Definitions /Dictionary/Glossary - nptel

Pick Count: The number of filling yarns per inch or per centimeter of woven fabric.
Pigment: the ingredient used in gel coats to impart color.
Pigment Separation: A mottled (varied colors) appearance of the gel coat surface.
Pinhole: A tiny hole in the surface of, or through, a plastic material; usually occurring in
multiples.
Pit: Small regular or irregular crater in the surface of a plastic, usually with width approximately
of the same order of magnitude as its depth.
Pitch: A residual petroleum product used in the manufacture of certain carbon fibers.
Pitch Fibers: Reinforcement fiber derived from petroleum or coal tar pitch.
Planar Winding: A type of filament winding in which the filament path lies on a plane that
intersects the winding surface.
Plastic: A material that contains one or more organic polymers of large molecular weight, is
solid in its finished state, and, at some state in its manufacture or processing into finished
articles, can be shaped by flow.
Plastic Deformation
Change in dimensions of an object under load that is not recovered when the load is removed;
opposed to elastic deformation.
Plasticizer: A material of lower molecular weight added to a polymer to separate the molecular
chains. These results in a depression of the glass transition temperature, reduced stiffness and
brittleness, and improved processability. (Note, many polymeric materials do not need a
plasticizer.)
Plastic Tooling: Tools (mostly for the metal forming trades) constructed of plastics, generally
laminates or casting materials.
Platens: The mounting plates of a press, to which the entire mold assembly is bolted.
Plied Yarn: It is a yarn formed by twisting together two or more single yarns in one operation.
Plug: See Master - Both terms used to imply the same meaning.
Ply: The number of single yarns twisted together to form a plied yarn; one of the layers that
make up a stack or laminate.