POLYMER

• Polymer


  Macromolecule comprising several interconnected, repetitive units
• Monomer


  Building block used to create polymers
• Homopolymer


  Polymer made from one type of monomer
• Copolymer


  Polymer made from two or more types of monomers
• Oligomer


  Molecule made up of fewer than twenty repeat units
• Repeat unit


  Structural component repeated one after the other along the polymer chain
• Polymerization


  Smaller molecules (monomers) chemically combined to form larger molecules (polymers)
• Polymerization


  • Requires temperature, pressure, and catalyst
  • Produces polymers with distinct properties suitable for various applications
• Polymer structures

  • Linear
  • Branched
  • Crosslinked
  • Networked
• Polymers


  • Highly resistant to chemicals
  • Serve as electrical and thermal insulators
  • Lightweight
  • Can be prepared through various methods
  • Can mimic various natural materials
• Heat capacity/conductivity


  Effectiveness of plastic/polymer in insulating against heat flow
• Thermal expansion


  Degree to which a polymer expands or contracts when heated or cooled
• Crystallinity


  Regular arrangement of polymer chains
• Permeability


  Tendency of a polymer to pass extraneous materials
• Elastic modulus


  Force required to stretch the plastic in one direction
• Tensile strength


  Strength of the plastic (force required to stretch it until it breaks)
• Resilience


  Ability of the plastic to resist abrasion and wear
• Refractive index


  Extent to which the plastic affects light as it passes through
• Resistance to electric current


  Whether the material is an insulator or conducts electricity
• Copolymer


  Polymer created by polymerizing two or more monomers together
• Types of copolymers

  • Random
  • Graft
  • Block
  • Alternating
• Conducting polymers


  Polymers that can be charged and discharged, and photo conducting polymers
• Copolymers


  Polymers created by polymerizing two or more monomers together, resulting in a polymer with varying repeating units
• Copolymerization


  • Commonly utilized to improve the properties of plastics
  • Different monomers are mixed together to create a polymer with characteristics different from the monomers involved
  • Proper utilization can aid in the manufacturing of materials needed for a specific function
• Types of Copolymers

  • Random copolymer
  • Graft copolymer
  • Block copolymer
  • Alternating copolymer
• Random copolymer


  Polymers with randomly located monomer residues in the polymer molecule, more soluble and pliable than homopolymers, can be shaped mechanically at lower temperatures, used in surface coatings and products for exceptional flow and mold surface reproduction
• Graft copolymer


  Branched copolymers with different main and side chains, formed by combining two distinct monomers, one serving as the main chain and the other as the side chain
• Block copolymer


  Polymers with two or more homopolymer chains linked by covalent bonds, characterized by a linear arrangement of blocks, blocks are parts of a polymer molecule with at least one constitutional or configurational feature absent from adjacent portions
• Alternating copolymer


  Consist of a single main chain with alternating monomers, arranged in a regular pattern along the polymer chain, form when monomers have different polar substituents and similar reactivities toward radicals, like styrene and acrylonitrile copolymerizing largely alternating
• Thermoplastics


  Polymers that can be softened through heating and processed using methods like extrusion, injection molding, thermoforming, and blow molding, harden once cooled, making them easily recyclable
• Thermoplastics


  • Easily recyclable
  • Diverse mechanical properties
  • Lightweight compared to metals
  • Superior surface finish compared to thermosets
  • Good chemical resistance
  • Energy-efficient processing
• Thermosets


  • Able to be molded with different tolerances
  • Allows for flexible product designs
  • Improved structural integrity through variable wall thicknesses
• Calendaring


  A process used to create continuous films and sheets, consisting of polished metal rollers rotating in opposite directions and a guide roller that passes the calendared sheet to form the wind-up roll
• Casting


  A process where liquid polymeric material is poured into a mold, creating a hollow cavity of desired shape and size, the solidified part is then ejected out of the mold
• Types of Casting

  • Die casting
  • Rotational casting
  • Film casting
• Die casting


  A low-cost process that converts liquid pre-polymer into desired shapes and sizes, such as sheets, tubes, and rods, the pre-polymer is poured into a petri dish, cured in an oven, and then pulled out of the petri dish, the solid product has the same shape as the interior, cylindrical shapes are produced using a cylindrical die
• Rotational casting


  A process used to create hollow articles like balls, dolls, and rain boots, it involves using compounded thermoplastic materials in a hollow mold, which is rotated and heated to distribute the molten plastic uniformly, the mold is then chilled with cold water under rotation, allowing the plastic to solidify, this process can also use thermosetting polymers and creative mixtures, with curing done under rotation at an elevated temperature
• Film casting


  A process where a polymer solution is allowed to fall on a metallic belt at a constant speed, forming a sheet, the solvent evaporates at the belt, converting the polymer into a hard sheet
• Compression molding


  A widely used method for producing thermosetting articles by subjecting the material to heat and pressure in a single stroke, with temperatures and pressures reaching up to 200°C and 70 kg/cm2, depending on the material's properties
• Injection molding


  A method used to produce thermoplastic articles by injecting molten thermoplastic material into a cold mold, which solidifies into the mold's shape, this process involves feeding compounded plastic materials through a hopper, softening them, and applying pressure through a piston to push the molten material into the mold