Barrier effect of flame retardant systems in poly(methyl methacrylate): Study of the efficiency of the surface treatment by octylsilane of silica nanoparticles in combination with phosphorous fire retardant additives

In this work, flame retardant systems comprising ammonium polyphosphate (AP423) and hydrophilic (A200) or hydrophobic (R805) nanometric silica were incorporated into PMMA. The following techniques were performed to detail the fire behaviour of the composites: mass loss cone calorimetry, pyrolysis‐combustion flow calorimetry, pyrolysis‐gas chromatography–mass spectrometry, thermogravimetric analysis, X‐ray diffraction analysis, Fourier transform infrared spectroscopy and microscopic observations. The best fire behaviour was obtained with the surface‐treated silica in the presence of AP423. The formation of a new crystalline phase from the interactions between AP423 and R805 silica and a strong barrier effect due to a layered residue were the main modes of action of this system. Moreover, we have shown that the difference between the AP423 + R805 and AP423 + A200 systems was due to poor dispersion of the silica into the PMMA matrix in the latter formulation. Copyright © 2011 John Wiley & Sons, Ltd.     

Ignition and Charring of PVC-Based Electric Cables

Fire Technology - The ignition of four different PVC-based electric cables was studied using cone calorimeter and the influence of the charring phenomenon on ignition was investigated. The...     

New alginate foams: Box‐Behnken design of their manufacturing; fire retardant and thermal insulating properties

A new method for preparing alginate foams with progressive release of copper in the presence of sodium lauryl sulfate (SLS, foaming agent) has been designed. Copper acts as the ionotropic gelling agent through the reaction of copper carbonate with gluconolactone. The process does not require freeze‐drying contrarily to the conventional method used for preparing macroporous alginate foams. The new materials investigated in this study have remarkable thermal properties, including thermal conductivity lower than 0.041 W m^?1 K^?1 and low heat release (below 2 kJ g^?1), which allows labeling these foams self‐extinguishing materials. An experimental design methodology, based on a Box‐Behnken plan with three parameters and three levels, is successfully used for evaluating the impact of the amounts of alginate, SLS, and copper carbonate on the productivity, apparent density, and shrinking at air‐drying. It yielded an optimization of the process for the manufacturing of light, and stable/rigid insulating and thermally stable materials. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45868.     

Assessment of olive pomace wastes as flame retardants

Olive pomace (OP) is a lignocellulosic waste from olive oil industry. In order to valorize these wastes as flame retardant (FR) fillers into polymers, OP residues are milled and screened into three different fractions. Two strategies are then investigated. The first one is to modify OP particles by phosphorus molecules using radiation grafting as already done successfully with flax. Nevertheless, pyrolysis combustion flow calorimetry analyses show that the introduction of phosphorus does not promote charring of OP and flame retardancy is not significantly improved whichever the considered fraction. The second strategy is to replace pentaerythritol by OP as char source into well-known FR systems based on ammonium polyphosphate. The incorporation of such system into ethylene-vinyl acetate copolymer leads to satisfying FR performances according to cone calorimeter tests. Moreover, the presence of high amount of extractives into OP such as oleic acid does not appear detrimental. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 47715.     

Spontaneous bony exposure: a report of 4 cases of idiopathic exposure and sequestration of alveolar bone

This paper describes 4 cases of spontaneous exposure and sequestration of alveolar bone. While one case was associated with an allergic mucositis, the other three were idiopathic involving large lingual exostoses.     

A flat surface robotic gripper for handling limp material

A prototype flat-surface, single-chambered and multi-chambered gripper, based on the operational principle of suction and pressure differential has been designed, implemented and experimentally tested. The prototype grippers are proven sufficient to pick and place fabric material accurately and reliably without causing any distortion and/or folding of the fabric. Both prototype grippers have been mounted on AdeptOne and AdeptThree robot arms for experimental and reliability analysis. They both meet requirements as set by the US apparel industry, related to pick and place single cut plies of several types of fabric     

Behavioral observations of sensory substitution in neonate macaques (Macaca arctoides).

The ability of neonate macaque monkeys to learn to respond to artificial spatial sensory information was studied through the use of compact, head-worn, electronic spatial sonars with audible displays, which translate spatial information into auditory dimensions specifying distance, direction, and surface characteristics. Three animals were born in the dark and raised without vision for 1 to 3 months while wearing either the Binaural Sensory Aid (Animal 1; Kay, 1974) or the Trisensor (Animals 2 and 3; Easton & Jackson, 1983) airborne sonars. Each animal demonstrated alertness to information transmitted by the devices in spontaneous reaching or reinforced discrimination tasks, and more device-related, perceptual-motor activities were observed when the sensors were switched on than when they were switched off. The results show that neonate monkeys can learn effective use of information obtained from sensory substitution devices through unstructured interaction with the environment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Study of the combustion efficiency of polymers using a pyrolysis–combustion flow calorimeter

The combustion efficiency of various polymeric materials was studied using a pyrolysis–combustion flow calorimeter (PCFC). Decreasing the combustion temperature in a PCFC leads to partial combustion and lower heat release rates. Combustion efficiency versus combustion temperature was modeled using a phenomenological equation and model parameters were related to the chemical structures of eight pure polymers. The flame inhibition effect was evaluated for two classical approaches in flame retardancy by plotting the combustion efficiency versus the combustion temperature. In the first one (the reactive approach), polystyrenes with different chemical groups substituted on the aromatic ring were studied. In the second one (the additive approach), three well-known flame retardants were incorporated into an ABS matrix: ammonium polyphosphate, tetrabromobisphenol A (TBBA), and a TBBA/antimony trioxide system. Results confirm the flame inhibition effect of halogenated compounds in both approaches. Finally, a correlation between peaks of heat release rate (pHRR) in a cone calorimeter and in a PCFC was attempted. Predicting pHRR in a cone calorimeter using a PCFC appears possible when no barrier effect is expected, if PCFC tests are carried out at a precise combustion temperature, for which the combustion efficiencies in both tests are the same.     

Influence of the morphology on the fire behavior of a polycarbonate/poly(butylene terephthalate) blend

Polycarbonate/Poly(butylene terephthalate) (PC/PBT) blends are used in various industrial sectors, particularly in the cable industry. In this work, the fire behavior of PC/PBT blends was studied for the entire range of blend composition to investigate the relation between fire properties and blend morphology. The morphology of the binary blends used presents a phase inversion point for 25–30 wt % PBT. Various tests have been performed to characterize the fire behavior [limiting oxygen index (LOI), epiradiator test, cone calorimeter, and pyrolysis combustion flow calorimeter (PCFC)]. A change in fire behavior has been observed when the PBT content increases from 20 to 30 wt %, corresponding to the phase inversion, from a continuous rich-PC phase to a continuous rich-PBT phase. Consequently, it can be suggested that the control of the morphology of binary polymer blends is crucial to improve their fire properties. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012