melamine is a thermosetting plastic true or false

For this reason, thermoset materials are typically considered to be non-recyclables. Across Can you tell why he selected nylon ropes instead of ropes made up of cotton or jute? False, most of the plastics are non-biodegradable. These dinner plates by Carlisle feature a white body with a multi-coloured mosaic effect around the rim; they are perfect for meeting the tough demands of everyday use in schools, hospitals and care homes. Answer. Melamine formaldehyde is a thermosetting plastic and cannot be melted. (d) Aluminium can (a) paper (b) woollen clothes While p olyethylene is a thermoplastic polymer consisting of long hydrocarbon chains, PVC or Polyvinyl chloride , is also a thermoplastic produced by polymerization of vinyl chloride monomer (VCM) and nylon belongs to a … Conclusion 4. (b) Thermoplastics become soft on heating. The correct matching is as given: Burning of plastics and synthetic fabrics produces lots of poisonous gases causing air pollution. Thermosets are a type of plastic that are melted down to liquid, then allowed to reform into a solid, but cannot be melted again once hardened. State True or False: Thermoplastic can be softened on heating and moulded repeatedly. Which is a thermosetting plastic? Melamine plastic, also known as melamine formaldehyde, is a hard, thermosetting plastic material made from melamine and formaldehyde. Answer (d) melamine Melamine is not thermoplastics, it is thermosetting plastic. 2 Which of the following is a source of rayon? 6. Melamine resin or melamine formaldehyde (also shortened to melamine) is a hard, thermosetting plastic material made from melamine and formaldehyde by polymerization. Disadvantages of Melamine Cabinets. Plastics It is used to store food item, water, milk, pickles, dry food, etc. Answer. ? Another way to prevent getting this page in the future is to use Privacy Pass. They can be easily washed at home. • (c) Durable 11 Cotton is a natural polymer. Question. (b) Cotton, polycot, rayon Question. FALSE; HDPE is a tough plastic used for making toys. 11. Answer. (a) Melamine (b) Polythene – (d) (a)-(iii), (b)-(ii), (c)-(i) The disposal of plastic waste is a major problem because plastic is non-biodegradable, it takes.several years to decompose. Hang cotton, thread from a stand. A plastic used for making containers and carry bags. 1. Short Answer Questions: Why should we not use plastics? (c) nylon and cotton (d) polyester and cotton A thermosetting plastic is a polymer that irreversibly becomes rigid when heated. What is its common name? Thus, cause environmental pollution. The articles mades of plastics are non-biodegradable. Codes Answer: Melamine is a versatile material. So, we should avoid use of plastics, as for as possible. (c) (a)-(ii), (b)-(i), (c)-(iii) (7) (a) Thermosetting plastics remain hard on reheating and can sustain high temperatures. If you are at an office or shared network, you can ask the network administrator to run a scan across the network looking for misconfigured or infected devices. Question. Why? A polymer used for making ropes. True or False : Question 1. Answer. 19 Rohit took with him some nylon ropes, when he was going for rock climbing. 4. Such a material is also known as a thermoset or thermosetting polymer. This causes a great problem in the disposal of plastic wastes. 8 Which of the following represents the correct match for items in Column A with those in Column B. (a) Melamine is a thermosetting plastic which when moulded once, cannot be softened by heating. Question. Answer. Answer. Answer. is a good conductor of plastics. 10. 16 Why is it not advisable to burn plastic and synthetic fabrics? (c) PVC, polythene and bakelite are synthetic substances. Choose the correct answer: Example of thermosetting plastic is . (d) Acrylic, silk, wool 4 Which is a thermosetting plastic? Attach a pan at the other end of the thread. Nylon It is used for making ropes for rock climbing, fishing nets, raincoats, parachutes and tyre cords, etc. Thermosetting Plastics:There are some plastics which when moulded once cannot be softened by heating. Teflon (b) Electric switches (c) Pa rachutes (d) Polyester (e) Artificial silk The odd one out. TRUE ? State True or False: Thermoplastics are hard and brittle. The raw material to make plastic is oil. 9 Which of the following groups contains all synthetic substances? TRUE ? Please enable Cookies and reload the page. It is used for making floor tiles, kitchenware and fabrics which resist fire. Box Quantity: 48. (4) The reaction used to produce thermosetting plastic products involve a chemical interaction between specialized materials. (a) Anory (b) Lopmery So, it is not advisable to burn plastic and synthetic fibres. So, it is not advisable to dispose of the used plastic articles by burning. Plastic containers seem most convenient. View Answer. Thermosetting plastics do not melt when heated. (a) Non-reactive The importance of synthetic polymers in our life are as follows: Question. Activity Take threads of cotton and nylon (synthetic fibres) of about same length and thickness.. Question. Answer. When left exposed to moisture and air, it does not react with air and water which are essential for corrosion, therefore does not rust. (a) Rayon (b) Polymer Question. The chemical formula for melamine formaldehyde is C4H6N6O. 16. Question. Question. Terylene It is used in textile industry to make clothes like sarees, tapestry and dress material. Answer. This gives a measure of the tensile strength of the thread. Answer. (e) Polyester (f) Teflon. 