scholarly journals Hexamethylenetetramine reaction with graphite oxide (GO) as a strategy to increase the thermal stability of GO: Synthesis and characterization of a compound

2010 ◽  
Vol 75 (4) ◽  
pp. 497-504 ◽  
Author(s):  
Fariasa de ◽  
Claudio Airoldib

In this paper, the synthesis and characterization of a GO-hmta compound (GO = graphite oxide; hmta = hexamethylenetetramine) are presented. It is shown that the presence of hmta molecules inside the GO matrix, with very strong interactions, stabilize the GO matrix from a thermal point of view. Such a fact could be used to explore possible applications of GO matrix, especially in catalysis.

2011 ◽  
Vol 197-198 ◽  
pp. 606-609 ◽  
Author(s):  
Ti Feng Jiao ◽  
Yuan Yuan Xing ◽  
Jing Xin Zhou ◽  
Wei Wang

Some functional luminol derivatives with aromatic substituted groups have been designed and synthesized from the reaction of the corresponding aromatic acyl chloride precursors with luminol. It has been found that depending on the size of aromatic groups, the formed luminol derivatives showed different properties, indicating distinct regulation of molecular skeletons. UV and IR data confirmed commonly the formation of imide group as well as aromatic segment in molecular structures. Thermal analysis showed that the thermal stability of luminol derivatives with p-phthaloyl segment was the highest in those derivatives. The difference of thermal stability is mainly attributed to the formation of imide group and aromatic substituent groups in molecular structure. The present results have demonstrated that the special properties of luminol derivatives can be turned by modifying molecular structures of objective compounds with proper substituted groups, which show potential application in functional material field and ECL sensor.


2012 ◽  
Vol 560-561 ◽  
pp. 174-178
Author(s):  
Yan Zou ◽  
Hui Min Qi ◽  
Mei Ling Xu ◽  
Fa Rong Huang ◽  
Lei Du

Hyperbranched poly(diethynylbenzene-silane) (hb-PDEBS) was synthesized through polycondensation reaction of diethynylbenzene Grignard reagent (A2) and trichlorosilane (B3), and its structure was characterized by FT-IR, 1H-NMR, GPC and Elemental Analysis. The degree of branching of hb-PDEBS was defined by 29Si-NMR and calculated to be about 0.68. The curing behavior of hb-PDEBS was investigated by DSC. Thermal stability of cured hb-PDEBS was examined by TGA, and its residue at 1000°C under nitrogen was 80.6%. Hb-PDEBS displayed a strong absorption due to π-π* transition and exhibited the most intensity structured emission with a maximum around 500 nm.


2011 ◽  
Vol 675-677 ◽  
pp. 295-298
Author(s):  
Liang Shao ◽  
Jian Hui Qiu ◽  
Ming Zhu Liu ◽  
Hui Xia Feng ◽  
Guo Hong Zhang ◽  
...  

New types of conducting composites using andalusite as an inorganic substrate and polyaniline as the conducting phase were prepared. The composites exhibited conductivities in the 0.14-2.08 S/cm range, depending on the amount of polyaniline. The thermal stability of andalusite/polyaniline composites were studied by thermogravimetric analysis. The resulting composites were also characterized by using FTIR spectroscopy and scanning electron microscopy.


BioResources ◽  
2011 ◽  
Vol 6 (3) ◽  
pp. 2492-2503
Author(s):  
Nour-Eddine El Mansouri ◽  
Qiaolong Yuan ◽  
Farong Huang

Epoxidization is an interesting way to develop a new application of lignin and therefore to improve its application potential. In this work, kraft lignin-based epoxy resins were obtained by the epoxidization reaction, using the kraft lignin recovered directly from pulping liquor and modified by a methylolation reaction. The methylolated lignins were obtained by the reaction of original kraft lignin with formaldehyde and glyoxal, which is a less volatile and less toxic aldehyde. 1H-NMR spectroscopy showed that methylolated kraft lignin has more hydroxymethyl groups than glyoxalated kraft lignin. For the epoxidization reaction we studied the influence of the lignin:NaOH (w/w) ratio, temperature, and time of the reaction on the properties of the prepared epoxidized lignins. The structures of lignin-based epoxy resins were followed by epoxy index test and FTIR spectroscopy. Optimal conditions were obtained for lignin-based epoxy resin produced at lignin/NaOH = 1/3 at 70 ºC for 3h. Thermogravimetry analysis (TGA) revealed that the epoxidization enhances the thermal stability of lignins and may allow a wider temperature range for applications with lignin epoxy-PF blends.


e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Xiao-Song Huang ◽  
Feng-Ling Qing

AbstractA new serious of fluorinated polybenzoxazoles (PBOs) were prepared from 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane together with 2,5- difluoroterephthalic acid (DFTA) and terephthalic acid by the one-pot polycondensation in polyphosphoric acid. The resulting PBOs showed good solubility in many common organic solvents and the thermal stability of PBOs was improved by the introduction of DFTA monomer.


