TBDMCl) to form the–C–OSiR and–C–OOSiR structures on the surface of CB. The formation of–C–OSiR and–C–OOSiR structures on CB was verified by FTIR and XRD measurements. The modified carbon black (MCB) has relative high electrochemical performance, which was determined by electrochemical studies. The first charging capacity of MCB is at 343 mAh g^–1 and the conductivity of MCB is at 148.1 Sm^–1 which is similar to that of CB 155.2 Sm^–1. These results indicate that application of the obtained MCB will be promising for lithium anode materials. Meanwhile, these results can also suggest solving the overproduction problem of CB in China.     

Preparation and Characterization of Polysulfone/Nanosilver-Doped Activated Carbon Nanocomposite

In this study, nano silver-doped activated carbon (Ag/C) acted as an inorganic additive and was blended with a polysulfone (PSF) matrix in a tetrahydrofuran (THF) solution, thereby forming nano silver- doped activated carbon/polysulfone (Ag/C/PSF) composites. Subsequently, the silver content and characterization of the Ag/C were identified using energy-dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The FTIR, XRD, EDS and SEM were used to characterize the structure and morphology of the Ag/C/PSF composites. The FTIR spectra analysis revealed that adding a small volume of Ag/C in a PSF matrix did not substantially affect the functional groups of the matrix. The XRD results showed that the characteristic crystallization peaks of Ag/C/PSF (2θ = 26°) increased as the Ag/C content increased. The EDS results revealed that silver elements were inlaid into Ag/C/PSF composites, and the SEM results demonstrated strong interfacial interaction between the Ag/C particles and PSF matrix. The results of thermogravimetric analysis and differential scanning calorimetry appeared that adding Ag/C particles increased the thermal decomposition temperature and glass transition temperature of the Ag/C/PSF composites. From a stress–strain analysis, the added Ag/C particles enhanced the tensile strength of the PSF matrix. The results of contact-angle and atomic-force microscopy measuring showed that the hydrophobicity and surface roughness increased when Ag/C content increased. The antibacterial test results revealed that the Ag/C/PSF composites exhibited excellent antibacterial activity against both Staphylococcus aureus and Escherichia coli. In addition, the electrical conductivity measurements showed that volume resistivity of the Ag/C/PSF composites decreased with the amount of Ag/C increase.     

Reactive blending toughened PLA by in situ formation of polyurethane crosslinked elastomer

Polylactide (PLA)/polyurethane (PU) composites were prepared by reactive blending method with in-situ formation of PU particles via the reaction between polyester polyol (PPG) and toluene-2,4-diisocyanate (TDI). The interfacial compatibility and adhesion between the PLA and PU phases were greatly improved by the reaction of the terminal hydroxyl groups of PLA and N=C=O groups of TDI forming graft copolymer, as confirmed by FTIR spectroscopy. The elongation at break and notch impact strength of PLA/PU composites increased considerably with increasing PU content, and the tensile strength of PLA/PU composites decreased slightly compared with that of pure PLA. The excellent interfacial adhesion, dispersed PU elastomeric particles acting as stress concentration areas and the triggering of large matrix shearing yielding and many fibrils by internal cavitation were the main mechanical toughening mechanisms.     

Novel synthesis of nano‐calcium carbonate (CaCO3)/polystyrene (PS) core–shell nanoparticles by atomized microemulsion technique and its effect on properties of polypropylene (PP) composites

Calcium carbonate (CaCO₃)/polystyrene (PS) nanoparticles (<100 nm) with core–shell structure were synthesized by atomized microemulsion technique. The polymer chains were anchored onto the surface of nano‐CaCO₃ through triethoxyvinyl silane (TEVS) as a coupling agent. Ammonium persulfate (APS), sodium dodecyl sulfate (SDS) and n‐pentanol were used as initiator, surfactant, and cosurfactant, respectively. Polymerization mechanism of core–shell latex particles was discussed. Encapsulation of nano‐CaCO₃ by PS was confirmed by using transmission electron microscope (TEM). Grafting percentage of core–shell particles was investigated by Thermogravimetric Analyzer (TGA). Nano‐CaCO₃/PS core–shell particles were characterized by Fourier transform infrared (FTIR) spectrophotometer and differential scanning calorimeter (DSC). The results of FTIR revealed existence of a strong interaction at the interface of nano‐CaCO₃ particle and PS, which implies that the polymer chains were successfully grafted onto the surface of nano‐CaCO₃ particle through the link of the coupling agent. In addition, TGA and DSC results indicated an enhancement of thermal stability of core–shell materials compared with the pure nano‐PS. Nano‐CaCO₃/PS particles were blended with polypropylene (PP) matrix on Brabender Plastograph by melt process with different wt% of loading (i.e. 0.1–1 wt%). The interfacial adhesion between nano‐CaCO₃ particles and PP matrix was significantly improved when the nano‐CaCO3 particles were grafted with PS, which led to increased thermal, rheological, and mechanical properties of (nano‐CaCO₃/PS)/PP composites. Scanning electron microscope (SEM) and atomic force microscope (AFM) images showed a perfect dispersion of the nano‐CaCO₃ particles in PP matrix. Copyright © 2011 John Wiley & Sons, Ltd.     

