Classification of Plastics

This presentation was prepared as "plastic technology course" task, and was presented in class. For any mistakes, i'm saying sorry in advance.

1. Classification of Plastics (Different approaches) PRESENTATION POLYMER TECHNOLOGY-1 BY: WALI KHAN TALLINN UNIVERSITY OF TECHNOLOGY

2. 2 PLASTIC The word plastic derives from the Greek (plastikos) meaning "capable of being shaped or molded“ Plastic is material consisting of any of a wide range of synthetic or semi-synthetic organic compounds that are malleable and so can be molded into solid objects. Plasticity is the general property of all materials which can deform irreversibly without breaking but, in the class of moldable polymers, this occurs to such a degree that their actual name derives from this specific ability.

3. Definition A polymer, Greek poly (many) + mer (part) is a large molecule, or macromolecule, composed of many repeated subunits. Due to their broad range of properties, both synthetic and natural polymers play essential roles in everyday life. Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteins that are fundamental to biological structure and function. Polymers, both natural and synthetic, are created via polymerization of many small molecules, known as monomers. Their consequently large molecular mass relative to small molecule compounds produces unique physical properties, including toughness, viscoelasticity, and a tendency to form glasses and semi-crystalline structures rather than crystals. POLYMER

4. Classification of plastics Plastics are classified by following methods By Origins Chemical Structure Chemical process Physical properties Type of monomer

5. 1 Classification based on origins There can be three types of origin of polymers Natural Polymers: These are obtained from nature, e.g., plant origin, animal origin etc. Biologically degradable polymers are also present, called biopolymers. Examples- Rubber, Cellulose, Protein etc. Synthetic Polymers: These have been prepared by humans in laboratories and are currently produced industrially. Example – Plastic, PVC etc. Semi-synthetic polymers: These polymers are derived from natural sources and undergo further chemical/physical treatment before attaining their final form. Example – Rayon, Terylene etc.

6. Structure based 1. Linear Polymer : Monomers join with each other to form long straight chains. Example – Poly Vinyl Chloride or PVC is a linear polymer 2. Branched Chained Polymers : These polymers are made of branching of linear chains of monomers. They have low melting points and low densities. Example Low-density polythene 3. Crosslinked / Network polymers ; These polymers are formed by bi-functional and tri-functional monomers with a strong covalent bond between the various linear polymer chains. These polymers are brittle by nature. Example – Melamine Fuctional group based examples Acrylics Polyesters Silicones Polyurethane Halogenated plastics Olefins 2 Classification of plastic by structure and functional group

7. 1. Acrylics Compounds containing acryloyl group can be referred as acrylic compounds e.g. PMMA 2. Polyester Polyester is a category of polymers that contain the ester functional group in their main chain e.g. PET 3. Silicones Silicones, also known as polysiloxanes, are polymers that include any inert, synthetic compound made up of repeating units of siloxane e.g. Silicon Rubber 4. Polyurethane –NH–(C=O)–O– Polyurethane (PUR and PU) is a polymer composed of organic units joined by carbamate (urethane) links 5. Halogenated Plastics Halocarbon compounds are chemicals in which one or more carbon atoms are linked by covalent bonds with one or more halogen atoms e.g. PVC Acryloyl Group Carboxylate Ester Siloxane Urethane group CL, Br, F, I

8. Classification of plastics by chemical processes Chemical processes 1. Addition polymers 2. Condensation polymers 3. Cross linked polymers 1. Addition polymer : An addition polymers are polymers that forms by simple linking of monomers without the co-generation of other products e.g. polyethylene, polypropylene, polyvinylchloride, polytetrafluoroethylene 2. Condensation polymer : Condensation polymers are any kind of polymers formed through a condensation reaction—where molecules join together—losing small molecules as byproducts such as water or methanol e.g. polyamides (Nylon), polyesters (polyethylene terephthalate PET) 3. Cross linked polymers : Cross linked polymers are polymers in which monomer units are cross linked together to form a three dimensional network polymers . These polymers are hard, rigid and brittle because of network structure . Some important examples are Bakelite , melamine formaldehyde etc. 3

9. Classification by physical properties Most common ones Hardness Density Tensile strength Resistance to heat Glass transition temperature Meting temperature Impact strength Molecular weight On the bases of physical properties polymers are divided in three groups: Thermoplastic Thermoset Rubbers 4

10. Classification by type of monomer Homo-polymer – When the same monomer is repeated throughout the chain of the polymer, it is called homo-polymer Co-polymer – When there are at least 2 different monomers along the entire chain, it is called co-polymer Block copolymers are long sequences of different units of monomer. Polymers with two or three blocks of two distinct chemical species are di-block copolymers and triblock copolymers, respectively, whereas those with three distinctly different chemical blocks are called triblock terpolymers Graft copolymers are segmented copolymers with a linear backbone of one composite and randomly distributed branches of another composite 5

11. Jens Martensson [email protected]