Preparation And Properties Of Siloxane-Terminated Oligomers/Epoxy Resin Composites

A series of star siloxane-terminated oligomers containing 1,1,1-trihydroxylmethylpropane (TMP) and polycaprolactone triol (PCL), i.e. TPSi-A, TPSi-B and TPSi-C (0%, 5%, 10% wt TMP contents, respectively) were directly synthesized via -OH and -NCO nucleophilic addition reaction. Epoxy resin was then modified with these oligomers. The modified systems were cured with amino curing agent via amino-glycidyl reaction and sol-gel technology. The effects of TMP, silane coupling agent (KBE-9103 selected) and the contents of oligomers on the surface properties, swelling properties, solvent-resistance performances, tensile properties and thermal stability performances were studied.1. The critical surface tensile force on various samples was increased with content of TPSi in the composite system, and also enhanced when KBE-9103 was introduced in the samples. The maximum critical surface tensile force could be attained when TPSi-B was incorporated; The swelling degree of TPSi modified epoxy resins was bigger than that of unmodified epoxy resin, however, the swelling degree of the KBE-9103 and TMP incorporated systems was decreased.2. Water-resistance properties of modified epoxy resin composites were enhanced. The mass loss was found when the composites were soakedin 10% H2SO4, but mass increased when soaked in 30% H2SO4; Similiarly, the mass loss was also found in NaOH soaked composites. But basic-resistance properties of the modified systems were improved evidently when 0-30% oligomers were composited in the system, however, basic-resistance properties of the 30%~50% oligomers modified systems were decreased. Salt-resistance performances of the modified composite systems were improved when samples were soaked in the 10% NaCl solution. Acid and basic resistance properties were enhanced when KBE-9103 were added in the composite systems.3. Elongation-at-break of the TPSi modified systems was improved. The tensile strength of the composites was enhanced when 0-30% TPSi oligomers were added, but those tensile strength were decreased when epoxy resin were modified by 30%~50% TPSi oligomers. The tensile strength was increased when KBE-9103 were mixed in the composite systems. The phenomenon was demonstrated well in scanning electron microscope (SEM), where the KBE-9103 could increase the dispensability of TPSi in the epoxy resin. The thermogravimetric analyzer was carried out and indicated that the thermal stability of TPSi modified epoxy resin was improved.All of research methods, experimental data and results in the paper are benefit to modify epoxy resin in the future.