Synthesis and characterization of poly(p-phenylene terephthalate) crystals obtained by crystallization during polymerization

1994 ◽  
Vol 6 (1) ◽  
pp. 83-93 ◽  
Author(s):  
Kunio Kimura ◽  
Seiji Endo ◽  
Yasuo Kato ◽  
Yuhiko Yamashita

Poly(p-phenylene terephthalate) (PPTE) crystals were prepared by hightemperature solution polymerization via three different types of reaction as follows: bimolecular condensation of (1) 1,4-diacetoxybenzene and terephthalic acid and (2) hydroquinone and diphenyl terephthalate and self-condensation of (3) mono(4'-acetoxyphenyl) terephthalate. In spite of the reaction types, needle-like crystals are not obtained as found with poly(oxy-l,4-benzenediylcarbonyl) (POB) whiskers, under polymerization conditions identical with those used to produce POB whiskers. PPTE and POB have similar molecular structure that is, they comprise 1,4-phenylene groups and ester linkages. whereas the morphologies of the crystals obtained are quite different. From the structural study, PPTE crystals are single crystals, and polymer chains align perpendicular to the plane of the sheaf-like or plate-like crystal.

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 721 ◽  
Author(s):  
Jorge A. Ramírez-Gómez ◽  
Javier Illescas ◽  
María del Carmen Díaz-Nava ◽  
Claudia Muro-Urista ◽  
Sonia Martínez-Gallegos ◽  
...  

Atrazine (ATZ) is an herbicide which is applied to the soil, and its mechanism of action involves the inhibition of photosynthesis. One of its main functions is to control the appearance of weeds in crops, primarily in corn, sorghum, sugar cane, and wheat; however, it is very toxic for numerous species, including humans. Therefore, this work deals with the adsorption of ATZ from aqueous solutions using nanocomposite materials, synthesized with two different types of organo-modified clays. Those were obtained by the free radical polymerization of 4-vinylpyridine (4VP) and acrylamide (AAm) in different stoichiometric ratios, using tetrabutylphosphonium persulfate (TBPPS) as a radical initiator and N,N′-methylenebisacrylamide (BIS) as cross-linking agent. The structural, morphological, and textural characteristics of clays, copolymers, and nanocomposites were determined through different analytical and instrumental techniques, i.e., X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). Adsorption kinetics experiments of ATZ were determined with the modified and synthesized materials, and the effect of the ratio between 4VP and AAm moieties on the removal capacities of the obtained nanocomposites was evaluated. Finally, from these sets of experiments, it was demonstrated that the synthesized nanocomposites with higher molar fractions of 4VP obtained the highest removal percentages of ATZ.


2011 ◽  
Vol 83 (10) ◽  
Author(s):  
T. H. Han ◽  
J. S. Helton ◽  
S. Chu ◽  
A. Prodi ◽  
D. K. Singh ◽  
...  

2021 ◽  
Vol 36 (4) ◽  
pp. 557-561
Author(s):  
Zhengzai Cheng ◽  
Junpeng Cheng ◽  
Jun Chen ◽  
Jing Xiong ◽  
Xin Sun ◽  
...  

Inorganics ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 97 ◽  
Author(s):  
Marie Gaschard ◽  
Farzaneh Nehzat ◽  
Thomas Cheminel ◽  
Bruno Therrien

The synthesis and characterization of three metalla-rectangles of the general formula [Ru4(η6-p-cymene)4(μ4-clip)2(μ2-Lanthr)2][CF3SO3]4 (Lanthr: 9,10-bis(3,3’-ethynylpyridyl) anthracene; clip = oxa: oxalato; dobq: 2,5-dioxido-1,4-benzoquinonato; donq: 5,8-dioxido-1,4-naphthoquinonato) are presented. The molecular structure of the metalla-rectangle [Ru4(η6-p-cymene)4(μ4-oxa)2(μ2-Lanthr)2]4+ has been confirmed by the single-crystal X-ray structure analysis of [Ru4(η6-p-cymene)4(μ4-oxa)2(μ2-Lanthr)2][CF3SO3]4 · 4 acetone (A2 · 4 acetone), thus showing the anthracene moieties to be available for reaction with oxygen. While the formation of the endoperoxide form of Lanthr was observed in solution upon white light irradiation, the same reaction does not occur when Lanthr is part of the metalla-assemblies.


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