5. True, a disadvantage as synthetic fibre is that they melt on heating. 4. Thermosetting plastics are normally made up of lines of polymers which are highly cross-linked. Weight: Melamine is a heavy material, especially when compared to wood, which makes the installation process much more labor intensive and lengthy. (d) Plastics are non-reactive, light in weight and durable but they do not conduct electricity. (b) Electric plugs/ switches/ plug boards are saucepan is made of thermosetting plastic because it is a bad conductor of electricity. Name one natural fibre. Write the names of the fibres. Explanation: Thermosetting plastics when moulded once can not be softened by heating. It is made from melamine and formaldehyde by condensation of the two monomers. Which is a thermosetting plastic? Substance used as synthetic wool. A nylon thread is actually stronger than a steel wire of similar thickness. They tend to char and burn when heated, but they are resistant to much higher temperatures than thermosoftening plastics. (a) (a)-(ii), (b)-(iii), (c)-(i) We hope the NCERT Exemplar Class 8 Science Chapter 3 Synthetic Fibres and Plastics help you. Answer. Bakelite is a thermosetting plastic and is used for making electrical switches, handles of various utensils, etc. Name two thermosetting plastic items. Melamine-Formaldehyde Resins Properties. A) true B) false 17. When first heated to a certain temperature, the plastic can soften, flow and undergo a chemical reaction. d) Bakelite is a thermoplastics plastics. Answer. Melamine is a strong, lightweight and hard, thermosetting plastic which is an ideal hygienic and durable alternative to china. The burning of plastic wastes gives out harmful gases which pollute the air. Polycot, Polywool, Terrycot ,Acrylic State whether the given statements are true or false… As the containers used for microwave cooking should be able to sustain reheating without causing any damage to the food kept in them, these containers can be made of thermosetting plastics. Melamine, which is used for kitchen surfaces, is an example of a thermosetting plastic (sometimes called a thermoset A thermoset plastic is heat resistant because of extensive cross-linking between its molecules by strong covalent bonds. Why do we use melamine for making kitchenware? a) Saucepan handles. Soln: Answer is (b) Rayon 9. Multiple Choice Questions 3. ? Thermosetting polymer composites are made using a laminating process, which binds together resins such as epoxy, silicone, melamine, etc. Thermosetting plastics 5. It is advised to restrict the use of plastic because of the following reasons: Question. 1 Pick the synthetic fibre out of the following. c) Acrilon is pure wool obtained from sheep. Initially, the polymer is a liquid or soft solid. Answer. Down Silk, jute, Nylon, wool 4. (i) The fabric terywool is obtained by mixing terylene and wool. (a) nylon (b) rayon Question. Why? (d) melamine. Question 4. Another name for this compound is artificial silk. NCERT Solutions for Class 6, 7, 8, 9, 10, 11 and 12. They do not decompose (or rot) easily. (c) Wood Rayon is often regarded as artificial silk. The resin of thermosetting plastic is linear or with branched chain, after curing, III. Also write the false statements in their correct form. (f) Peels of vegetables However its most common use is to combine it with formaldehyde, to create a melamine resin which is a type of plastic. ? Its physical properties and appearance has made it a popular material for manufacturing hard wearing products across a number of industries. Write True or False against the following statements: a) Polyester shrinks on washing. 7. e) P.V.C. Question. (b) Light in weight (c) PVC (d) Nylon 5. The shopkeeper showed her blankets made up of acrylic fibres as well as made up of wool. Answer. Its common name is rayon. TRUE ? Answer. Performance & security by Cloudflare, Please complete the security check to access. 13 Terrycot is made by mixing two types of fibres. Can you guess why? (d) PET is ‘poly-ethylene’ terephthalate’ PET as a plastic is very light weight and is commonly used for making kitchen containers. Short Answer Type Questions Question. Can you tell why? It is made without using any natural raw material. Which is a thermosetting plastic? The biodegradable articles are: (b) Woollen clothes It resists fire and can tolerate heat better than other plastics. (c) Nylon —-> Fibre , PVC —->Thermoplastic , Bakelite —->Thermosetting plastic. 