Sol-gel and SPS combined synthesis of highly porous wollastonite ceramic materials with immobilized Au-NPs

Here we present a prospective method of sol-gel synthesis of highly porous wollastonite ceramic powders with controlled macroporous structure (mean pore size ~160 nm) and immobilized gold nanoparticles (particle size is less than 50 nm). The method's distinction is based on using the colloidal template (micelles of "core-shell" polymer latex) both as a poreforming agent and as nanoreactors for nanoparticle synthesis in the system wollastonite/Au-NPs. We revealed the impact of template thermal removal on the morphology of nanostructured wollastonite. We also optimized thermal treatment to obtain defect-free macroporous calcium silicates. Template functionalization by size stabilized gold nanoparticles with their following immobilization into the porous volume of synthesized wollastonite has been described. Besides, an original nonstandard method of combined sol-gel (template) synthesis and spark plasma sintering (SPS) is suggested to obtain the wollastonite ceramic compounds with bimodal pore size distribution (100–500 nm and not less than 1 µm), high mechanical strength (compressive strength limit ~120 MPa) and containing immobilized Au-NPs. Peculiarities of biporous silicate framework formation has been studied using two types of poreforming agents (templates) of various origin, shape and size, introduced during different stages of sol-gel and SPS processes. These templates are organoelemental polymer latex of “core-shell” type and nonorganic carbon filler. Developed approaches are innovative and provide to make new materials with unique characteristics and functional properties as bone-like structure, mechanical stability, antibacterial and anti-inflammatory effects and etc. The materials meet all the biomaterials requirements and are in high demand by modern medicine.     

Innovative polyelectrolytes/poly(ionic liquid)s for energy and the environment

This paper presents the work carried out within the European project RENAISSANCE‐ITN, which was dedicated to the development of innovative polyelectrolytes for energy and environmental applications. Within the project different types of innovative polyelectrolytes were synthesized such as poly(ionic liquid)s coming from renewable or natural ions, thiazolium cations, catechol functionalities or from a new generation of cheap deep eutectic monomers. Further, macromolecular architectures such as new poly(ionic liquid) block copolymers and new (semi)conducting polymer/polyelectrolyte complexes were also developed. As the final goal, the application of these innovative polymers in energy and the environment was investigated. Important advances in energy storage technologies included the development of new carbonaceous materials, new lignin/conducting polymer biopolymer electrodes, new iongels and single‐ion conducting polymer electrolytes for supercapacitors and batteries and new poly(ionic liquid) binders for batteries. On the other hand, the use of innovative polyelectrolytes in sustainable environmental technologies led to the development of new liquid and dry water, new materials for water cleaning technologies such as flocculants, oil absorbers, new recyclable organocatalyst platforms and new multifunctional polymer coatings with antifouling and antimicrobial properties. All in all this paper demonstrates the potential of poly(ionic liquid)s for high‐value applications in energy and enviromental areas. © 2017 Society of Chemical Industry     

功能高分子在新型给药系统中的应用

功能高分子材料具有独特的物理和化学性能,近年来在各类给药系统中有着广泛的应用。该文对功能高分子在新型给药系统中的应用及研究进展进行了评述;结合具体药物剂型,针对不同给药系统的特点和实际需要以及功能高分子的相关特性,讨论了功能高分子材料在药物控缓释中的独特作用和在不同给药系统中的应用前景。     

采用高吸水树脂为模板制备新型纳米炭材料的研究

首先采用高吸水树脂为模板,制备了四重网络结构高吸水树脂,然后采用四重高吸水树脂为有机模板,蔗糖为炭源制备了新型纳米炭材料,研究了四重高吸水树脂的高分子网络结构及蔗糖溶液的浓度对新型纳米炭材料微观结构的影响。研究结果表明：采用四重高吸水树脂为模板可以制备出新型纳米炭颗粒,这些纳米炭颗粒可以自组装成不同的微观形貌。XRD和Raman的研究结果表明,蔗糖的浓度对新型炭材料的微观结构也有较大的影响。     

Reassessing the Physicochemical Properties of Ordered Mesoporous Polymer and Copolymer Nanocasts

Nanocasting is a convenient way for preparing highly porous, nanostructured soft materials. Mesoporous polymer nanocasts have been reported for over a decade, however, several aspects remain to be explored further. To do so, we report a comprehensive investigation of the physicochemical characteristics of high surface area functional organic polymers and copolymers obtained by nanocasting. Divinylbenzene, styrene and chloromethyl styrene were selectively polymerized within the pores of mesoporous SBA-15 or KIT-6 silicas. Following template removal, the resulting materials were characterized. The nanocast mesoporous polymers were also modified to introduce functional groups. The success of the functionalization was assessed analytically and by model catalytic tests. The study points to the advantages of the hard templating method for structuring organic materials but also its limitations.     

