纳米阻燃高分子材料:现状、问题及展望

纳米阻燃体系是一种新型的聚合物阻燃体系,被誉为阻燃技术的革命.极少量(≤5wt%)纳米阻燃剂的加入即能显著降低高分子材料燃烧时的热释放速率(HRR)和烟密度(SEA),延缓其燃烧过程,还能不同程度地提高材料的力学性能.本文总结了近年来国内外纳米阻燃领域的进展,介绍了本课题组在纳米阻燃方面所做的工作,探讨了纳米阻燃研究中存在的问题,并对其未来的发展进行了展望.     

Flame retarded polymer nanocomposites: Development,trend and future perspective

Polymer nanocomposites are a new class of flame retarded materials which have attracted much attention and considered as a revolutionary new flame retardant approach.A very small amount of nano flame retardants (normally < 5 wt%) can significantly reduce the heat release rate (HRR) and smoke emission (SEA) during the combustion of polymer materials.Moreover,the addition of nano flame retardants can also improve the mechanical properties of polymer materials compared with the deterioration of traditional fla...     

Polymer Nanocomposites in Building,Construction

Nanotechnology is an enabling technology allowing to do new things in almost every conceivable area. Initial efforts to exploit nanoscience/nanotechnology development in the construction industry focused mainly on understanding phenomena and improving performance of existing materials. Recently, polymer nanocomposites started to be introduced in other areas like the construction industry.

Polymer nanocomposite field attracts considerable attention these days due to a variety of potential practical applications. They have offered a great opportunity in sustainable construction/green building application due to their efficiency and environmental protection. Their use in the construction industry is still less known outside the research area. This paper is a short review of recent studies done in this area, taking into account that some nano based materials are ready to be used by the construction industry. This review covers some studies done in the polymer nanocomposite applications in construction basic materials such as concrete, asphalt, thermal and sound insulation, adhesives, coatings, plastics and in energy.     

Recent Progress in Two-dimensional Nanomaterials Following Graphene for Improving Fire Safety of Polymer (Nano)composites

The high fire safety of polymer nanocomposites is being pursued by research institutions around the world. In addition to intrinsic flame retardancy strategy, the additive-type flame retardants have attracted increasing attention due to low commercial cost and easy fabrication craft. However, traditional additive-type flame retardants usually need high addition amount to achieve a desirable effect, which causes many side-effects on the overall performance of polymer materials, such as deteriorated mechanical property and processability. At present, two-dimensional(2 D) nanomaterials have also been applied to reduce the fire hazards of polymer(nano)composites with the coupling of barrier function and catalysis as well as carbonization effect. Even though most research work mainly focus on graphene-based flame retardants, more emerging two-dimensional nanomaterials are taking away research attention, due to their complementary and unique properties, mainly including hexagonal boron nitride(h-BN), molybdenum disulfide(MoS_2), metal organic frameworks(MOF), carbon nitride(CN),titanium carbide(MXene) and black phosphorene(BP). In this review, except for graphene, the flame retardant mechanism involving different layered nanomaterials are also reviewed. Meanwhile, the functionalization method and flame retardancy effect of different layered nanomaterials are emphatically discussed for offering an effective reference to solve the fire hazards of polymer materials. Moreover, this work objectively evaluates the practical significance of polymer/layered nanomaterials composites for industrial application.     

Synthesis and properties of transparent luminescent nanocomposites with surface functionalized semiconductor nanocrystals

5-Amino-1,10-phenanthroline (Aphen) was used as an organic ligand to functionalize CdS nanocrystals (NCs) by a ligand-exchange process. The functional Aphen-CdS NCs have strong luminescent emission at 552 nm and good dispersibility in the polar organic monomers. The Aphen-CdS NCs were dispersed in polymeric monomers to prepare a series of transparent luminescent nanocomposites with excellent thermal stability via in-situ bulk polymerization. The fluorescent properties of the Aphen-CdS NCs were well retained in the polymer matrix. It was found that when the methacrylic acid (MAA) and glycidyl methacrylate (GMA) as the comonomers were introduced into the polymer matrix, the emission peaks of the resultant nanocomposites had a blue shift and the fluorescent intensities also increased due to the interaction between NCs and the polymer matrices. The transparent NCs/polymer nanocomposites with tunable fluorescent emission can be potentially used for the fabrication of optoelectronic devices.     

