7338-27-4Relevant articles and documents
Preparation and thermal properties of poly[acrylonitrile-co-(β- methylhydrogen itaconate)] used as carbon fiber precursor
Ju, Anqi,Xu, Hongyao,Ge, Mingqiao
, p. 1037 - 1047 (2014)
In order to replace terpolymer with bipolymer, a bifunctional comonomer β-methylhydrogen itaconate (MHI) containing carboxyl group and ester group was synthesized to prepare poly[acrylonitrile-co-(β-methylhydrogen itaconate)] [P(AN-co-MHI)] bipolymers used as carbon fiber precursor for improving the stabilization and spinnability at the same time. The P(AN-co-MHI) bipolymers with different monomer feed ratios were characterized by elemental analysis, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). The results show that both the polymerization conversion and molecular mass of P(AN-co-MHI) reduce with the increasing MHI amounts in the feed due to the larger molecular volume of MHI than acrylonitrile (AN). The monomer reactivity ratios were calculated by Fineman-Ross and Kelen-Tuedos methods, the results show good agreement and MHI possesses higher reactivity than AN. Two parameters Es = A1, 629 cm-1 / A2, 244 cm 1 and SI = (I0 - I S) / I0 were defined to evaluate the extent of stabilization, and the activation energy (E a) of the cyclization was calculated by Kissinger method and Ozawa method. The FTIR, XRD, and DSC results show that P(AN-co-MHI) bipolymers exhibit significantly improved stabilization characteristics than PAN homopolymer, such as larger extent of stabilization, lower initiation temperature, and smaller E a of cyclization, which is attributed to the ionic initiation by MHI comonomer and it is beneficial to preparing high-performance carbon fiber.
A novel poly[acrylonitrile-co-(3-ammoniumcarboxylate-butenoic acid-methylester)]copolymer for carbon fiber precursor
Ju, An Qi,Guang, Shan Yi,Xu, Hong Yao
, p. 1307 - 1310 (2012)
A novel bifunctional comonomer 3-ammoniumcarboxylate-butenoic acid-methyl ester (ACBM) was synthesized for preparing poly[acrylonitrile-co-(3- ammoniumcarboxylate-butenoic acid-methyl ester)] [P(AN-co-ACBM)] copolymer as a carbon fiber precursor. Differential scanning calorimetry results show that the P(AN-co-ACBM) exhibits a significantly improved stabilization performance compared with polyacrylonitrile (PAN), such as lower cyclization temperature and smaller rate of heat release, which is mainly attributed to the initiation of ACBM through an ionic cyclization mechanism. Simultaneously, the rheological analysis shows that P(AN-co-ACBM) possesses better spinnability than PAN.
A high molecular weight acrylonitrile copolymer prepared by mixed solvent polymerization: I. effect of monomer feed ratios on polymerization and stabilization
Ju, Anqi,Yan, Yafeng,Wang, Dawei,Luo, Jun,Ge, Mingqiao,Li, Mengjuan
, p. 64043 - 64052 (2014)
A bifunctional comonomer β-methylhydrogen itaconate (MHI) was employed to prepare high molecular weight poly[acrylonitrile-co-(β-methylhydrogen itaconate)] [P(AN-co-MHI)] copolymers by radical polymerization in a mixed solvent of dimethyl sulfoxide/deionized water = 60/40 (wt/wt), which was used as a carbon fiber precursor instead of acrylonitrile terpolymers for improving the stabilization and spinnability simultaneously. The structure and stabilization of P(AN-co-MHI) copolymers with different monomer feed ratios were characterized by elemental analysis (EA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The results show that both the polymerization conversion and molecular weight reduce with the increase of MHI content in the feed due to the larger molecular volume of MHI. The monomer reactivity ratios were calculated by Fineman-Ross and Kelen-Tüds methods and the reactivity of MHI is higher than that of AN. Two parameters Es = A1618 cm-1/A2244 cm-1 and SI = (I0 - Is)/I0 were defined to evaluate the extent of stabilization and the activation energy (Ea) of the cyclization. The FTIR, XRD and DSC results show that P(AN-co-MHI) copolymers exhibit significantly improved stabilization characteristics than the PAN homopolymer and poly(acrlonitrile-methyl acrylate-acrylic acid) terpolymer, such as a larger extent of stabilization, lower initiation temperature and smaller Ea of cyclization, which is attributed to the ionic initiation of the MHI comonomer and is beneficial for preparing high performance carbon fiber.
A Br?nsted acidic, ionic liquid containing, heteropolyacid functionalized polysiloxane network as a highly selective catalyst for the esterification of dicarboxylic acids
Rajabi, Fatemeh,Wilhelm, Christian,Thiel, Werner R.
supporting information, p. 4438 - 4444 (2020/08/10)
A Br?nsted acidic, ionic liquid containing, heteropolyanion functionalized polysiloxane network was formed by self-condensation of dodecatungstophosphoric acid and a zwitterionic organosilane precursor containing both imidazolinium and sulfonate groups. The resulting hybrid material POS-HPA-IL was investigated as a catalyst for the selective esterification of dicarboxylic acids.
