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SAI INTERNATIONAL SCHOOL


                                                    CHEMISTRY
                                                      Class-VIII


                                Topic - SYNTHETICFIBRES AND PLASTICS
                       Sub-Topic – Thermoplastics and Thermosetting Plastics,


                                          Useful Properties of Plastics



                                                  LESSON NOTES

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        TYPES OF PLASTICS:

              Plastic is easily mouldable in all types of possible shapes and can be recycled, coloured,
               reused, rolled into sheets or made into wires.
              Plastic polymer unit can be arranged either in a linear or cross-linked pattern.

              Linear polymers are those in which the polymer chains are in a long-chain linearly and are
               not cross-linked as shown in the figure.

              Cross-linked polymersare those in which chemical bonds are formed between adjacent
               polymer chains, so that a network of cross-linked structure forms.

              Plastics are of two types: Thermoplastics and Thermosetting Plastics.
              A Thermoplastic has a Linear Polymer Chain, whereas, Thermosetting plastics have a
               cross-linked polymer chain.












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