Transforming polymer blends into composites: a pathway towards nanostructured materials

Polymer blends and polymer‐based composites are two of the most rapidly developing groups of materials being of industrial, as well as of academic, interest. More than a decade ago a new group of polymer materials was introduced, which became known under the name ‘microfibrilar composites’ (MFCs). They were obtained by the transformation of blends of thermoplastic polymers into micro‐ or nanostructured systems by combination of appropriate mechanical and thermal treatments. Since then, the importance of these novel materials, both for theory and for engineering practice, has increased significantly. It is an objective of this review to outline the place of MFCs within the whole variety of polymer‐based composites. Furthermore, the methods of their preparation, the ways of investigating their structure and the relation of the structure and mechanical properties are discussed. Ultimately, an evaluation of the future trends in this exiting interdisciplinary research field is attempted. Copyright © 2007 Society of Chemical Industry     

Solar-absorbing metamaterial microencapsulation of phase change materials for thermo-regulating textiles

This paper presents a novel concept for designing solar-absorbing metamaterial microcapsules of phase change materials (PCMs) integrated with thermo-regulating smart textiles intended for coats or garments, especially for wear in space or cold weather on earth. The metamaterial is a periodically nanostructured metal-dielectric-metal thin film and can acquire surface plasmons to trap or absorb solar energy at subwavelength scales. This kind of metamaterial microencapsulation is not only able to take advantage of latent heat that can be stored or released from the PCMs over a tunable temperature range, but also has other advantages over conventional polymer microencapsulation of PCMs, such as enhanced thermal conductivity, improved flame-retardant capabilities, and usage as an extra solar power resource. The thermal analysis for this kind of microencapsulation has been done and can be used as a guideline for designing integrated thermo-regulating smart textiles in the future. These metamaterial microcapsules may open up new routes to enhancing thermo-regulating textiles with novel properties and added value.     

Smart Electroceramics

"Smart" materials have the ability to perform both sensing and actuating functions. Passively smart materials respond to external change in a useful manner without assistance, whereas actively smart materials have a feedback loop which allows them to both recognize the change and initiate an appropriate response through an actuator circuit. Many smart materials are analogous to biological systems: piezoelectric hydrophones are similar in mechanism to the "ears" by which a fish senses vibrations. Piezoelectrics with electromechanical coupling, shape-memory materials that can "remember" their original shape, electrorheological fluids with adjustable viscosities, and chemical sensors which act as synthetic equivalents to the human nose are examples of smart electroceramics. "Very smart" materials, in addition to sensing and actuating, have the ability to "learn" by altering their property coefficients in response to the environment. Integration of these different technologies into compact, multifunction packages is the ultimate goal of research in the area of smart materials.     

Recent Advances for Intumescent Polymers

Summary: This paper reviews recent approaches for making intumescent systems. The mechanisms of action involving intumescence are described and commented on. Synergistic aspects using zeolites and organoclays are also considered and discussed. New strategies are examined on the basis of the mechanism of intumescence. The approach of using char forming polymers as additives (blend technology) is also fully discussed. This consists of substituting classical polyols (char forming agents) with char forming polymers (polyamides and thermoplastic polyurethane). It will be shown that the advantages of this concept are to obtain flame‐retarded (FR) polymer blends with improved mechanical properties in comparison with polymers loaded with classical formulations, and the avoidance of problems due to the water solubility of the polyols and their migration. The “nanocomposite approach” enhances the performance of intumescent systems by using a nanostructured char forming polymer. It will be shown that this combination of intumescence via the blending approach and nanocomposites enhances both flame retardancy and mechanical properties, and allows many specifications to be produced (for example, the design of EVA‐based materials for flame retarded low voltage cables and wire). This appears to be one of the most promising ways for designing new efficient intumescent materials.

Intumescent residue after LOI test of an intumescent poly(propylene).     

