脂肪族聚酮的加工性能

Processing Properties of Aliphatic Polyketones

以2种不同相对分子质量的脂肪族聚酮(POK)树脂作为研究对象,利用毛细管流变仪、拉伸流变仪、旋转流变仪、差示扫描量热仪(DSC)和热重分析仪(TGA)研究了POK1和POK2的挤出特性、熔体强度和加工稳定性。结果表明,在相同温度下,与POK1相比,POK2的幂律指数较高,同时当剪切速率小于600 s^(-1)时,与POL2相比,POK1的黏流活化能较低,当剪切速率大于600 s^(-1)时,二者保持一致。拉伸黏度测试表明,POK1和POK2的熔体强度分别为15和40 m N。加工稳定性方面,在小幅震荡流变测试中,POK1和POK2分别在16.6和4.7 min处出现分子间环化和交联现象,2种POK树脂的熔点和结晶温度均降低。并且,交联后2种树脂的热失重残炭率由30.3%和28.4%提升至32.6%和30.8%,这表明,此时POK树脂出现了降解交联,影响其结晶性能和可加工性。

The extrusion properties,melt strength and processing stability of POK1 and POK2 were investigated by capillary rheometer,tensile rheometer,rotational rheometer,differential scanning calorimeter(DSC)and thermogravimetric analyzer(TGA)using two aliphatic polyketone(POK)resins with different molecular weights.The results showed that the power law index of POK2 was higher than that of POK1 at the same temperature,while the viscous flow activation energy of POK1 was lower than that of POK2 when the shear rate was lower than 600 s^(-1),and the two remained the same when the shear rate was higher than 600 s^(-1).The melt strengths of POK1 and POK2 were 15 and 40 m N,respectively,and the processing stability of POK1 and POK2 showed intermolecular cyclization and cross-linking at 16.6 and 4.7 min in the small-amplitude oscillatory rheology test,and the melting points and crystallization temperatures of both POK resins decreased.Moreover,the thermal weight loss residual carbon rate of the two resins increased from 30.3%and 28.4%to 32.6%and 30.8%after crosslinking,indicating that the POK resins were degraded and crosslinked at this time,which affected their crystallization properties and processability.