含硅芳炔树脂/苯并噁嗪/氰酸酯三元聚合体系研究

Studies on the Terpolymer of Poly(silylene-acetylenearyleneacetylene)/Benzoxazine/Cyanate Ester

以双酚A型氰酸酯(BADCy)和含炔丙氧基苯并噁嗪(P-appe)为改性剂,通过与含硅芳炔树脂(PSA)的溶液混合与浓缩制备了含硅芳炔树脂/氰酸酯/苯并噁嗪三元共混体系(PPB),研究了该共混体系的热固化过程、共混树脂的热稳定性和动态力学性能、弯曲性能和冲击性能.结果表明,开环后的苯并噁嗪能催化氰酸酯的环三聚反应,可降低氰酸酯的固化温度;PPB热固化中三嗪环可与噁嗪环反应形成氰酸酯与苯并噁嗪共聚;当PPB树脂中PSA树脂的质量分数为70%时,三元共混树脂浇铸体在氮气中质量损失5%的温度(Td5)高于500oC,玻璃化转变温度高于450oC;BADCy/P-appe改性PSA树脂的三元共混体系相容性好,共混树脂浇铸体PPB-5的弯曲强度较PSA树脂提高了115%,冲击强度提升了104%,断裂面出现明显的韧性断裂特征.

Bisphenol-A based cyanate ester（BACDy） and propargyloxy-containing benzoxazine（P-appe） were used to improve the mechanical properties of poly（silylene-acetylenearyleneacetylene）（PSA）. PSA/P-appe/BADCy（PPB） terpolymers were prepared by blending in solution and concentrating with evaporation. The thermal cure reaction of the terpolymers were studied by differential scanning calorimetry（DSC） and in situ Fourier-transition infrared（FTIR） monitoring. The thermal properties, dynamic mechanical properties, flexural property and impact strength of the cured terpolymers were further investigated. The results show that the cure peak temperature of BADCy decreased from 325 oC to 247 oC when P-appe and PSA were added. In the blends, the ring opening of the P-appe firstly occurs with increasing cure temperature. Then the formation of the triazine ring arises. P-appe and phenolic hydroxyl groups on the ring-opened benzonxazine can catalyze the cyclotrimerization of the cyanate ester, making the cure temperature of the cyanate ester decrease effectively. Meanwhile, the self-polymerization of the terminal acetylene of PSA, P-appe and BADCy occurs simultaneously. The PPB terpolymer can polymerize at 130 oC within 2 h or at 170 oC within 30 min. The copolymerization of BACDy and P-appe arises from the coreaction of triazine ring cyclotrimeized by BADCy with oxazine of P-appe, by which the compatibility of PPB terpolymer is favorable. In comparison with cured PSA resin, the 5% mass loss temperature（Td5） of the cured PPB terpolymer in nitrogen is above 510 oC, and the residual yield at 800 oC and the glass transition temperature of the cured terpolymer are above 84% and 450 oC, respectively. For PSA blended with 15% mass fraction of P-appe and 15% mass fraction of BADCy, the flexural strength and impact strength of the cured PSA resin can increase by 115% and 104%, respectively. The fracture surface of the cured terpolymer is rough and displays obvious ductile feature.