Most varicose and spider veins appear in the legs due to the pressure of body weight, force of gravity, and task of carrying blood from the bottom of the body up to the heart. Compared with other veins in the body, leg veins have the toughest job of carrying blood back to the heart. They endure the most pressure.
Curing a thermosetting resin transforms it into a plastic, or elastomer by crosslinking or chain extension through the formation of covalent bonds between individual chains of the polymer. Crosslink density varies depending on the monomer or prepolymer mix, and the mechanism of crosslinking:
Curing is defined as a chemical process the concrete goes through in the days immediately after it is poured. While full strength does not occur for 28 to 60 days, depending on conditions, the building process can begin when the foundations are about 50 percent cured.