Polymer Engineering

Flashcards of key vocabulary about polymers

Natural Polymers

Polymers derived from natural sources.

Synthetic Polymers

Polymers synthesized from chemical processes.

Deformable Materials

Materials that can undergo significant deformation without breaking.

Non-Deformable Materials

Materials that resist deformation.

Thermoplasts

Polymers that soften when heated and harden when cooled, and this process is reversible.

Duromers

Polymers that undergo irreversible chemical change upon heating, resulting in a rigid, cross-linked structure.

Elastomers

Polymers that exhibit high elasticity and can return to their original shape after being stretched.

Dispersions

A two-phase system where one substance is dispersed in another.

Varnishes and Paints

Liquid coatings that dry to form a solid film.

Functional Polymers

Polymers with specific functionalities tailored for particular applications.

Linear Homopolymer

A polymer with a single type of repeating unit arranged in a straight chain.

Branched Homopolymer

A polymer with a single type of repeating unit with branches off the main chain.

Statistical Copolymer

A polymer composed of two or more different monomers distributed randomly.

Block Copolymer

A polymer composed of long sequences (blocks) of different monomers.

Multi-block Copolymer

A copolymer with multiple blocks of different monomers.

Graft Copolymer

A copolymer in which one polymer is grafted as side chains onto a main chain of a different polymer.

High Temperature Thermoplasts

Thermoplasts that can withstand high temperatures (150 °C – 260 °C).

Technical Polymers

Thermoplasts used in engineering applications (90 °C - 140 °C).

Standard Polymers

Thermoplasts with a continuous use temperature of less than 90 °C.

Unsaturated Polyester Resin (UP)

A crosslinked polymer with a high use temperature (120 – 150 °C).

Epoxy Resin (EP)

A crosslinked polymer with a high use temperature (80 – 180 °C).

Phenolic Resin (PF)

A crosslinked polymer with a high use temperature (110 – 150 °C).

Melamin-Formaldehyde Resin (MF)

A crosslinked polymer with a high use temperature (80 – 120 °C).

Vinylester Resin (VE)

A crosslinked polymer with a high use temperature (100 – 140 °C).

Chain-Growth Polymerization

A type of polymerization where monomers add to the growing chain one at a time.

Step-Growth Polymerization

A type of polymerization where monomers react together to form dimers, trimers, and longer oligomers, and eventually long polymer chains.

Polycondensation

A polymerization reaction where water or other small molecules are eliminated as the polymer forms.

Polyaddition

A polymerization reaction where monomers add to each other without the loss of any atoms.

Number Average (Mn)

Average molar mass based on the number of molecules.

Weight Average (Mw)

Average molar mass based on the weight fraction of each molecule.

Polydispersity Factor (PD)

A measure of the breadth of the molar mass distribution.

Low Density Polyethylene (LDPE)

Polyethylene with long-chain branches.

High Density Polyethylene (HDPE)

Polyethylene with very few short-chain branches.

Linear Low Density Polyethylene (LLDPE)

Polyethylene with variable C1 to C6-branches.

Tacticity

The arrangement of substituent groups in a polymer chain.

Osmometry

A technique for determining the number average molar mass (Mn) of a polymer by measuring the osmotic pressure of its solution.

Light Scattering

A technique used to determine the weight average molar mass (Mw) of a polymer by measuring the intensity of light scattered by the polymer solution.

Gel Permeation Chromatography (GPC)

A chromatographic technique that separates molecules based on their size in a gel matrix.

Viscometry

A technique that measures the resistance of a fluid to flow.

Theta (Θ)-Solution

A solution in which the polymer behaves as if it were in an ideal state.

Specific Viscosity

Viscosity of solution minus the viscosity of the solvent.

Relative Viscosity

Ratio of the viscosity of the solution to the viscosity of the solvent.

Intrinsic Viscosity

A measure of a polymer's ability to increase the viscosity of a solution.

Mark-Houwink Equation

Relates intrinsic viscosity to molar mass.

Viscosity

A measure of a fluid's internal resistance to flow.

Tetrahedral Angle

Spatial angle between two bonds.

End-to-End Distance

The distance between the ends of a polymer chain.

Radius of Gyration

A measure of the size of a polymer coil in solution.

Kuhn's Segment

A measure of a polymer chain's stiffness.

X-Ray Diffraction

A technique that uses X-rays to determine the structure of materials.

Differential Scanning Calorimetry (DSC)

A technique that measures the heat flow into or out of a sample as a function of temperature.

Differential Thermal Analysis (DTA)

A technique where the difference in temperature between a substance and a reference is measured as a function of temperature.

Elasticity (Hooke’s) Modulus

A measure of a material's resistance to elastic deformation under stress.

Shear Modulus

A measure of a material's resistance to deformation by shear stress.

Torsional Pendulum

An instrument used to measure the viscoelastic properties of materials.

Storage Modulus

A measure of the energy stored in a material during deformation.

Loss Modulus

A measure of the energy dissipated as heat during deformation.

Glass Transition

Temperature range where a polymer transitions from a rigid, glassy state to a more flexible, rubbery state.

Melting Temperature

Temperature at which a semi-crystalline polymer transforms from a solid to a viscous liquid.

Tg

Temperature where a transition from a rigid state to leathery state happens.

Entanglement

The entanglement of polymer chains in the amorphous region of a polymer.

Stress

Related to force per unit area.

Strain

Related the deformation of the material.

Liquid Crystal Polymers (LCP)

The arrangement of molecules in a state between liquid and crystal.

Cloud Point

The point at which a liquid crystal polymer transitions from an anisotropic to an isotropic state.

Viscosity

The resistance of a fluid to deformation under shear stress.

Creep Experiment

An experiment where a constant stress is applied to a material.

Creep Recovery Experiment

The removal of stress after creep.

Viscoelasticity

The delayed elastic response of a material to an applied stress.

Kelvin Model

A model for viscoelastic behavior consisting of a spring and dashpot in parallel.

Maxwell Model

A model for viscoelastic behavior consisting of a spring and dashpot in series.

Linear Materials

Materials for which the measured material function is independent of the strain and stress applied.

Boltzmann’s Superposition Principle

States that the total strain in a material is the sum of strains caused by each stress increment.

Creep Compliance

A measure of how well a material resists permanent deformation under a constant load over time.

Recoverable Creep Compliance

The component of creep deformation that is recovered after the stress is removed.

Entanglement

The condition where polymer chains are intertwined, restricting their movement.

Yield Stress

The point at which a material starts to deform permanently.

output rate

Also referred to as throughput and described the volume of output per unit time.

surface distortions

When the surface texture is no longer smooth.

Extruder

A machine that processes/converts raw plastic into a useable shape.

structural layers

The components of a plastic blend that make up the surface.

tie layers

Layers of adhesive polymers that are used as glue between the different layers of the blend.

barrier layers

The barrier that holds the layers tight together.

Antiblocking

A way to reduce surface contact area of materials.