structure of polymers pdf

0000001584 00000 n Polymers in the natural world have been around since the beginning of time. 0000004668 00000 n This leads to the important topic of the structure-property relations to which this book is devoted. /ProcSet [/PDF /Text /ImageC /ImageI] /Type /Page Low M High M â¢ Polymers can have various lengths depending on the number of repeat units. cleavage of covalent bonds between them and bio erodible polymers bring about erosion of the polymer due to dissolution of linking chains without bringing about any change in chemical structure of the molecule [2]. << Starch, cellulose, and rubber all possess polymeric properties. Polymers serving as drug carrier should The subject of polymer structure and characterization is typically a second course in polymer science. The general structure of these polymers is shown in Fig. These identical structures, we understand as a unit made up of two or more molecules, join together to form a long chain. >> Based on Structure/Shape of polymer Polymers can be linear, branched, cross linked or networked. This means that /Parent 3 0 R Polymers and PolymerizationsâArchitecture 12 The number of complementary reactive sites and geometry of monomer determine A primary reason that polymer properties are different is because the chemical compositions of metals, polymers and ceramics are totally different. Polymers are substances containing a large number of structural units joined by the same type of linkage. The spectrum of applications of polymers is immense. /Contents 4 0 R There may be extensive van der Waals and hydrogen bonding between the chains. 0000000729 00000 n The word âPolymerâ is derived from two Greek words, âPolyâ that means many (numerous) and âMerâ which means units. Polyethylene, light, versatile synthetic resin made from the polymerization of ethylene. information about structure or properties of polymers. Vari-ous drugrelease mechanisms can be studied comparatively in Figure 3. Thursday, February 23, 2017 Institute of Mechanical Systems - Structure Technology 34 Molecular weight -1-Molecular weight: mass of a mole of chains. 11 0 obj Polymers There are two types of polymerisation: addition and condensation Addition Polymerisation An addition polymer forms when unsaturated monomers react to form a polymer Monomers contain C=C bonds Chain forms when same basic unit is repeated over and over. structure. endstream endobj 49 0 obj<. unusual properties of high polymers are developed, it will be convenient to consider the chemical and structural aspects of polymers at three different levels: 1) The chemical structure (atomic composition) of the monomer (primary structure) 2) The single polymer chain (secondary level) 3) Aggregation of polymer chains (tertiary structure) â¢Silk is a polymer of the amino acids glycine and alanine â¢Wool is having disulphide (sulphur-sulphur) bonds to link the polymer â¦ The word polymer designates an unspecified number of monomer units. /Resources<< 0000003874 00000 n /XObject<< endobj When the number of monomers is very large, the compound is sometimes called a high polymer. polymer structures Each parameter is important to the properties Each parameter is important to Polymer Chemistry, Chem 466, Spring 2014, January 14, 2014 . /F1 9 0 R /F2 10 0 R>> 0000002800 00000 n Synthetic Polymer. PHYSICAL PROPERTIES OF POLYMERS The structure of polymers is hierarchical, and both the monomer organization and larger-scale structure affect the observable properties, such as phase transitions, strength, solubility, and elasticity. 0000004619 00000 n It is the most widely used plastic in the world, being made into products ranging from clear food wrap and shopping bags to detergent bottles and fuel tanks. The length of the side chain influences the packing of these polymer chains in the melt or glassy state. 48 21 10. 0000002050 00000 n 0000004116 00000 n endobj Engineering polymers include natural materials such as rubber and synthetic materials such as plastics and elastomers. For example, the window glass of airplanes made of polycarbonate cannot repair mechanical damages autonomously, which could lead to a â¦ 0000001643 00000 n 0000007147 00000 n Polymer Structure. â¢ Crystalline - regular chain structure - no bulky side groups. The process by which the polymers are formed is called polymerisation. The subjects are logically combined because understanding how structure a ects properties, as measured in characterization, is a key element of polymer materials science and engineering. Most of the polymers around us are made up of a hydrocarbon backbone. 0000001798 00000 n Polyethylene is a member of the important family of polyolefin resins. What is Polymer? A Hydrocarbon backbone being a long chain of linked carbon and hydrogen atoms, possible due to the tetravalent nature of carbon.A few examples of a hydrocarbon backbone polymer are polypropylene, polybutylene, polystyrene. Synthetic polymers are those which are human-made polymers. The molecular connectivity of polymerâmetalâorganic framework (polyMOF) hybrid materials was investigated using density functional theory calculations and solid-state NMR spectroscopy. ��1_��#ڝ,��GޤUi$c} Polymers are very useful materials because their structures can be altered and tailored to produce materials 1) with a range of mechanical properties 2) in a wide spectrum of colors and 3) with different transparent properties. Examples: polyethylene, PVC, nylon. Classification based on polymer structure Structure of polymer Copolymers Isomerism (Structural Isomerism, Sequence Isomerism, Tacticity) Chain arrangement (Topology) Molecular weight in polymers Thermal transitions glass transition and melting Mechanical properties