Skip to main content

Exam Ready Notes SYNTHETIC FIBRES AND PLASTICS

  1. A synthetic fibre is also a chain of small units joined together. Each small unit is actually a chemical substance. Many such small units combine to form a large single unit called a polymer. The word ‘polymercomes from two Greek words; poly meaning many and mer meaning part/unit. So, a polymer is made of many repeating units.
  2. Polymers occur in nature also. Cotton, for example, is a polymer called cellulose.  Cellulose is made up of a large number of glucose units
  3. Rayon : 
  4. Nylon  is another man-made fibre. In 1931, it was made without using any natural raw material (from plant or animal). It was prepared from coal, water and air. It was the first fully synthetic fibre. Nylon fibre was strong, elastic and light. It was lustrous and easy to wash. So, it became very popular for making clothes.
  5. Polyester is another synthetic fibre. Fabric made from this fibre does not get wrinkled easily. It remains crisp and is easy to wash. So, it is quite suitable for making dress material
  6. Terylene is a popular polyester. It can be drawn into very fine fibres that can be woven like any other yarn.  
  7. PET is a very familiar form of polyester. It is used for making bottles, utensils, films, wires and many other useful products.  
  8.  Polyester (Poly+ester) is actually made up of the repeating units of a chemical called an ester. Esters are the chemicals which give fruits their smell. Fabrics are sold by names like polycot, polywool, terrycot etc. As the name suggests, these are made by mixing two types of fibres. Polycot is a mixture of polyester and cotton. Polywool is a mixture of polyester and wool.
  9.  All the synthetic fibres are prepared by a number of processes using raw materials of petroleum origin, called petrochemicals.
  10.   Polythene (Poly+ethene) is an example of a plastic. It is used for making commonly used polythene bags.
  11. Plastic is also a polymer like the synthetic fibre. All plastics do not have the same type of arrangement of units. In some it is linear, whereas in others it is cross-linked.
  12. . Plastic can be recycled, reused, coloured, melted, rolled into sheets or made into wires.
  13.  plastic which gets deformed easily on heating and can be bent easily are known as thermoplastics. Polythene and PVC are some of the examples of thermoplastics. These are used for manufacturing toys, combs and various types of containers.
  14. there are some plastics which when moulded once, can not be softened by heating. These are called thermosetting plastics. Two examples are bakelite and melamine. Bakelite is a poor conductor of heat and electricity. It is used for making electrical switches, handles of various utensils, etc. Melamine is a versatile material. It resists fire and can tolerate heat better than other plastics. It is used for making floor tiles, kitchenware and fabrics which resist fire 
  15. Plastics  as Materials  of   Choice
    • Plastic is non-reactive
    • Plastic is light, strong and durable
    • Plastics are poor conductors
    • Plastics find extensive use in the health-care industry.    Some examples of their use are the packaging of tablets, threads used for stitching wounds, syringes, doctorsgloves and a number of medical instruments
      Special plastic cookware is used in microwave ovens for cooking food. In microwave ovens, the heat cooks the  food but does not affect the plastic vessel.

  16. asa

Comments

Popular posts from this blog

UNIT 13 FEATURES OF 73rd AND 74th CONSTITUTIONAL AMENDMENT

Structure

13.0 Learning Outcome

13.1 Introduction

13.2 Initiatives towards Constitutional Status to Local Governance

13.2.1 Features of 73rd Constitutional Amendment

13.2.2 Features of 74th Constitutional Amendment

13.2.3 Decentralised Planning in Context of 73rd and 74th Constitutional Amendment Act

13.3 Initiatives after Economic Reforms

13.4 Functioning of PRIs in Various States after 73rd Amendment

13.5 Functioning of Local Governance after 73rd and 74th Constitutional Amendment: Observations

13.6 Conclusion

13.7 Key Concepts

13.8 References and Further Reading

13.9 Activities

13.0 LEARNING OUTCOME

After studying this Unit you should be able to:

• Identify the background of revitalisation of local governance;

• Understand the features of 73rd and 74th constitutional amendment;

• Discuss the initiatives after economic reforms; and

• Outlines the functioning of local governance in various states after the amendment.

13.1 INTRODUCTION

The revitalization of Pancha…

UNIT 1 CONCEPT, EVOLUTION AND SIGNIFICANCE OF DEMOCRATIC DECENTRALISATION

Structure

1.0 Learning outcome

1.1 Introduction

1.2 Concept of Democratic Decentralisation

1.3 Evolution of Democratic Decentralisation

1.4 Significance of Democratic Decentralisation

1.5 Democratic Decentralisation in India

1.6 Conclusion

1.7 Key concepts

1.8 References and Further Reading

1.9 Activities

1.0 LEARNING OUTCOME

After studying this unit, you should be able to:

• Understand the concept of Democratic Decentralization;

• Know the evolution and significance of Democratic Decentralization; and

• Describe the Democratic Decentralization pattern in India.

1.1 INTRODUCTION

The dawn of 21st century is marked by decentralized governance both as a strategy and philosophy of brining about reforms and changes in democracies. These changes led to such virtues of transparency, responsiveness and accountability and ensures good governance. Today decentralization and democracy are the most significant themes in the development discourse. In the present contex…

General Studies :: Indian Polity #1

Constitutional evolution under British ruleRegulating Act 1773beginning of British parliamentary control over the East India Companysubordination of the presidencies of Bombay and Madras to BengalGovernor of Bengal made Governal-Generalcouncil of Governor-General establishedSupreme Court established in CalcuttaPitt’s India Act 1784commercial and political activities of the Company separatedestablished a board of control over the CompanyCharter Act 1813trade monopoly of the Company abolishedmissionaries allowed to preach in IndiaCharter Act 1833Governor-General of Bengal becomes Governor-General of Indiafirst Governor-General Lord William Bentickends commercial activities of the CompanyCharter Act 1853legislative and executive functions of the Governor-General’s council separatedopen competition for Indian Civil Services establishedIndian Council Act 1861establishes legislative councils at the centre, presidencies and provincesGovernor-General’s executive council to have Indians as non…