1. Introduction Polymeric materials play a functional role in every aspect of daily life, from clothing to infrastructure. Polymers differ greatly from other materials, such as ceramics or metals, based upon the types of bonding. Metals bond metallically, creating a sea of electrons, and ceramics generally bond ionically, strongly tying electrons to lattice points. Polymers bond covalently in carbon chains, which (in general) make their properties more variable due to the possibilities of arrangement in bond length, angle, and molecular configuration. Polymers, on average, tend to be more lightweight, have a greater range of colors, lower thermal and electrical conductivity, less brittleness, more resistance to acids, bases, and moisture, and higher dielectric strength than their ceramic or metallic counterparts, but with great range. This variety of properties leads to a variety of classifications, and therefore differing processing methods based on the classification of polymer. 2. Polymer Classifications Polymer processing differs greatly based on the category of polymer within the system. Polymers can be classified by chemical composition, structure, or testing behavior (thermal or mechanical). 2.1. By Chemical Composition Most polymers are organic molecules, based upon a repeating carbon skeleton, but can also include other elements within the chain, most often oxygen, nitrogen, or sulfur. The base unit of a polymer chain is known as a monomer, or mer. The composition of the monomer will greatly affect the properties exhibited. Monomers can either be natural or synthetically created. Examples of common monomers can be seen in Figures 1-4. Within the monomer, the electronegativity and bonding properties of the constituent e... ... middle of paper ... ..., Expert Services. "INTRODUCTION TO POLYMER ADDITIVES AND STABILIZATION." "CES EduPack." Granta, 2013. Colton, Prof. J.S. "Injection Molding." Injection Molding. Georgia Institute of Technology, 2009. —. "Polymer Processing." Polymer Processing. Georgia Institute of Technology, 2009. —. "Polymer Review." Polymer Review. Georgia Institute of Technology, 2011. Kailas, Prof. Satish V. Material Science. Indian Institute of Science, Chapter 11. Applications and Processing of Polymers. "Rotary Wheel Blow Molder." http://upload.wikimedia.org/wikipedia/en/thumb/4/40/Rotary_Wheel_Blow_Molder.png/450px-Rotary_Wheel_Blow_Molder.png. William D. McCallister, David G. Rethwisch. Materials Science and Engineering: An Introduction. John Wiley and Sons, Co., 2009. Zehev Tadmor, Costas G. Gogos. Principles of Polymer Processing. Hoboken, New York: John Wiley and Sons, Inc., 2006.
The first term that I noted during the movie was Conductive Polymers. Conductive polymers are almost always organic meaning a large class of chemical compounds whose molecules contain carbon. These polymers have extended delocalized bonds which are bonds found in a molecule that do not belong to a single atom or covalent bond. They are conjugated systems of double bonds and in a aromatic systems. The conjugated systems are atoms covalently bonded with alternating single and double bonds. When the electrons are removed or added into the valence bands the electrical conductivity increases. The conductive polymer has a low conductivity until the electron is removed from the valence band called (p-doping) or (n-doping) until it becomes more conductive. The movement of the charges is what is responsible for electrical conductivity. These polymers are plastic which are organic polymers and with mechanical properties such as flexibility and elasticity.
The purpose of this experiment was to create a polymer by reacting a mixture of decanedioyl dichloride and dichloromethane with a mixture of water, 1,6-hexadiamine and sodium carbonate. Specifically, we created the polymer Nylon-6,10. Nylon-6,10 polymers are used in a vast majority of things we use in everyday life such as zippers, the bristles in brushes, and even car parts. This experiment was different from the industrial method of making nylon because that takes place at a much higher temperature. A polymer is a substance that has a structure made of similar or identical units bonded together. All polymerizations fall into two categories: step-growth and chain-growth (both of which we used to form our polymer). Step growth polymerization
rapid development of polymer chemistry after World War II a host of new synthetic fibers
Kevlar Aramid Fiber is a synthetic (man-made) material known as a Polymer. A polymer is a chain that is made up of many similar molecular groups, better known as ‘monomers’ that are bonded together. ‘Monomers’ are made up of fourteen Carbon atoms, two Nitrogen atoms, two Oxygen atoms and ten Hydrogen atoms. A single Kevlar polymer chain could possibly have anywhere from one to five million monomers bonded together.
