Abstract  Flame retardants for polypropylene (PP) and their potential suitability for use in fibre applications are reviewed. Five principal types of generic flame retardant systems for inclusion in polypropylene fibres have been identified as phosphorus-containing, halogen-containing, silicon-containing, metal hydrate and oxide and the more recently developed nanocomposite flame retardant formulations. The most effective to date comprise halogen–antimony and phosphorus–bromine combinations, which while having limited performance also are falling environmental pressures. Alternatives are discussed as well as means of enhancing the effectiveness and hence usefulness of phosphorus–nitrogen formulations normally used at concentrations too high for fibre inclusion. Of special interest is the potential for inclusion of functionalised nanoclays and recent observations that certain hindered amine stabilisers are effective at concentrations of 1% or so.

Abstract  The possibility of antisolvent precipitation of hydrophobic, organic soluble functionalized carbon nanotubes (f-CNTs), where water acts as an antisolvent is presented. Octadecylamine functionalized multiwall carbon nanotubes (MWCNT-ODA) was used as the model compound and was found to form highly stable dispersions in different water/solvent systems, and the particle sizes ranged from 170 to 400nm. Colloidal behavior was studied using dynamic light scattering and particle aggregation was found to increase with the addition of electrolytes, with tetrahydrofuran (THF) and ethanol showing the maximum effect. The aggregation behavior of the antisolvent precipitated system did not follow the conventional Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, which was different from what has been reported previously for hydrophilic, water soluble f-CNTs. Based on this study, it is evident that hydrophobic f-CNTs are potential water pollutants.

Abstract  The semester thesis here present was written in the frame of the “Nanosafe Textiles” project of the TVS Textilverband Schweiz and the Empa St. Gallen. In a first part, it gives an overview over nanotechnology related research activities in order to point out textile functions which can be achieved by nanoengineering. For each textile function, the used nanoparticles are listed together with the applied production methods to give references about how the respective nanoparticle (NP) could be bound in the textile matrix and thereby provide a basis for later exposure risk assessments. In a second part, an Internet research for nanoengineered textile products was run to draw a spectrum of possible commercial applications. The found consumer goods were then sorted according to their function and scanned for available information about the used nanoparticles and production methods.

Abstract  The objective of this review is to make the field of “flame retardants for polymer materials” more accessible to the materials science community, i.e. chemists, physicists and engineers. We present the fundamentals of polymer combustion theory, the main flame retardant properties and tests used to describe fire behavior, together with the nature and modes of action of the most representative flame retardants and the synergistic effects that can be achieved by combining them. We particularly focus on polymer nanocomposites, i.e. polymer matrices filled with specific, finely dispersed nanofillers, which will undoubtedly pave the way for future materials combining physicochemical and thermo-mechanical performances with enhanced flame retardant behavior.

Abstract  The understanding of the fate and the transport of carbon nanotubes (CNTs) in the water treatment process will provide important information for assessing the environmental risks of CNTs. To fill the knowledge gap, this study investigated the removability of multiwalled carbon nanotubes (MWNTs) stabilized by humic acid (HA) during the coagulation-flocculation-sedimentation (CFS) process. The structure characteristics of the produced flocs were systematically investigated using a variety of characterization approaches. The configuration resembling a root-soil system is shown in the images of scanning and transmission electron microscopy (SEM and TEM). With the incorporation of HA-MWNTs into the produced flocs, the X-ray diffraction (XRD) patterns of MWNTs completely disappeared. Fourier transform infrared spectra (FT-IR) and Mössbauer spectra suggested that the intervention of HA-hinged MWNTs increased the degree of polymerization and the particle size of the produced hydrous ferric oxide (HFO). Finally, both the effective sequestration of MWNTs by CFS demonstrated here and the high sorption capacity of MWNTs for phenanthrene implied that MWNTs might be used as a potential coagulant aid in water processing for the enhanced removal of hydrophobic organic chemicals.

