多面体低聚倍半硅氧烷在环氧树脂改性中的应用进展

综述了近几年多面体低聚倍半硅氧烷(POSS)在环氧树脂改性中的应用。POSS单独修饰环氧树脂,可提高其力学性能及热稳定性能;POSS协同9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物等功能性分子一起修饰环氧树脂,可增强其阻燃性能;POSS与碳纳米管、石墨烯等纳米材料共同修饰环氧树脂,可提高纳米材料在环氧树脂中的分散性,改善纳米复合材料的导电能力和黏结强度等性能;POSS与纤维共同修饰环氧树脂,可有效增强纤维与环氧树脂间的界面性能。最后展望了POSS修饰改性环氧树脂的未来方向:开发更简易的引入方式,引入更多样的官能分子,协同多种纳米材料修饰环氧树脂。     

Dynamic rheological behavior and mechanical properties of PVC/CPE/MAP–POSS nanocomposites

Poly(vinyl chloride)/chlorinated polyethylene (PVC/CPE)/methylacryloylpropyl‐containing polyhedral oligomeric silsesquioxane (MAP–POSS) nanocomposites are prepared. The plastic behavior and dynamic rheological behavior of PVC/CPE/MAP–POSS are investigated. The influences of composition on dynamic storage modulus G′, loss modulus G″, and complex viscosity η* of PVC/CPE/MAP–POSS melts are discussed. The dynamic mechanical properties, mechanical properties, and morphology are determined. The results show that both plastic time and balance torque of the nanocomposites decrease, but the G′, G″, and η* all increase with increasing MAP–POSS content. The maximum value of the dynamic mechanical loss tan δ decreases and elasticity increases when MAP–POSS is added. The impact strength of the nanocomposites increases with increasing MAP–POSS content and has the best value at 10% content of MAP–POSS, which is 5.38 kJ/m² higher than that of the blend without MAP–POSS. The MAP–POSS can be used as an efficient process aid and impact aid for the PVC/CPE blend. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

The synthesis, characterization and biocompatibility of poly(ester urethane)/polyhedral oligomeric silesquioxane nanocomposites

The primary goal of this study is to develop a facile and inexpensive synthesis method for a new biodegradable and biocompatible poly(ester urethane) (PEU)/polyhedral oligomeric silesquioxanes (POSS) nanocomposite via in situ homogeneous solution polymerization reaction into prescribed macromolecular structure and properties including improved biocompatibility, thermal and hydrolytic stability, and stiffness and strength. Cell culture studies, nuclear magnetic resonance spectroscopy, X-ray diffraction, differential scanning calorimetry, thermogravimetry, and dynamic mechanical analysis measurements were used to confirm the structure and property improvements. The results show that the targeted PEU/POSS nanocomposites (which are remarkably different from conventional polymers, polymer nanocomposites and microcomposites) have significant improvements in mechanical properties and degradation resistance at small POSS concentrations (≤6 wt%). The nanocomposites exhibited excellent support for cell growth without any toxicity. POSS concentration did not affect cell adhesion or cell growth, but it significantly changed the surface structure of the PEU into a 3-dimensional matrix with regular pores that may allow cells to better access the growth factors/nutrients, waste exchange, and tissue remodeling. The PEU/POSS nanocomposites were resistant to degradation over a period of six months when exposed to a buffer solution. These desirable characteristics suggest that the nanocomposites may hold great promise for future high-end uses such as in biomedical devices, especially at cardiovascular interfaces.     

