Semi-interpenetrating Network Structure Modified Cyanate Ester Resin System

In the last decades, cyanate ester resin has become established as one of the most important high performance thermosetting resins and its polymeric composites have attracted more and more attentions for their advantages in mechanical properties, lightweight and easy processing. The unique chemical characteristic of cyanate ester monomer endow them excellent properties, such as good mechanical properties, high thermal properties, outstanding dielectric properties and low moisture absorption and so on. They have been widely use in aerospace structures, dielectrics, adhesives and encapsulants in recently years. At the present time, reports on cyanate ester are focus on toughening. Hereby, the following aspects in cyanate esters have been studied in this dissertation.In the studied systems, cyanate esters can undergo thermal or catalytic polycyclomerization to give a high crosslink degree polymer, and styrene (St) and methyl methacrylate (MMA) both formed by a free-radical polymerization is linear component. The two networks formed simultaneously by independent and non-interfering reactions. And BADCy/St/MMA semi interpenetrating polymer networks (semi-IPN) has been prepared. The temperature of cure reaction of cyanate esters is higher than the temperature of free-radical reaction, so dibutyl tin dilaraute (DBTDL) was chosen as a cure catalyst of cyanate esters in this work. Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) has been employed to investigate the cure reaction of semi-IPNs. The curing schedules used for the systems of this work are as follow: 90℃/4h+120℃/2h+160℃/2h+200℃/2h and post-curing of 220℃/3h. The curing cycle of E-glass cloth reinforced composites as same as the castings.The BADCy/St/MMA semi-IPN was studied in respect to mechanical properties, dielectric properties, thermal properties and hygrothermal aging properties. The effect of MMA and St on the properties of the semi-IPN was discussed. The result indicated that certain contents of MMA and St could increase the mechanical properties of...