Recycling of Flexible Polyurethane Foams by Regrinding Scraps into Powder to Replace Polyol for Re-Foaming
Lei Guo, Wenchao Wang, Xiurui Guo, Kuanfa Hao, Haichao Liu, Yuan Xu, Gongxu Liu, Shouyun Guo, Lichen Bai, Donghui Ren, Fumin Liu
Abstract
In the context of protecting the ecological environment and carbon neutrality, high-value recycling of flexible polyurethane foam (F-PUF) scraps, generated in the production process, is of great significance to save petroleum raw materials and reduce energy consumption. In the present study, F-PUF scraps were ground into powder by strong shear regrinding using two-roll mill and then reused as a partial replacement of polyol for re-foaming. A series of characterizations were employed to investigate the effect of milling cycles, roller temperatures, and content of the powder on the properties of the powder and F-PUF containing powder. It was revealed that the mechanochemical effect induced breaking of the cross-linking structure and increased activity of the powder. The volume mean diameter (VMD) of powder prepared with 7 milling cycles, at room temperature, is about 97.73 μm. The microstructure and density of the F-PUF containing powder prepared in the above-mentioned manner to replace up to 15 wt.% polyol, is similar to the original F-PUF, with resilience 49.08% and compression set 7.8%, which indicates that the recycling method will play an important role in industrial applications.