Polymeric ionic liquids: Broadening the properties and applications of polyelectrolytes

The introduction of new ionic moieties, cations and anions, is extending the properties and classical applications of polyelectrolytes. These new polyelectrolytes are being named polymeric ionic liquids (PILs) in analogy to their monomeric constituents (i.e. cations such as imidazolium, pyridinium, pyrrolidonium and anions such as hexafluorophosphate, triflates, amidotriflates). This is giving rise to a new family of functional polymers with particular properties and new applications. The first part of this review will focus on the synthetic aspects of PILs and the main aspects related to their physico-chemical properties. In the second part we will review the new technological applications of these polymers such as polymer electrolytes in electrochemical devices, building blocks in materials science, nanocomposites, gas membranes, innovative anion sensitive materials, smart surfaces, and a countless set of applications in different fields such as energy, environment, optoelectronics, analytical chemistry, biotechnology or catalysis.     

导电高分子材料在智能隐身技术中的应用

介绍了导电高分子材料的结构特点及导电机理。简要叙述了导电高分子材料在雷达波智能隐身、红外智能隐身、可见光智能隐身方面的应用情况。指出导电高分子材料在智能隐身领域的良好发展前景,及其作为智能隐身材料实用化应注意的问题。     

Polymer in MOF Nanospace: from Controlled Chain Assembly to New Functional Materials

Preparation of composites by inclusion of polymers inside metal-organic frameworks (MOFs) is a very powerful strategy to prepare innovative functional materials. MOF's nanosized pores disrupt polymer chains natural coiling and constrain them in an extended conformation, bringing new properties. At the single nanochannel scale, polymerization reactions are significantly modified due to confinement, and control over the primary structure (sequence, tacticity or branching) can be achieved. Because of confinement and chain extension, physical and chemical properties can also be significantly improved compared to the bulk state. Inclusion is also useful to control organization at a higher scale, for instance for precise polymer positioning or by acting as scaffold for an accessible microporous polymer network. Furthermore, the MOF ordering can be maintained in pure polymer systems even after removal of the host.     

Wettability reversal of reservoir rock surface through surfactant stabilized microemulsion

In the process of the tertiary recovery of oil and gas resources, it is necessary to use external fluids to displace the crude oil in the reservoir. Whether the crude oil on the surface of the rock can be effectively displaced and the wettability of the rock can be changed to avoid re-adsorption by the crude oil is directly related to the level of oil recovery. Therefore, it is critical to study the cleaning and wettability reversal of reservoir rock surface. Because microemulsions have outstanding performance in changing the wettability of rocks and solubilizing crude oil, this paper uses cetyl trimethyl ammonium bromide (CTAB) as a surfactant and n-butanol as a co-surfactant to prepare microemulsions. The performance of microemulsions with different microstructures on the cleaning and wettability changes of crude oil on the rock surface were studied. The results show that the water-in-oil (W/O) microemulsion has good cleaning efficiency, and the oil removal rate on the sandstone core surface can reach 79.65%. In terms of changing the wettability of the rock surface, W/O, bi-continuous phase (B.C.) and oil-in-water (O/W) microemulsions can change the core surface from lipophilic to hydrophilic. And the effects of the B.C. and O/W microemulsions are more obvious. The microemulsion system that was prepared based on cationic surfactants has a good application prospect in changing the wettability of the reservoir and cleaning the adsorbed crude oil.     

A review on lignin-based polymeric,micro- and nano-structured materials

Next to cellulose, lignin is the second most abundant biopolymer, and the main source of aromatic structures on earth. It is a phenolic macromolecule, with a complex structure which considerably varies depending on the plant species and the isolation process. Lignin has long been obtained as a by-product of cellulose in the paper pulp production, but had rather low added-value applications. Changes in the paper market have however stimulated the need to focus on other applications for lignins. In addition, the emergence of biorefinery projects to develop biofuels, bio-based materials and chemicals from carbohydrate polymers should also generate large amounts of lignin with the potential for value addition.These developments have brought about renewed interest in the last decade for lignin and its potential use in polymer materials. This review covers both the topics of the direct use of lignin in polymer applications, and of the chemical modifications of lignin, in a polymer chemistry perspective. The future trend toward micro- and nanostructured lignin-based materials is then addressed.     