纳米碳/聚甲基丙烯酸甲酯复合材料的研究

采用脉冲激光轰击浸于流动液相中固体靶的方法,直接连续制备了纳米碳/PMMA的乙酸乙酯溶液,经浇膜法得到了纳米碳/聚甲基丙烯酸甲酯复合材料.光谱分析表明复合体系中存在某种作用,导致该复合材料的玻璃化转变温度明显下降.透射电镜结果表明纳米碳可与聚甲基丙烯酸甲酯形成核/壳结构,使得纳米碳均匀分散于聚合物基体中.热分析结果表明纳米碳的加入对聚甲基丙烯酸甲酯的热分解性能没有显著影响.     

利用高压水射流技术制备天然橡胶复合材料

首先利用超声空化作用将炭黑团聚体破碎、切割、分散在水中制得炭黑悬浮液,然后在高速射流场中,炭黑悬浮液被高速射流卷吸到天然胶乳中,在射流边界,由于二者存在极大的速度差,而形成一个湍流混合层,炭黑在湍流拉伸、剪切作用下微观分散到天然胶乳中.结果表明,与传统干法工艺相比,射流工艺可以使炭黑更均匀的分散到天然橡胶基体中.Payne效应结果表明射流工艺减弱了炭黑与炭黑之间的相互作用,增强了炭黑与橡胶之间的相互作用.同时射流工艺制备的复合材料硫化时间变短,硫化程度增加,硫化胶的撕裂强度提高了78%,回弹性提高了20%,DIN磨耗减小了33%.动态力学性能结果表明,射流工艺制备的复合材料在60℃左右具有更低的损耗因子.     

粒子填充HDPE复合体系动态流变行为研究

研究了炭黑(CB)和石墨(GP)填充高密度聚乙烯(HDPE)复合体系的动态流变行为.发现高填料含量时出现似固体行为,并认为它归因于无机粒子网络逾渗结构的形成.在相同聚合物基体条件下,粒子种类和粒子几何参数(粒子形状、大小、粒径分布)对低频区域流变行为、流变参数的逾渗行为和逾渗阈值(φ_c)有决定性影响,且种类的影响相比于粒子几何参数更为显著.此外,高表面活性及高比表面积(大径厚比、小尺寸)粒子填充体系具有较低的φ_c.     

电响应聚合物薄膜的表面图案化

研究了炭黑(CB)和石墨(GP)填充高密度聚乙烯(HDPE)复合体系的动态流变行为.发现高填料含量时出现似固体行为,并认为它归因于无机粒子网络逾渗结构的形成.在相同聚合物基体条件下,粒子种类和粒子几何参数(粒子形状、大小、粒径分布)对低频区域流变行为、流变参数的逾渗行为和逾渗阈值(φc)有决定性影响,且种类的影响相比于粒子几何参数更为显著.此外,高表面活性及高比表面积(大径厚比、小尺寸)粒子填充体系具有较低的φc.     

Multiple melting behavior of poly(lactic acid) filled with modified carbon black

Two melting peaks are generally observed in a heating scan for isothermally crystallized poly(lactic acid) (PLA)/carbon black (CB) and PLA/modified carbon black (MCB) composites. To investigate the origin of the above double melting behavior, the melting behavior after isothermal crystallization was analyzed with differential scanning calorimetry, wide‐angle X‐ray diffraction, and small angel X‐ray scattering techniques. The double melting of the crystallized samples can be explained by the model of two populations of lamellae, the double peaks of low and high temperatures are contributed to the melting of the small lamellae produced by secondary crystallization and that of the major crystals formed in the primary crystallization process, respectively. Spherulitic growth rates of the neat PLA and PLA/MCB composite were analyzed and the occurrence of a regime transition was demonstrated. For the PLA, a clear regime transition was observed at around 125 °C. For the PLA/MCB, it occurred at 130 °C. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1971–1980, 2009