聚合物基氧化石墨烯纳米复合材料研究进展

氧化石墨烯作为石墨烯的重要衍生物，原料来源广泛，制备过程简单，成本低廉，具有优异力学性能、耐磨性能以及吸附性能等，其还原产物具有优良的导电性能和导热性能等，是聚合物基纳米复合材料的理想填料。近年来，随着复合材料制备方法的不断革新，聚合物基氧化石墨烯纳米复合材料得到了快速发展，并在储能、阻燃等领域实现了规模化应用，有助于引领聚合物基氧化石墨烯纳米复合材料相关产品的进一步开发和应用。本文系统介绍了氧化石墨烯的改性方法，综述了聚合物基氧化石墨烯纳米复合材料的研究进展，展望了聚合物基氧化石墨烯纳米复合材料的发展前景。     

纳米材料改性水性聚氨酯研究进展

综述了近几年纳米材料对水性聚氨酯的改性研究,包括天然高分子纳米材料改性、黏土矿石类纳米材料改性、纳米碳素材料改性、金属与金属氧化物纳米材料改性。化学改性能提高纳米材料与聚合物基质间的相容性,有利于得到稳定的复合乳液。物理共混改性能更好地将纳米材料的优异特性赋予复合材料。在水性聚氨酯中均匀分散的纳米粒子可以显著提高复合材料的热稳定性与力学性能。开发高效实用的纳米材料有机化改性技术和优化复合材料的制备工艺将是未来制备高性能水性聚氨酯纳米复合材料的发展趋势。     

Low‐Dielectric Constant and Low‐Temperature Curable Polyimide/POSS Nanocomposites

With the rapid development of ultra large scale integrated circuits, low stress, low thermal expansion, low dielectric constant, and low temperature curable (<250 °C) polyimides (PIs) with excellent mechanical, thermal properties are required. Unfortunately, high curing temperatures above 300 °C and limited dielectric property still remain to be solved. Herein, a new type of aminopropyl isobutyl polysilsesquioxane (POSS) with single vertex activity is introduced by in situ polymerization resulting in the PI‐POSS nanocomposites which exhibit a low dielectric constant (κ ≤ 2.6). Furthermore, low‐temperature curing at 200 °C (99.4% imidization) under the catalysis of quinoline is also achieved. The as‐prepared PI‐POSS nanocomposites also show excellent mechanical properties of which the tensile strength can reach up to 148 MPa and the elongation at break achieves 98%. Moreover, the temperature of weight loss 5% is as high as 550 °C and the glass transition temperature can also reach 349 °C. The as‐prepared PI‐POSS nanocomposites prove excellent electrical performance and mechanical properties, showing a huge market prospect of 5G chip packaging and millimeter wave antenna in the future.     

Rheological behavior and mechanical properties of PVC/MAP‐POSS nanocomposites

The polyhedral oligomeric silsesquioxanes which contains methylacryloylpropyl groups (MAP‐POSS) was synthesized. The MAP‐POSS/PVC nanocomposites were prepared. The influences of composition, shear rate' shear stress on melting rheological behavior of MAP‐POSS/PVC nanocomposites were discussed. The dynamic mechanical properties, mechanical properties, and morphology were determined by DMA, material tester and SEM, respectively. The result shows that the plastic times decreases and melt viscosity increases with increasing MAP‐POSS content. The n has a maximal value at 5 wt% MAP‐POSS content, but have best impact strength at 3%. MAP‐POSS can use as process aid and impact aid of PVC at appropriate contents. POLYM. COMPOS., 31:1822–1827, 2010. © 2010 Society of Plastics Engineers.     

POSS related polymer nanocomposites

This review describes the syntheses of polyhedral oligomeric silsesquioxane (T₈-POSS) compounds, the miscibility of POSS derivatives and polymers, the preparation of both multifunctional and monofunctional monomers and polymers containing POSS including styryl-POSS, methacrylate-POSS, norbornyl-POSS, vinyl-POSS, epoxy-POSS, phenolic-POSS, benzoxazine-POSS, amine-POSS, and hydroxyl-POSS. The thermal, dynamic mechanical, electrical, and surface properties of POSS-related polymeric nanocomposites prepared from both monofunctional and multifunctional POSS monomers are discussed. In addition, we describe the applications of several high-performance POSS nanocomposites in such systems as light emitting diodes, liquid crystals, photo-resist materials, low-dielectric constant materials, self-assembled block copolymers, and nanoparticles.     

