This article reviews the photo cationic polymerization initiator（ or the photo acid generator） as a latent curing agent for epoxy resin. One of the major type photo initiators used in the market is the combination product of triarylsulfonium cation and antimony hexafluoride anion（ SbF₆^-） or phosphrous hexafluoride one （PF₆^-）. The triarylsulfonium structure without substituents on the benzene ring creates drawbacks such as the benzene emission from the film during and after curing, the migration of undesirable material from the cured film, and the nasty odor originated from Sulphur. In order to improve these disadvantages, various modifications of triarylsulfonium salt have been performed including the introduction of substituents on benzene ring and the formation of cyclic structure consisting of triarylsulfonium salt. Another important improvement needed is to heighten the photosensitivity under the light of wavelength longer than 365 nm（ i-line） because of the increasing demand in the precision semiconductor manufacturing industry. The photosensitivity has been improved by incorporating the conjugated photosensitive structure into the triarylsulfonium salt. Taking CAS registration number as identification of the commercially available product, the article focuses mainly on reviewing the chemical structures and properties of above-mentioned triarylsulfonium salts together with the photo-activation mechanism of initiator and the cationic polymerization mechanism of epoxy resin.

Improvement of reinforcement effect of alkoxy silanes for conservation of stone cultural assets was investigated. The effect of oligomers of methyltrimethoxysilane with three different molecular weights was compared with the commercial stone reinforcement agent（ OM50, Wacker Chemie AG., Germany）. The compressive strength of solidified model sand with oligomer and an organotin catalyst was higher than that with the commercial stone reinforcement agent of OM50 and it was more significant with the increase of molecular weight. The addition of oligomer to OM50 was also effective. However, the permeability of oligomer to the model sand decreased with the increase of molecular weight. The fracture behavior of the oligomer added system was brittle. The compression test for the solidified model sand with 3-methacryloxypropylmethy ldimethoxysilane and an organotin catalyst showed the ductile fracture. It was found that the fracture behavior is dependent on the chemical structure of alkoxy silane.

Polytetrafluoroethylene（ PTFE） is extremely difficult to adhere to other materials due to its low surface energy and week boundary layer. Therefore, surface modification of PTFE is essential for expanding application range. Although heat-assisted plasma treatment was developed recently, stable treatment was impossible when the width of PTFE sheet was more than 300 mm because PTFE sheet waved and touched electrode due to thermal expansion of PTFE. In this study, we performed two types of heat-assisted plasma treatment in wide gap between electrode and PTFE surface in order to solve the problem and examined the influence of the gap on adhesion property of the plasma-treated PTFE. Heat-assisted plasma treatment by heating with increasing applied power for plasma generation successfully maintained high adhesion property when the gap between electrode and PTFE surface increased, so we solved the problem. On the other hand, adhesion strength decreased when the gap increased in heat-assisted plasma treatment by heating using a heater. In conclusion, we found that a heat-assisted plasma treatment by heating with increasing applied power is more useful for increasing adhesion property of PTFE than heat-assisted plasma treatment by heating using a heater when the gap increased.