Physical modification of polyacrylonitrile precursor fiber: Its effect on mechanical properties

Wang, P. H.; Liu, J.; Li, R. Y.

doi:10.1002/app.1994.070521201

Cited by 23 publications

(13 citation statements)

References 10 publications

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“…Surface modification including physical and chemical methods is a particular way to improve the compatibility of incompatible systems. Stretching (Wang et al 1994), calendaring (Semsarzadeh et al 1984) and corona discharge (Bledzki et al 1996) are some examples of physical modification methods; polymer grafting and esterification are some examples of chemical surface modification methods in which diverse functional groups are grafted on the surface of CNWs. Except for two surface modification methods mentioned heretofore, using surfactant in incompatible systems is another popular and much simpler method, usually referred to as non-covalent surface chemical modification (Habibi et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Use of surfactants in cellulose nanowhisker/epoxy nanocomposites: effect on filler dispersion and system properties

et al. 2015

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Cellulose nanowhiskers (CNWs) prepared via TEMPO mediated oxidation are used as biodegradable filler in an epoxy matrix. Since CNWs are hydrophilic and epoxy is hydrophobic, amphiphilic block copolymer surfactants are employed to improve the interactions between the filler and the matrix. The surfactants used are Pluronics, a family of triblock copolymers containing two poly(ethylene oxide) blocks and one poly(propylene oxide) block. In this study, Pluronic L61 and L121 with molecular weight of 2000 and 4400 g/mol and hydrophilic to lipophilic balance of 3 and 1 respectively, are used and their effect on the dispersion of CNWs in epoxy is discussed. The hydrophilic tails of Pluronics interact with the hydroxyl and carboxylic groups on the CNW surface and then these surfactant-treated CNWs are directly incorporated into epoxy by high speed mixing. The dispersion state of the surfactant-treated CNWs in epoxy is assessed by rheological measurements and the mechanical properties of the resulting composites are characterized by tensile test and dynamic mechanical thermal analysis. The Pluronic L61 treated CNW/ epoxy composites show the highest storage modulus at high temperatures (about 77 % increases) indicative of improved interfacial interactions between the CNWs and the epoxy matrix. Also, an increase of around 10°C in the glass-rubbery transition temperature of the L61 treated CNW/epoxy composite leads to potential application at higher service temperatures.

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Section: Introductionmentioning

confidence: 99%

Use of surfactants in cellulose nanowhisker/epoxy nanocomposites: effect on filler dispersion and system properties

et al. 2015

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“…Now, it is popularly accepted that the quality of high‐performance carbon fibers depends mainly on the composition and quality of the precursor fibers. However, the physical5 and/or chemical modification of a PAN precursor is useful for reducing the stabilization time when a PAN fiber is preoxidized and for improving the properties of resultant carbon fibers. Bahl et al6 treated PAN fibers with a CuCl aqueous solution to yield good‐quality carbon fibers, which showed an improvement in the tensile strength of about 100% and an improvement in Young's modulus of 50%.…”

Section: Introductionmentioning

confidence: 99%

Structural changes during the thermal stabilization of modified and original polyacrylonitrile precursors

Liu

Zhang

2005

J of Applied Polymer Sci

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A polyacrylonitrile (PAN) precursor fiber of a special grade for preparing carbon fibers was modified by the impregnation of an aqueous KMnO 4 solution. The effects of the modification on the lateral and morphology structure, related to the crystalline properties of both the precursors and preoxidized fibers, such as the orientation index, crystal size, and crystallinity index, were measured by wide-angle X-ray diffraction. For both modified and original PAN fibers, a comparative study of the changes of the elemental content during the process of preoxidation, the relations between the thermal stress and heat-treatment temperature, and the effect of the modification on the skin/core structure of a preoxidized fiber were also introduced by the use of elemental analysis, optical microscopy, and so on. The modification of KMnO 4 was demonstrated to increase the density, increase the crystallinity index, increase the preferred orientation index, and decrease the crystal size for a modified precursor fiber and for a preoxidized fiber developed from a modified precursor fiber after a different heat-treatment temperature. KMnO 4 also showed a catalytic action, accelerating the rate of preoxidation and reducing the time of thermal stabilization; this improved the homogenization of the cross-section structure and led to an improvement in the tensile strength of 15-20% and an improvement in the elongation of 20 -30% in the resulting carbon fibers.

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“…Polyacrylonitrile (PAN) is the primary precursor to prepare highperformance carbon bers. 1,2 The manufacture of PAN-based carbon bers typically involves three main processes: spinning of PAN precursor bers, thermal oxidative stabilization, and carbonization. 3 The stabilization is the most essential step since the structural integrity of stabilized bers signicantly inuences the mechanical properties of the resultant carbon bers.…”

Section: Introductionmentioning

confidence: 99%

Effects of oxygen on the structural evolution of polyacrylonitrile fibers during rapid thermal treatment

et al. 2020

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Physical modification of polyacrylonitrile precursor fiber: Its effect on mechanical properties

Cited by 23 publications

References 10 publications

Use of surfactants in cellulose nanowhisker/epoxy nanocomposites: effect on filler dispersion and system properties

Use of surfactants in cellulose nanowhisker/epoxy nanocomposites: effect on filler dispersion and system properties

Structural changes during the thermal stabilization of modified and original polyacrylonitrile precursors

Effects of oxygen on the structural evolution of polyacrylonitrile fibers during rapid thermal treatment

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