D. Bakelite. 5. Question 20. Question 21. ? A plastic substance which once moulded into a shape cannot be melted or made soft on reheating is said to be a thermosetting plastic. Alibaba.com offers 571 is pvc a thermosetting plastic products. Sample Density B. PVC (Poly vinyl chloride) and Polythene are: (A) examples of thermosetting plastics. At best, an object made from a thermosetting plastic can be re-used when you have finished with it. Check the below NCERT MCQ Questions for Class 8 Science Chapter 3 Synthetic Fibres and Plastics with Answers Pdf free download. It was the first fully synthetic fibre. False. Thermosetting plastics contain polymers that cross-link together during the curing process to form an irreversible chemical bond. For Any Sample Of Plastic, It Is Generally Too Costly To Count The Number Of Repeating Units On Each Of The Polymer Chains. T/F- PVC fittings are made by the extrusion process in which plastic resins are heated, softened, and forced through a circular die, which forms the cylindrical pipe shape. Answer. Thermoplastics are the polymers which loses their shape on heating and regain their shape on cooling. Plastics can be easily moulded into any shape. All the synthetic fibres are prepared using raw materials of petroleum origin called.............. . A thermosetting plastic is a polymer that irreversibly becomes rigid when heated. (a) Melamine (b) Polythene – (c) PVC (d) Nylon Answer. Fill in the blanks. Instead, For Processing Reasons, Which Value Is Given To Designate Polymer Chain Length? If subjected to extremely high temperatures, the material may unwantedly soften, deform, and … A) False 13. Question 40. T/F- PVC fittings are made by the extrusion process in which plastic resins are heated, softened, and forced through a circular die, which forms the cylindrical pipe shape. 2) Plastic is suitable for building large and heavy structures. ? A. Solution for What are the differences between thermosetting and thermoplastic polymers ? Question 2. A wide variety of is pvc a thermosetting plastic options are available to you, such as plastic, steel. The melting point of PVC is normally 212 0 C. Glass transition temperature is about 81 0 C. Glass transition temperature is the temperature at which the polymer transits from a hard glassy state to a rubbery state upon the increasing of temperature. (C) examples of natural substances. 7. Answer (d) bakelite Bakelite is a thermosetting plastic. (D) examples of heavy fibers. The raw material to make plastic is oil. False. Question 3. b. To play this quiz, please finish editing it. ... EPDM and PVC, PVC is generally. It is used to make many items like socks, ropes, tents, toothbrushes, car seat belts, sleeping bags, curtains etc. 5) HDPE is a tough plastic used for making toys. Thermosetting plastics become softer upon heating. Answer: True. A) true B) false 18. State True or False: Polymers the small units used in making synthetic fibers. Assertion: Bakelite is a thermosetting plastic. Answer: (a) melamine Melamine is a thermosetting plastic. TRUE ? If you own a recently manufactured aquarium or terrarium, it’s likely made of acrylic plastic. Plastic Applications. Examples of thermoset types include rubber insulations such as silicone rubbers and EVA (Ethylene-Vinyl Acetate). T/F- An expansion loop is a loop in plastic tubing and provides an area for the tubing to expand and contract without stressing. C. PET. ? TRUE ? Perlite board (as cover board), sandwiched between the insulation and the roof membrane, is generally used with. They are dangerous to be worn near fire or heart as they catch fire easily. Page No 44: Question 4: Which of the following is a thermosetting plastic? Answer: Nylon. Bakelite is obtained from phenol by reacting with (a) Vinyl chloride (b) Ethylene glycol (c) Ethanal (d) Methanal Answer: (d) Methanal. Explain the difference between thermoplastic and thermosetting plastics. Plastic Identification with the Burn Test. PVC (polyvinyl chloride) is a thermoplastic and is used for making toys, chappals, etc. Polyester fibres are used for making hand knit sweaters. MCQ Questions for Class 8 Science with Answers were prepared based on the latest exam pattern. Synthetic The lap seams in an EPDM roof membrane are typically sealed by. Bakelite is a thermosetting plastic and is used for making electrical switches, handles of various utensils, etc. Rayon is the first man-made cellulose fibre. FALSE; Plastic is suitable for building large and heavy structures. Nylon, rayon, acrylic, terene and polycot are synthetic fibres. True or False : Question 1. a. Epoxy resin. FALSE; PVC is a thermoplastic. PVC is polyvinyl chloride and it is a type of vinyl polymer. It can be dyed in a wide variety of colors. PE and PVC may also be cross-linked making them thermosetting types. (C) PVC. False. Thermosetting plastics, also called . Answer: Nylon. Urea, Ammonia nitrate and ammonium sulphate are examples of: These are man-made polymers extensively used in daily life as well as in industry, e.g. Bakelite is a thermosetting plastic and is used for making electrical switches, handles of various utensils, etc. Rayon is a natural fibre. Bitumen-treated fiberglass felt. Vinyl plastic and PVC are often the same thing. This problem has been solved! Many small units combine to form a large single unit called a ……... . True or False State whether the given statements are true or false. Heat provides energy for chemical reactions that increase the cross-linking between polymer chains, curing the plastic. MCQ Questions for Class 8 Science with Answers were prepared based on the latest exam pattern. Artificial silk is another name for silk. Page No 46: Question 5: Plastics are very useful materials. Hence these plastics cannot be reprocessed and they can maintain their shape and size even at very high temperatures. What are polymers? Thermosetting plastic once set do not soften on heating. 21 PVC (polyvinyl chloride) is a thermoplastic and is used for making toys, chappals, etc. Bakelite is a thermosetting plastic and is used for making electrical switches, handles of various utensils, etc. 1M 4. State True or False: Thermoplastic can be softened on heating and moulded repeatedly. cure. True Or False? Thermosets usually are three-dimensional networked polymers in which there is a high degree of cross-linking between polymer chains. False, EPDM is a thermosetting plastic. PVC can be made either as a flexible plastic or a rigid plastic by means of additives. Give the name of a plastic used for making fibres. Thermoplastic recycling. Flexible polyurethane foams are commonly shredded into small flakes and re-manufactured into carpet underpayment. Polyester is the strongest synthetic fibre. Synthetic fibres are also called ……... or …….. fibres. Refuse (avoid) is the best way to manage plastic. B. Thermoplastics and thermosetting plastics . FALSE; Epoxy resin is a thermoplastic? Instead, thermoplastic chains are held together by van der waal forces, weak attractions between molecules. 7 true less flexible but more fire resistant. 3. Heat is not necessarily to be applied externally. Even with prolonged heating (it may char), thermosetting plastics retain their strength and shape. ... State whether the following statements are True or False: Question 1. A thermosetting polymer, resin, or plastic, often called a thermoset, is a polymer that is irreversibly hardened by curing from a soft solid or viscous liquid prepolymer or resin. What is the difference between thermoplastic and thermosetting plastics? Chemistry Questions & Answers for Bank Exams : Which of the following is an example of thermosetting plastic? 7. 4) PVC is a thermoplastic. Plastics can be recycles, reused, colored melted, rolled into sheets or made into wires. Some common thermoplastics are polyethylene, PVC, polystyrene, nylon, and acetate.. Thermosetting plastics: Thermosetting Plastics are cross-linked polymers, which become soft only on first heating with pressure and get hard permanently on cooling due to chemical changes by condensation and polymerization, and becomes unaffected by the heat or solvents. No 46: Question 1 for rock climbing the Answers you need, pvc is a thermosetting plastic true or false ; is. 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