Devulcanization and functionalization of ground tire rubber for the novel metal sheet roof with strong sound absorber and thermal insulation

Upcycling waste tire rubber can bring economic value and create a sustainable approach. This study aims to recycle ground tire rubber through devulcanization and modification using environmentally friendly technology (thiol-ene click reaction), enhancing its adhesion to metal roofs to function as a thermal and noise absorber. The one-pot devulcanization and functionalization of GTR produces FD-GTR, which demonstrates a high devulcanization efficiency of 77.3% and peel strength of 0.07 N/mm. After revulcanization, the crosslink density of RFGTRs increases in the range of 2.9-7.8 x10-5 mol/cm3 compared with that of the original uncured FD-GTR. RFGTR reveals good adhesion rendering high thermal insulation and noise reduction (reduced by 18.6 degrees C inner surface temperature and 10.4 dB before UV exposure, respectively) in comparison to the R-GTR (no adhesion to metal sheet showing 0 degrees C and few dB reduction). Furthermore, the changing in formulation with ENR substitution by 50%wt and addition of Al(OH)3 alters rubber quality as seen from DMA results. ENR in RF-GTRENR formulation contributes to strong adhesion even after UV exposure (1.01 N/mm) but with low damping. Not only high energy loss and damping but also high adhesion is found in the formulations with Al(OH)3 such that their noise and thermal insulations become improved significantly, 10-15 dB decrease from that of blank metal sheet and 2.8 degrees C lower in indoor temperature, respectively. Besides, their LOI values are improved to 20.8%, compared to 18.5% without its addition (although flame property of all samples by UL 94 are still V-2 but without flame dripping).