| Epoxy resins are the most important thermosetting polymers, which widely usedas matrices in coatings, adhesives, electrical insulators, reinforced composites andastronautics industries due to their excellent properties, such as good adhesion to varioussubstrates, high tensile strength and modulus, good chemical and corrosio n resistance, highheat distortion temperature, good environmental stabilities, low shrinkage on curing andeasy processibility.However, the cured epoxy resin is a products of high cross linkingthree-dimensional structure, in which the movement of the segments is very difficult andresults in brittle materials. Hence, it limits the application in high impact resistance andanti-fracture properties. Therefore, the toughening of epoxy resin has become particularlyimportant.The main research content of this paper is on silicone-modified epoxy. The basicstructural units of organic silicone is consisting of silicon-oxygen (Si-O-Si) chain, and theside chain with the other connected to a variety of organic groups. Both contain "organicstructure" and "inorganic structure". Silicon-containing polymers are described that candegrade, forming thermally stable silica. Compared with other polymer materials, The softsilicone chains (Si-O-Si) was introduced into the molecular structure of epoxy resin, andsilicone chains makes the molecular structure of epoxy resin more flexible molecular. Andsilicone chains have migrated to the tendency of epoxy surface, making the surface ofepoxy materials relatively rich siloxane chains, thereby reducing the surface tension andsurface energy of epoxy materials, and improved the flexibility, thermal stability, weatherresistance, electrical insulation of epoxy material.In this paper, the modification of epoxy resin in three ways:(1) selecting theanhydride curing agent containing organic silicone group.(2) selecting the epoxy resincontaining organic silicone group.(3) selecting a thermoplastic resin containing organicsilicone group as the modified material of epoxy resin.Studies on curing kinetics of epoxy resin were carried out using differential scanning calorimeter (DSC, Linseis PT-10, Germany). The calorimeter was operated inboth isothermal and dynamic modes. Study on the relationship between curing kinetics ofepoxy resin system and the curing temperature, silicon-containing epoxy content,silicon-containing anhydride content. The results show that:(1) For theDGEBA/Me-THPA, DGEBA/DMS-Z21, and DMS-E09/Me-THPA system, the curingmechanism and curing reaction order was the same, but the activation energy, the curingreaction rate, curing degree of the DGEBA/Me-THPA system was higher thanDGEBA/DMS-Z21and DMS-E09/Me-THPA systems. This results indicate that the curingreaction in DGEBA and Me-THPA was difficulter than the other system.(2) For theDGEBA/mixed anhydride system, with the anhydride containing the organic siliconecontent increasing, the curing mechanism and curing reaction order have not change, butthe activation energy, curing reaction rate, curing degree decreases with anhydride curingagent containing the silicone content increase, This results indicate that as increasing thecontent of DMS-Z21, made the curing reaction betweenthe epoxy resin and mixedanhydride easier.(3) For the DGEBA/Me-THPA/PEI-Siloxane system, the addtion of thethermoplastic resin(PEI-Siloxane), the curing mechanism and curing reaction order in theDGEBA/Me-THPA system have not change, but the activation energy and curing degreedecrease with PEI-Siloxane content increases, This results indicate that adding differentamounts of PEI-Siloxane, leading to dilution effects and promoting the curing reaction inDGEBA and Me-THPA.The phase morphology evolution and final phase structure were determined byoptical microscope (OM) and Scanning electron microscopy (SEM). For each cured epoxysystem, with the PEI-Siloxane content increases, the phase morphology evolution and thefinal phase structure is different, the trends for the two-phase structure of cuerd epoxysystem is that dispersed phase gradually transformed into a co-continuous phase, inversionphase.Study the thermal stability of each system by the TGA. The results show that: thethermal stability in the epoxy system enhanced with the silicon-containinganhydride(DMS-Z21), the silicon-containing epoxy(DMS-E09) and the silicon-containingthermoplastic resin(PEI-Siloxane) content increased. |
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