Untitled Quiz

Polymers: Classification and Examples

• Polymers are large molecules composed of repeating smaller units called monomers ("poly" meaning many, "mer" meaning parts).
• Polymers are classified as natural, synthetic, or semi-synthetic.
• Natural polymers: examples include proteins (like collagen), carbohydrates (like glycosaminoglycans or GAGs), and nucleic acids (like DNA).
• Synthetic polymers: examples include thermoplastics (like polyethylene terephthalate or PET) and thermosets (like polydimethylsiloxane or PDMS).
• Semi-synthetic polymers: examples include GelMA (gelatin methacryloyl), MeTro (methacrylated tropocollagen), and modified alginates, derived from natural polymers.

Polymer Applications in Medical Devices

• Polymers are widely used in medical devices.
• Examples of applications include joint separators, sutures, catheters, and gloves.

Polymer Structure and Properties

• Polymers can have amorphous (disordered) or crystalline (ordered) 3D structures.
• The molecular structure influences the polymer's flexibility or rigidity. More rigid structures lead to less flexible polymers.
• Crosslink sites in polymers impact their properties, particularly in thermosets and elastomers.

Polymer Types: Thermoplastics vs. Thermosets vs. Elastomers

• Thermoplastics: have entangled polymers held together by weak forces; their shape can be changed with heat or stress.
• Thermosets: have crosslinked networks held together by strong covalent bonds; their shape is fixed.
• Elastomers: are crosslinked amorphous polymers with long chains; they are elastic and recover their original shape after deformation.

Key Differences & Clarifications

• Plastic ≠ Polymer: Plastics are deformable materials; polymers are a broader category that includes plastics.
• Elastic ≠ Deformable: While all elastic materials are deformable, not all deformable materials are elastic.

Additional Topics

• Copolymers: Polymers composed of two or more different types of monomers.
• Molecular Weight and Chain Entanglement: These factors influence polymer properties; higher molecular weight and greater entanglement typically lead to stronger, more viscous materials. Calculations for average molecular weight are provided in an accompanying exercise.