Biomass upcycling of waste rPET to higher-value new-easy-recyclable microcellular thermoplastic (co)polyamide foams and hot-melt adhesives. (December 2022)

• Record Type: Journal Article
• Authors: Ranganathan, Palraj; Chen, Yu-Hao; Rwei, Syang-Peng; Lee, Yi-Huan
• Is Part Of: Materials today chemistry. Volume 26(2022)
• Publication Date: 2022-12
• Subjects: Biomass upcycling -- rPET -- Biomass monomers -- scCO2 foaming -- Hot-melt adhesives; Chemistry -- Periodicals; Materials -- Research -- Periodicals; Materials science -- Periodicals; Chemistry; Materials -- Research; Electronic journals; Periodicals; 660.282
• DOI: 10.1016/j.mtchem.2022.101101
• Languages: English
• ISSNs: 2468-5194

Abstract

Abstract: Poly(ethylene terephthalate) (PET) is one of the extremely used fossil-based products in the chemical industry, accounting for about 13% of the world's production. Today, most PET waste accumulates in landscapes or the environment, causing severe pollution. From the perspective of sustainability, scientists have tried to recycle waste PET through chemical and mechanical methods. Mechanical recycling offers some limitations because of the properties of the final product decrease from the second cycle. Rather, chemical recycling has attracted much attention because it can selectively convert plastic waste into high-value-added products including fuel, monomer, and refinery feedstock. Therefore, in this study, the chemical depolymerization of PET was investigated experimentally. After successfully deconstructing waste PET into polymerizable N 1, N 4 -bis(6-aminohexyl)terephthalamide (BAHT) monomer, the obtained BAHT was combined with a bioderived dimer fatty acid (DA; renewable content 100%) building block for the synthesis of bio-based thermoplastic (co)polyamides (TPCPAs) via solvent-free melt polycondensation. The obtained TPCPAs underwent a scCO2 foaming process to give the higher value-added microcellular foams. Interestingly, scCO2 foaming has zero formamides, which meets the safety requirements and is suited to commercial uses. Moreover, TPCPA foams showed an excellent shape recovery property and recyclability due to the entangled DA structure. Adhesive tests also show that TPCPAs exhibit a higher Tpeel strength (185.2 N/cm–420.5 N/cm) than commercial PA glues. This strategy to recycle PET into value-added biomass TPCPAs has a promising application prospect. Graphical abstract: Image 1 Highlights: Bio-based upcycling is the ability to produce value-added products from recycled materials. Recycled PET (rPET) is coalesced with biomass monomers to incentivize plastic retrieval. Upcycling with biomass monomers outcomes in TPCPAs with superior attributes. These TPCPAs result in good microcellular foams with uniform cell textures and high shape recovery. Additionally, TPCPAs result in better non-woven textile adhesive attributes than commercial grade PA glues.