Technology of crystallization of polyamide 6 via a mesophase for generation of a semicrystalline structure with specific properties. Part II: Kinetics of homogeneous nucleation

可结晶聚合物的超分子结构和性能受结晶途径的强烈控制。这个项目的重点是聚酰胺6从玻璃态结晶，但还没有详细的研究。将这种重要聚合物的熔体快速冷却到环境温度与非晶态相的完全玻璃化有关，并有机会通过随后的高温退火产生可变完美和形态的有序域。这包括产生由非层状晶体和非晶相组成的非球晶半晶结构，具有熔化结晶无法获得的特定性能。在项目的第一部分中，确定了产生具有结节晶体的非球晶半晶聚酰胺6的技术先决条件。特别地，评估了实现这种特殊结晶途径所需的冷却熔体以获得完全非晶玻璃样的条件，并分析了退火条件对冷有序结晶的影响。在本项目的第二部分，将首次定量分析高过冷下主导结构形成的均匀成核动力学，并作为获得非层状有序畴/晶体的关键。分析将使用快速扫描芯片量热法的新技术进行，该技术允许产生不同稳定性的无定形状态，因此不同的冷结晶行为/均匀成核动力学。在这个项目中特别重要的是考虑非晶相在低于玻璃化转变温度下的弛豫和有序过程。均匀成核动力学的研究在熔体的高过冷下有效，可以获得聚合物结晶的基本见解，例如局部有序也发生在玻璃态，最终影响非晶相的稳定性和高温下的结构形成。在接近玻璃化转变的温度下，局部有序的证明对于聚酰胺6具有高度的应用相关性，因为它与物理老化有关，并且由于在纳米尺度上控制结构的可能性，它允许生成具有特殊性能的材料。

The supermolecular structure and properties of crystallizable polymers are strongly controlled by the pathway of crystallization. This project focuses on crystallization of polyamide 6 from the glassy state which has not been investigated in detail yet. Rapid cooling of the melt of this important polymer to ambient temperature is connected with complete vitrification of the amorphous phase, with the opportunity to generate ordered domains of variable perfection and morphology by subsequent annealing at elevated temperature. This includes the generation of non-spherulitic semicrystalline structures composed of non-lamellar crystals and amorphous phase with specific properties which cannot be obtained by melt-crystallization. In the first part of the project, the technological pre-requisites for generation of non-spherulitic semicrystalline polyamide 6 with nodular crystals were determined. In particular, the conditions of cooling the melt to obtain fully amorphous glassy samples, necessary for realization this special pathway of crystallization, were evaluated, and the effect of the conditions of annealing on cold-ordering/-crystallization was analyzed. In the second part of this project, the kinetics of homogeneous nucleation, dominating structure formation at high supercooling and being the key to obtain non-lamellar ordered domains/crystals, will quantitatively be analyzed for the first time. The analysis will be performed using the novel technique of fast scanning chip calorimetry which permits generation of amorphous states of different stability and therefore different cold-crystallization behavior/kinetics of homogeneous nucleation. Of particular importance in this project is the consideration of relaxation and ordering processes of the amorphous phase at temperature below the glass transition. The investigation of the kinetics of homogeneous nucleation, effective at high supercooling of the melt, allows gaining fundamental insights about polymer crystallization such that local ordering also occurs in the glassy state, ultimately affecting the stability of the amorphous phase and structure formation at elevated temperature. The prove of local ordering at temperatures close to the glass transition is of high application-related relevance for polyamide 6 since it is connected to physical aging and since it allows generation of materials with special properties due to the possibility for controlled structuring at the nanometer scale.