Effect of solid-state shear milled natural rubber particle size on the processing and dynamic vulcanization of recycled waste into thermoplastic vulcanizates
Effect of solid-state shear milled natural rubber particle size on the processing and dynamic vulcanization of recycled waste into thermoplastic vulcanizates
复制标题
DOI：
10.1016/j.susmat.2022.e00424
复制
发表时间：
2022-04-06
影响因子：
9.6
通讯作者：
Kelly, A.
中科院分区：
文献类型：
--
作者：
Innes, J. R.;Shriky, B.;Kelly, A.
天然橡胶(NR)和交联型聚乙烯(XLPE)废气经固态剪切球磨(S3M)脱硫化后，可制得更易于再加工的细粉。了解脱硫化和解交联热固性材料的性质对于将这些废蒸汽转化为功能性产品至关重要。发现硫化粉末中含有大量的自由基，这些自由基在随后的再硫化过程中可能是活跃的。通过双螺杆挤出将硫化粉末转化为可回收的热塑性硫化胶。将这些粉末再加工成增值产品是回收利用的重要一步，挤压的使用可以实现高产量和工业可行性。在这里，我们论证了最佳的后处理条件取决于脱硫粉的粒度。此外，动态硫化受这些回收粉末的性质影响。成功制备的热塑性硫化弹性体具有与原始材料相似的性能，具有较高的断裂伸长率。因此，将废橡胶转化为热塑性硫化橡胶的橡胶相在迈向可持续产品方面显示出巨大的希望，前提是再硫化步骤能够得到很好的控制。
Natural rubber (NR) and crosslinked polyethylene (XLPE) waste streams were devulcanized by solid state shear milling (S3M), producing a fine powder that may be more easily reprocessed. Understanding devulcanization and the nature of decrosslinked thermoset materials is of utmost importance for turning these waste steams into functional products. It was found that the devulcanized powders contained significant concentrations of radicals, which may be active in the subsequent revulcanization process. The produced devulcanized powders were converted into recyclable thermoplastic vulcanizates (TPVs) by twin screw extrusion. Reprocessing of these powders into value-added products is an important step in recycling and the use of extrusion allows for high throughput and industrial viability. Herein, we demonstrate that the optimal conditions for reprocessing are dependent upon the particle size of the devulcanized powder. Furthermore, dynamic vulcanization is affected by the nature of these recyclate powders. The successfully prepared TPVs showed similar properties to virgin materials, with a high elongation to failure. Therefore, the conversion of waste rubber into the rubber phase of a TPV shows significant promise in moving towards sustainable products, providing the revulcanization step can be well controlled.