Modification of silicon-containing arylacetylene resin and its composite properties by copolymerization with styrene

Quartz fiber (QF) reinforced poly(silica-containing arylacetylene) (PSA) composite is a new type of highly promising new wave-transparent materials with highly heat-resistance. However, the brittleness and low molecular polarity of PSA resins, combined with the smooth surface of quartz fibers, results in a weak interfacial adhesion, and low interlaminar shear strength (ILSS) of the composites. In this paper, silicon-containing arylacetylene resin was modified by copolymerizing with styrene (ST). As a consequence, the crosslinking density was decreased, the crosslinking network got homogenized, and the crack resistance of the resin against load was improved. Finally, the ILSS of Quartz fiber reinforced PSA composites was improved. The properties of the resin and composites were characterized with differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), mechanical property testing, dielectric property testing, rheological property testing. The results showed that the addition of ST didn’t affect the curing process of the resin. With the increase of ST content, the heat resistance of modified PSA resin decreased to some extent, but its mass loss 5wt% temperature T_d5 was still close to 500℃, which was much higher than the expected application temperature of 350℃. The modified composite also maintained the good dielectric properties with dielectric constant of 3.09 and loss factor tanδ of 0.002. The results also showed that the addition of ST significantly improved ILSS. For instance, the ILSS of QF/PSA-15ST increased by 53.0% at room temperature and 98.3% at 350℃. Compared with that at room temperature, the retention rate of interlaminar shear strength at 350℃ was 78.3%, which was much higher than that before modification (60.4% ).