Flame-retardant compounds are designed to decrease the flammability of polymeric materials but in many cases the presence of flame retardants in the polymeric materials increases smoke production and toxicity of degradation products. Smoke evolution and the degradation products, either particulate or gaseous is an important aspect of fire hazard. Smoke is defined as a cloud of particles individually invisible but due to light scattering and/or absorption of light, the particles appear opaque. It occurs due to incomplete combustion of the polymeric materials. Coaker et al. [59] described the soot formation and the chemistry of flames. Smoke is different from combustion gases as the later are gaseous molecules; predominantly carbon monoxide, carbon dioxide, hydrogen cyanide, nitrogen oxides and sulfur oxides released during combustion of polymeric materials. It is important to understand that the species formed during pyrolysis are a major factor in smoke formation. The smoke production is dependent on the burning conditions, the amount and chemical structure of polymeric material burnt. In general, polymers that are largely aliphatic and contain oxygen have a tendency of low smoke production [47]. On the other hand, polymers containing aromatic groups generate high amount of smoke on decomposition. Poly (vinyl chloride) and poly (vinylidene chloride) are exceptions, although they contain aromatic groups resulting in little smoke formation on decomposition.
Most of the fire hazards in a confined space are due to smoke production and toxic gases released as products of combustion. Cellulosic materials, polyesters and polyolefins release CO, CO2 and water vapor on burning, which can cause suffocation, but CO is more dangerous because it reduce the oxygen supply in the bloodstream just like cyanide. The inhalation of smoke and toxic gases, predominantly carbon monoxide, is the main cause of death in fires. Polyamides and acrylics contain nitrogen and on burning they may produce hydrogen cyanide, another toxic gas.
1.5.0 PYROLYSIS AND COMBUSTION OF COTTON
When fibres comes in contact with heat, they may undergo both physical and chemical changes [60]. The physical changes occur at glass-transition temperature (Tg) and at melting point (Tm). On the other hand, chemical changes occurs at thermal degradation temperature (pyrolysis) (Tp) and at combustion temperature (Tc). The thermoplastic fibres have lower glass-transition temperature and melting point than their thermal degradation temperature and combustion temperature. The non-thermoplastic fibres have higher glass-transition temperature and melting point than their thermal degradation temperature and combustion temperature.
When cotton is subjected to heat, it undergoes pyrolysis and then combustion at higher temperatures.
Fire and thermal properties of PA 66 resin treated with poly-N- aniline- phenyl phosphamide as a flame retardant
During the performance, as part of the act, pyrotechnics were deployed. The pyrotechnics were gerbs. Gerbs are cylindrical devices that are designed to make a spray of 15-foot plumes of sparks for 15 seconds. Gerbs are befitting for use indoors, as long as the appropriate precautions are taken. The pyrotechnics ignited a polyurethane (egg crate foam) material that is used for packing and product display--but not for "sound proofing," as it was used lining the stage. Considering that this foam is not intended for use as a sound treatment in buildings, it was not treated with fire retardants.
Sun L. et al studied the thermal stability and fire retardant properties of wood flour/polypropylene composites containing magnesium hydroxide (MH), expandable graphite (EG), and ammonium polyphosphate(APP) as flame retardant. The results showed that both expandable graphite and ammonium polyphosphate promoted thermal degradation of wood flour and char formulation, and magnesium hydroxide did not influence on the wood flour decomposition. Cone calorimeter results indicated that EG showed the best properties on fire retardant and suppression smoke
oxygen, and cannot be smothered. If you start a chemical fire indoors, it can be
Stephania A. Cornier, S. L. (2006). Origin and Helth Impacts of Emissons of Toxic By-Produts and Fine Particles from Combustion and Thermal Treatment of Hazardous Wastes. Environmental Health Perspectives, 810-817.
