Affiliation:
1. Department of Chemistry Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
2. Polyurethane Systems Department Performance Materials Division BASF Corporation 1609 Biddle Avenue Wyandotte MI 48192 USA
Abstract
AbstractThermoset polyurethane (PU) foams are widely used in industrial applications, but they cannot be recycled by conventional melt reprocessing because of their cross‐linked structures. The introduction of carbamate exchange catalysts converts thermoset PU into covalent adaptable networks (CANs), which are amenable to reprocessing at elevated temperatures. However, this approach has produced solid PU films, which have fewer uses and lower commercial demand. In this work, simultaneous reprocessing and refoaming of thermoset PU foams is demonstrated by leveraging the melt‐processability of PU CANs and allowing cell growth by gas generation in a twin‐screw extruder. The optimal operating temperature of the refoaming process is determined through chemical, thermal, and structural analysis of PU foam extrudates. The foam‐to‐foam extrusion process produces controllable, continuous, and uniform foam structures, as characterized by cell diameter and cell number density. Low‐density PU foams are obtained through a process simulating injection molding. The compression properties of reprocessed PU foam are compared with as‐synthesized PU foam to demonstrate efficacy of the refoaming processes. These results demonstrate that PU foams can be prepared through recycling while maintaining microstructural and chemical integrity. In the future, this strategy may be applied to thermoset PU foams of various chemical compositions and shows promise for scalability.
Subject
Mechanical Engineering,Mechanics of Materials,General Materials Science
Reference51 articles.
1. Polyurethane Recycling and Disposal: Methods and Prospects
2. Material Flows of Polyurethane in the United States
3. D. E. Nestle (MillerKnoll Inc) US 5292462 A 1994.
4. J. J. M. Rees G. Fowler (Columbia Insurance Co) US 9410026 B1 2016.
5. J.DiGangi J.Strakova A.Watson A Survey of PBDEs in Recycled Carpet Padding Dioxin PCBs and Wastes Working Group IPEN 2011 available from http://ipen.org/sites/default/files/documents/A‐survey‐of‐PBDEs‐in‐recylcled‐carpet‐padding.pdf.
Cited by
31 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献