1. Answer. Thermoset plastic products are typically produced by heating liquid or powder within a mold and allowing the material to cure into its hardened form. 10 The material which is commonly used for making kitchen containers is Answer. Question. Question. (e) Yespolter (f) Felton Therefore among consumer uses, when people say “melamine” they are referring to the plastic made with it. (d) Polycot is obtained by mixing polyester and cotton. (c) Terylene (d) Plastic Add weights, one by one, to the pan until the thread breaks (see fig.) Here we have given NCERT Exemplar Class 8 Science Chapter 3 Synthetic Fibres and Plastics. Terrycot is made by mixing terylene and cotton. 5 The material similar to silk in appearance is … 3 Polycot is obtained by mixing Answer. Acrylic It is used for sweaters, track suits, linings for boots and gloves and In furnishing fabrics and carpets. (c) Relyteen (d) Laspict (a)—(iii), (b)—(iv), (c)—(v), (d)—(ii), (e)-(i), Question. (a) Cotton (b) Nylon (c)Jute (d)Wool Answer. A lot of plastic pollutes our environment. 14 Plastic articles are available in all possible shapes and sizes. It is prepared from coal, water and air. Question. Also write the false statements in their correct form. State, whether the following statements are True or False. Answer. Question. 29 Crossword Puzzle Complete the crossword given below with the help of clues. Bakelite is used for making electrical switches, handles of various utensils etc. Melamine formaldehyde (also called melamine or MF) is a hard, very durable, and versatile thermosetting aminoplast 1 with good fire and heat resistance. Answer. 21 PVC (polyvinyl chloride) is a thermoplastic and is used for making toys, chappals, etc. (a) nylon and wool (b) polyester and wool Nylon ropes are strongfelastic and lighter as compared to cotton and jute ropes. The material similar to silk in appearance is ... Indicate whether the following statements are True or False. The material similar to silk in appearance is (a) Nylon (c) Polyester ... Indicate whether the following statements are True or False. Answer: True. b) Plastics are not affected by heat. Your IP: 138.201.32.27 Thermoplastics get deformed easily on heating and can be bent easily on heating. It is also mixed with natural fibre like cotton and wool to make more variety of clothes. Thermosetting plastics —–> Bakelite and melamine, Question. Substance made up of large number of smaller molecules. Once cured, the plastic will become hard. Very Short Answer Type Questions Answer: (b) thermosetting polymer Why is it so? Long Answer Type Questions (a) Paper A type of fibre obtained naturally from cocoon. Question 2. As a result, there is a risk of melamine and formaldehyde discharge into foods prepared or stored in melamine-containing dishes, bowls, and other products in the home. Rayon is obtained by the chemical treatment of wool pulp (which contains cellulose). It is, therefore, known as artificial silk. She preferred to buy an acrylic blanket. Whether a saucepan can be used in an oven usually depends on the type of material from which the pan's handles are made. Question. Answer: True. (c) polyester (d) terylene Question. You may need to download version 2.0 now from the Chrome Web Store. 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Melamine resin or melamine formaldehyde (also shortened to melamine) is a resin with melamine rings terminated with multiple hydroxyl groups derived from formaldehyde.This thermosetting plastic material is made from melamine and formaldehyde. 2. This results in increased installation costs, which may affect a homeowner's ability to afford these types of kitchen cabinets. Question. (9) If you are on a personal connection, like at home, you can run an anti-virus scan on your device to make sure it is not infected with malware. with reinforcement base materials such as glass, linen and graphite. This material is called thermosetting plastic. Prior to curing, the reinforcement substrate is dipped into the resin binder in its liquified form. words given below, related to synthetic Examples are bakelite and melamine. Statement: The articles made of thermoplastics can be recycled whereas the articles made of thermosetting plastics cannot be recycled. Repeat the same with nylon thread. (e) Plastic bag (c) wood (f) peels of vegetables. Heat provides energy for chemical reactions that increase the cross-linking 17 Select the articles from the following list which are biodegradable. Melamine is … Completing the CAPTCHA proves you are a human and gives you temporary access to the web property. Rayon 7.Which raw material is used to make nylon? Answer. 25 State whether the following statements are True/False. Answer 4 (a) Question 5. (5) MEDIUM (8) Question. NCERT Exemplar Class 8 Science Chapter 3 Synthetic Fibres and Plasticst are part of NCERT Exemplar Class 8 Science. 