. Smoking is the leading cause of death by cancer. 1 out of every 5 deaths occurring in America is due to its cancerous effects. The Center for Disease Control estimates that over 46 million Americans smoke cigarettes daily. The International Agency for Research on Cancer is a world health organization that identifies causes of cancer. Through the use of patterns and lab results they can classify certain elements as carcinogens. A carcinogen can be defined as any substance or toxin that is known to produce cancer. There are more than 6000 of these cancer producing toxins found within cigarettes. Arsenic, Benzene, and Vinyl chloride are just a few of the most harmful carcinogens used by tobacco companies. Vinyl chloride is a basic component in manufacturing plastic. Excessive exposure to vinyl chloride has been proven to be pre-cancerous ultimately manifesting into full blown malignant cancer. The most notable effect of vinyl chloride is the cause of...
As most of you know, smoking is bad for your health, but what some of you might not know is that you don’t actually have to smoke to be harmed by smoking. Lung cancer, which is the leading cause of cancer deaths in men and women, is mainly caused by cigarette smoking. Secondhand smoking causes approximately 2 percent of lung cancer deaths each year. It causes respiratory disease, Sudden Infant Death Syndrome (SIDS), middle ear disease, and asthma attacks in children.
Flame retardants that contain phosphorus produce phosphoric acid when exposed to the heat of the flame. Phosphoric acid reacts with the burning material to create a thick glassy layer of carbon that protects the rest of the material from thermal degradation, slows the fire down and eventually stops it.
Many, many things that we wear, sleep on, sleep under, walk on, or utilize in wound-care, etc., contain some percentage of cotton. It is a fiber that is used everyday, by everyone, in one way or another. It has qualities that have made it a choice crop for centuries around the world. Today though, cotton is being largely displaced by synthetic fibers that have qualities that exceed the natural crop plant. These fibers can also be mass-produced and sold at relatively lower costs.
Torrefaction of bio-solid is the preparation stage of pyrolysis. However based on heating rate, pyrolysis can be further divided into many types, such as slow pyrolysis, fast pyrolysis, flash pyrolysis and hydropyrolysis. Once the temperature reaches its peak level (650°C) initial state of gasification process initiates. The main difference between fast and slow pyrolysis is the heating time (theating) vs. pyrolysis reaction time (tr). For example if the time required to heat biomass or bio-solid is larger than pyrolysis reaction time, it is considered as slow pyrolysis and vice
One of the materials commonly used in manufacturing shirts is cotton. Cotton is a natural fiber harvested from the cotton plant. The word ‘cotton’ refers to four species in the genus Gossypium (family Malvaceae), which are G.hirsutum L., G.barbadense L., G.arboreum L., and G.herbaceum L. (Tripathi & Warrier, 2011). The taxonomy of cotton is as follow:
These fuels include coal, oil products such as gasoline, and natural gas. Use of these fuels has a number of harmful health and environmental effects. According to the World Health Organization, outdoor air pollution, most of it from burning fossil fuels, especially coal kills at least 800,000 people each year and causes health problems for tens of millions of others. Technology is available to reduce such air pollution, but using it is costly and results in higher fuel
The contents of these cigarettes are a big factor why smoking is such a dangerous habit. Tobacco smoke has more than 4,000 chemicals that include many carcinogens, substances that are known to help cause cancer. There are other chemicals in tobacco smoke that coat and dissolve the air ways of the lungs and mess with the blood and blood vessels regular function. Cigarette smoke also has carbon monoxide, a colorless and odorless ga...
To begin with, the first type of hazard/exposure is fire and explosion. Fire is highly flammable and the vapor is heavier than normal air. It can travel for a considerable distance to source of ignition and flash back. Fire can be of 3 types: small, large and fire involving tanks or cars or trailer loads. An acute hazard can be the vapor/air mixtures that cause explosions. One way of preventing is to not open flames and sparks as well as no smoking. It is also preferable to take off reactions in clo...
In cotton processing, cotton are fibre that are classified as the natural fibre that is obtain from natural resources which is plant. Cotton is a seed-hair fibre from plant of the genus Gossypium, belong to the hibiscus or mallow, family (Malvaceae). Cott...