Gelation

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\ji-lā-shәn\ n [L gelation-, galatio, fr. gelare] (1854) The formation of a Gel. With regard to vinyl plastisols and organosols, gelation is the change of state from the liquid suspension of the solid condition that occurs in the course of heating and/or aging, when the plasticizer has been mostly absorbed by the resin, resulting in a dry but weak and crumbly mass. Within normal proportions of resin and plasticizer, this state is attained when the resin particles have soaked up so much plasticizer that they touch each other. As heating progresses, the swollen particles begin to fuse together, resulting in some cohesive strength. Gelation is considered to continue until useful levels of mechanical properties are attained, such as have developed at the Clear Point. Much confusion has existed regarding the meaning of gelation because in the early years of the art, especially in Europe, gelation was used in place of the term fusion, now employed in the US. (Handbook of polyvinyl chloride ...