Synthetic Fibres and Plastics

Science Class 8 : Chapter 03

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Quick Revision : Synthetic Fibres and Plastics

  • Synthetic Fibres: Man-made fibres prepared from chemical substances (petrochemicals).
  • Polymer: Large single unit formed by combining many small units (monomers).
  • Rayon (Artificial Silk): Made from wood pulp; cheaper than silk; mixed with cotton/wool.
  • Nylon: First fully synthetic fibre; strong, elastic, light, lustrous; used in ropes, parachutes, stockings.
  • Polyester: Does not get wrinkled easily; Terylene is popular polyester; PET used for bottles.
  • Acrylic: Synthetic wool; cheaper than natural wool; used in sweaters, shawls, blankets.
  • Characteristics of Synthetic Fibres: Durable, less expensive, dry quickly, easy to maintain.
  • Plastics: Also polymers; can be molded into various shapes; some are thermoplastic, some thermosetting.
  • Thermoplastics: Get deformed on heating, can be bent easily (Polythene, PVC).
  • Thermosetting Plastics: Once molded cannot be softened by heating (Bakelite, Melamine).
  • Properties of Plastics: Non-reactive, light, strong, durable, poor conductors of heat/electricity.
  • Plastics and Environment: Non-biodegradable, cause pollution, take several years to decompose.
  • 4R Principle: Reduce, Reuse, Recycle, Recover to minimize plastic waste.
  • Biodegradable vs Non-biodegradable: Materials that decompose naturally vs those that don't.
  • Plastic Waste Management: Avoid plastic use, use cotton/jute bags, recycle, proper disposal.

Questions

Chapter Summary : Synthetic Fibres and Plastics

What You Will Learn: This chapter covers man-made fibres and plastics - their types, properties, uses, and environmental impact. Learn about polymers, different synthetic fibres (rayon, nylon, polyester, acrylic), and plastics (thermoplastics vs thermosetting).

Key Concepts: Understanding polymer structure, differences between natural and synthetic fibres, characteristics and uses of various synthetic materials, plastic classification, and environmental concerns related to plastic waste.

Exam-Oriented Importance: Important chapter with questions on fibre properties, plastic types, polymer concept, and environmental awareness about plastic pollution.

Practical Applications: Knowledge applicable to material selection in daily life, understanding product labels, and adopting environmentally friendly practices.

How This Website Helps: Provides graded MCQs from basic to advanced levels with detailed explanations to strengthen conceptual understanding and prepare for exams.

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