Preparation of a high-performance synthetic pitch from aromatic hydrocarbons containing N/Cl

The preparation of a synthetic pitch from aromatic monomers could easily regulate structure orientation at the molecu-lar level,which would be useful in fabrication.An isotropic synthetic pitch was prepared by a chlorine-and/or nitrogen-induced sub-stitution polymerization reaction method using aromatic hydrocarbon precursors containing Cl and N,which for this study were chloromethyl naphthalene and quinoline.This method was verified by investigating the structural changes under different synthesis conditions,and the synthesis mechanism induced by aromatics containing Cl was also probed.The result shows that the pyridinic N in quinoline contains a lone pair of electrons,and is an effective active site to induce the polymerization reaction by coupling with aromatic hydrocarbons containing Cl.The reaction between such free radicals causes strong homopolymerization and oligomeriza-tion.A higher reaction temperature and longer reaction time significantly increased the degree of polymerization and thus increased the softening point of the pitch.A linear molecular structure was formed by the Cl substitution reaction,which produced a highly spinnable pitch with a softening point of 258.6℃,and carbon fibers with a tensile strength of 1163.82 MPa were obtained.This study provides a relatively simple and safe method for the preparation of high-quality spinnable pitch.

Preparation of pitch precursor with excellent spinnability for general-purpose carbon fibre using coal tar pitch as raw material

Tetrahydrofuran(THF) extract of coal tar pitch(CTP) was used instead of blending CTP with pretreated pyrolysis fuel oil to prepare an isotropic pitch precursor with excellent spinnability for general-purpose carbon fibre through bromination-dehydrobromination. The feasibility and effectiveness of synthesising an isotropic pitch precursor derived from THF-soluble(CTP-THFs) is demonstrated in this study.The results show that CTP-THFs contains more light components than CTP;CTP-THFs and CTP monomer proportions were 62.52% and 45.32%, respectively. However, based on comparisons of CTP-THFsBr0 and CTPBr0 characterisations, CTP-THFs exhibits better polycondensation than CTP. Bromination-dehydrobro mination promotes polycondensation of pitch precursors, leading to greater carbon aromaticity in CTP-THFsBr5, CTP-THFsBr10, and CTP-THFsBr15 than that in CTP-THFsBr0 and CTPBr0. CTP-THFsBr5 and CTP-THFsBr10 have excellent spinnability even with softening points as high as 230 ℃. The pericondensed carbon and carbon aromaticity of CTP-THFsBr5 and CTP-THFsBr10 are high owing to the higher degree of polycondensation;however, they still possess a more linear molecular structure. The as-prepared carbon fibre exhibits homogeneity and uniformity, and the mechanical performance is comparable with that of commercial general-purpose carbon fibre products.

Suitability of Nettle Fiber for Textile Production

Nettle plants widely exist in China, but up to now there is no research regarding Chinese nettle fiber properties, especially about its spinnability. This paper has studied the properties of Chinese nettle fiber and its spinnability. The research results show that the average length of nettle fiber is about 34 mm, the nettle fiber fineness ranging from 0.589 to 0.769 tex. Nettle fiber has high breaking strength, low breaking extension and high initial modulus. Both the biochemical method and chemical method can meet the requirement of nettle degumming, with the residual being less than 4%. Nettle fiber can be utilised as textile material and can be spun in rotor-spinning machines after well degummed.

Preparation of ferromagnetic metal fine fibers by organic gel-thermal reduction process

The organic gel-thermal reduction process was used for the preparation of ferromagnetic metal Ni, Co and Fe fine fibers from the raw materials of citric acid, lactic acid and metal salts. The structure, thermal decomposition process and morphologies of the gel precursors and fibers derived from thermal reduction of these gel precursors were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermo-gravimetric/differential scanning calorimetry and scanning electron microscopy. The results show that spinnability of gel largely depends on molecular structure of metal-carboxylate complex that is a linear-type structure formed in the gel. As a result, the gels exhibit a good spinnability. Metal Ni, Co and Fe fine fibers are featured with diameters of around 1 μm and a high aspect ratio up to 1×106.

Influence of Molecular Weight of Ultra-high Molecular Weight Polyacrylonitrile on Its Rheological Behavior in Dimethylsulfoxide

Ultra-high molecular weight polyacrylonitrile (UHMW PAN ) was prepared by aqueous suspension polymerization, and the effect of molecular weight on its rheological behaviors in dimethylsulfoxide (DMSO) and the spinning stability were investigated. It shows that,compared with common polyacrylonitrile (C-PAN),UHMW- PAN/DMS0 solution has smaller non- Newtonian index, larger structural viscosity index, much longer maximum relaxation time, and no first- Newtonian region appears in the flow curves under the same experimental conditions. The explanations for these phenomena are given in the view of chain- entanglements. The optimal technology of preparing UHMW-PAN fibers and hollow fiber membranes could be obtained based on the theological study.

Spinning System for Pineapple Leaf Fiber via Cotton Spinning System by Solo and Binary Blending and Identifying Yarn Properties

By nature, pineapple fiber (PALF) obtained from pineapple leaf is a smooth, shiny and white natural cellulosic fiber. In current investigation of spinning technique for pineapple leaf fiber based on cotton spinning method comparison of produced yarn properties has been reported. For one of the investigations of this study, the fibers were cut into staple length and various properties of fibers were analyzed. Data and results acquired from this illustrated that there is excellent spinnability on the fiber. Two separate researches were conducted with consideration to produce resultant yarn by spinning of PALF. Yarn derived by solo spinning technique of 100% PALF and PALF blending with polyester and cotton fibers through binary blending technique in equal proportion has been spun, then yarn count, tensile properties, yarn evenness, hairiness have been evaluated and analyzed. The results from numerical simulations analysis indicated that yarn obtained from the Pineapple leaf fiber (PALF) had great potential to be used in apparels.

Poly(acrylonitrile-co-3-aminocarbonyl-3-butenoic acid methyl ester):A better precursor material for carbon fiber than acrylonitrile terpolymer

In order to improve the stabilization and spinnability of polyacrylonitrile, a bifunctional comonomer containing both ester and amide groups was synthesized to prepare poly（acrylonitrile-co-3- aminocarbonyl-3-butenoic acid methyl ester） [P（AN-co-ABM）] copolymers used as the carbon fiber precursor instead of poly（acrylonitrile-acrylamide-methyl acrylate） [P（AN-AM-MA）] terpolymer. The differential scanning calorimetry and thermogravimetry results show that the stabilization of P（AN-co- ABM） have been remarkably improved by ABM compared with P（AN-AM-MA） terpolymer, such as lower initiation temperature, broadened exothermic peak and smaller activation energy. Moreover, the spinnability of P（AN-co-ABM） is also improved by ABM due to the lubrication of ester groups in ABM. This study clearly shows that P（AN-co-ABM） copolymer is a better material for use as a carbon fiber precursor than P（AN-AM-MA） terpolymer.