Describe in detail the production of a typical plastic like High density Polythene or PVC. from cracking to monomer and polymer.
Askeland, Donald R., and Pradeep P. Fulay. The Science and Engineering of Materials. Pacific Grove, CA: Thomson Brooks/Cole, 2003. Print.
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
Plastics Engineering manufacturing and handbook (Volume 2) (Dominik V Rosato, Donald V Rosato, Nick R Schott) PAGE: 1300-1303
Extrusion produces material such as pipe or tubing, weather-stripping, fencing, plastic films and sheeting, deck railings, window frames, thermoplastic-coatings, and wire insulation. In the plastics extrusion, the raw compound material is usually in the form of nurdles, small beads which often called resin, that are gravity fed into a top mounted hopper then into the barrel of the extruder. Additives like colorants and U.V. inhibitors (liquid/pellet form) are often used and which then can be mixed into the resin precede to arrive at the hopper. The process has very much in common with plastics injection molding from a point of the extruder technology though it may differs in that as it is usually a continuous process. While pultrusion be capable of offering many same profiles in continuous lengths which comes usually with added reinforcing, this is achieved with pulling the finished result out of the die instead of extruding a typical polymer melt through the die. A large number of polymers are used in the production of pipes, rods, rails, plastic tubing, seals, and sheets or films. For example, ABS, HIPS
Naturally occurring polymers will be proteins like silk. It will definitely depend on the type of polyamide being made because they will take many different forms such as, Nylons can help to make the inner structure of tires but can also take the shape of solids and used for machine parts and Kevlar is used in bulletproof vests. When describing the properties of polyamides it will need to be done based on the type of polyamide so I will be describing the chemical and physical properties of Nylon 6 a polyamide fiber. Nylon 6 has a density of 1.14 g/c.c, a melting point of 215℃, it also has a very good elasticity, its natural color is going to be white but it can be dyed, and has the ability to protect heat up to 150℃. The main chemical property of Nylon 6 is it is an organic solvent which means it becomes soluble in any dense acid or phenol. You have almost definitely used polyamides there are polyamides in tents, toothbrush bristles, rope, they don't have to be fibers they are sometimes used for gears, lots of times polyamides are used in packaging. Polyamides are used because they are so strong
Conductive polymer has been known to have poor process ability due to their physical and mechanical characteristics. In order to overcome this difficulty, it has to be treated with a conductive polymer.Such treatment with a conducting polymer reduces the surface resistivity to (1–104 Ω).”6”
Polymers: A great variety of polymers are used as biomaterials in medicine. Their applications vary from facial prostheses to tracheal tubes, from dentures to hip and knee joints and from kidney and liver parts to heart components. Polymeric materials are also used for medical adhesives and sealants and are also used for coatings that perform a range of functions.
Polymers are made from relatively small molecular fragments known as monomers that are joined together. Synthetic polymers which include the large group known as plastics are divided into three groups: commodity thermoplastic, engineering thermoplastics (ETP), and advanced engineering thermoplastics (AETP). The engineering thermoplastics (ETP) have heat resistance, strong mechanical properties, lightness, self-lubrication, and easy manufacturing. This plastic category has been lately used to replace wood and metal applications.
There are many different polymers available depending upon the starting raw ingredients. There are several broad categories, each with numerous variations. The most common are known as polyester, vinyl ester, epoxy, phenolic, polyimide, polyamide, polypropylene, polyether ether ketone (PEEK), and others. The reinforcement materials are often fibers but can also be common ground minerals.
"polypropylene." Encyclopaedia Britannica. Encyclopaedia Britannica Online. Encyclopædia Britannica Inc., 2014. Web. 13 Apr. 2014. .