Highly Chlorinated Polyvinyl Chloride as a Novel Precursor for Fibrous Carbon Material

Abstract

Pure, highly chlorinated polyvinyl chloride (CPVC), with a 63 wt % of chlorine, showed a unique-thermal-pyrolytic-phenomenon that meant it could be converted to carbon material through solid-phase carbonisation rather than liquid-phase carbonisation. The CPVC began to decompose at 270 °C, with a rapid loss in mass due to dehydrochlorination and novel aromatisation and polycondensation up to 400 °C. In this study, we attempted to prepare carbon fibre (CF) without oxidative stabilisation, using the aforementioned CPVC as a novel precursor. Through the processes of solution spinning and solid-state carbonisation, the spun CPVC fibre was directly converted to CF, with a carbonisation yield of 26.2 wt %. The CPVC-derived CF exhibited a relatively smooth surface; however, it still demonstrated a low mechanical performance. This was because the spun fibre was not stretched during the heat treatment. Tensile strength, Young’s modulus and elongation values of 590 ± 84 MPa, 50 ± 8 GPa, and 1.2 ± 0.2%, respectively, were obtained from the CPVC spun fibre, with an average diameter of 19.4 μm, following carbonisation at 1600 °C for 5 min.

Chlorinated plastics offer unique opportunities and challenges in upcycling

“…Compared to depolymerization, carbonization methods seem to be more tolerant to chlorinated plastics other than PVC. [47][48][49] There are similarities between carbonization and depolymerization as thermal treatment seems to be the primary current method to produce carbon-based materials from chlorinated plastics.…”

“…Despite that, the leftover solid materials from pyrolysis, for example, can be considered carbonization products 46 and have their own uses. Compared to depolymerization, carbonization methods seem to be more tolerant to chlorinated plastics other than PVC 47–49 . There are similarities between carbonization and depolymerization as thermal treatment seems to be the primary current method to produce carbon‐based materials from chlorinated plastics.…”

Mechanism and application of halogenation–dehalogenation in the development of pitch-based carbon fiber: A review

“…The purpose of stabilization is to change the pitch fiber from the thermoplastic state to the thermosetting state through the oxidation reaction. 46,47 In the carbonization process, the side chains of non-carbon atoms are removed, and aromatic groups perform further polycondensation, thus shrinking the fiber diameter as well as enhancing the degree of aromaticity, carbonization, and graphitization. 48 In addition, the orientation of the carbon groups further aligned along the axial direction, forming a carbon content of more than 96% of the cross-layer graphite structure.…”

A combined phenomenological artificial neural network approach for determination of pyrolysis and combustion kinetics of polyvinyl chloride

“…18,19 Since PVC has such a wide range of products and industrial application fields, it has its significance in the entire plastics usage and end of life PVC wastes are accumulated worldwide. Meanwhile a huge potential exists in converting PVC wastes to chemical feedstock, [20][21][22] resins, 23 fuel grade intermediates, [24][25][26] and carbonaceous materials such as pitch, carbon fiber, and porous carbon [27][28][29][30][31] via pyrolysis process.…”