Study On Structure And Properties Of Hot-wet Epoxy Resin Modified Systems

In order to prepare and study on new hot-wet epoxy resin （EP） modification system,tracking and reference the latest research methods and results on hot-wet EP. EP modificationsystems were prepared by graft polymerization and sol-gel in-situ composition. The hot-wetresistance, optical properties, mechanical properties and micro-morphology were analyzed bythermogravimetric （TGA）, index analysis, ultraviolet analysis, infrared spectroscopy （FT-IR）and scanning electron microscope （SEM）. The EP-HTPDMS copolymers were applied toLED’s package, and its further optical properties were studied by luminous decay.EP-CAB copolymers were synthesized and prepared, and the effects of CABconcentration on the hot-wet resistance, optical properties, mechanical properties andmicro-morphology were analyzed. The results indicated that when CAB concentrationreached10%, the contact angle and water absorption of the copolymer were85.1°and0.213%, and the weight maintenance rate of EP-CAB copolymer at650℃was28%.Comparing with EP, the hot-wet resistance of EP-CAB copolymer was obviously improved.The optical properties were also enhanced. The hardness of the copolymer was decreased, andthe introduction of CAB made the copolymer exhibit the features of tough fracture.EP-HTPDMS copolymers were prepared, and the effects of HTPDMS concentration onthe properties were analyzed. The results showed when HTPDMS concentration was6%, thecontact angle and water absorption of the copolymer were80.7°and0.233%, and the weightmaintenance rate of EP-HTPDMS copolymer at650℃was11%. Comparing with EP, thehot-wet resistance of EP-HTPDMS copolymer was obviously improved. The index andtransmittance of the copolymer were1.5305and94.31%, and the optical properties wereenhanced. The introduction of HTPDMS made the copolymer exhibit the features of toughfracture.EP/SiO₂composites were prepared by sol-gel in-situ composition, the effects of SiO₂concentration on the properties were analyzed. The results indicated that when SiO₂concentration reached7.5%, the contact angle and water absorption of the copolymer were 83.6°and0.485%. When the thermogravimetric was5%, the temperature was273℃.Comparing with EP, the hot-wet resistance of EP/SiO₂composite was improved. The opticalproperties were enhancd to some extent.Comparing with the hot-wet resistance, optical properties and mechanical properties ofthe three systems, EP-HTPDMS copolymers were applied to LED’s package. The resultsshowed that when HTPDMS concentration was less than9%, the relative light output ofEP-g-HTPDMS copolymers were higher than that of unmodified EP and luminous decayreduces significantly.