Performance enhancement of polylactide by nanoblending with POSS and graphene oxide

We report the effect of filler modification on the properties of polylactide (PLA)‐based nanocomposites, where graphene oxide (GO) nanosheets and polyhedral oligomeric silsesquioxane (POSS) nanocages are employed as nanofillers. The organically treated nanofillers are termed as GO‐functionalized and POSS‐functionalized. The synthesis of the nanocomposites was carried out via in situ ring‐opening polymerization of lactic acid (LA). The following four naocomposite systems were prepared, characterized, and compared to achieve a better understanding of structure‐property relationship (1) PLA/GO‐functionalized, (2) PLA/POSS‐functionalized, (3) PLA/physical mixture of GO‐functionalized and POSS‐functionalized, and (4) PLA/GO‐graft‐POSS (with eight hydroxyl groups). As revealed by the thermal and mechanical (nanoindendation) characterization, that the nanocomposites having a combination of GO and POSS as nanofiller, either as physical mixture of GO‐functionalized and POSS‐functionalized or as GO‐graft‐POSS, is far more superior as compared with the nanocomposites having individually dispersed nanofillers in the PLA matrix. Observed enhancement is attributing to the synergistic effect of the nanofillers as well as better dispersion of the modified‐fillers in the matrix. POLYM. COMPOS., 35:118–126, 2014. © 2013 Society of Plastics Engineers     

Rheological and crystallization enhancement in polyphenylenesulfide and polyetheretherketone POSS nanocomposites

Polyhedral oligomeric silsesquioxane (POSS) additives have been shown to increase melt‐flow and crystallization in thermoplastics. In this study, the effect of incorporation of trisilanolphenyl‐POSS molecules in polyphenylenesulfide (PPS) and polyetheretherketone (PEEK) on rheology, crystallization kinetics, and thermal and mechanical properties was evaluated. Parallel plate rheometry revealed a reduction in the viscosity of PPS and PEEK with the addition of POSS. The magnitude and concentration dependence of rheological modification were shown to depend on the polymer structure and POSS solubility. Isothermal crystallization kinetics were analyzed using the Avrami model and it was found that the addition of POSS accelerated the crystallization rate of PPS blends with no significant effect on PEEK blends. Interestingly, no statistical difference in degradation temperature, tensile modulus, or tensile strength of PPS or PEEK blends was observed. The findings indicate the potential for improvements in melt viscosity and crystallization of high temperature thermoplastics with tailored POSS/polymer interactions. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44462.     

Shape memory polyester-based nanomaterials: cutting-edge advancements

ABSTRACT

Shape memory polymers have gained immense importance across technical industries ranging from aerospace and electronics to biomedical fields. This article presents state-of-the-art overview of versatile shape memory polyesters and derived nanocomposites. Shape memory polyesters such as polylactic acid, polyhydroxyalkanoate, polycarbonate, and polyester blends have been identified. Shape memory polyesters have also been reinforced with nanoreinforcements including fullerene, graphene, carbon nanotube, and polyhedral oligomeric silsesquioxane (POSS). Consequently, different groups of stimuli-responsive polyester nanocomposites have been discussed such as polyester/graphene, polyester/carbon nanotube, polyester/fullerene, and polyester/POSS. Future development of shape memory polyesters may reveal superior electrical, mechanical, and thermal performance for technical applications.     

Thermal dehydroxylation of clay as alternative to organic modification: effects on properties of nanocomposites

Abstract

This study presents a novel approach towards clay modification via thermal dehydroxylation, for polymer nanocomposite application. The feasibility of modification of clay via thermal dehydroxylation and its influence on the polymer properties was investigated, with reference to the polyproplylene (PP) nanocomposites. In spite of ample available literatures on organophillic clay/polymer composites, use of organic compound for the clay modification has been found detrimental in various aspects. Therefore, in order to corroborate the advantage of the thermal dehydroxylation method over organophillic modification, a comparative aspect of the effect of the organically modified and thermally dehydroxylated clay on the polymer properties has been established. Wherein, remarkably greater mechanical, dynamic mechanical, thermal and microstructural properties were noticed in case of nanocomposites reinforced with thermally dehydroxylated clay. Modification of clay via thermal dehydroxylation method was found to be an effective approach for polymer nanocomposite application.     

