title: Pyrolysis mechanism for recycle renewable resource from polarizing film of waste liquid crystal display panels.
abstract: Liquid crystal display (LCD) panels mainly consist of polarizing film, liquid crystal and glass substrates. In this study, a novel pyrolysis model and a pyrolysis mechanism to recover the reusable resource from polarizing film of waste LCD panels was proposed. Polarizing film and its major components, such as cellulose triacetate (TAC) and polyvinyl alcohol (PVA) were pyrolyzed, respectively, to model the pyrolysis process. The pyrolysis process mainly generated a large ratio of oil, a few gases and a little residue. Acetic acid was the main oil product and could be easily recycled. The pyrolysis mechanism could be summarized as follows: (i) TAC, the main component of polarizing film, was heated and generated active TAC with a low polymerization, and then decomposed into triacetyl-d-glucose. (ii) Some triacetyl-d-glucose generated triacetyl-d-mannosan and its isomers through an intramolecular dehydration, while most triacetyl-d-glucose generated the main oil product, namely acetic acid, through a six-member cyclic transition state. (iii) Meanwhile, other products formed through a series of bond cleavage, dehydration, dehydrogenation, interesterification and Diels-Alder cycloaddition. This study could contribute significantly to understanding the polarizing film pyrolysis performance and serve as guidance for the future technological parameters control of the pyrolysis process.
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, People's Republic of China.
authors.forename: Ruixue
authors.initials: R
authors.lastname: Wang
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, People's Republic of China. Electronic address: zmxu@sjtu.edu.cn.
authors.forename: Zhenming
authors.initials: Z
authors.lastname: Xu
mesh_terms: D019342:Acetic Acid; D002482:Cellulose / Q000031:analogs & derivatives / Q000737:chemistry; D006358:Hot Temperature; D050866:Liquid Crystals / Q000737:chemistry*; D011142:Polyvinyl Alcohol / Q000737:chemistry; D059027:Recycling / Q000379:methods*; D013818:Thermogravimetry
chemical_list: D011142:Polyvinyl Alcohol; D002482:Cellulose; C024671:cellulose triacetate; D019342:Acetic Acid
keywords: Polarizing film; Pyrolysis; Pyrolysis mechanism; Waste LCD panels