Accelerating the formation of the conjugated ladder structure of Poly(acrylonitrile-co-vinyl acetate) by cross-linked poplar lignin doped with boron phosphate

Abstract

Utilizing renewable resources and accelerating thermal stabilization have been two main effective technical means to reduce the cost of poly(acrylonitrile) (PAN) based carbon fibre (CF). In this work, cross-linked poplar lignin (CPPL) with higher carbon content and 15 times the weight-average molecular weight of poplar lignin (PPL) was formed by doping boron phosphate (BP) in situ composites, which was blended with poly(acrylonitrile-co-vinyl acetate) (PANVA) to prepare a lowcost partially bio-based composite PANVA/CPPL-BP. During thermal stabilization, the C1s curvefitting of x-ray photoelectron spectroscopy (XPS) spectra showed that the conjugated ladder structure of PANVA/CPPL-BP started to form at 230°C, which was 20°C lower than PANVA. And the acceleration in forming conjugated ladder structures was further confirmed by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric (TG), and TG-FTIR. During simulated low-temperature carbonization for composites stabilized at 230°C in advance, the addition of CPPL-BP greatly improved the order of graphitic structure for PANVA. The mechanical property of CF mats has also been obviously improved by CPPL-BP. The possible mechanism that CPPL-BP accelerating the formation of conjugated ladder structures for PANVA/ CPPL-BP during thermal stabilization was proposed. With such improvement on accelerating thermal stabilization and utilizing cheap bio-material at the same time, this PANVA/CPPL-BP composite has a great potential in developing low-cost CF.

Analysing trimethylaluminum infiltration into polymer brushes using a scalable area selective vapor phase process

“…The PS ( Figure 4c) has two main components, the carbon backbone signal at 285.0 eV, and the carbon signal arising from the phenyl ring, at 284.5 eV. 60 The spectrum undergoes no significant change after ALD deposition, showing that the aluminium has not chemically bonded with the polymer.…”

A review on the effects of doping elements on the properties and applications of lignin-based carbon materials

“…In addition to the various non-metallic dopants mentioned above, boron and phosphorus sources can also be introduced to catalyze the formation of ordered carbon structures, thus improving the mechanical properties of carbon materials. Shi et al 62 cross-linked poplar lignin composites formed by in situ doping with boron phosphate, which was blended with poly (acrylonitrile–vinyl acetate copolymer) to prepare low-cost partially lignin-based composites. During the carbonization process, the addition of boron phosphate to poplar lignin greatly improved the graphite structural ordering of poly(acrylonitrile–vinyl acetate copolymer) and also significantly improved the mechanical properties of carbon fiber mats.…”