| EduRev Class 8 Question is disucussed on EduRev Study Group by 118 Class 8 Students. We know that bakelite is a thermosetting plastics, which is used for making electrical switches, handles of various utensils, etc. Bakelite and melamine are examples of thermosetting plastic. Thermosetting plastics are hard and brittle in nature. Bakelite is a very poor conductor of heat and electricity and it is used for making electrical switches. Polymers can be separated into plastics and rubbers. Popular Questions of Class Chemistry. Such plastics are called thermosetting plastic. We have provided Synthetic Fibres and Plastics Class 8 Science MCQs Questions with Answers to help students understand the concept very well. Others are 'thermosetting': like eggs, they cannot revert to their original viscous state, and their shape is thus fixed for ever Bakelite had the distinction of being the first totally synthetic thermosetting plastic. Heat provides energy for chemical reactions that increase the cross-linking Thermoplastics have low melting points and low tensile strength. As engineering materials, they are relatively new compared to metals and ceramics, dating only from around the mid-1800 s. It is appropriate to divide them into the following three categories; Thermoplastic polymers (thermoplastics/TP) Thermosetting polymers (thermosets/TS) Elastomers (rubbers/E) Basically there are two types of thermoplastic, thermoset and thermoform. Thermoplastic and Thermosetting plastic are two separate forms of polymer powders, which are differentiated based on their behavior when reacting to the application of heat. In option A, it is given that bakelite is a thermoplastic. Thermoplastics, on the other hand, will melt down into a liquid when you heat it, and then they will refreeze again upon cooling. Fill in the blanks. Thermoplastic is a form of a polymer which will likely be merely melted by providing heat in an effort to recycle the material. Wire made from which fibre is strongest: (a) nylon (b) cotton (c) wool (d) steel. When heat and pressure are applied to the layers, a chemical reaction (polymerization) transforms the layers into a high-pressure thermosetting industrial laminated plastic. This is hard and strong plastics. b) Plastic bag, … Acrylic, polyethylene and polystyrene are thermoplastic. Now, let’s discuss the Processing of Plastics. Thermosetting Plastic: Some plastics do not get deformed on heating, and cannot be re-molded into a new shape. softening and hardening can be repeated again and again. Plastic which cannot be melted and moulded repeatedly? Such a material is also known as a thermoset or thermosetting polymer. Hence, the correct answer is option (A). Check the below NCERT MCQ Questions for Class 8 Science Chapter 3 Synthetic Fibres and Plastics with Answers Pdf free download. Which of the following characteristics does not affect the properties of plastics? Bakelite is a thermosetting polymer i.e. What is the difference between thermoplastic and thermosetting 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. Bakelite Phenolic is produced in dozens of commercial grades to meet mechanical, electrical and thermal requirements. Can you write the major difference between these two types of plastics? Thermosetting plastics have primary bonds between molecular chains and held together by strong cross-links. A number of glucose units make up the polymer a) Protein b) viscose c) cellulose d) Rayon 3. 4. Plastics are divided into two groups depending on how it reacts to heat. Bakelite is used for making electrical switches and switchboards because it is a poor conductor of heat and electricity. Is it thermoplastic or thermosetting plastic? Thermoplastic is lower in molecular weight, compared to thermosetting plastic. Examples of thermosetting plastics include bakelite, urea-formaldehyde resins. But it is not. (a) Thermoplastic (b) PET (c) Thermosetting plastic … Synthetic fibres a) wrinkle free b) dry quickly c) catch fire easily d) all of these 5. I think you had understood about the properties of polymers, thermoplastics, and thermosetting plastics in a detailed way. Nov 25,2020 - Bakelite is -. The synthetic polymer which can be used as a substitute for wool for making; sweaters and shawls etc. Thermosetting plastics have an excellent aesthetic appearance. Thermosetting vs. Thermoplastic Polymers Last updated; Save as PDF Page ID 5435; Contributors; Most of the polymers described above are classified as thermoplastic. I think you had understood about the properties of polymers, thermoplastics, and thermosetting plastics in a detailed way. Thermoset becomes hard when heated an example would be Bakelite. PVC (polyvinyl chloride) is a thermoplastic and is used for making toys, chappals, etc. Bakelite is a thermosetting plastic. Melamine is not thermoplastics, it is thermosetting plastic. Thermosetting plastics will develop … Thermosetting plastics have high melting points and tensile strength. 2. Question 4. I thought that thermosets were "set solid" by a chemical reaction that was irreversible. they can be softened by heating only once i.e. Bakelite and melamine are examples of thermosetting plastic. Thermosetting Plastic can not be reshaped. It is insolvent. So, option (C) and (D) are also not the solution to this question. 4. Such plastics are called thermosetting plastic. 