Pyrolysis mechanism for recycle renewable resource from polarizing film of waste liquid crystal display panels.
Pyrolysis mechanism for recycle renewable resource from polarizing film of waste liquid crystal display panels.
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DOI：
10.1016/j.jhazmat.2014.05.095
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发表时间：
2014-08
影响因子：
13.6
通讯作者：
Ruixue Wang;Zhenming Xu
中科院分区：
文献类型：
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作者：
Ruixue Wang;Zhenming Xu
液晶显示器（LCD）面板主要由偏光膜、液晶和玻璃基板组成。本研究提出了一种新的热解模型和热解机理，以回收废旧液晶面板偏光膜中的可再利用资源。分别对偏光膜及其主要组分三醋酸纤维素（TAC）和聚乙烯醇（PVA）进行热解，模拟热解过程。热解过程主要是生成大比例的油、少量气体和少量残渣。乙酸是主要的油产品，并且易于回收。其热分解机理可归纳为：（1）偏光膜的主要组分TAC受热生成低聚合度的活性TAC，然后分解为三乙酰基-d-葡萄糖。(ii)一些三乙酰基-d-葡萄糖通过分子内脱水生成三乙酰基-d-甘露聚糖及其异构体，而大多数三乙酰基-d-葡萄糖通过六元环过渡态生成主要的油产物，即乙酸。(iii)同时，通过一系列的键断裂、脱水、脱氢、酯交换和Diels-Alder环加成反应生成了其它产物。该研究对了解偏光膜的热裂解性能具有重要意义，并为今后偏光膜热裂解过程的工艺参数控制提供指导。
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.