改性HA纳米粒子在骨组织工程中的应用[ ]

羟基磷灰石(HA)具有优异的生物活性和生物相容性,广泛应用于骨修复、再生和置换等骨组织工程,但HA纳米粒子难分散、强度低、高分子相融性差等缺点限制了其应用。为了克服这些缺点,研究员致力于探索改性或复合HA的方法,以改善其分散性、亲水性、抗菌性以及机械强度等,来满足临床应用的要求。本篇综述总结归纳了当前主流的HA纳米粒子改性方法,包括离子掺杂、表面改性、材料复合等。最后,我们还讨论了当前HA复合材料的研究热点,以期为HA复合材料相关基础研究提供有益的借鉴与启示。     

Exploitation of Carbon Nanotubes in High Performance Polyvinylidene Fluoride Matrix Composite: A Review

Among nanocarbon fillers, carbon nanotubes are considered to be an ideal reinforcement due to their miniscule size, and excellent electrical, thermal, and mechanical properties. However, carbon nanotubes can be utilized in polymer nanocomposites only if they are homogenously dispersed into polymer matrices. The multiwalled carbon nanotube has been concentrated as a reinforcement for an important type of thermoplastic polyvinylidene fluoride. This review initially focuses on carbon nanotubes modification both by mechanical methods and chemical functionalization to improve their dispersion. Moreover, the processing methods for polyvinylidene fluoride/carbon nanotubes nanocomposite have been discussed. Multiwalled carbon nanotubes facilitate the electrical conductivity, thermal, rheological, and mechanical properties of polyvinylidene fluoride.     

Synthesis of eugenol‐based polybenzoxazine–POSS nanocomposites for low dielectric applications

Nanocomposites of eugenol‐based polybenzoxazines/amine containing polyhedral oligomeric silsesquioxane (POSS) have been prepared through copolymerization of allyl‐containing benzoxazine compounds and amine containing POSS. Their structures, curing behaviour, and thermomechanical properties were characterized by Fourier transform infrared, ¹H‐NMR, ¹³C‐NMR, X‐ray diffraction, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and thermogravimetric analysis (TGA). The nanoscale dispersion of POSS cores in the nanocomposites was verified by scanning electron microscopy, atomic force microscopy, and transmission electron microscopy studies. The results from DMA and TGA show that the thermal stability, crosslink density and flame retardance of the nanocomposites increased when small amounts of POSS cores (5 wt%) were incorporated into the system. Further the POSS incorporation reduces the dielectric constant of the benzoxazines to about 1.32. Hence, the prepared nanocomposites could be used as ultra‐low‐k materials for advanced microelectronics. POLYM. COMPOS., 36:1973–1982, 2015. © 2014 Society of Plastics Engineer     

Morphology and mechanical properties of high density polyethylene‐POSS hybrid nanocomposites obtained by reactive blending

The high density polyethylene‐polyhedral oligomeric silsesquioxane (HDPE‐POSS) organic–inorganic hybrids were obtained and their properties studied. The hybrids were prepared by grafting of POSS on polyethylene chains during reactive melt‐blending of HDPE, maleic anhydride functionalized HDPE and amine‐functionalized POSS, taking advantage of the high efficiency of amine‐anhydride reaction in the molten state. The structure, morphology, and physical properties of the obtained hybrids and blends were studied to find the influence of POSS chemical structure and grafting degree on the morphological characteristics and mechanical properties of hybrid nanocomposites. It was found that grafting of POSS cages on HDPE chains leads to the POSS dispersion at the molecular level. On the contrary, when POSS was mixed with plain HDPE any grafting of POSS on polyethylene chains was not possible, which resulted in phase‐separated blend. The mechanical tests revealed that modification of polyethylene by grafting with POSS molecules does not affect significantly its mechanical properties, both static and dynamic, except ultimate strain, which is lower in hybrids and their blends than in plain HDPE. The impact properties (Izod impact strength) were slightly improved by grafting of HDPE with POSS. HDPE‐g‐POSS hybrids demonstrated also much enhanced thermo‐oxidative stability comparing to plain polyethylene. POLYM. ENG. SCI., 55:2058–2072, 2015. © 2014 Society of Plastics Engineers     