22. The polymerization process creates the polymers used for making plastics. Thermosetting plastics have extreme thermal stability, extreme dimensional stability, and extreme thermal and electrical insulating properties. Also, thermoplastics can be deformed easily, while thermosetting plastics cannot. Phenolic(Bakelite) Vinyl Ester Resin; Cyanate Ester; Polyester; This is the complete explanation with its top 10 properties. Others are 'thermosetting': like eggs, they cannot revert to their original viscous state, and their shape is thus fixed for ever Bakelite had the distinction of being the first totally synthetic thermosetting plastic. 1 answer. Key Differences between Thermoplastics and Thermosetting The primary difference between the two is that a thermoset is a material that becomes strong when heated, but cannot be regenerated or heated after initial formation, while thermoplastics are not necessarily … The crude oil contains hydrocarbons, which make up the monomers. Question 5. Choose the thermoplastics and thermosetting plastics from the following: Melamine, Polythene, Bakelite, Polyvinyl chloride synthetic fibers and plastics class-8 Thermosetting Plastic: Some plastics do not get deformed on heating, and cannot be re-molded into a new shape. Thermoplastics vs Thermosetting Plastics. Thermoplastic is used for making combs, toys, buckets, mugs, etc. PET is form of: (a) steel (b) glass (c) polyester (d) nylon. are : (a) Nylon (b) Terylene (c) Polyester (d) Acrylic. Thermoplastic is a long-chain linear. ... Related questions 0 votes. 3. This reflects the fact that above Tg they may be shaped or pressed into molds, spun or cast from melts or dissolved in suitable solvents for later fashioning. Synthetic fibres cause soil pollution because they are a) Biodegradable b) Non - biodegradable c) Tough d) soft 4. Understand the Key Differences Between Thermoplastic and Thermosetting Plastic with detailed explanations and examples. Some are 'thermoplastic', which means that, like candlewax, they melt when heated and can then be reshaped. Q:-Give simple chemical tests to distinguish between the following pairs of compounds. Thermoset vs thermoplastic, and Bakelite. (i) A polymer is a chain of many small units joined together which are called _____. As in, if you heat up the plastic after it sets, it burns instead of melts. Thermoplastic is soft, weak and less brittle. MCQ Questions for Class 8 Science with Answers were prepared based on the latest exam pattern. Thermoplastic: Thermosetting Plastic: 1. (a) Bakelite (c) Wool (c) Nylon (d) Cotton. In lab I made samples that were mounted in bakelite. A thermosetting plastic is a polymer that irreversibly becomes rigid when heated. Engineering thermoplastic performance is governed by the architecture of the polymer backbone, which determines the strength, rigidity, softening temperature, Tg, and melt temperature, Tm, (if crystalline) of the matrix. Tångavägen 5, 447 34 Vårgårda info@futureliving.se 0770 - 17 18 91 Few examples of thermosetting plastics are phenolic resins, epoxy resins, amino resins, melamine, Bakelite. Phenolic(Bakelite) Vinyl Ester Resin; Cyanate Ester; Poly Ester; This is the complete explanation with its top 10 properties. (a) thermoplastic (b) polyester (c) thermosetting plastic (d) nylon Related: MCQ - Synthetic Fibers And Plastics? Thermoplastic properties: When you heat thermoplastics … Thermoplastics can be repeatedly softened by heating and hardened by cooling.Thermosetting plastics, however, harden permanently after being heated once. Answer (a) nylon Wire made from nylon fibre is the strongest. Thermoset plastics are frequently used for sealed products due to their resistance to deformation and are also among some of the most impact resistant plastics available. Thermosets are in the liquid state before processing. Thermoplastic polymer chains are free to move past each other and separate when subjected to heat (melt), chemicals (dissolve) or load (cold flow or creep). Bakelite is a) thermoplastic b) ployester c) thermosetting plastic d) Nylon 2. once they are moulded and harden on cooling, they cannot be softened again. Thermoplastics vs. Thermosetting Plastics. Thermoplastic can be reshaped and reused. Plastics will likely be divided into each thermoplastic or thermosetting plastics. The plastics which cannot be softened by heating, when moulded once are called thermosetting plastics. Whereas, polythene is a thermoplastic polymer i.e. 4. 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. Thermosetting plastics have a relatively higher melting points and tensile strength. asked Jun 20 in Chemistry by BhratJha (44.3k points) synthetic fibers and plastics; class-8; 0 votes. Thermoplastics are solvent in organic compounds. Previous Question Next Question. Hope this article is helpful to you. Now, let’s discuss the Processing of Plastics. Bakelite is a thermosetting plastic and is used for making electrical switches, handles of various utensils, etc. Write the full form of PVC. The fabrication process for thermoplastic and thermoset start outs with the same raw materials, such as ethylene and propylene, made from crude oil. Bakelite: Used to make plastic ware, vehicle disc brake cylinders, plugs and sockets, ... Thermosetting plastics have a relatively higher molecular weight when compared to thermoplastics. Some are 'thermoplastic', which means that, like candlewax, they melt when heated and can then be reshaped. Hope this article is helpful to you. 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