Mizzou CHEM 1100 - Polymers (5 pages)

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All about polymers and polymerization

Lecture number:
Lecture Note
University of Missouri
Chem 1100 - Atoms and Molecules With Lab
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Chem 1100 Lecture 20 Outline of Last Lecture I Hybrid Car II Photovoltaic III Economics IV Solar Thermal Outline of Current Lecture I Plastics Polymers II Common Plastics III Polymerization IV HDPE vs LDPE V Addition Polymers VI Intermolecular Forces Current Lecture I Plastics Polymers a Polymer is made up of many different units and there are many different kinds i Natural Polymers Silk Cotton DNA Proteins ii Man Made synthetic Polyester Nylon b Monomer one unit and multiple monomers make up a polymer i The building blocks of polymers c Plastics i All plastics are polymers but not all polymers are plastics ii Plastics are used for a wide variety of materials clothing rubber packaging construction sports insulators iii Useful for their ability to be molded into different shapes iv Synthesized from available starting materials v DNA and cellulose are polymers that are NOT plastics These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute II d Polymer Characteristics i Molecular weight is based on the length of the chain ii Chain arrangement depends on how tightly they are packed and how they are organized iii Chain Branching determines how close the individual chains can come together iv Monomer Orientation v Monomer Identity different groups of atoms on these molecules that determines the molecules chemical properties vi Inter chain bonds cross linking if you don t have the right type of monomers in your sequence cross linking won t be possible because not all bonds interact Common Plastics a The Big 6 i 60 000 types of plastics are known ii Six are the most common iii 1 PETE 2 HDPE 3 V 4 LDPE 5 PP 6 PS and all other are in group 7 OTHERS iv The numbers above indicate the recycling that you find on your food products that can be recycled III b Tuning Plastic Functionality i The functional groups of the monomer determine the polymer s chemical properties ii H CH3 C6H5 COOH iii Common Properties 1 Thermoplastics flexible melt shape 2 Crystalline tight packing regular shape makes tougher plastics 3 Amorphous regions random orientation more flexible Polymerization a Polyethylene PE from ethylene ethane b c Cheapest and simplest synthetic polymer invented shortly before WW2 d Two Forms High Density HDPE 2 Low Density LDPE 4 IV e f The free radical is the unpaired electron and it s looking for a partner It s very reactive on its own The easiest electron to find is one of the electrons in that double bond of carbon It grabs one and forms a new bond Now there s a bond between the radical and the carbon The carbons are still bonded together as well The radical is connected to one carbon and now there is a new unpaired electron on the other carbon and it wants a partner Now it s grabbing from the ethylene bond Now there s ANOTHER free radical on the right side of the ethylene bond on the carbon Then the process continues There s always going to be an odd man out until two radicals bump into each other and then they pair up and everyone is happy HDPE vs LDPE a HDPE have straight lines b LDPE has branches c V VI d HDPE can get closer together so they have more matter in less space and a higher density Is also easier to recycle e There are specialized catalyst that control this Addition Polymers a HDPE LDPE PP PVC PS b No monomer atoms are lost they are only added to a growing chain c There are no side products d MW 10K to 100K Intermolecular Forces a Hydrogen Bonding is the electrostatic attraction between polar molecules that occurs when a hydrogen H atom bound to a highly electronegative atom such as nitrogen N oxygen O or fluorine F experiences attraction to some other nearby highly electronegative atom b Dispersion Forces is an intermolecular attraction force that exists between all molecules These forces are the result of the movement of electrons which cause slight polar moments c Rigidity d Phenyl Group know what it looks like

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