26 Write the importance of synthetic polymers in our life. Silk 6. Melamine crockery is a thermoset plastic resin made from organic compounds. What is its chemical name? (a) Melamine (c) PVC (b) Polythene (d) Nylon . (5) PVC, melamine, polythene, natural ru bber 2. • (b) (a)-(iii), (b)-(i), (c)-(ii) 27 Despite being very useful, it is advised to restrict the use of plastic. 28 Write an activity to show that synthetic fibres are stronger than the cotton fibres. (c) nylon (d) bakelite This characteristic is used to shape and process plastics and then solidify into products of definite shape and size. The heavily cross-linked structure produced by chemical bonds in thermoset materials is directly responsible for the high mechanical and physical strength compared with thermoplastics or elastomers. Can you write the major difference between these two types of plastics? 6 The most suitable material for the preparation of handles of cooking utensils is (a) polythene (b) PVC note the total weight required to break the cotton thread. These are called thermosetting plastics e.g., bakelite and melamine. Question. FALSE; Epoxy resin is a thermoplastic? Cloudflare Ray ID: 6076c08d7e3f1f95 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. 5 The material similar to silk in appearance is Answer. (a) Melamine (c) PVC (b) Polythene (d) Nylon 5. Question 3. Thermoplastics —–>Polythene and PVC ‘ FALSE; PVC is a thermoplastic. FALSE; Plastic is suitable for building large and heavy structures. TRUE ? Question. A) PVC B) Polythene C) Bakelite D) None of these 19. Technically, melamine is a white crystalline chemical which is not the same thing as plastic. It is good to wear clothes made of synthetic fibres while cooking. Refuse (avoid) is the best way to manage plastic. 7 Which of the following is not a common property of plastics? (a) Melamine is a thermosetting plastic which when moulded once, cannot be softened by heating. Is melamine plastic? Melamine is (a) thermoplastic polymer (b) thermosetting polymer (c) fibre (d) elastomer. 20 A lady went to the market to buy a blanket. The material similar to silk in appearance is (a) Nylon (b) Rayon (c) Polyester (d) Terylene. Much more weight is required to break the nylon thread showing that nylon thread has a grater strength that the cotton thread. 23 Match items in Column A with the terms of Column B. (a) Wool (b) PET (c) Wood pulp (d) Silk (7) 18 A bucket made of plastic does not rust like a bucket made up of iron. (c) teflon (d) PET Electrical insulator and tableware. On the other hand, thermosetting plastics when moulded once cannot be softened on heating. ? (d) Good conductor of electricity But it is advised to avoid the use of plastic as far as possible. Answer. Plastic is non-reactive material. Which synthetic fibre is called synthetic silk? A) true B) false 18. 24 Unscramble the jumbled materials. Question. 15 Plastic is used for making a large variety of articles of daily use and these articles are very attractive. A synthetic fibre classified as polyester. (a) PVC (b) acrylic (a) Nylon, tprylene, wool Can you suggest some methods to limit its consumption? ? 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. Soln: Answer is (a) Melamine. Melamine plastics degrade and release chemical constituents upon heating to temperatures utilized for cooking in ovens and microwaves, as well as upon exposure to acidic foodstuffs. If you have any query regarding NCERT Exemplar Class 8 Science Chapter 3 Synthetic Fibres and Plastics, drop a comment below and we will get back to you at the earliest. State whether the given statement is true or false. (a) Melamine (b) Polythene (c) PVC (d) Nylon. Polycot = polyester + cotton. Answer. Cotton, jute and wool are natural fibres. Acrylic, polyethylene and polystyrene are thermoplastic. Question. (b) Nylon Is a synthetic fibre. (c) Wool pulp Chemical name of natural polymer of cotton is cellulose. Acrylic blankets are cheap, light in weight, more durable and are available in variety of colours and designs. (c) PVC, polythene, bakelite (d) Bakelite is used for making the handles of various cooking utensils because it is a poor conductor of heat and does not become soft on getting heated. Answer: (False) Correct statement: It is good to wear clothes made of fibres while cooking. Write full forms of: a) P.V.C. 12 A synthetic fibre which looks like silk is obtained by chemical treatment of wood pulp. Answer. The molder can remove the part from the mold before it cools. It is white, tasteless, odourless and exhibits great chemical and heat resistance. Question. (b) Rayon resembles silk in appearance, therefore, rayon is also called artificial silk. Question. NCERT Exemplar SolutionsNCERT Exemplar MathsNCERT Exemplar Science. Answer. Plastics can be easily moulded, so they are used to make a large variety of articles (or objects) having different shapes and sizes. Wood, paper, woolen clothes, aluminum can 3. Answer. TRUE ?

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