of polymer Topics: 8 Topic: Principle Characteristics of Polymers [1-7] 0000188681 00000 n Structure features of polymers Each bond angle between three adjacent C atoms is near 109.5º and the angle can be rotated freely in space. For each startxref 0000003206 00000 n These substances often form into a chain-like structure. Networked polymers are complex polymers that are heavily linked to form a complex network of three-dimensional linkages. /MediaBox[0 0 842 595] Overview; What is a Polymer? Explore how the properties of polymers depend on their structure and different types of intermolecular bonds using this lesson plan for 16â18 year olds In this activity, polymers are used as illustrative materials for intermolecular bonds to help students to learn how the structures of polymers relate to their practical uses and properties. Also, there are polymers which instead of carbon have other elements in its backbone. 3.12. Polymers. As the side chain becomes longer, the average interchain distance increases.10 This increased spacing between chain For example, Nylon, which contains nitrogen atoms in the repeated unit backbone. £ù`?ÉÿCüeÿãøó×ýOTÇ_ûÿ¨2þüÅÿkâÏ_ÿÿ¤þ1þO+ óVþQþÏ+àéÿ¢8þüùGú¿,¼ÿ«øóçÏ?Üÿuqÿoà÷ÿ¶ þüùÇý¿?þ±ÿïàÏ?ÿðÿ£áÏ?ÿÿ½ñÏõÿÔþüsý?÷À?þüù'ûé?þüùóÏùÿ:-þüùóçÏ?ÿÄÿoSáÏ?þüùóçÏ?þÉÿßk÷ÿãþüùóoõÿ`ÃS Polymers are composed of non-metallic elements, found at the upper right corner of the periodic table. >> Polymers are substances consisting of macromolecules and the high molecular weight and chain-like structure of the macromolecules are responsible for the unique properties of polymers. â¢ Crystalline structure: arrangement of unit cells in a well-defined spatially-ordered manner, which is characterized by translational symmetry â¢ Amorphous structures: random arrangement of units In polymers the crystalline order can be established by a regular arrangement of the chains. 11 The length of of the polymeric molecule L = l m l: the length of a single bond in the backbone of the hydrocarbon chain m: the number of bonds /Font<< 0000001100 00000 n Article Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. 0000007635 00000 n �2�~��e.>�sҔ?��`wuHy�r��&ep�D�HS�ǣS}�g��*��'y��B}(5�4=�C_\��e�M��U��0Y��MW͎K��$x� E6+ �َ��[�ή(��>�3P�Ѐl%n^�dSA!�I�\��M H��ՂG�1�:�m��G6��Ok`�N�O7��y�5�ɽ�)��a{�ч�d��931�>]s��FZ�)cRw�c�J�4H Man-made polymers have been studied since 1832. â¢ Linear polymers have monomeric units joined end to end in single chains. 0 The unit substance or substances from which the polymer is obtained is called a monomer. Cold-drawing â¢ When a polymer is stretched a âneckâ forms. %PDF-1.6 %�� Crystalline polymers â¢ Areas in polymer where chains packed in regular way. specific chemical structures. The first chapter is devoted to this broad objective. Glassy polymers are widely used as structural materials in aerospace vehicles, airplanes, automobiles, biomedical devices, and so on. Polyethylene is considered to be as one of the simplest polymer, it has ethene or ethylene as the monomer unit whereas the linear polymer is known as the high density polyethylene-HDPE. Carbon is the most common element in polymers. 0000188918 00000 n Introduction: Organic polymers are normally insulators, it can be presumed that conducting polymers must have an unusual structure. 15. /Im1 6 0 R>> A polymer is a high molecular mass compound ranging from 5000 to one million and they are formed by the combination of a large number of one or more low molecular weight compounds. â¢ During the polymerization process not all chains in a polymer grow to the same length, so there is a distribution of molecular weights. 48 0 obj <> endobj CHEM 379 â W20 Physical Properties of Polymers 6-1 6. Polymers are those which consists of repeated structural units known as monomers. trailer endstream 0000004371 00000 n 0000001236 00000 n In basic terms, a polymer is a long-chain molecule that is composed of a large number of repeating units of identical structure. Polymers are not restricted to monomers of the same chemical composition or molecular weight and structure. â¢ More crystalline polymer - stronger and less flexible. These polymers are nearly impossible to soften when heating without degrading the underlying polymer structure and are thus thermosetting polymers. Polymers: Lecture 2 Prepared by Dr Arunima Nayak and Dr Brij Bhushan Classification of Polymers 1. 0000000016 00000 n Some natural polymers are composed of one kind of monomer. 8 0 obj <> stream G H I I J K L M N N O P Q R S T U V W X X Y Z [ \ ] ] ^ _ ` a b c d !e "e "f "g "h #h #i #j #k #l $l $m $n $o %p %q %r &s. Lesson 5: Structure and Applications of Metals; Lesson 6: Types and Applications of Metal Alloys; Lesson 7: Structure and Applications of Ceramics; Lesson 8: Structure and Applications of Polymers. Frozen molecules and the angle can be linear, branched, cross or. 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The word âPolymerâ is derived from two Greek words, âPolyâ that means many ( numerous ) and âMerâ structure of polymers pdf! At the upper right corner of the periodic table be studied comparatively in Figure 3 the chains polymer chains the. Of carbon have other elements in its backbone it can be presumed that conducting must... Calculations and solid-state NMR spectroscopy the repeated unit backbone used as structural materials aerospace... Made up of two or More molecules, join together to form a long chain is very large the! Are formed is called polymerisation materials in aerospace vehicles, airplanes, automobiles biomedical! That means many ( numerous ) and âMerâ which means units W20 properties... Chain structure, it can be linear, branched, cross linked or.!

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