2012 ◽  
Vol 217-219 ◽  
pp. 551-554
Author(s):  
Ting Xi Li ◽  
Yu Hua Zhao ◽  
Qian Li ◽  
Cheng Qian Yuan ◽  
Quan Liang Chen ◽  
...  

Abstract. Polyaniline (PANI) and p-phenylenediamine (p-PDA)-aniline copolymer were prepared via a same microemulsion method. The structures of the PANI and p-PDA-aniline copolymer were characterized by infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis(TGA). The results revealed the difference of synthesis and characterization between PANI and p-PDA-aniline copolymer. It was shown that structure of the copolymer is almost similar to that of PANI, but the p-PDA-aniline copolymer has a better crystallization than PANI, and the thermal stability of the copolymer is higher than that of pure PANI.


2011 ◽  
Vol 328-330 ◽  
pp. 1533-1536
Author(s):  
Guang Shuo Wang ◽  
Zhi Yong Wei ◽  
Lian Liu ◽  
Pei Wang ◽  
Min Qi

The novel biodegradable poly (ε-caprolactone)/TiO2 nanocomposites were prepared by in situ polymerization of ε-caprolactone in the presence of modified-TiO2 nanoparticles as initiator. The molecular weight of poly (ε-caprolactone) (PCL) matrix was dependent on the amount of the TiO2 fillers. The incorporation of TiO2 did not significantly affect the crystalline structure of PCL. An astounding nucleating effect of TiO2 on PCL crystallization was observed. The enhanced thermal stability of PCL nanocomposites was observed. The novel biodegradable poly (ε-caprolactone)/TiO2 nanocomposites were prepared by in situ polymerization of ε-caprolactone in the presence of modified-TiO2 nanoparticles as initiator. The molecular weight of poly (ε-caprolactone) (PCL) matrix was dependent on the amount of the TiO2 fillers. The incorporation of TiO2 did not significantly affect the crystalline structure of PCL. An astounding nucleating effect of TiO2 on PCL crystallization was observed. The enhanced thermal stability of PCL nanocomposites was observed.


Author(s):  
El-Sayed Negim ◽  
◽  
A.M. Konysbay ◽  
G. Irmukhametova ◽  
S.N. Kalugin ◽  
...  

Grafting polymerization based on polypropylene glycol (PPG) and styrene (St) was synthesized with different composition of styrene using the free radical technique in the presence of potassium persulphate as an initiator. The grafted copolymers (PPG-g-St) used different styrene composition (65/15, 65/25, 65/35), respectively. The grafted copolymers were investigated through FTIR (Fourier-transform spectroscopy), Differential scanning calorimeter and thermogravimetric analyzer. FTIR showed new peaks at 1450 cm-1 and 1135 cm-1 due to the grafting process of St on PPG. Thermal stability of grafted copolymer increases by increasing the ratio of styrene, while Tg decreases by increasing the ratio of styrene.


e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Hongchun Zhang ◽  
Zaijun Lu

AbstractA p-cyanophenol and allylamine based benzoxazine has been synthesized and characterized. This benzoxazine has nitrile and allyl functionalities that can polymerize, resulting in a highly crosslinked material. The DSC spectra of novel benzoxazine monomer reveal that incorporation of the nitrile and allyl group greatly decreases the ring-opening temperature of oxazine rings (140°C). The IR spectra of curing process indicate that the polymerization of oxazine ring accompany with the curing reaction of allyl and nitrile groups. Benzoxazine monomers with one or none of the two functionalities were also prepared to study structure effect on thermal properties of resulted polymer. The comparison of results confirms that introducing the two functionalities improved glass transition temperature (238 °C), thermal stability of polybenzoxazine (T5%=340 °C), and char yield (57%).


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