4 Polymers - Encapsulated microbes, and waterproof coatings for fabrics

Page 1: Student Information

  • Name: Miss Denby

  • Room: R

Page 2: Learning Objectives and Challenge

Title: Encapsulated Microbes and Waterproof Coatings for Fabrics

  • Learning Objective (LO): Describe how polymers can be categorized

  • Success Criteria (SC):

    1. Explain what is a water-saving hydrogel

    2. Explain the difference between natural and synthetic polymers; provide examples

    3. State differences between polyethene, polypropene, and polystyrene

  • Instructions:

    • Complete questions in full sentences in your book, including prior day's questions

      1. Describe microbial encapsulation with examples

      2. Identify a polymer used for microbial encapsulation

      3. Discuss negative side effects of conventional water repellents

      4. Describe water repellent coating structure

      5. Detail an ideal waterproof coating structure

      6. Define Durable Water Repellency (DWR)

      7. Explain why DWR must be reapplied

      8. Describe how polyurethane (PU) coatings work

      9. Identify what PU stands for

Page 3: Overview of Polymers

  • Polymers can be made from alkenes (e.g., polyethene, polypropene, polystyrene).

  • Polymers are formed by joining many small molecules called monomers.

  • Applications include plastics, water-saving hydrogels, microbial encapsulation, and waterproof coatings.

  • Plastic packaging specifies types and recycling processes; many polymers are not biodegradable.

    • Issue: Non-biodegradable polymers create waste disposal problems.

Page 4: Microbial Encapsulation

  • Definition: Encapsulation involves coating or entrapping materials within another material/system.

  • Microbial Encapsulation: Coating microbes for safe absorption in the body, used in probiotics and vaccines.

  • Polymers used: Gelatin, alginate (ALG), chitosan, starch, gellan gum, milk protein.

Page 5: Waterproof Coatings for Fabrics

  • Essential for diverse applications (e.g., rainwear, military tents).

  • Conventional coatings persist in the environment and build up in human bodies.

    • Consist of long polymers with perfluorinated side-chains.

  • Shorter-chain polymers are less hydrophobic but can be enhanced chemically for better performance.

  • Waterproof clothing can be made using a synthetic fiber with a polymer coating (e.g., polyurethane).

Page 6: Durable Water Repellency (DWR)

  • DWR adds protection against water droplets when applied over a laminate/membrane.

  • Note: DWR isn’t waterproof but reduces condensation and moisture ingress.

  • Requires reapplication due to sensitivity to oils, dirt, and regular cleaning.

Page 7: DWR Continuation

  • Highlighted again that DWR is beneficial yet needs constant maintenance due to environmental factors.

Page 8: Coated Membranes with PU

  • Manufacturing Process: Applying a thin layer of PU resin on the fabric's inner face; known as a hydrophilic coating.

  • Functionality: This coating allows body moisture to escape while preventing external moisture from entering.

  • Seams sealed to enhance waterproofing, ensuring efficient moisture management within the garment.

Page 9: Categorization of Polymers

  • Overview of polymer categorization maintained throughout the lesson.

Page 10: Final Instructions

  • Learning Objective: Reiterate polymer categorization and properties.

  • Required Actions: Complete the previously mentioned questions in full sentences.