Curing mechanism and thermal properties of a certain liquid crystalline epoxy resin cured with different curing agents

Curing mechanism and thermal properties of a certain liquid crystalline epoxy resin (LCER), 4,4'-bis(4-hydroxybenzoyloxy)-3,3',5,5'-tetramethyl biphenyl (DGE-BHBTMBP) cured with three different curing agents 4,4'-diaminodiphenylsulphone (DDS), biphenyl diamine (BPDA), dihydroxybiphenyl (DOD) were investigated. Curing mechanism of DGE-BHBTMBP reacted with three different curing agents were investigated by non-isothermal differential scanning calorimetry (DSC). Thermal properties of different cured systems were evaluated by dynamical mechanical analysis (DMA) and thermo gravity analysis (TGA). The results indicated that DGE-BHBTMBP cured with DOD belongs to epoxy-hydroxy reaction scheme leading to low reaction activity and thus low cross-linking degree, which results in poor thermal properties. Cured systems DGE-BHBTMBP/DDS and DGE-BHBTMBP/BPDA belonged to epoxy-amine reaction scheme have excellent thermal properties due to the high cross-linking degree. Specially, DGE-BHBTMBP cured with DDS possesses high glass transition temperature (above 180°C) and thermal decomposition temperature (above 370°C). The obtained results are important for applications of DGE-BHBTMBP as polymer matrix in the application of electronic packaging materials.