Correlation of aqueous-physical, structural-mechanical, and thermophysical properties of moist disperse materials

It is shown that the cohesiveness and plastic strength of moist materials and their thermophysical and drying properties are determined by the ratio of capillary-mobile and capillary-immobile moisture forms and natural properties of materials which can be best estimated based on the least capillary moisture or the maximum molecular moisture capacity which are the most significant aqueous-physical parameters of materials. Formulas are proposed for the calculation of the dependence of cohesiveness and plastic strength of materials on their moisture content and drying sensitivity, as well as formulas for the calculation of thermophysical properties of moist materials. Translated from Steklo i Keramika, No. 5, pp. 17–21, May, 2000.     

THERMOPLASTIC,FLEXIBLE, AND RECYCLABLE COMPOSITES,DESIGN, PREPARATION,AND CHARACTERIZATION

Glass fiber reinforced composites based on thermosets are the traditional materials used for many applications due to their good mechanical properties. The non-recyclability of these materials has led to the necessity to develop thermoplastic composites and industrial processes for their manufacture [1]. The present paper deals with the preparation of thermoplastic pre-pregs unidirectionally reinforced with Twarn® and their mechanical characterization.     

High-temperature vacuum electric furnaces for sintering,heat treatment,and synthesis of ceramic materials

The main characteristics of vacuum electric furnaces for sintering, heat treatment, and synthesis of ceramic materials are presented. Some manufacturing parameters of the materials treated in the furnaces are presented, and the heat losses in heating units made of refractory metals and of carbon composite materials are compared. It is shown that vacuum furnaces with heating units made of the composite materials are very efficient.Translated from Ogneupory, No. 11, pp. 26–29, November, 1994.     

Mesostructured Silica for Optical Functionality, Nanomachines, and Drug Delivery

Silica thin films and nanoparticles prepared using sol–gel chemistry are derivatized with active molecules to generate new functional materials. The mild conditions associated with sol–gel processing allow for the incorporation of a range of dopants including organic or inorganic dyes, biomolecules, surfactants, and molecular machines. Silica nanoparticles embedded with inorganic nanocrystals, and films containing living cells have also been synthesized. Silica templated with surfactants to create mesostructure contains physically and chemically different regions that can be selectively derivatized using defined techniques to create dynamic materials. Using two different techniques, donor–acceptor pairs can be doped into separated regions simultaneously and photo-induced electron transfer between the molecules can be measured. Mesoporous silica materials are also useful supports for molecular machines. Machines including snap-tops and nanoimpellers that are designed to control the release of guest molecules trapped within the pores are described. Mesoporous silica nanoparticles are promising materials for drug delivery and other biomedical applications because they are nontoxic and can be taken up by living cells. Through appropriate design and synthesis, multifunctional mesoporous silica nanoparticles for sophisticated bio-applications are created.     

Emerging Synthetic Methods and Applications of MOF-Based Gels in Supercapacitors,Water Treatment,Catalysis, Adsorption,and Energy Storage

Metal–organic frameworks (MOFs), which are synthesized through the self-assembly of organic ligands and inorganic metals, have drawn considerable research interest owing to their unique properties and attractive structures. Many studies on various MOF derivatives, such as MOFs and cellulose aerogels, hydrogel composite materials, and bimetallic-centered MOF materials, have provided the potential for wide application of MOFs. However, MOFs mostly exist in the form of powder particles, which are difficult to form. In addition, MOFs have problems with structural instability. MOF-based gels can overcome this problem. MOF-based gels also have significant advantages in secondary processing. In this review, synthetic methods for MOF-based gels, particularly the synergistic effect with other materials, are introduced. The applications of MOF-based hydrogels and aerogels in supercapacitors, water treatment, catalysis, adsorption, and energy storage are also discussed.     

Recent advances in mechanism,influencing parameters,and dopants of electrospun EMI shielding composites: A review

The rapid development and popularization of smart and portable electronic devices have led to increasingly related electromagnetic pollution affecting human health and equipment safety. Thus, designing high-performance electromagnetic interference (EMI) shielding materials with lightweight, flexible, and easy preparation is urgent. The intrinsic physiochemical properties of electrospun micro/nanofibers provide an attractive potential to ease and accelerate the next-generation EMI shielding materials. Here, a detailed review of the electrospun EMI shielding materials is established. First, this article outlines the shielding mechanism of EMI shielding materials obtained via electrospinning. Then, the affecting factors of electrospinning process conditions on the resulting EMI shielding micro/nanofibers are discussed. Next, diverse fillers that contribute to the EMI shielding efficiency of electrospun materials are demonstrated. Finally, the conclusion and prospects are introduced, hopefully contributing to assisting with more comprehensive and rational designs of high-performance electrospun fiber-based EMI shielding for various applications. Priority measures and future directions are suggested for the future development of electrospun EMI shielding materials.     

