The concept of intumescence was applied to flame retard ethylene vinyl acetate copolymer (EVA). The paper examines two types of intumescence based on expandable graphite (EG, physical expansion) and on modified ammonium polyphosphate (AP760, chemical expansion). The incorporation of expandable graphite (EG) at relatively low loading (10 wt%) in EVA permits the reduction up to 65% of peak of heat release rate (pHRR) measured by cone calorimetry. The mode of action occurs via the formation of an expanded carbonaceous layer acting mainly as heat barrier limiting heat and mass transfer as evidenced by the temperature measurement as a function of time during cone calorimetry. The incorporation of small amount of ZnCO₃ in EVA-AP760 enhances strongly the performance: pHRR was not reduced using the sole AP760 while it is decreased by 54% when only 2 wt% of AP760 is substituted by ZnCO₃. A strong synergistic effect was therefore observed. Solid state NMR of ³¹P and ¹³C on cone residues prepared at different characteristic times evidenced the mechanism involved is the reinforcement of the protective char by the formation of phosphate glass limiting the creation of cracks and increasing the char strength.

膨胀的概念被应用于阻燃乙烯乙酸乙烯酯共聚物（EVA）。本文研究了两种类型的膨胀，它们基于可膨胀石墨（EG，物理膨胀）和改性聚磷酸铵（AP760，化学膨胀）。在EVA中以相对较低的负载量（10 wt％）掺入可膨胀石墨（EG）可以减少通过锥体量热法测得的放热速率（pHRR）峰值的65％。作用方式是通过形成膨胀的碳质层而发生的，该碳质层主要用作限制热量和质量传递的热障，这由锥体量热法中的温度测量随时间的变化证明。少量ZnCO ₃的掺入EVA-AP760中的pHRR可以显着提高性能：使用单独的AP760不会降低pHRR，而当仅2 wt％的AP760被ZnCO ₃取代时，pHRR降低了54％。因此观察到强烈的协同作用。在不同特征时间制备的圆锥残基上的³¹ P和¹³ C固态NMR证明，所涉及的机理是通过形成磷酸盐玻璃来增强保护性炭，从而限制了裂纹的产生并提高了炭强度。