Synthesis And Characterization Of Adamantane-containing Aromatic Amine Curing Agent

Adamantane is a highly symmetrical tricyclic hydrocarbon, having a cage-like structure with excellent stability. Studies show that the incorporation of adamantane into the backbones of many polymers can subsequently produce increased thermal stability, glass transition temperature(Tg), and reduce the moisture absorption and dielectric constant. Curing agent as an indispensable component for epoxy resin applications has a great influence on the final performance of the cured epoxy resin. So far, there are few reports about curing agents containing adamantine. Therefore, the development of new curing agents containing adamantine has important significance. In this dissertation, two different special curing agents containing adamantine were synthesized through molecular structure design.The curing agent and epoxy resin E51were subjected to curing reaction, which was followed by differential scanning calorimetry (DSC) analysis and in situ infrared method. The properties of the cured epoxy were investigated.1. Two novel curing agents1,3-bis[4-(4-aminophenoxy)pheny] adamantane(BAPA) and1,3-bis[4-(2,4-diaminophenoxy)pheny] adamantine (TAPA) were synthesized. The production rates were60.7%and58.5%, respectively, and their processes were optimized.2. The curing reaction kinetics of the E51/BAPA and E51/TAPA resin systems was studied by using nonisothermal differential scanning calorimetry. The calculated activation energy and reaction order of E51/BAPA is43.57KJ/mol and0.855. The calculated activation energy and reaction order of E51/TAPA is48.72KJ/mol and0.871.3. TGA of the cured epoxy E51/BAPA, E51/TAPA, E51/DDM and E51/BAPP systems indicates that TGA curves of the four different cured epoxy are very similar when the temperature is below400℃. However, when the temperature is above400℃, E51/BAPA and E51/TAPA exhibit more excellent high-temperature resistance.The wet and heat analysis of the four systems indicates that after75h of75℃constant temperature water bath, the water absorption of E51/BAPA is close to saturation. The moisture gain percentage is only1.25%after200h soaking treatment, which is34.9%lower than that of cured E51/DDM.The material analysis of the four systems indicates that the tensile strength of E51/BAPA and E51/TAPA are98MPa and103MPa, respectively. The tensile shear strength of E51/BAPA and E51/TAPA are18.2MPa and23.6MPa, respectively. The tensile strength and tensile shear strength of E51/TAPA are increased by25.6%and87.3%, compared to E51/DDMThe dynamic thermal mechanical analysis (DMA) of the four systems indicates that Tg of E51/BAPPA and E51/TAPPA are176℃and205℃, which are20℃and59℃higher than that of the cured E51/DDM. After75℃water bath for100h, Tg of the four systems decrease to various extent. Tg of E51/TAPA and E51/BAPA reduce to199.7℃and165.5℃, and have more excellent wet and heat resistance.The dielectric properties analysis of the four kinds of cured epoxy and by75℃water bath for100h indicates that with the frequency increasing, the dielectric constant of four kinds of cured epoxy gradually reduces. The dielectric constant of E51/TAPA is lowest. When f=107Hz, the dielectric constants of E51/BAPA, E51/TAPA, E51/BAPP and E51/DDM are4.3,4.1,4.9and5.1, respectively. The dielectric constants of E51/TAPA are reduced by16.3%and19.6%, compared to those of E51/BAPP and E51/DDM. After75℃constant temperature water bath for100h, the dielectric constant of four kinds of cured epoxy increased, but E51/BAPA and E51/TAPA are still lower than E51/DDM without water bath.