Biodoped Ceramics: Synthesis, Properties, and Applications

This feature article focuses on biodoped ceramics. These are inorganic materials in which biological materials are incorporated, thus adding new functionality to them. A brief overview of the prominent synthesis techniques for biodoped ceramics, with emphasis on modified sol–gel processes for metal oxide matrices, is given first. Theoretical treatments of the encapsulation of biologicals within a porous ceramic matrix are reviewed. Experimental studies of the stability and dynamics of protein entrapment in silica and other ceramic matrices are also discussed. Finally, key applications of biodoped ceramics in biochemical species detection, bio-catalysis, and drug delivery are presented.     

Solid-State Ionics: Roots, Status, and Future Prospects

This review represents the authors' view of the evolution of solid-state ionics over approximately the past 100 years. A brief history, introducing milestones of the development of this discipline, is followed by a short summary of the theory of ionic conduction in the bulk and the more recently developed theory of ionic conduction at interfaces. The central part of the article gives examples of ionic-conducting materials systems with structures ranging from one- to three-dimensional disorder. Important experimental techniques for analyzing ionic conduction, including alternating-current impedance spectroscopy, direct-current coulometry, and direct-current current-voltage measurements with blocking electrodes, are also summarized. The main technological applications, that is, batteries, solid-oxide fuel cells, electrochemical sensors, electrochromic windows, and oxygen-separation membranes, are reviewed. Finally, new concepts in solid-state ionics are presented, including the investigation of new materials (such as nanostructured phases), the study of boundaries (for example, using microelectrodes), the development of computational techniques, and the connections with other classes of materials (notably magnetic and semiconducting materials).     

Polyaniline: Synthesis,properties, and application

The methods of synthesis and the properties of polyaniline—a representative of the family of conducting polymers—are reviewed briefly. It is shown that variation in the conditions of aniline polymerization makes it possible to synthesize polymer materials with the desired structures and properties and, thus, to provide for the use of polyaniline in various fields of science and engineering. Special attention is given to the matrix synthesis of polyaniline as the main approach to obtain electroactive and conducting composite materials. The use of polyaniline and the related composite materials in polymer electronics is analyzed briefly.     

Nanoparticles in Liquid Crystals: Synthesis,Self-Assembly,Defect Formation and Potential Applications

Revolutionary developments in the fabrication of nanosized particles have created enormous expectations in the last few years for the use of such materials in areas such as medical diagnostics and drug-delivery, and in high-tech devices. By its very nature, nanotechnology is of immense academic and industrial interest as it involves the creation and exploitation of materials with structural features in between those of atoms and bulk materials, with at least one dimension limited to between 1 and 100 nm. Most importantly, the properties of materials with nanometric dimensions are, in most instances, significantly different from those of atoms or bulk materials. Research efforts geared towards new synthetic procedures for shape and size-uniform nanoscale building blocks as well as efficient self-assembly protocols for manipulation of these building blocks into functional materials has created enormous excitement in the field of liquid crystal research. Liquid crystals (LCs) by their very nature are suitable candidates for matrix-guided synthesis and self-assembly of nanoscale materials, since the liquid crystalline state combines order and mobility at the molecular (nanoscale) level. Based on selected relevant examples, this review attempts to give a short overview of current research efforts in LC-nanoscience. The areas addressed in this review include the synthesis of nanomaterials using LCs as templates, the design of LC nanomaterials, self-assembly of nanomaterials using LC phases, defect formation in LC-nanoparticle suspensions, and potential applications. Despite the seeming diversity of these research topics, this review will make an effort to establish logical links between these different research areas.     

Loading,unloading, storage,drying, and cleaning of vegetable oil-bearing materials

Handling of various oil-bearing materials and special problems of loading, cleaning, drying, and storage are discussed, along with considerations for preventing quality deterioration during storage.     