Abstract  On behalf of the Swedish Chemicals Inspectorate, IFP Research has surveyed and carried out a technical assessment of flame-retardant alternatives to decabromodiphenyl ether (decaBDE) currently available for textile applications. Coated textile materials, furniture and similar seating and bedding products but also other technical textile items are common textile applications for decaBDE. The protection against flames is based on the synergy between antimony and bromine, usually in the form of decabromodiphenyl ether, applied in the ratio of one part antimony to three parts bromine, which has historically proved to be the most effective synergetic molar ratio to achieve the best possible flame-retardant properties. The market for flame retardants has grown principally because of increasingly stringent international and national safety requirements. This trend has been pushed ahead in particular in the United Kingdom, Ireland and the United States, especially California. Customers’ requirements are absolute, whether they are public institutions, international organisations or businesses active in the market. If the fire requirements are not met, there is no market for the individual supplier and the manufacturer. On the other hand, there are no descriptive fire requirements at all stipulating that particular flame retardants have to be used for the requirements to be met. The choice of flame retardant is left entirely to the manufacturer. In some cases the requirements are so strict that the alternatives are not economically feasible or the environmental requirements in that part of the world do not make the alternatives possible. Inferior quality characteristics, such as a deterioration in the comfort and durability of the textile product, may also be limiting factors in the manufacturer’s choice of flame retardant. As well as statutory and safety requirements for these products, the focus on the environmental impact of flame retardants and their impact on human health has led the major manufacturers of flame retardants around the world to add non-halogenated products to their traditional ranges of halogenated flame retardants in recent years. There are established flame-retardant materials and potential new variants based on other synergistic combinations as possible substitutes for antimony-decaBDE. These may be organic phosphorus compounds or phosphorus-chlorine compounds, aluminium and zinc hydrate, swelling (intumescent) systems, new synergistic combinations, for example antimony – bromine/phosphorus – silicon, surface-active fibre systems and systems with graft copolymers. Some of these alternatives have been established on the market for decades. The fact that organic bromine compounds continue to be used instead of halogen-free alternatives is due to a number of factors, only a few of which are technical in nature. Together with low price, one of the most common reasons why the alternatives do not always become accepted is that the market prefers to make use of tried-and-tested flame retardants. The types of flame protection likely to entirely replace antimony-decaBDE, with the backing of clear rules and regulations, are the intumescent systems and phosphorus chemistry. The flameresistant fibres combined with combustible fibres will probably also be used successfully in some applications. However, a number of fire-related problems remain to be solved in some applications, for example for polyurethane foam, but this trend too will accelerate when the halogenated alternatives no longer have a role to play in the international sustainable society. It is now up to the legislators to create this incentive. The technology already exists.

Abstract  Dictionary of over 400,000 chemicals (names, synonyms, and structures)

Abstract  In the present work, the influence of multiwalled carbon nanotubes (MWCNTs) on the flame retardancy and rheological, thermal and mechanical properties of polybutilen terephthalate (PBT) and polypropylene (PP) matrixes has been investigated. The carbon nanotube content in the thermoplastic materials was 2 and 5 wt‐%. The nanocomposites were obtained by diluting a masterbatch containing 20 wt‐% nanotubes using a twin‐screw extruder and the thermal properties were analysed by differential scanning calorimetry and thermogravimetric analysis; thermomechanical properties were determined by dynamic mechanical thermal analysis and the rheological behaviour was studied by a Thermo Haake Microcompounder. The results concerning the flame retardancy show that the MWCNTs are not equally effective as flame retardants in PP and PBT. The ignition time is increased only for PBT whereas the extinguishing time is decreased for PP and PBT. The reinforcement of the thermoplastics with multiwall carbon nanotubes is improved regarding the mechanical and thermal properties of the nanocomposites compared to pristine materials and the behaviour of thermoplastic nanocomposites regarding fire retardancy depends on the nature of the polymeric matrix.

Abstract  This document is a starting point to determine what is known and what needs to be known about selected nanomaterials as part of a process to identify and prioritize research to inform future assessments of the potential ecological and health implications of these materials. Two specific applications of nanoscale titanium dioxide (nano-TiO2) are considered: (1) as an agent for removing arsenic from drinking water; and (2) as an active ingredient in topical sunscreen. These case studies are organized around a comprehensive environmental assessment (CEA) framework that combines a product life cycle perspective with the risk assessment paradigm. They are intended to help identify what may need to be known in order to conduct a comprehensive environmental assessment of the potential risks related to nano-TiO2.