Sheppard Daylan T, Jin Kailong, Hamachi Leslie S, Dean William, Fortman David J, Ellison Christopher J, Dichtel William R
Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States.
Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States.
ACS Cent Sci. 2020 Jun 24;6(6):921-927. doi: 10.1021/acscentsci.0c00083. Epub 2020 Apr 29.
Cross-linked polyurethane (PU) is extensively used as thermoset foam; however, methods to directly reprocess PU foam waste derived from commercial sources into similar value materials have not been developed. We demonstrate that introducing dibutyltin dilaurate (DBTDL) into cross-linked PU foams and films enables their reprocessing at elevated temperatures via dynamic carbamate exchange reactions. Both model and commercial cross-linked PU foams were continuously reprocessed using twin-screw extrusion to remove gaseous filler and produce PU filaments or films with elastomeric or rigid thermoset mechanical properties. The properties of microcompounded model PU foam were in excellent agreement with PU film synthesized using the same monomers, indicating that this process occurs efficiently. These findings will enable the bulk reprocessing of commercial thermoset PU waste and inspire the further development of reprocessing methods for other thermosets and the compatibilization of chemically distinct cross-linked materials.
交联聚氨酯（PU）被广泛用作热固性泡沫材料；然而，尚未开发出将商业来源的PU泡沫废料直接再加工成类似价值材料的方法。我们证明，将二月桂酸二丁基锡（DBTDL）引入交联PU泡沫和薄膜中，能够通过动态氨基甲酸酯交换反应在高温下对其进行再加工。使用双螺杆挤出对模型和商业交联PU泡沫进行连续再加工，以去除气态填料，并生产具有弹性体或刚性热固性机械性能的PU长丝或薄膜。微复合模型PU泡沫的性能与使用相同单体合成的PU薄膜非常吻合，表明该过程高效发生。这些发现将使商业热固性PU废料能够进行大规模再加工，并激发其他热固性材料再加工方法的进一步发展以及化学性质不同的交联材料的增容。
