Design Technology - Topic 4.2d-f

Raw Materials for Plastics

Raw Materials for Plastics

Derived from non-renewable petroleum resource, such as crude oil, coal, or natural gas

Thermoplastics

Linear chain molecules with weak secondary bonds between the chains. Ductile, low stiffness, and can be reshaped after heating

Thermosetting Plastics

Linear chain molecules with strong primary bonds between adjacent polymer chains. High stiffness and strength, but cannot be reheated and remolded.

Natural Fibers

Materials produced by plants/animals that can be spun into a thread, rope, or filament. High absorbency, but low tensile strength/elasticity. Burns

Synthetic Fibers

Fibers made from a man-made material that are spun into a thread. Joining of monomers into polymers by the process of polymerization. Low absorbency, but high tensile strength/elasticity. Burns and melts

Weaving

Forming a sheet-like material by interlacing long threads passing in one direction with others at a right angle to them

Knitting

Converting a yarn into fabric by creating consecutive rows of interlocking loops of yarn

Lacemaking

Creating a decorative fabric that is woven into symmetrical patterns and figures

Felting

Converting yarn into fabric by matting the fibers together

Ethical Considerations

Material harvesting can be labor intensive and the making of textiles is often done by a low-skilled labor force in poor conditions

Composites

Mixture composed of two or more materials with one acting as the matrix and the other acts as a reinforcement. Made through weaving, molding, pultrusion, or lamination