Study On UV/Moisture Dual-Curing Polysiloxane Acrylate Resin Curing Behavior And Performance

Polysiloxane resin (also called organic silicon), its main chain is constituted of Si-O-Si unit alternately. There are lots of excellent physical and chemical properties because of the special structure, such as good flexibility and heat resistance performance and so on. It has very important value in the aerospace, electronics appliances, daily life and many other areas. A new functionalized polysiloxane acrylate resin (PSA) had been synthesized by our laboratory that could be cured by UV irradiation, and also could be cured by moisture. It can realize rapid curing under UV radiation, improve the surface hardness and reduce surface pollution, then improve physical and mechanical properties by moisture curing at room temperature. UV curing combine the excellent performance of organic silicon material together can extend the application of silicone materials.The traditional small molecule photoinitiator is incompatible with PSA resin which reduce UV curing efficiency and the performance of cured product. Silicon-based macromolecular photoinitiator (1173-PMHS) was synthesized which was similar to the structure of polysiloxane, could reduce the polarity of photoinitiator, improve the compatibility with polysiloxane resin and the efficiency of UV curing. At the same time, due to the low surface energy and surface tension of organic silicon, it can migrate to the surface and prevent oxygen polymerization effectively. Polysiloxane acrylate resin which contain UV curing (C=C) and moisture curing groups (Si-OCH3) was synthesized use methyl acryloyl trimethoxysilane (KH570) and hydroxyl-terminated polydimethylsiloxane (107) resin by hydrolysis condensation reaction. At the same time, the structure of the resin was characterized by FT-IR,’H-NMR. We also study the influence of diluent contents, curing order to the performance of resin. As for the moisture curing process, we study the influence of catalyst to moisture curing. The results are as follows:1. The ratio of raw material and107molecular weight were investigated on the influence of resin properties, the results showd that: the products had good performance when the molecular weight of107was30000and addition amount of KH570was10wt%.2. The addition of diluents not only improved the rheological properties of systems but participated in photopolymerization process, enhanced the mechanical properties by increasing the crosslinking degree and modulating cross-linked network.3. Moisture curing after UV exposure had a relatively higher conversion.4. The heat resistance performance of resin was different because of different curing order, DSC results showd that dual-curing resin had excellent resistance to low temperature performance.5.1173-PMHS had good compatibility with PSA. The results of UV absorption showd that1173-PMHS had the same maximum absorption wavelength with the small molecule photoinitiator1173.