High-Performance Low-k Poly(dicyclopentadiene) Nanocomposites as Achieved via Reactive Blending with Norbornene-Functionalized Larger POSS

Low dielectric constant (k) polymers with excellent comprehensive properties are useful materials in the microelectronics industry as matrix resins or encapsulation layers. With the inherent low polarization, high reactivity, good processability, and low cost, poly(dicyclopentadiene) (PDCPD) has received considerable attention as low-k materials. However, its practical application is limited by the relatively high thermal expansion and k value. Herein, three norbornene-functionalized polyhedral oligomeric silsesquioxanes (POSSs) with T₈, T₁₀, and T₁₂ polyhedral cores are synthesized and employed for enhancing the dielectric and comprehensive properties of PDCPD via reactive blending. The results show that these POSSs have good compatibility with PDCPD matrix and nano-dispersed POSSs particles could be obtained. As a result, the materials’ properties can be largely enhanced by varying the POSS content and POSS size. Especially, PT₁₂N₁₂-40 (40 wt% of T₁₂N₁₂) shows the lowest k value (2.1) and coefficient of thermal expansion (63.4 ppm°C⁻¹), highest glass transition temperature (202.5 °C), yield strength (78.0 MPa), and elastic modulus (2.36 GPa), along with excellent hydrophobicity. This study highlights a useful strategy to fabricate high-performance low-k polymer nanocomposites by using larger POSS and reactive blending, which provides useful materials for the future microelectronic industry and high frequency communication.     

Synthesis and modification of silica-based epoxy nanocomposites with different sol–gel process enhanced thermal and mechanical properties

This research article describes the results of nano-silica composites filled with different epoxy contents containing nano-SiO₂ particles from (5–25 wt%). Reinforcing hybrid composites enhance thermal and mechanical properties to achieve vital and sustainable products. Silica-based nanocomposites with high purity were prepared and used for the surface modification of nanosized silica particles. The surface structure's composition and physical properties of modified nano-SiO₂ particles were characterized through Fourier transferred infrared spectrometer, X-ray photoelectron spectroscopy, thermogravimetric analyzer, and scanning electron microscopic. Silica-based nanocomposites were prepared by incorporating of modified nano-SiO₂ as an enhancing filler. The morphology of fracture surface and dynamic mechanical properties were investigated. Results showed that the silica-based epoxy nanocomposites are bearing a long chain structure that could improve the compatibility of silica nanocomposites with epoxy resin and contribute to a better dispersion state in the matrix, which enhanced the overall performance of epoxy-cured products.     

Thermoset/graphene polymer composites—A review of processing and properties

Polymer-carbon nanocomposites incorporate the exceptional properties of both the polymer matrices, such as low cost and simple processing, with the distinctive features of the carbon-based fillers, such as high electrical and thermal conductivities, and excellent mechanical properties. Various fillers like carbon black (CB), graphite, expanded graphite (EG), and carbon nanotubes (CNTs) are being used to produce materials with advanced properties. However, at high filler loading, these filler materials have some major challenges such as filler agglomeration. Recently, graphene has gained increased interest as an alternative filler to produce polymer nanocomposites with advanced characteristics. Thermosetting polymer composites with graphene fillers are being considered for multiple applications and are a subject of interest for researchers because of enhanced properties like excellent corrosion resistance and low density. This review outlines studies to improve the mechanical, electrical, and thermal properties of thermoset/graphene composites.