Blázquez-Blázquez Enrique, Díez-Rodríguez Tamara M, Pérez Ernesto, Cerrada María L
Instituto de Ciencia y Tecnología de Polímeros (ICTP-CSIC), Madrid, Spain.
J Therm Anal Calorim. 2022;147(23):13363-13374. doi: 10.1007/s10973-022-11505-2. Epub 2022 Aug 12.
Recycling of plastics is absolutely essential in a circular economy, especially in the case of commodity polymers from fossil resources, like isotactic polypropylene (iPP). Therefore, evaluation of the factors that are decisive for an optimum performance of the recycled based materials becomes mandatory for the obtainment of new products with optimal properties. One of the most important aspects is the protection of the plastics materials not only against the external degradation agents, but also from the radicals generated during their previous service life. Accordingly, several materials have been prepared by extrusion based on virgin iPP with different amounts of the same polypropylene severely degraded, which has been used as model component to be recycled. Previous to the extrusion, a mixture of antioxidants was added to all the samples, and special attention has been paid to consumption of those additives during the extrusion. The results show an increasing reduction of antioxidants with rising content of the degraded material. But, importantly, a rather analogous mechanical response has been found for all the recycled materials in relation to the virgin iPP, pointing out a satisfactory dilution effect of the existing degradation points within the virgin polymeric chains, and indicating the very relevant action of the antioxidants used.
在循环经济中，塑料回收绝对至关重要，尤其是对于源自化石资源的商品聚合物，如等规聚丙烯（iPP）。因此，对于获得具有最佳性能的新产品而言，评估决定再生材料最佳性能的因素变得不可或缺。最重要的方面之一是保护塑料材料，不仅要防止其受到外部降解剂的影响，还要防止其在先前使用寿命期间产生的自由基的影响。相应地，基于纯iPP和不同量的严重降解的相同聚丙烯，通过挤出制备了几种材料，该严重降解的聚丙烯已用作待回收的模型组分。在挤出之前，向所有样品中添加了抗氧化剂混合物，并特别关注了这些添加剂在挤出过程中的消耗情况。结果表明，随着降解材料含量的增加，抗氧化剂的减少量也在增加。但重要的是，相对于纯iPP，所有再生材料都发现了相当类似的机械响应，这表明原始聚合物链中现有降解点具有令人满意的稀释效果，并表明所使用的抗氧化剂具有非常重要的作用。
