Vasiljević Jelena, Čolović Marija, Čelan Korošin Nataša, Šobak Matic, Štirn Žiga, Jerman Ivan
Faculty of Natural Sciences and Engineering, University of Ljubljana, Aškerčeva 12, 1000 Ljubljana, Slovenia.
National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia.
Polymers (Basel). 2020 Mar 13;12(3):657. doi: 10.3390/polym12030657.
The production of sustainable and effective flame retardant (FR) polyamide 6 (PA6) fibrous materials requires the establishment of a novel approach for the production of polyamide 6/FR nanodispersed systems. This research work explores the influence of three different flame-retardant bridged 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) derivatives on the comprehensive properties of in situ produced PA6/FR systems. To this end, in situ water-catalyzed ring-opening polymerization of -caprolactam was conducted in the presence of three different bridged DOPO derivatives, e.g., one P-N bond phosphonamidate derivative and two P-C bond phosphinate derivatives. The selected bridged DOPO derivatives mainly act in the gas phase at the temperatures that relatively match the PA6 pyrolysis specifics. The effects of the FRs on the dispersion state, morphological, molecular, structural, melt-rheological, and thermal properties of the in situ synthesized PA6 were evaluated. The specific advantage of this approach is one-step production of PA6 with uniformly distributed nanodispersed FR, which was obtained in the case of all three applied FRs. However, the applied FRs differently interacted with monomer and polymer during the polymerization, which was reflected in the length of PA6 chains, crystalline structure, and melt-rheological properties. The applied FRs provided a comparable effect on the thermal stability of PA6 and stabilization of the PA6/FR systems above 450 °C in the oxygen-assisted pyrolysis. However, only with the specifically designed FR molecule were the comprehensive properties of the fiber-forming PA6 satisfied for the continuous conduction of the melt-spinning process.
生产可持续且有效的阻燃聚酰胺6（PA6）纤维材料需要建立一种生产聚酰胺6/阻燃剂纳米分散体系的新方法。本研究工作探讨了三种不同的阻燃桥连9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物（DOPO）衍生物对原位制备的PA6/阻燃剂体系综合性能的影响。为此，在三种不同的桥连DOPO衍生物（例如一种P-N键膦酰胺衍生物和两种P-C键次膦酸酯衍生物）存在的情况下，进行了ε-己内酰胺的原位水催化开环聚合。所选的桥连DOPO衍生物主要在与PA6热解特性相对匹配的温度下在气相中起作用。评估了阻燃剂对原位合成PA6的分散状态、形态、分子、结构、熔体流变和热性能的影响。这种方法的具体优点是一步法生产具有均匀分布的纳米分散阻燃剂的PA6，在所有三种应用的阻燃剂的情况下均能获得。然而，所应用的阻燃剂在聚合过程中与单体和聚合物的相互作用不同，这反映在PA6链的长度、晶体结构和熔体流变性能上。所应用的阻燃剂对PA6的热稳定性以及在氧辅助热解中450℃以上的PA6/阻燃剂体系的稳定性提供了可比的效果。然而，只有使用专门设计的阻燃剂分子，才能满足成纤PA6的综合性能，以实现熔体纺丝过程的连续进行。
