Glossary | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | PCB Printed circuit board. See printed circuit.   Pentafluoropropanol A fluorinated alcohol.   Perchloroethylene A perhalogenated chlorocarbon solvent used extensively in industrial degreasing and in dry cleaning.   Perhalogenation An organic molecule is perhalogenated if all the parent hydrogen atoms in a hydrocarbon are replaced with halogen atoms (astatine, bromine, chlorine, fluorine or iodine). For example, carbon tetrachloride (CCl4) is perchlorinated methane (CH4). Chloroform (CHC13) is an example of a simple chlorinated methane, where only three of the hydrogen atoms have been replaced.   Photochemical reaction A chemical reaction caused by light or ultraviolet radiation.   Photoresist A photomechanical product, in the form of a liquid or a laminated dry film, used in the manufacture of printed circuits. Certain types require the use of large quantities of ozone-depleting hydrochlorocarbon solvents, mostly 1,1,1-trichloroethane and methylene chloride, for their processing.   Pickling The removal of oxides (rust) with acidic materials.   Polymers Compounds of very high molecular weights that are made up of a large number of simple molecules which have reacted with one another.   POTW Publicly owned treatment works, local water/sewage treatment facility.   Precision cleaning Cleaning of high-precision mechanical parts and electronic sensory devices, as opposed to general metal cleaning. This is usually done under controlled atmospheres, notably in clean-rooms with low particle contamination.   Printed circuit A printed circuit is an electronic component designed for interconnecting the other components. It usually consists of a metallic conductor pattern on an organic insulating substrate. After fabrication, it is known as a printed circuit board (PCB); after assembly where components are added, it is known as a printed wiring assembly (PWA).   PWA Printed wiring assembly. See printed circuit.   | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | State Information | Glossary | Conversion Checklist | Comments Home | Process Advisor | Alternatives | Links | Search All SAGE material, Copyright© 1992, Research Triangle Institute Last Update: 09 March 1999 sage@rti.org http://clean.rti.org/gloss.cfm?letter=P