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首页> 外文期刊>Journal of Applied Polymer Science >Effect of ambient atmosphere on crosslinking of polysilazanes
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Effect of ambient atmosphere on crosslinking of polysilazanes

机译：环境气氛对聚硅氮烷交联的影响

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摘要

The influence of ambient atmosphere on the crosslinking process of two commercially available polysilazanes with different molecular units in the backbone structure (one polysilazane with and one without urea units) was studied at different temperatures using oscillatory rheometry under isothermal conditions. The measurements were performed using cone/plate, plate/plate, and Couette geometries to assess the influence of the contact surface of the samples with air on their crosslinking behavior. The crosslinking process of the investigated polysilazanes in ambient atmosphere was found to occur faster than that in inert atmosphere. DSC and FTIR-spectroscopic investigations indicate that hydrolysis and polycondensation processes occur in both polysilazanes when crosslinked in air. Interestingly, the effect of moisture was found to be more pronounced in the case of the urea derivative. The evolution of the measured complex viscosity and dynamic moduli supported this finding. Furthermore, the variation of the time derivative of complex viscosity (dη*/dt) emphasizes structural changes during crosslinking of the samples which were ascribed to their contact with the ambient atmosphere. This study emphasizes the high potential of rheometry in investigating the crosslinking behavior of polymers in inert and ambient atmosphere.
机译：在等温条件下，采用振荡流变法研究了环境气氛对两种在主链结构中具有不同分子单元的市售聚硅氮烷（一种含硅氮烷的聚硅氮烷和一种不含尿素单元的聚硅氮烷）的交联过程的影响。使用圆锥/板，板/板和库埃特几何形状进行测量，以评估样品与空气的接触表面对其交联行为的影响。发现所研究的聚硅氮烷在环境气氛中的交联过程比惰性气氛中的交联过程发生得更快。 DSC和FTIR光谱研究表明，两种聚硅氮烷在空气中交联时都会发生水解和缩聚过程。有趣的是，在尿素衍生物的情况下，发现水分的影响更为明显。测得的复数粘度和动态模量的变化支持了这一发现。此外，复数粘度的时间导数（dη* / dt）的变化强调了在样品交联期间的结构变化，这归因于它们与周围大气的接触。这项研究强调了流变学在研究聚合物在惰性和环境气氛下的交联行为方面的巨大潜力。

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