Preparation and characterization of nano‐platelet‐like hydroxyapatite/gelatin nanocomposites

Nature has succeeded in creating numerous bionanocomposites such as bones and teeth consisting of nano‐platelets and biopolymers. Understanding of the mechanisms of formation and of the relation between structure and properties is vital for development of new materials for biomedical and engineering applications. In this work, varying contents of nano‐platelet‐like hydroxyapatite (HAp) has been used to reinforce gelatin (Gel) to produce nanocomposites. The prepared HAp/Gel nanocomposites were characterized by X‐ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric (TG/DTG) analyses. XRD, TEM, and FTIR results confirm the synthesis of intercalated and exfoliated nanostructures depending on the amount of gelatin. TG results reveal that the intercalated HAp/gelatin nanocomposites show improved thermal properties as compared to pristine gelatin. The results reported here can be expanded to other HAp–polymer systems, thus paving a new way of designing and fabricating biomemitic nanocomposites for future engineering and particularly for biomedical applications. Copyright © 2010 John Wiley & Sons, Ltd.     

Role,effect, and influences of micro and nano‐fillers on various properties of polymer matrix composites for microelectronics: A review

Ever since the discovery of polymer composites, its potential has been anticipated for numerous applications in various fields such as microelectronics, automobiles, and industrial applications. In this paper, we review filler reinforced polymer composites for its enormous potential in microelectronic applications. The interface and compatibility between matrix and filler have a significant role in property alteration of a polymer nanocomposites. Ceramic reinforced polymeric nanocomposites are promising candidate dielectric materials for several micro‐ and nano‐electronic devices. Because of its synergistic effect like high thermal conductivity, low thermal expansion, and dielectric constant of ceramic fillers with the polymer matrix, the resultant nanocomposites have high dielectric breakdown strength. The thermal and dielectric properties are discussed in the view of filler alignment techniques and its effect on the composites. Furthermore, the effect of various surface modified filler materials in polymer matrix, concepts of network forming using filler, and benefits of filler alignment are also discussed in this work. As a whole, this review article addresses the overall view to novice researchers on various properties such as thermal and dielectric properties of polymer matrix composites and direction for future research to be carried out.     

原位自组装形成二氧化硅/十六烷基三甲基溴化铵纳米网络粒子

提出了以具有纳米尺寸孔径及孔壁厚度的MCM 48作为无机基体、以无机 有机原位自组装的方法形成纳米网络粒子 .研究结果表明 ,在一定实验条件下 ,有机相可进入无机相的三维孔道自组装形成立方有序结构的纳米网络复合粒子 .通过研究纳米网络粒子在极性介质和非极性介质中的分散发现 ,有机相的存在有利于纳米网络粒子的分散     

Strong,Supertough and Self-Healing Biomimetic Layered Nanocomposites Enabled by Reversible Interfacial Polymer Chain Sliding

Despite the remarkable progress in ultrastrong mechanical laminate materials, the simultaneous achievement of toughness, stretchability and self-healing properties in biomimetic layered nanocomposites remains a great challenge due to the intrinsic limitations of their hard essences and lack of effective stress transfer at the organic-inorganic fragile boundary. Here, an ultratough nanocomposite laminate is prepared by constructing chain-sliding cross-linking at the interface between sulfonated graphene nanosheets and polyurethane layers based on the ring molecules sliding on the linear polymer chains to release stresses. Unlike traditional supramolecular bonding toughening with limited sliding spacing, our strategy enables interfacial molecular chains reversible slippage when the inorganic nanosheets bear stretching force, providing sufficient interlayer spatial distance for relative sliding to dissipate more energy. The resulting laminates exhibit strong strength (22.33 MPa), supertoughness (219.08 MJ m⁻³), ultrahigh stretchability (>1900 %) and self-healing ability (99.7 %), which far surpass most of reported synthetic and natural laminate materials. Moreover, the fabricated proof-of-concept electronic skin shows excellent flexibility, sensitivity and healability for human physiological signals monitoring. This strategy breaks through the challenge that traditional layered nanocomposites are intrinsically stiff and opens up the functional application of layered nanocomposites in flexible devices.     

Two-dimensional nanocomposites based on chemically modified graphene

The multiple functional groups and unique two-dimensional (2D) morphology make chemically modified graphene (CMG) an ideal template for the construction of 2D nanocomposites with various organic/inorganic components. Additionally, the recovered electrical conductivity of CMG may provide a fast-electron-transport channel and can thus promote the application of the resultant nanocomposites in optoelectronic and electrochemical devices. This Concept article summarizes the different strategies for the bottom-up fabrication of CMG-based 2D nanocomposites with small organic molecules, polymers, and inorganic nanoparticles, which represent the new directions in the development of graphene-based materials.     

Nanocelluloses: a new family of nature-based materials

Cellulose fibrils with widths in the nanometer range are nature-based materials with unique and potentially useful features. Most importantly, these novel nanocelluloses open up the strongly expanding fields of sustainable materials and nanocomposites, as well as medical and life-science devices, to the natural polymer cellulose. The nanodimensions of the structural elements result in a high surface area and hence the powerful interaction of these celluloses with surrounding species, such as water, organic and polymeric compounds, nanoparticles, and living cells. This Review assembles the current knowledge on the isolation of microfibrillated cellulose from wood and its application in nanocomposites; the preparation of nanocrystalline cellulose and its use as a reinforcing agent; and the biofabrication of bacterial nanocellulose, as well as its evaluation as a biomaterial for medical implants.     