Estimated Detonation Velocities for TKX‐50, MAD‐X1, BDNAPM,BTNPM, TKX‐55, and DAAF using the Laser–induced Air Shock from Energetic Materials Technique

Since new energetic materials are initially produced in very small quantities for both safety and cost reasons, laboratory‐scale methods for characterizing their performance are essential for determining the most promising candidates for scale‐up. Laser‐induced air shock from energetic materials (LASEM) is a promising new method for estimating the detonation velocity of novel explosives using milligram amounts of material, while simultaneously investigating their high temperature chemical reactions. LASEM has been applied to 6 new explosives for the first time: TKX‐50, MAD−X1, BDNAPM, BTNPM, TKX‐55, and DAAF. Emission spectroscopy of the laser excited materials revealed the formation of the high pressure bands of C₂ during the ensuing exothermic reactions. The low thermal sensitivity of the materials also led to unusual laser‐material interactions, visualized with high‐speed video. The estimated detonation velocities for the 6 explosives were compared to predicted values from EXPLO5 and CHEETAH. The LASEM results suggest that TKX‐55, BDNAPM, and BTNPM have higher detonation velocities than predicted by the thermochemical codes, while the estimated detonation velocities for MAD−X1 and TKX‐50 are slightly lower than those predicted.     

Pressure-driven phase transition and energy conversion in ferroelectrics: Principles,materials, and applications

The pressure-driven explosive energy-conversion (EEC) effect of ferroelectric (FE) materials has been extensively studied in scientific research and high-tech applications owing to its high pulse-power output capability. The fundamental principle of this effect is pressure-driven phase transition and depolarization in FE materials, accompanied by discharging behavior from the charge release upon pressure loading. Pb(Zr,Ti)O₃ has been an excellent example of a materials exhibiting these properties. However, recent investigations have been focused on developing other lead-based or lead-free materials with a higher energy-storage ability and better temperature stability. In this article, we review the recent progress achieved in the past decades on different types of lead-based and lead-free ceramics, single crystals, and multilayer films, based on their unique pressure-driven phase transition and energy-conversion properties. Their pulse power discharging performance under actual shock-wave compression is also summarized, followed by a detailed discussion of the failure mechanism under shock-wave compression. Finally, several issues and perspectives are proposed for future investigation in this area. All these not only assist in the design of new materials for high-performance EEC but are also helpful for the practical application of these promising materials in pulse-power technologies.     

Transmission physics and consequences for materials selection,manufacturing, and applications

The differences of translucency and transparency request special conditions for a right photographic presentation and for correct transmission measurements. These differences also influence the materials design of products because of the effect of thickness. Prerequisites of a clear transparency of ceramics are derived for inherent materials properties and for the microstructures starting from a comparison of amorphous, single crystalline and sintered polycrystalline transparent materials. Manufacturing principles differ for transparent cubic and non-cubic ceramics; they have to respond to frequently extreme microstructural requirements, to the available basis of raw materials, and to individual shape, size, and property objectives of applications. A range of present and future applications is addressed and evaluated as governed by, on the one hand, a sensible balance of stringent needs in different fields of the industry with, on the other hand, the costs of development and manufacture.     

Biobased adhesives,gums, emulsions,and binders: current trends and future prospects

Biopolymers derived from renewable resources are an emerging class of advanced materials that offer many useful properties for a wide range of food and nonfood applications. Current state of the art in research and development of renewable polymers as adhesives, gums, binders, and emulsions is the subject of this review. Much of the focus will be on major biopolymers such as starch, proteins, lignin, oils, and their derivatives found in both natural and modified forms, but other biopolymers of promising commercial interest will also be included where warranted. Polymers produced in nature are remarkably diverse in their chemistry, thermomechanical properties, rheology, plasticity, and chemical reactivity. In particular, their capacity to undergo a wide array of chemical modifications yields materials with tailored properties suitable for use as adhesives, gums, coatings, emulsions, and binders. Many such materials are now widely used in commercial products like building materials, lubricants, sealants, coatings, bonding aids, pharmaceuticals, paper, glues, flocculants, processed and frozen foods, as well as tissue engineering and bone repair products. This review provides a general overview of biobased polymers highlighting their source, availability, properties, and usage in industrial products along with the future prospects, challenges, and opportunities they offer.     

PREPARATION AND CHARACTERIZATION OF ACTIVATED CARBONS FROM SCRAP TIRES, ALMOND SHELLS, AND ILLINOIS COAL

Scrap tires, almond shells, and high sulfur coal are examples of materials that are currently an environmental liability, but which have potential as raw materials for the production of value-added solid products. In this study, activated carbons were prepared by first pyrolyzing these materials, and then partially gasifying the pyrolysis chars with steam. The pyrolysis chars were characterized by solid-state ^l3C nuclear magnetic resonance. Nitrogen adsorption experiments were performed on the chars before and after steam activation. Activation increased the surface areas of chars from all three raw materials. Surface areas greater than 400m²/g were obtained when burnoff was above 40%. A 670 m²/g carbon was prepared from Illinois No. 5 coal at 52% burnoff. The results of this study indicate that the conversion of these environmentally problematic materials to activated carbon is a viable strategy for resource recovery and improving pyrolysis economics.     

