- Functionalized MWCNTs, an efficient reinforcement for the preparation of eugenol based high performance PBz/BMI/CNT nanocomposites exhibiting outstanding thermo-mechanical properties
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The chemistry of benzoxazine synthesis offers wide molecular design flexibility and thus facilitates preparation of various polybenzoxazine based composites. In this paper, we reported the preparation of polybenzoxazine/BMI blend and subsequent preparation of nanocomposites with amine functionalized multiwalled carbon nanotubes (F-MWCNTs). The curing mechanism and the material properties of the blend and nanocomposites were studied extensively. DSC analysis showed two exothermic maxima, corresponding to benzoxazine and allyl group polymerization. Furthermore, by the incorporation of F-MWCNTs into the PBz/BMI system, the properties of the PBz/BMI/F-MWCNT nanocomposites were improved significantly. The enhancement in the material properties is due to the strong interaction between the F-MWCNTs and PBz, resulting in the formation of interpenetrating polymer networks. The morphology and fracture surface of the nanocomposites were studied by scanning electron microscopy. The thermal, mechanical and dielectric properties of the nanocomposites are found to be outstanding when compared with the neat PBz and PBz/BMI blend.
- Periyasamy, Thirukumaran,Asrafali, Shakila Parveen,Kim, Seong-Cheol
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p. 6607 - 6615
(2017/07/17)
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- Thermal transition behaviors, solubility, and mechanical properties of wholly aromatic para -, meta -poly(ether-amide)s: Effect on numbers of para -aryl ether linkages
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In order to make clear how the numbers of para-aryl ether linkages affect the solubility, thermal transition behavior and mechanical properties of para-(p-PEAs), meta-poly(ether-amide)s (m-PEAs), a series of para-substituted aryl ether diamine monomers with 2, 3, 4 or 5 ether linkages were synthesized, and then reacted with terephthalic acid and isophthalic acid via the Yamazaki-Higashi phosphorylation method to prepare wholly aromatic PEAs. The PEAs with intrinsic viscosity values in the range of 0.81-1.16 dL g-1 were obtained and characterized by FT-IR, NMR, and elemental analysis. Although the Tgs and Tms of PEAs decrease with the increasing numbers of aryl ether linkages, their Tgs and Tms still are above 180 °C and 320 °C, respectively. p-PEAs have a high crystallinity making it difficult to dissolve them in common organic solvents even when 5 aryl ether linkages are introduced. Conversely, except for m-PEA5 with a lower polarity, the other m-PEAs show good solubility due to their low crystallinity. Besides, the decomposition temperatures at 5% weight loss of all PEAs exceed 430 °C and their residual yields at 700 °C are above 50% in N2, illustrating that they have excellent thermal stability. It is found that by casting m-PEAs DMAc solution in a dish, the transparent films with high Young's modulus (2.6-3.5 GPa) can be successfully obtained.
- Zhang, Wen-Qiang,Wang, Xiu-Li,Liu, Gui-Cheng,Chen, Li,Wang, Yu-Zhong
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p. 84284 - 84293
(2016/10/12)
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- Novel diisocyano-based dinuclear gold(I) complexes with aggregation-induced emission and mechanochromism characteristics
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A series of constitutional isomers containing dinuclear gold(I) units were designed, synthesized and characterized using IR spectrometry, NMR spectroscopy and elemental analysis. The aggregation-induced emission (AIE) characteristics of the complexes were investigated by photoluminescence (PL) and UV/Vis spectroscopy. The results indicated that gold(I) complexes 1-3 exhibited significant AIE phenomena. PL spectroscopy, used to probe their solid-state mechanochromic properties, suggested ortho-isomer luminogen 1 exhibited reversible mechanochromic fluorescence, whereas meta-isomer luminogen 2 showed switchable mechanical force-induced luminescence enhancement behavior. No mechanochromism behavior was observed for para-isomer luminogen 3. Powder X-ray diffraction indicated that the morphology phase conversion between crystalline and amorphous states is responsible for the mechanochromism or mechanical force-induced emission enhancement characteristics.
- Chen, Zhao,Li, Zheng,Yang, Lan,Liang, Jinhua,Yin, Jun,Yu, Guang-Ao,Liu, Sheng Hua
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p. 170 - 177
(2015/06/16)
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- Synthesis and characterization of novel bio-based benzoxazines from eugenol
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Polybenzoxazines are phenolic-like materials that possess dimensional and thermal stability, and they release no by-products during their polymerization. In this study, a new class of benzoxazine-containing monomers has been prepared from renewable resource (eugenol, a natural phenol obtained from clove oil), paraformaldehyde and various aromatic diamines. The structures of the monomers were supported by Fourier Transform Infrared (FT-IR), 1H-NMR and 13C-NMR spectral analysis, proving the existence of the benzoxazine ring containing eugenol moiety in its molecular structure. The monomers were polymerized/cured via ring-opening polymerization by heating as indicated by FT-IR and Differential Scanning Calorimetry (DSC). This is confirmed by the disappearance of the peaks due to oxazine ring (942 cm-1). The exothermic peak associated with curing was observed from 170°C to 250°C. The thermal and mechanical properties of the polybenzoxazines were investigated through thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). The temperatures corresponding to 5% and 10% weight loss is from 240 to 295°C and from 290 to 340°C, respectively. The completely cured materials could achieve char yields up to 36.5% at 800°C in nitrogen atmosphere. DMA revealed that the glass transition temperatures of PBz-SUL and PBz-PHE were higher than that of PBz-DDS and PBz-OXY.
- Thirukumaran,Shakila,Muthusamy, Sarojadevi
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p. 7959 - 7966
(2014/02/14)
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- METHOD FOR PREPARING A POLY(ETHER SULFONIMIDE OR -AMIDE) COPOLYMER USING CYCLIC OLIGOMERS
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Disclosed is a method for preparing a poly(ethersulfonimide or ethersulfonamide) copolymer using cyclic oligomers, and more particularly, to a method for preparing a poly(ethersulfonimide or ethersulfonamide) copolymer by preparing a cyclic ether sulfone oligomer and a cyclic imide or amide oligomer and subjecting the cyclic ether sulfone oligomer and the cyclic imide or amide oligomer to ring-opening copolymerization in the presence of an alkali metal fluoride catalyst.
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- Functionalized Photoreactive Compounds
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The present invention concerns functionalized photoreactive compounds of formula (I), that are particularly useful in materials for the alignment of liquid crystals. Due to the adjunction of an electron withdrawing group to specific molecular systems bearing an unsaturation directly attached to two unsaturated ring systems, exceptionally high photosensitivities, excellent alignment properties as well as good mechanical robustness could be achieved in materials comprising said functionalized photoreactive compounds of the invention.
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- Synthesis of phthalonitrile resins containing ether and imide linkages
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Imide-containing phthalonitrile monomers are prepared from a phthalonitrile and an aromatic dianhydride. The monomer and a method for preparing the monomer is disclosed. These monomers are synthesized into heat resistant polymers and copolymers with aromatic ring structure incorporating imide and ether linkages. The synthesis of the high temperature thermosetting polymers and copolymers is also disclosed.
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