Thermal and mechanical properties of syndiotactic polystyrene/organoclay nanocomposites with different microstructures

The fabrication of syndiotactic polystyrene (sPS)/organoclay nanocomposite was conducted via a stepwise mixing process with poly(styrene‐co‐vinyloxazolin) (OPS), that is, melt intercalation of OPS into organoclay followed by blending with sPS. The microstructure of nanocomposite mainly depended on the arrangement type of the organic modifier in clay gallery. When organoclays that have a lateral bilayer arrangement were used, an exfoliated structure was obtained, whereas an intercalated structure was obtained when organoclay with a paraffinic monolayer arrangement were used. The thermal and mechanical properties of sPS nanocomposites were investigated in relation to their microstructures. From the thermograms of nonisothermal crystallization and melting, nanocomposites exhibited an enhanced overall crystallization rate but had less reduced crystallinity than a matrix polymer. Clay layers dispersed in a matrix polymer may serve as a nucleating agent and hinder the crystal growth of polymer chains. As a comparison of the two nanocomposites with different microstructures, because of the high degree of dispersion of its clay layer the exfoliated nanocomposite exhibited a faster crystallization rate and a lower degree of crystallinity than the intercalated one. Nanocomposites exhibited higher mechanical properties, such as strength and stiffness, than the matrix polymer as observed in the dynamic mechanical analysis and tensile tests. Exfoliated nanocomposites showed more enhanced mechanical properties than intercalated ones because of the uniformly dispersed clay layers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1685–1693, 2004     

REVIEW Polymer Nanocomposites: Flammability

Flame retardation of materials has become a very important issue of concern to researchers and producers. Recently, it has been found that the nano fillers are ecologically friendly and having a high aspect ratio, their dispersion in the polymer matrix leads to significant improvements of many properties. From the point of view of flame retardancy, the nano fillers are able even in small amounts to significantly decrease important flammability characteristics such as heat release rate and increase the oxygen index. This paper covers some recent contributions and progresses to the flammability characteristics of different groups of polymer nanocomposites such as: thermoplastics, thermosettings, elastomers, thermoplastic elastomers and polyblends.     

Polymer/montmorillonite nanocomposites with improved thermal properties: Part I. Factors influencing thermal stability and mechanisms of thermal stability improvement

The results of recent research indicate that the introduction of layered silicate - montmorillonite - into polymer matrix results in increase of thermal stability of a number of polymer nanocomposites. Due to characteristic structure of layers in polymer matrix and nanoscopic dimensions of filler particles, several effects have been observed that can explain the changes in thermal properties. The level of surface activity may be directly influenced by the mechanical interfacial adhesion or thermal stability of organic compound used to modify montmorillonite. Thus, increasing the thermal stability of montmorillonite and resultant nanocomposites is one of the key points in the successful technical application of polymer-clay nanocomposites on the industrial scale. Basing on most recent research, this work presents a detailed examination of factors influencing thermal stability, including the role of chemical constitution of organic modifier, composition and structure of nanocomposites, and mechanisms of improvement of thermal stability in polymer/montmorillonite nanocomposites.     

Organic/inorganic nanocomposite polymer electrolyte

The organic/inorganic nanocomposites polymer electrolytes were designed and synthesized. The organic/inorganic nanocom-posites membrane materials and their lithium salt complexes have been found thermally stable below 200℃. The conductivity of the organic/inorganic nanocomposites polymer electrolytes prepared at room temperature was at magnitude range of 10-6 S/cm.     

树形大分子/金属配合物及其纳米复合材料的制备与性能研究进展

树形大分子是具有确定代数和末端基的蓬勃发展的新型合成高分子。大量具有不同的中心核、支链和末端基团的树形大分子已经被合成和应用于不同的领域,其功能化和应用是目前树形大分子研究领域的热点。本文综述了树形大分子/金属配合物及其纳米复合材料的制备与性能的研究进展,重点介绍了树形大分子/金属配合物材料和树形大分子/金属纳米复合材料的制备与性能研究的最新进展。     

A Nanocage for Nanomedicine: Polyhedral Oligomeric Silsesquioxane (POSS)

