Thermal Characteristics of Different Plastics
Thermal decomposition of different plastic through pyrolysis can be achieved at different temperature range. Through TGA analysis of various plastics, including PP, PS, LDPE and HDPE, carried by Lee and Shin [10], it was found that PS has the lowest degradation temperature compared to PP and PE thus will decompose more easily into liquid products. Degradation of PS occurs almost in the range of 350 to 460̊C, similarly to Jude et al. [23] where complete degradation occurred at 400̊C, while PP degradation occurs between 380 to 490̊C. Moreover, LDPE and HDPE decompose in temperature range of 400 to 500 and 550̊C. This is also been determined by Lopez et al [15] in terms of rate of mass loss of PE, PP, PS, PET and PVC. The results showed almost similar temperature range as in [10] for PE, PP and PS. Moreover, maximum degradation showed to occur at 490, 470 and 420̊C for PE, PP and PS. Therefore, it can be determined that temperature in the range of 450 and 500̊C will be suitable for pyrolysis of plastic.
Effect of plastic composition on the pyrolytic oil yield and composition
The role of plastic waste composition on the yield of the pyrolysis end-products was studied in which seven different plastic mixtures were pyrolysed using autoclave at 430̊C with heating rate of 20̊C/min [7]. Plastic mixtures were a combination of three main types of plastic; PE, PP and PS with different fraction resulting in 68PE, 68PP, 68PS, 100PE, 100PP, 100PS and 33 of individual type (numbers indicate the percentage fraction each type in the plastic mixture). Oil analysis showed that plastic sample with 100PS led to highest liquid yield (>90%) while the remaining samples show almost similar yield. PS corre...
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...in the pyrolysis of polyethylene in a conical spouted bed reactor. Applied Catalysis B: Environmental. 102, 224-231
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39. Wikipedia: The free encyclopedia. Scanning electron microscope. [Online]. 2014. [Accessed 07 March 2014]. Available from: http://en.wikipedia.org/wiki/Energy-dispersive_X-ray_spectroscopy
40. Wikipedia: The free encyclopedia. Energy-dispersive X-ray spectroscopy. [Online]. 2013. [Accessed 07 March 2014]. Available from: http://en.wikipedia.org/wiki/Scanning_electron_microscope
Solid triphenylmethanol (0.200 g, 0.768 mmol) and sulfuric acid (2 mL) were added to a reaction tube, which was then ground using a glass rod until it dissolved and turned a dark orange color. The mixture was then added dropwise via a glass pipette into another reaction tube containing methanol (1 mL). An extra amount of methanol (2 mL) was used to transfer the rest of the contents of the first reaction tube. Formation of crystals was facilitated by scratching the side of the tube and adding additional methanol until the color changed to an off-white color. The contents of the tube were then vacuum filtered with water and the resulting crude product was weighed and then recrystallized using hot methanol to form triphenylmethyl methyl ether (0.051 g, 0.186 mmol, 24.2%). The melting point was 81 – 83˚
Scibd. N.p. Web. 17 Mar 2014. Beller, Michele.
Have you ever wondered why the plastic bag that you left on the porch during winter cracks or breaks more easily than when you left it during summer time but a piece of wood which was left just like the plastic bag has no effect whatsoever? This is because of a phenomenon, which only happens to polymers, known as the glass transition. For each polymer, there is a certain temperature at which the amorphous polymers undergo a second order phase transition from a rubbery and viscous amorphous solid to a brittle and glassy amorphous solid called the glass transition temperature, Tg.1 When the polymer, or in this case, the plastic bag, is cooled below their glass transition temperature, it becomes hard and brittle like a glass but when it is used above their glass transition temperatures, it might have a different effect than when used at room temperature or below the glass transition temperature as normally, different types of polymers like clothes, food packaging, insulations for wires, etc. are either used above their glass transition temperatures or
"The Discovery of X-Rays." The Discovery of X-Rays. N.p., n.d. Web. 17 Feb. 2014. .
These different techniques are essentially part of one instrument. The EDX facility (an X-Ray detector and associated software) is incorporated intimately as part of the SEM itself. The EDX facility cannot function without the operation of the SEM, since the generation of the analytical X-Ray signal is dependent on the interaction between the incident electron seam and the sample in the SEM. EDAX() and DES (Energy Dispersive Spectrometer) are often used interchangeably in place of EDX by different instrument manufactures but are essentially the same technique.
Michael P. Broadribb, C. (2006). Institution of Chemical Engineers . Retrieved July 26, 2010, from IChemE: http://cms.icheme.org/mainwebsite/resources/document/lpb192pg003.pdf
The most common form of polyethylene is petroleum based or olefins based; as before mentioned polyethylene compounds have a wide commercial applicability and are made from non-renewable resources (Harding, Dennis, von Blottnitz, Harrison, & S.T.L., 2007). Its manufacturing processes are regarded as energy intensive and release significant amount of CO2 and heat into the atmosphere (Broderick, 2008). Next a little more detailed description of polyethylene’s production processes will be presented, with a focus on the way the material inputs are extracted and synthesized.
The synthesis of polymers starts with ethylene, (or ethene). Ethylene is obtained as a by-product of petrol refining from crude oil or by dehydration of ethanol. Ethylene molecules compose of two methylene units (CH2) linked together by a double carbon
The Olefins II Unit makes hydrocarbons from naphtha or natural gas using furnaces. After distillation, the p...
Ever since I began studying science and mathematics at all levels of educations I have always had an interest in the production of useful materials. In the growing turmoil of today; a world full of global warming and diminishing resources, questions often arise in my mind such as, "can we make a more efficient, more durable and a renewable resource that will overshadow fossil fuels? and have less of an impact on our environment?" Up to now, I have not found a solution to these questions and answering these questions is a personal aspiration of mine which I aim to fulfil by achieving a degree in Chemical engineering and eventually I will contribute to the field in my own unique way. The debate surrounding sustainable energy fascinates me, having recently learned from personal research I have understood what an authoritative role chemists and chemical engineers play in the industry at the present time and how, by working as a team, they contribute to an improved future for the whole world. However, one of the main reasons that has single-mindedly driven me this far to want to study chemical engineering is a book I have read, “Beyond the Molecular Frontier: Challenges for Chemistry and Chemical Engineering” While reading this book, I had solidified my understandings of what chemical engineering is all about. Also, one of the main processes mentioned was polymerisation and is something I already study in A-level chemistry, it is something that not only interests me, but is a personal career aspiration of mine. Reading this book gave me a determination to be the person who helps improve the future of the industry and provide an answer to the questions I always ask myself by studying this degree.
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Jessica Knoblauch, an author for the Environmental Health News, writes about the toll plastic has on the environment, "the process of creating plastic can produce biological effects in a range of wildlife species, crippling the local ecosystem." All forms of plastic are created using oil. Oils are refined, mixed with poisonous chemicals, and cooked at high temperatures in order to produce items. This process produces toxic byproducts and greenhouse gases, reducing our air quality and can disrupt the
are required and less energy is needed to make recycled plastic products than to make
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