Fabrication of low-cost carbon fibers using economical precursors and advanced processing technologies

The kinetics of the cyclization reaction in the poly(acrylonitrile/itaconic acid) (PAN) copolymer in the temperature range 175–200°C was studied by isothermal differential scanning calorimetry (DSC). The reaction conforms to an nth-order autocatalytic model, with an overall order of 2. The kinetic parameters were derived by multiple regression analysis. The activation energy is 110.3 kJ/mol for the acid-catalyzed reaction and 153.2 kJ/mol for the autocatalytic part. The autocatalysis indicates the catalysis of the nitrile group cyclization by the initially formed pyrimidine groups. The kinetic parameters were used to predict the reaction profile at a given temperature. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 915–920, 2003

Cyclization reaction in poly(acrylonitrile/itaconic acid) copolymer: An isothermal differential scanning calorimetry kinetic study

Polyacrylonitrile (PAN) and copolymer of acrylonitrile–vinyl acids prepared by solution polymerization technique have been characterized by Differential Scanning Calorimetry (DSC) (under dynamic as well as isothermal conditions), themograviemetric analysis (TGA), and on-line DSC-FTIR spectroscopy. The DSC of copolymers was carried out at 5°C/min in nitrogen and air. In nitrogen atmosphere the DSC exotherm show a very sharp peak, whereas, in air atmosphere DSC exotherm is broad, and starts at a much lower temperature compared to what is observed in nitrogen atmosphere. The initiation temperature of PAN homopolymer is higher than that for the copolymers. For instance, the initiation temperature of PAN in air is 244°C, whereas, the onset of exothermic reaction is in the range of 172 to 218°C for acrylonitrile–vinyl acid copolymers. As the vinyl acid content increases the ΔH value reduces. The ΔH value of PAN in air was 7025 J/g, whereas, for P(AN-AA) with 5.51 mol % of acid it was 3798 J/g. As the content of acrylic acid comonomer is increased to 17.51 mol % the value of ΔH decreases further to 1636 J/g. The same trend was observed with MAA and IA as well. DSC-FTIR studies depict various chemical changes taking place during heat treatment of these copolymers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 685–698, 2003

Thermal behavior of acrylonitrile carboxylic acid copolymers

Polymer-nanoinclusion interactions in carbon nanotube based polyacrylonitrile extruded and electrospun fibers

Influence of electron beam pre-irradiation on the thermal behaviors of polyacrylonitrile

The thermal degradation of polyacrylonitrile and copolymers of acrylonitrile (AN) with each of vinylacetate (VAC), methallyl sulfonate sodium salt (MASS), and 2-acrylamido 2-methyl propane sulfonate sodium salt (2-AMPSS) i.e., P(AN–VAC), P(AN–MASS), P(AN–AMPSS), and P(AN–VAC–MASS), has been investigated using the technique of thermogravimetry and differential scanning calorimetry (DSC). The initial decomposition temperature (IDT) and integral procedural decomposition temperature (IPDT) for all the copolymers are less than that for polyacrylonitrile irrespective of the nature of the vinyl comonomers. TGA thermograms indicate faster rate of degradation in copolymers compared to polyacrylonitrile. Variation in the glass transition temperature is correlated to the polarity of the functional groups in the polyacrylonitrile copolymers.

R. C. Sharma

Papers

Effect of comonomers on thermal degradation of polyacrylonitrile