High char‐yielding poly[acrylonitrile‐co‐(itaconic acid)‐co‐(methyl acrylate)]: synthesis and properties

Abstract

Polyacrylonitrile terpolymers of various compositions consisting of acrylonitrile (AN), itaconic acid (IA) and methyl acrylate (MA) were synthesized by solution polymerization in dimethylsulfoxide. Increase in concentration of either IA or MA retarded the overall polymerization rate and the polymer molecular weight. The system consisting of AN + MA and varying IA concentration was more prone to retardation in comparison with the system composed of AN + IA with variable MA concentration. The retardation factors were quantified. Minor quantities of MA boost the reactivity of IA in the terpolymer system. The terpolymer was richer in MA vis-à-vis the feed. The thermal characteristics of the terpolymer were examined as a function of its composition. In contrast to the copolymer of AN and IA requiring 1-1.5 mol% IA, the terpolymer required an IA content of approximately 2.5 mol% for optimum thermal stability. The polymer with 90 mol% AN, 2.5 mol% IA and 7.5 mol% MA exhibited reasonably good charforming characteristics and thermal stability. The overall crystallinity and crystallite size of the polymers were found to decrease on incorporation of the comonomers. The 'aromatization index' of the copolymer increased with the temperature of pyrolysis through re-organization of the tetrahydropyridine ladder structure.

Simple Efficient Synthesis of Strongly Luminescent Polypyrene with Intrinsic Conductivity and High Carbon Yield by Chemical Oxidative Polymerization of Pyrene

“…This strongly implies that the product obtained is a true polypyrene rather than low molecular weight crystalline oligopyrene. Noteworthily, the X-ray diffractogram of THF-insoluble polyA C H T U N G T R E N N U N G pyrene-based carbon particles obtained at up to 1300 8C displays different characteristics with a strong diffraction at 2 q = 23.448 with a d spacing close to 0.34 nm corresponding to graphite d 002 , accompanied by an additional weak diffraction peak at 2 q = 43.408 corresponding to graphite d 100 , [32] much stronger diffraction around 2 q = 38, but with relatively weaker diffraction between 2 q = 10 and 188. This indicates transformation of polypyrene macromolecular chains into a graphite-like carbon network structure.…”

Polymerization and Thermal Characteristics of Acrylonitrile/Dicyclohexylammonium 2-Cyanoacrylate Copolymers for Carbon Fiber Precursors

“…In binary copolymerization, the presence of the second monomer increases the mutual termination reactions and the cross termination rate [11]. When CA concentration was increased, the rate of polymerization (R p ) and the degree of polymerization (D p ) of P(AN-CA) copolymers were decreased, leading to the decrease in conversion, molecular weight and intrinsic viscosity.…”

High Char-Yield in AN-AM Copolymer by Acidic Hydrolysis of Homopolyacrylonitrile

“…The content of char in the obtained fiber should be enhanced as much as possible in the form of a graphite-like structure after high-heat treatment. The enhanced formation of char can endow the obtained precursor fiber with higher homogeneity and compactness, and provides the the resultant carbon fiber with better mechanical properties [3]. Therefore, enhancement of char-yield in the polymer is necessary to obtain high performance carbon fiber.…”

“…Considering structural homogeneity and char yield, homopolymers are highly sought raw materials [2]. Owing to outstanding molecular cohesive energy (237 cal/cm 3 ), however, the fiber exhibits poor flexibility. Moreover, upon preoxidation, PAN precursors obtained from homopolymers tend to release heat at a rapid speed, thereby increasing the likelihood of the fiber being broken.…”

“…It is well known that the properties of polyacrylonitrile (PAN)-based carbon fiber are strongly determined by the nature of the precursor [1][2][3][4]. Considering structural homogeneity and char yield, homopolymers are highly sought raw materials [2].…”