Glossary - Introduction to Polymeric Composites with Rice Hulls - page 157

Ratio control - the ability to change and regulate the ratio or proportion between
two or more fluid components.
Raw materials - the chemical ingredients used in the manufacture of polymeric
composites.
Reactants - general term for any of the raw material or intermediates used in a
manufacture.
Reaction balance - the important balance between the relative reaction rates of gas
generation (blowing) and gelation (polymerisation).
Regulator - a device used to control the flow of fluids.
Remote drive - a drive motor (usually for a mixing head) that is located separately.
Reodorant - a powerful, pleasant-smelling chemical that is added to a formulation
to mask unpleasant odours (sometimes associated with amine catalysts).
Resilience - an indicator of the surface elasticity or 'springiness' of a sample of
composite.
Resin - unsaturated polymers or monomers. Also called 'plastic resins'.
Rheology - the study of flow and deformation of matter.
S
Schematic diagram - drawing that illustrates the design and layout of a machine,
circuit or process in an abstract or symbolic manner.
Scrap - generally refers to waste from a plastic manufacturing process and is an
inherent waste-generation.
Screw - a grooved or specially designed rotating steel shaft that transfers the
heated material forward in injection moulding and extrusion.
Self-extinguishing - the ability of a material to stop burning after it has started
burning.
Shaping saws - cutting devices that can produce any special shape desired.
Shear resistance - the ability of a composite to resist laterally applied forces.
Shiny foam - foams with high proportion of uniform cell membranes that glitter
from reflected light.
Shot - the total amount of a composite resin dispensed from an injector during one
cycle.
Shot cycle - the total time spent on 'on' and 'off' in a single unit of operation.
Shot cycle timer - a timing device used for automatic control of a shot cycle.
Shredder - a mechanical device used to reduce waste to small pieces.
Shrinking - the loss in size that occurs during production. Can be due to excess
heat and faulty formulations.
Silicones - complex chemicals formed from a combination of silicon and organic
groups. These are used widely in urethane foam formulations for cell structures.
Skins - describes the high-density outer surface of an extruded composite profile.
Solid elastomer - rubber-like compounds that have no internal cavities or gas bubbles.
Solid filler - an insoluble additive used in foam formulations. Adds weight and
reduces the cost of foam products.