Ground‐breaking advances in nanomedicine (defined as the application of nanotechnology in medicine) have proposed novel therapeutics and diagnostics, which can potentially revolutionize current medical practice. Polyhedral oligomeric silsesquioxane (POSS) with a distinctive nanocage structure consisting of an inner inorganic framework of silicon and oxygen atoms, and an outer shell of organic functional groups is one of the most promising nanomaterials for medical applications. Enhanced biocompatibility and physicochemical (material bulk and surface) properties have resulted in the development of a wide range of nanocomposite POSS copolymers for biomedical applications, such as the development of biomedical devices, tissue engineering scaffolds, drug delivery systems, dental applications, and biological sensors. The application of POSS nanocomposites in combination with other nanostructures has also been investigated including silver nanoparticles and quantum dot nanocrystals. Chemical functionalization confers antimicrobial efficacy to POSS, and the use of polymer nanocomposites provides a biocompatible surface coating for quantum dot nanocrystals to enhance the efficacy of the materials for different biomedical and biotechnological applications. Interestingly, a family of POSS‐containing nanocomposite materials can be engineered either as completely non‐biodegradable materials or as biodegradable materials with tuneable degradation rates required for tissue engineering applications. These highly versatile POSS derivatives have created new horizons for the field of biomaterials research and beyond. Currently, the application of POSS‐containing polymers in various fields of nanomedicine is under intensive investigation with expectedly encouraging outcomes.

     

Synthesis,characterization, and functionalization of zirconium tungstate (ZrW2O8) nano‐rods for advanced polymer nanocomposites

Nanomaterials based on zirconium tungstate (ZrW₂O₈) exhibit numerous outstanding properties that make them ideal candidates for the development of high‐performance composites. Low coefficient of thermal expansion for advanced materials is a promising direction in the field of insulating nanocomposites. However, the agglomeration of zirconium tungstate (ZrW₂O₈)‐based nanomaterials in the polymer matrix is a limiting factor in their successful applications, and studies on surface functionalization ZrW₂O₈ for advanced nanocomposites are very limited. In this work, ZrW₂O₈ nano‐rods were synthesized using a hydrothermal method and subsequently functionalized in a solvent‐free aqueous medium using dopamine. Both pristine and functionalized nano‐rods were thoroughly characterized using Fourier transform infrared spectroscopy, Raman spectroscopy, thermogravimetric analysis, X‐ray diffraction, Scanning Electron Microscopy (SEM), and transmission electron microscopy techniques, which confirmed the successful functionalization of the nanomaterials. Polymer nanocomposites were also prepared using epoxy resin as a model matrix. Polymer nanocomposites with functionalized ZrW₂O₈ nano‐rods exhibited low coefficient of thermal expansion and enhanced tensile properties. The improved properties of the nanocomposites render them suitable for electronic applications. Copyright © 2017 John Wiley & Sons, Ltd.     

Recent Progress in the Synthesis and Property Enhancement of Waterborne Polyurethane Nanocomposites: Promising and Versatile Macromolecules for Advanced Applications

Abstract

Waterborne polyurethanes (WPUs), owing to their environmental friendliness and non-flammability, are considered as a green class of materials for a wide spectrum of applications, like adhesives, coatings, drug delivery, and tissue engineering. However, to strengthen their thermal stability, water resistance, mechanical properties, and introduce new peculiarities to these polymers, the incorporation of different types of (nano) fillers within their molecular state, emerged novel opportunities and challenges in material sciences. This approach provides new vitality to these materials since the strong interactions between WPU matrices and fillers facilitate the formation of desired WPU composites (WPUCs). Therefore, WPUCs have greatly promoted the construction and designing of novel materials, like hyperbranched WPUs and their nanocomposites. Thus, the aim of the present article is to deeply overview the properties and application of WPUCs in the various realm. The review also provides a brief discussion on the design and synthesis of WPUs, WPUCs, hyperbranched WPUs, and their nanocomposites along with the implementation of naturally derived materials for the development of sustainable WPUCs.     

A novel method for preparation of exfoliated UV-curable polymer/clay nanocomposites

The half adduct of isophorone diisocyanate and 2-hydroxyethyl acrylate (IPDI-HEA), as a reactive organic modifier, was used to functionalize Na-montmorillonite (Na-MMT) clay. Unlike the electronic interaction in the conventional cation-exchange method, the driving force for the organic modification came from the chemical reaction between IPDI-HEA and framework hydroxyl groups on the surface of clay. With high degree of organic modification (48%), the d-spacing of clay layer was greatly enlarged to 3.32 nm, and the clay became more organophilic. After in situ photopolymerization among the IPDI-HEA grafted MMT clay, monomers and oligomers, the exfoliated polymer/clay nanocomposites were obtained. X-ray diffraction and transmission electron microscopy were used to detect the structure and morphology of the clay dispersed in the polymer matrix. Compared with the pure polymer materials, the exfoliated polymer/clay nanocomposites exhibited enhancements in mechanical and thermal properties.