Comparison of the high-temperature corrosion of aluminium nitride,alumina, magnesia and zirconia ceramics by coal ashes

Higher-grade reactor lining materials are needed to withstand the higher working temperatures and gas pressures used in gasification reactors to improve their efficiency. Both conventional oxide materials and nonoxide materials such as SiC and AlN are suitable refractory materials for the reducing atmospheres prevailing in gasifiers. Interactions between the reactor lining and the slag constitute the main corrosion mechanism. In previous investigations on the high-temperature corrosion of aluminium nitride by coal ash [1] AlN materials were tested in basic and acidic coal ashes at temperatures of 900–1300 °C. In the present work the high-temperature corrosion of aluminium nitride by different coal ashes is compared with that of alumina, magnesia and zirconia.     

Carbon materials for structural self-sensing,electromagnetic shielding and thermal interfacing

This paper reviews carbon materials for significant emerging applications that relate to structural self-sensing (a structural material sensing its own condition), electromagnetic interference shielding (blocking radio wave) and thermal interfacing (improving thermal contacts by using thermal interface materials). These applications pertain to electronics, lighting (light emitting diodes), communication, security, aircraft, spacecraft and civil infrastructure. High-performance and cost-effective materials in various forms of carbon have been developed for these applications. The forms of carbon materials include carbon fiber, carbon nanofiber, exfoliated graphite, carbon black and composite materials. Short carbon fiber cement-matrix composites and continuous carbon fiber polymer-matrix composites are particularly effective for structural self-sensing, with the attributes sensed including strain, stress, damage and temperature. Flexible graphite as a monolithic material and nickel-coated carbon nanofiber as a filler are particularly effective for electromagnetic shielding. Carbon black paste, graphite nanoplatelet paste and flexible graphite (filled with carbon black paste) are particularly effective for thermal interfacing; carbon nanotube arrays are less effective than these pastes. The associated science pertains to the relationship among processing, structure and properties in relation to the abovementioned applications. The criteria behind the design of materials for these applications and the mechanisms of the associated phenomena are also addressed.     

A review on degradation mechanisms of polylactic acid: Hydrolytic,photodegradative, microbial,and enzymatic degradation

Recently, thoughtful disagreements between scientists concerning environmental issues including the use of renewable materials have enhanced universal awareness of the use of biodegradable materials. Polylactic acid (PLA) is one of the most promising biodegradable materials for commercially replacing nondegradable materials such as polyethylene terephthalate and polystyrene. The main advantages of PLA production over the conventional plastic materials is PLA can be produced from renewable resources such as corn or other carbohydrate sources. Besides, PLA provides adequate energy saving by consuming CO₂ during production. Thus, we aim to highlight recent research involving the investigation of properties of PLA, its applications and the four types of potential PLA degradation mechanisms. In the first part of the article, a brief discussion of the problems surrounding use of conventional plastic is provided and examples of biodegradable polymers currently used are provided. Next, properties of PLA, and (Poly[L-lactide]), (Poly[D-lactide]) (PDLA) and (Poly[DL-lactide]) and application of PLA in various industries such as in packaging, transportation, agriculture and the biomedical, textile and electronic industry are described. Behaviors of PLA subjected to hydrolytic, photodegradative, microbial and enzymatic degradation mechanisms are discussed in detail in the latter portion of the article.     

Life cycle assessment of functional materials and devices: Opportunities,challenges, and current and future trends

Functional ceramics such as piezoelectrics, thermoelectrics, magnetic materials, ionic conductors, and semiconductors are opening new frontiers that underpin numerous aspects of modern life. This widespread usage comes with a responsibility to understand what impact their mass production has on the environment. Life-cycle assessment (LCA) is a tool employed for the identification of sustainable materials pathways through the consideration of environmental burdens of materials both during fabrication and as a final product. Although the LCA technique has been widely used for the evaluation of environmental impacts in numerous product supply chains, its application for environmental profiling of functional ceramics is now gaining attention. This paper presents a review of current developments in LCA, including existing and emerging applications with emphasis on the development and fabrication of functional materials and devices (FM&D). Selected published works on LCA of functional ceramics are discussed, highlighting the importance of adopting LCA at the design stage and/or at laboratory stage before expensive investments and resources are committed. Drawing from the extant literature, we show that the integration of environmental and sustainability principles into the overall process of FM&D manufacturing, in a way that anticipates foreseeable harmful consequences while identifying opportunities for improvement, can aid the timely communications of key findings to functional materials developers. This guides the orientation of research, development and deployment, and provides insights toward the prioritization of research activities while potentially averting unintended consequences. It is intended that the review presented will encourage the materials science community to engage with LCA to address important materials design, substitution, and optimization needs.