required use. Polymer-Polyethylene is partially crystalline as well as amorphous because it has crystalline and amorphous regions. Also it has linear chains so this is the simplest structure compared to a branched or network chain. This can be of an advantage to it over other types of materials as its good toughness and elongation makes it very significant in the engineering industry as it can be moulded or extruded into shapes such as pipes which are made of HDPE. Polyethylene is a thermoplastic so
Manufacturing Cycle and Environmental Impact 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
German Chemist Hans von Pechmann first synthesized Polyethylene by accident in 1898 by heating diazomethane. His colleagues characterized the waxy substance polyethylene due to the fact that they recognized that it consisted of long ethene chains. It was then first industrially synthesized by accident in 1933 by applying extremely high pressure to ethylene and benzaldehyde. Over the years, development of polyethylene has increased due to the additions of catalyst. This makes ethylene polymerization
Polyethylene Polyethylene (PE) is one of the most commonly used polymers which can be identified into two plastic identification codes: 2 for high-density polyethylene (HDPE) and 4 for low density polyethylene (LDPE). Polyethylene is sometimes called polyethene or polythene and is produced by an addition polymerisation reaction. The chemical formula for polyethylene is –(CH2-CH2)n– for both HDPE and LDPE. The formation of the polyethylene chain is created with the monomer ethylene (CH2=CH2). The
polyalkene has a waxy texture. This type of compound for the most part utilized in the field of research and production in the petrochemical and organic chemistry industries. The production of polyolefin was started in the research laboratories. Polyethylene was the first created polyolefin in 1933 at Imperial Chemical Company by E.W. Fawcett and R.O. Gibson. The production of polyolefin is expected to achieve 100 million of metric
NATURAL DNA POLYMERS Polymers are some of the core factors that enable the continuation of life, which is both the natural and the synthetic ones. Over time since the beginning of life, natural polymers were the main supports to living things. Eventually, in line with human development, synthetic polymers has become a valuable addition to the available and usable polymers. Natural Polymers are the RNA and DNA vital in genes for life processes. As a matter of fact, the messenger RNA is the main component
any more. They are distinguished by their extremely high strength and rigidity. Low density, excellent damping properties and a high resistance to impact combined with exactly changeable thermal expansion to complement the complex characteristics profile. Unlike glass fiber reinforced plastics (GFRP), CFRP exhibit considerably greater rigidity, sharply enhanced electrical and thermal conductivity and a lower density. Their positive characteristics (relative to the weight) mean that CFRP materials
different polymeric materials Introduction: Melt flow index is given by the weight of the extrudate in gram per 10 min [1]. Referring to Figure 1.1, the melt flow index measured according to Condition-E (190°C, 2160g) which is the normal condition for polyethylene is called “Melt Index (MI)”. Polypropylene requires Condition-L (230°C, 2160g) because of its high melting point, and the melt flow index at Condition-L is called “Melt Flow (MF)’. Figure 1.1: Conditions that found satisfactory for the material
The plastics industry has developed significantly since the invention of various methods for the manufacture of polymers. Plastic has several essential advantages, such as light weight, durability, an available cost relative to many other materials and an ability to be easily transformed (Andrady, and Neal, 2009). Plastics contribute to the safety of consumers’ food and water packaging usage as well as their health. Water has become an essential issue in urban areas, whereas the mechanism for the
Thai-style fried rice crackers. Namsai et al. (2008) conducted a study to show the effect of packaging condition on shelf-life stability of Thai-style fried rice cracker. Two types of packaging materials used are oriented polypropylene and linear low density polyethylene (OPP/LLDPE) plastic bag and laminated multilayer metalized (MET). Four conditions; none, oxygen absorber, desiccant and the combination of oxygen absorber and desiccant were used. Eight packaging systems were compared to the traditional
failures especially during manufacturing. Materials with different coefficients of thermal expansion (CTE) and stiffness are bonded together to form laminated stacks in microelectronic packaging. Halil Aykul and Sami Kaya (2010) [19] analyzed a low-density polyethylene thermoplastic composite beam, reinforced with steel fibers, which is loaded by a single force at its free end. They considered a closed-form solution is performed by satisfying both governing differential equation for an anisotropic system
the normal ignition and combustion of a propellant is usually in the order of milliseconds. Further more, the pressure level is normally several hundred pounds per square inch in most actual combustion environments. Then the direct application of the low-pressure isothermal decomposition data to the propellant combustion may be questionable [34, 35]. Thermogravimetry (TG) has been extensively used for the determination of the thermal decomposition kinetics of polymeric binders. The kinetic
nature which aids bone remodeling. 6. Polyethylene: The tibial and patellar components in knee replacements are made of polyethylene. Wear is less of a problem in knee implants as the bearing surfaces are flatter and do not result in the same kind of wear. The use of Ultra Highly Cross Linked Polyethylene (UHXLPE) or Ultra High Molecular Weight Polyethylene (UHMWPE) reduces even the minimal wear enabling the knee implants to last for a much longer time. Material Density Elastic Modulus Cobalt-Chrome alloy
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
FOOD PACKAGING Introduction Packaging is the enclosing of products inside another physical material like plastic, glass, metal, etc. that provides a physical barrier over the products. Packaging is now a thriving industry where, over 50% of the materials produced are used for packing of food products. Apart from being a physical barrier, it provides protection, makes the product more attractive to the consumers, makes storage, transportation and distribution easier, provides information such as
Chapter – 1 Introduction Bikaji Foods International Ltd. (formerly Shivdeep Industries Ltd.) was founded in 1987 at Bikaner, Rajasthan by Shri Shivratan Agarwal. It is one of India’s leading snacks and sweet producing company. It produces a variety of snacks ranging from Rasgulla to SoanPapdi. The company’s plant is situated in Bikaner Rajasthan . The plant is spread in 4000 square meters and employees around 2000 workers. Proper hygiene is maintained at the plant and face masks and caps are compulsory
shown in the figure 1.1 Figure 1.1: Male and Female terminal pins The terminals are fitted into the connector housings as shown in figure 1.2. Housing is a connector's casing which is made of molded plastics such as polyamide, polycarbonate, polyethylene etc. The main function of housing is to hold the terminals and protect them from electrical shorting, electrical interference, dust, dirt, and moisture.