Electrorheology of nanofiber suspensions

Electrorheological (ER) fluid, which can be transformed rapidly from a fluid-like state to a solid-like state under an external electric field, is considered to be one of the most important smart fluids. However, conventional ER fluids based on microparticles are subjected to challenges in practical applications due to the lack of versatile performances. Recent researches of using nanoparticles as the dispersal phase have led to new interest in the development of non-conventional ER fluids with improved performances. In this review, we especially focus on the recent researches on electrorheology of various nanofiber-based suspensions, including inorganic, organic, and inorganic/organic composite nanofibers. Our goal is to highlight the advantages of using anisotropic nanostructured materials as dispersal phases to improve ER performances.     

Nanostructured polymer blends: Synthesis and structure

Nanostructured polymer blends prepared via anionic ring opening polymerizations of cyclic monomers in the presence of a pre-made polymer melt exhibit a number of special properties over traditional polymer blends and homopolymers. Here, we report on a simple and versatile method of in situ polymerization of macrocyclic carbonates in the presence of a maleic anhydride polypropylene (mPP) matrix and a surface-active compatibilizer (i.e. PC grafted onto a mPP backbone generated in situ) to yield a micro- and nanostructured polymer blends consisting of a polycarbonate (PC) minor phase, and a polypropylene (PP) major phase. By varying the processing conditions and concentration of the macrocyclic carbonate it was possible to reduce the size of the PC dispersions to an average minor diameter of 150 nm. NMR and TEM characterizations indicate that the PC dispersions do not influence crystal content in the PP phase. Overall, the results point to a simple strategy and versatile route to new polymeric materials with enhanced benefits.     

Thermal Properties of Graphene Filled Polymer Composite Thermal Interface Materials

Recent years have witnessed a staggering escalation in the power density of modern electronic devices. Because increasingly high power density accumulates heat, efficient heat removal has become a critical limitation for the performance, reliability, and further development of modern electronic devices. Thermal interface materials (TIMs) are widely employed between the two solid contact surfaces of heat sources and heat sinks to increase heat removal for electric devices. Composites of graphene and matrix materials are expected to be the most promising TIMs because of the remarkable thermal conductivity of graphene. Here, the recent research on the thermal properties of graphene filled polymer composite TIMs is reviewed. First, the composition of graphene filled polymer composite TIMs is introduced. Then, the synthetic methods for graphene filled polymer composite TIMs are primarily described. This study focuses on introducing the methods for improving and characterizing the thermal properties of graphene filled polymer composite TIMs. Furthermore, the challenges facing graphene filled poly­mer composite TIMs for thermal management applications in the modern electronic industry and the further progress required in this field are discussed.

     

Intumescence: Tradition versus novelty. A comprehensive review

The objective of current research on intumescent formulations is on consolidated approaches for conferring flame retardancy properties to polymers and polymer blends. Numerous academic and industrial efforts have been carried out in the last fifteen years, by revisiting the traditional concept of intumescence on the basis of the new chemical synthesis or novel nano-technological developments. The main concepts of intumescence are reviewed in this report, highlighting the novelties as well as the most significant results achieved in the flame retardancy of polymeric materials in the last 10–15 years. Although the basic aspects of intumescence such as the chemical components, thermal and rheological aspects are well-known, the modeling and simulation of these systems are completely new and never reviewed. Analogously, the traditional chemical compositions will be compared with the novel systems, most of them based on the nanotechnology and synergistic aspects. Thus, the results collected up-to-now by using these new intumescent formulations will be dealt with the different polymer families. The use of current intumescent coatings for metals, steel, wood and plastics as well as the application of novel intumescent coatings deposited on fabrics, films and foams through layer-by-layer assembly are reviewed. Although the latter technique is not new, its use to confer flame retardancy properties to polymers is a recent development.     

Classifying nanostructured carbons using graphitic indices derived from Raman spectra

Raman scattering is known to be a unique characterization tool for carbon-based materials such as graphite, diamond, graphene and nanostructured carbons. In this article, we propose a new parameter for estimating the crystallinity of nanostructured carbons. This new parameter estimates the length of the curved graphene planes. To take into account the effect of curvature, the importance of the second-order band at about 2700 cm⁻¹ is emphasized. Using this new parameter, we propose a classification of different nanostructured carbons. The relevance of this new parameter for characterizing nanostructured carbons is confirmed by transmission electron microscopy.