阻燃聚乙烯改性水泥基复合板材的防火性能

Fire resistance of polymer composite modified cement-based panels

摘要:

针对地下结构火灾安全问题，提出了一种阻燃聚乙烯改性水泥基板材的主动式结构防火方法。首先介绍了基于同向双螺杆熔融挤出和冷却成型技术的阻燃聚乙烯的制备方法，该聚合物中膨胀型阻燃剂为三聚氰胺、聚磷酸铵和季戊四醇。在细观层面，通过热重分析、差示扫描量热分析和高温红外光谱分析，表征了阻燃聚乙烯的发泡过程，并对其产物进行了定性和定量的分析，发现阻燃聚合物在高温下存在三个明显的失重过程，且发泡产物具有蜂窝状的炭化结构。在宏观层面，通过单面明火高温试验试验，揭示了应用不同产状的阻燃聚乙烯改性水泥基复合板材的防火隔热效果。试验结果表明，在明火条件下，不同产状的阻燃聚合物通过熔融、聚合和发泡等过程，能够延长水泥基复合板材的“温升平台”，在一定程度上降低热量以热传导的方式向结构内部传递的速率，并且发泡产物能够溢出并覆盖结构受火面，充分发挥了隧道衬砌结构自身的防火能力，有一定的实际应用价值和推广前景。

Abstract:

Aiming at the fire safety of underground concrete structure under fire condition, an active self-fireproof method based on foamed polymer composite is proposed. Firstly, the preparation process of the polymer composite, which is mostly composed of melamine, pentaerythritol and ammonium polyphosphate, is introduced using a twin-screw extruder. A series of characterization methods, containing TGA and FTIR at elevated temperatures, are performed on the polymer composite. As revealed by the experimental results, the foamed polymer composite experiences three intensive weight-loss stages, coupled with multiple chain reactions and the formation of a honeycomb-like carbonization structure. Besides, one-side heating tests under open fire are conducted on double-layer concrete panels, illustrating the fire-resistant effect of polymer composite with multiple geometries in cement-based materials. It has been found that the foamed polymer composite plays an important role in prolong the “temperature platform” at around 100 oC and presents the effect of heat insulation. Therefore, the foamed polymer composite is regarded as a promising method in application to the active fire-resistant of underground structures.