ABSTRACT
During polymerization, in some systems, the reverse step of depolymerization is as favored as the propagation polymerization steps. Some inexpensive monomers, whose polymers properties are desirable, have not achieved the levels of commercial success as some of the other monomers. For example, alphamethyl-styrene, AMS, monomer does not form into polymer above 61°C at atmospheric pressures; whereas, a small beaker ™lled with AMS monomer left to sit near the window for a few weeks will polymerize photocatalytically into polyalphamethyl-styrene. Poly-AMS has interesting properties, such as high glass transition temperature of 171°C. This can be used to design automotive components with increased heat resistance and higher VICAT temperature. VICAT temperature is measured using testing methods as listed in ASTM D 1525 and ISO 306. It is taken as the temperature at which the specimen is penetrated to a depth of 1 mm by a ®at-ended needle with a 1 mm2 circular or square cross-section.
