Abstract  This book contains published investigations presented at the 10th International Conference on Textile Composites that will benefit scientists and engineers in the textile composites industry.

Abstract  This paper is a review of polymer nanocomposites used for flame retardancy applications, including commercial materials and open literature examples. Where possible, details on how the nanocomposite and flame retardant work together will be discussed. The key lesson from this review is that while the polymer nanocomposite can be considered to be flame retarded (or a flame retardant) by definition, these materials by themselves are unable to pass regulatory fire safety tests such as UL-94 V. Therefore, additional flame retardants are needed in combination with the polymer nanocomposite to pass these tests. In multiple examples, the nanocomposite works with other flame retardants in a synergistic or cooperative manner to lower the polymer flammability (heat release rate). Finally, a discussion on research needs and outlook for polymer nanocomposite flammability research is included.

Abstract  Triphenylphosphine-linked multiwalled carbon nanotubes (Tpp-MWCNT) were prepared in aprotic media and under anhydrous conditions by treating bromo-arylated-MWCNT with potassium diphenylphosphine (Tpp-MWCNT (1)), or with chlorodiphenylphosphine and butyllithium (Tpp-MWCNT (2)). Tpp-MWCNT were characterised by various techniques, including transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The presence of the expected elements (C and P) is evident in the XPS spectra. Furthermore XPS results showed the presence of phosphorus with average concentrations of 0.7% and 2.6% in Tpp-MWCNT (1) and Tpp-MWCNT (2), respectively. TGA results revealed the following thermal decomposition order: Tpp-MWCNT (2) < Tpp-MWCNT (1) < purified MWCNT, thus suggesting that the thermal stability of the MWCNT decreases with increasing amount of triphenylphosphine moieties attached to their surface. Moreover TGA results demonstrate that Tpp-MWCNTs have improved flame retardant behaviour since they produce 4-5 times more char than purified MWCNT. (C) 2012 Elsevier Ltd. All rights reserved.

Abstract  This critical review of the available human health safety data, relating to carbon nanotubes (CNTs), was conducted in order to assess the risks associated with CNT exposure. Determining the toxicity related to CNT exploitation is of great relevance and importance due to the increased potential for human exposure to CNTs within occupational, environmental and consumer settings. When this information is combined with knowledge on the likely exposure levels of humans to CNTs, it will enable risk assessments to be conducted to assess the risks posed to human health. CNTs are a diverse group of materials and vary with regards to their wall number (single and multi-walled CNTs are evident), length, composition, and surface chemistry. The attributes of CNTs that were identified as being most likely to drive the observed toxicity have been considered, and include CNT length, metal content, tendency to aggregate/agglomerate and surface chemistry. Of particular importance, is the contribution of the fibre paradigm to CNT toxicity, whereby the length of CNTs appears to be critical to their toxic potential. Mechanistic processes that are critical to CNT toxicity will also be discussed, with the findings insinuating that CNTs can exert an oxidative response that stimulates inflammatory, genotoxic and cytotoxic consequences. Consequently, it may transpire that a common mechanism is responsible for driving CNT toxicity, despite the fact that CNTs are a diverse population of materials. The similarity of the structure of CNTs to that of asbestos has prompted concern surrounding the exposure of humans, and so the applicability of the fibre paradigm to CNTs will be evaluated. It is also necessary to determine the systemic availability of CNTs following exposure, to determine where potential targets of toxicity are, and to thereby direct in vitro investigations within the most appropriate target cells. CNTs are therefore a group of materials whose useful exploitable properties prompts their increased production and utilization within diverse applications, so that ensuring their safety is of vital importance.

Abstract  EPA's Science Policy Council has issued the Nanotechnology White Paper (EPA/100/B-07/001, February 2007). The purpose of the White Paper is to inform EPA management of the science issues and needs associated with nanotechnology, to support related EPA program office needs, and to communicate these nanotechnology science issues to stakeholders and the public. Nanotechnology is the understanding and control of matter at dimensions of roughly 1 to 100 nanometers, where unique phenomena enable novel applications. Encompassing nanoscale science, engineering and technology, nanotechnology involves imaging, measuring, modeling and manipulating matter at this scale. At the nanoscale, the physical, chemical and biological properties of materials may differ in fundamental and valuable ways from the properties of individual atoms and molecules or bulk matter. Nanotechnology presents new opportunities to improve how we measure, monitor, manage and minimize contaminants in the environment. New generations of nanomaterials will evolve and with them new and possibly unforeseen environmental issues.

Abstract  OBJECTIVE: Toxicology studies suggest that carbon nanotube (CNT) exposures may cause adverse pulmonary effects. This study identified all US engineered carbonaceous nanomaterial (ECN) manufacturers, determined workforce size and growth, and characterized the materials produced to determine the feasibility of occupational ECN exposure studies.

METHODS: Eligible companies were identified; information was assembled on the companies and nanomaterials they produced; and the workforce size, location, and growth were estimated.

RESULTS: Sixty-one companies manufacturing ECN in the United States were identified. These companies employed at least 620 workers; workforce growth was projected at 15% to 17% annually. Most companies produced or used CNT. Half the eligible companies provided information about material dimensions, quantities, synthesis methods, and worker exposure reduction strategies.

CONCLUSIONS: Industrywide exposure assessment studies appear feasible; however, cohort studies are likely infeasible because of the small, scattered workforce.

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  We have shown that the addition of certain nanoparticles mixtures can enhance flame retardancy to a greater degree than the addition of either of the nanoparticles alone. The effect is particularly efficient in polymer blends, where more variables need to be considered in the flame behavior. We studied PS/PMMA blends and the respective homopolymers. In this paper we focused on the combination of multiwall carbon nanoutubes (MWCNTs) with clays. We found that the flame retardant (FR) particles segregate to the MWCNTs preferentially, thereby allowing the clays to segregate to the blend interfaces. In this manner both phase stabilization and good dispersion can be achieved. Both long (0.5−40 μm) and short (1−2 μm) MWCNTs were studied and the results indicated that the s-MWCNTs produced the superior flame retardant properties. Addition of all types of nanoparticles, including the standard FR formulations, decreased the time to ignition. On the other hand, the combination of s-MWCNT and clay significantly reduced the heat release rate (HRR) and mass loss rate (MLR) relative to compounds with only one type of nanoparticles. Electron microscopy images of the nanocomposites and the chars showed that after heating the s-MWCNTs were able to diffuse and form a distinct phase in the nanocomposite. Exclusion of the clays allowed the s-MWCNTs to achieve better physical contacts, thereby improving the thermal conductivity. In contrast, the l-MWCNTs were entangled and therefore unable to move. The clays formed a barrier between the tube contacts, resulting in an increase of the specific heat and the HRR and MLR relative to the unfilled or the compound with only clays. We therefore conclude that one must consider the organization of nanoparticles, as well as their chemical nature when designing flame retardant nanocomposites, since specific synergies may be established which can reduce the overall concentration of fillers.

Abstract  The addition of aluminium trihydrate as a microfiller to organoclays or carbon nanotubes is essential to generate nanocomposites with sufficient flame retardant properties as requested by the industry. Cables using the combination of organoclays or carbon nanotubes and aluminium trihydrate demonstrate the applications of these nanocomposites as a new concept for flame retardancy.

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.