1. Science MCQs for Class 8 Chapter Wise with Answers PDF Download was Prepared Based on Latest Exam Pattern. A thermosetting plastic is a polymer that irreversibly becomes rigid when heated. Why are electric witches, plugs and sockets made of thermosetting plastics? It … and can only be formed once. 3. d) Silk 10 The coating on modern non- stick cookware and electric iron is of. Thermosetting plastics are plastics do not soften on heating. Mr.Mukherjee. Thermosetting plastics or Thermoset plastic are synthetic materials that strengthen during being heated but cannot be successfully remolded or reheated after their initial heat-forming called as Thermoset material. Followings are examples of thermosetting polymers : Phenol Formaldehyde resin , Urea Formaldehyde resin ,Melamine Formaldehyde resin . Answer Save. Which of the following can be re-melted time and again without producing any change? Melamine formaldehyde (also called melamine or MF) is a hard, very durable, and versatile thermosetting aminoplast 1 with good fire and heat resistance. (a) Protein Choose the correct answer: The synthetic plastic used for making insulation cover in electrical wires and cables is . Thermosetting substances can be melted and formed into shapes that become hard and cannot be…. Students can solve NCERT Class 8 Science Synthetic Fibres and Plastics MCQs Pdf with Answers to know […] Followings are examples of thermosetting polymers : Phenol Formaldehyde resin , Urea Formaldehyde resin ,Melamine Formaldehyde resin . Examples of thermosetting plastics are- melamine- used for making fire ressistant fabrics and floor tiles. Learn more. Thermosetting substances can be melted and formed into shapes that become hard and cannot be…. Some other examples of thermoset plastic polymers include silicones, vulcanized rubber, epoxies, polyesters and phenolics. It is a type of thermosetting plastic which is very tough and heat resistant and if once given a shape, it could not be changed by heating. Thermosetting plastics -- thermosetting plastics are those plastics which ☺broke while bending. Give two examples of thermosetting plastics. Articles fabricated from melamines are rigid and have one of the hardest surface finishes of any plastic material. Examples of thermosetting plastics are vulcanised rubber, bakelite (which is used in electrical insulators), duroplast (used to produce car parts), urea-formaldehyde foam (used to produce plywood, fibreboard, and particleboard), melamine resin (used to produce worktop surfaces), epoxy resin (used in fibre reinforced plastics, e.g. a) Thermosetting plastics. In fact, 80% of the polymers found in the market are Thermoplastics. Science MCQs for Class 8 Chapter Wise with Answers PDF Download was Prepared Based on Latest Exam Pattern. Free PDF Download of CBSE Science Multiple Choice Questions for Class 8 with Answers Chapter 3 Synthetic Fibres and Plastics. Curing is induced by heat or suitable radiation and may be promoted by high pressure, or mixing with a catalyst.Heat is not necessarily to be applied externally. They are hard to recycle. (d) 0 to 2 are substituents selected from the group consisting of Z--CH 2--O--CH 2-- and Z--CH 2--, wherein Z is a melamine group of the formula ##STR2## The substituted melamine additives are useful as additives in molding compositions based on thermosetting condensation resins to improve the moldability of the composition. Thermosetting plastics can be synthesized by condensation polymerization. Bakelite and melamine are examples of thermosetting plastic. polymers are brittle. Bakelite sheets, PCBs 4. Which of the following is thermosetting polymer (a) Neoprene (b) PVC (c) Nylon-6,6 (d) Bakelite. Epoxy bushings and insulators 2. ☺ these plastics molded ones and can be softened by heating. Choose the thermoplastics and thermosetting plastics from the following: Melamine, Polythene, Bakelite, Polyvinyl chloride. It is used to make floor tiles, kitchenware and fire resistant fabrics. Curing is induced by heat or suitable radiation and may be promoted by high pressure, or mixing with a catalyst.Heat is not necessarily to be applied externally. For example, Bakelite is a thermosetting plastic which is a poor conductor of heat and Melamine is a thermosetting plastic which is resistant to fire and can tolerate heat better than other plastics.It is used to make floor tiles, kitchenware and fire resistant fabrics. It is used to make floor tiles, kitchenware and fire resistant fabrics. Basically melamine is a white powder. Pupils can then try the ‘quiz time’ questions to test their thermosetting plastic knowledge. 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