Synthesis and characterization of epoxidized polyhedral oligomeric cubic silsesquioxanes (CSSQ) for UV curing applications

• Main Author: Yeo, Reuben Jueyuan.
• Other Authors: Marc Jean Medard Abadie
• Format: Final Year Project
• Language: English
• Published: 2011
• Subjects: DRNTU::Engineering::Materials::Nanostructured materials; DRNTU::Science::Chemistry::Organic chemistry::Organometallic compounds; DRNTU::Engineering::Materials::Material testing and characterization
• Online Access: http://hdl.handle.net/10356/44766
• Institution: Nanyang Technological University

Polyhedral oligomeric silsesquioxanes (POSS) have emerged in recent years as a novel class of nanostructured organosilicon compounds which have been applied in the design of new inorganic-organic hybrid nanocomposite materials. The versatility of preparing POSS compounds functionalized with different functional groups allows for the properties of such materials to be tailored for various applications. One such application that was explored is the design of UV-curable photoresists using epoxidized POSS incorporated into an epoxy resin. A general synthesis route was proposed in this work to prepare unfunctionalized cubic POSS (CSSQ), mono-epoxy and di-epoxy CSSQ via hydrolytic condensation of alkoxysilane precursors, which was followed by characterization to investigate their chemical and physical properties. Fourier-transformed infrared (FTIR) spectroscopy confirmed the presence of CSSQ and epoxidized CSSQ structures in the as-synthesized samples, although the presence of other cage structures of POSS in the samples were not determined. Thermogravimetric analyses (TGA) showed a higher thermal stability for epoxidized CSSQ compared to CSSQ, whereas X-ray diffraction (XRD) revealed an amorphous structure for epoxidized CSSQ. Differential photocalorimetry (DPC) was also performed on epoxidized CSSQ to study their UV curing kinetics. However, the epoxidized CSSQ samples were observed not to undergo photopolymerization under a strong intensity of UV irradiation (~800 mW/cm2), which could have been due to insufficient concentrations of photoinitiator used in the formulation. Subsequent studies could be done to further investigate the UV curing kinetics of epoxidized CSSQ.