Two polymer manufacturing processes are shown at A and B below - Leaving Cert Engineering - Question 6 - 2013

Transfer moulding is ideal for creating components from thermosetting plastics, such as those required for electrical plug casings. This process provides a detailed component profile, which ensures that the plug casing has the precise dimensions and features necessary for functionality. Additionally, transfer moulding results in a robust component, which is critical for electrical applications in order to ensure reliability and safety.

The split mould allows for the efficient release of the component produced via injection moulding. At the end of the moulding cycle, the component can be pushed out by ejector pins, facilitating automated production and reducing handling time, which enhances productivity.

Condensation polymerisation involves the reaction of monomers that leads to the elimination of a small molecule, such as water, during the process. This type of polymerization is often used for producing thermosetting plastics. In contrast, addition polymerisation does not eliminate any by-products; instead, it forms long-chain polymers directly by the repeated addition of monomer units.

Plasticisers are additives that increase the flexibility and workability of polymers by embedding themselves between polymer chains. Stabilizers, on the other hand, are compounds that prevent degradation of the polymer due to environmental factors, such as UV light or heat, thus extending the lifespan of the material.

Extrusion is a continuous process that produces uniform shapes by forcing plastic through a die to create products like tubing or sheets. Compression moulding, however, is a batch process where a pre-measured amount of plastic is placed in a heated mould, allowing the material to conform to the shape of the mould. This method is particularly suitable for producing larger, complex shapes.

Natural rubber is derived from the sap of rubber trees and consists mainly of polyisoprene. It exhibits high elasticity and good tensile strength but can be affected by environmental factors. Synthetic rubber, produced through chemical processes, can be engineered to enhance specific properties, making it more durable and heat resistant compared to natural rubber.

Structure X is a linear structure, while Structure Y is a cross-linked structure.

Structure X is associated with thermoplastics such as polyethylene or PVC, while Structure Y is linked to thermosets such as epoxy resins.

Structure X has properties such as:

1. It can be heated and reformed without losing shape, making it easy to process.
2. It has a high melting point and is generally resistant to chemical degradation.

Structure Y, on the other hand, possesses properties like:

1. High tensile strength and durability, making it suitable for load-bearing applications.
2. Good thermal insulation, which allows it to withstand high temperatures without compromising its integrity.