Synthesis and thermal properties of azo-peroxyesters

Zawadiak, Jan; Hefczyc, Barbara; Janeczek, Henryk; Kowalczuk, Marek

doi:10.1007/s00706-008-0023-4

Cited by 6 publications

(5 citation statements)

References 13 publications

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“…The diazo decomposition reaction was readily observed by the exothermic peak on the DSC thermogram, which shows a reaction enthalpy of −45.6 J/g with an extrapolated peak onset at 107.9 °C and peak decomposition temperature at 129.2 °C. Additionally, the TGA thermogram indicated initial weight loss of the sample begins at ∼90 °C and plateaux at ∼160 °C, with a total weight loss of 0.165 mg (1.13%), which can be attributed to the loss of N 2 upon generation of the reactive carbene species, corresponding to a maximum conversion of the diazo compound to diarylcarbene of 33%. , …”

Section: Resultsmentioning

confidence: 97%

“…Additionally, the TGA thermogram indicated initial weight loss of the sample begins at ~90 ºC and plateaux at ~160 ºC, with a total weight loss of 0.165 mg (1.13 %), which can be attributed to the loss of N2 upon generation of the reactive carbene species, corresponding to a maximum conversion of the diazo compound to diarylcarbene of 33 %. 32,33 Further analysis of the functionalized CB by thermogravimetric analysis (TGA) (Figure 4) indicates the thermal stability of the modification and affords the opportunity to directly estimate the surface loading from the determined mass losses ( Table 2). The pristine and modified CB samples showed a similar weight loss, 0.3 -1.0 %, in the temperature range 30 -200 ºC, due to degassing and volatilization of water or residual solvents.…”

Section: Tga-dsc Thermal Analysis Of Pristine and Modified Cb The Camentioning

confidence: 99%

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New Routes to Functionalize Carbon Black for Polypropylene Nanocomposites

et al. 2016

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Methods for chemical surface functionalization for carbon black (CB) nanoparticles were studied to produce (CB)/polypropylene (PP) nanocomposites with superior electrical and thermal properties. Nanoparticle dispersion is known to directly control the extent to which nanocomposites maximize the unique attributes of their nanoscale fillers. As a result, tailored nanoparticle surface chemistry is a widely utilized method to enhance the interfacial interactions between nanoparticles and polymer matrices, assisting improved filler dispersion. In this work, a rapid chemical functionalization approach using a number of diarylcarbene derivatives, followed by the azo-coupling of substituted diazonium salts, for the covalent introduction of selected functional groups to the CB surface, is reported. Characterization of the modified CB by XPS, TGA, CHN, and ATR-IR collectively confirmed surface functionalization, estimating surface grafting densities of the order of 10(13) and 10(14) molecules/cm(2). Nanocomposites, synthesized by solvent mixing PP with pristine and modified CB, demonstrated macroscopic property changes as a result of the nanoparticle surface functionalization. Pronounced improvements were observed for PP nanocomposites prepared with a dodecyl-terminated diaryl functionalized CB, in which TEM analysis established improved nanofiller dispersion owing to the enhanced CB-PP interfacial interactions in the nanocomposite. Observed dielectric relaxation responses at 20 wt % loading and a reduced percolation threshold realized conductivities of 1.19 × 10(-4) S cm(-1) at 10 wt %, compared to 2.62 × 10(-15) S cm(-1) for pristine CB/PP nanocomposites at the same filler loading. In addition, thermal properties signify an increase in the number of nucleation sites by the raised degree of crystallinity as well as increased melting and crystallization temperatures.

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Section: Resultsmentioning

confidence: 97%

Section: Tga-dsc Thermal Analysis Of Pristine and Modified Cb The Camentioning

confidence: 99%

New Routes to Functionalize Carbon Black for Polypropylene Nanocomposites

et al. 2016

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“…The compounds investigated were synthesized as described elsewhere [5]. Thermogravimetric measurements were carried out using a Mettler Toledo TGA/SDTA-851 instrument under the following conditions: platinum crucible, sample mass 1-1.5 mg, heating rate 1-6 K min -1 , N 2 atmosphere (gas flow rate, 100 cm 3 min -1 ).…”

Section: Methodsmentioning

confidence: 99%

“…The details of the synthesis of azo-peroxyesters by the reaction of sodium salts of organic hydroperoxides with acid chlorides, as well as investigations of their spectroscopic features and stability are given elsewhere [5]. On the other hand, peroxy and azo compounds have been analysed by isothermal and dynamic thermoanalytical methods [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

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Analysis of the thermal decomposition of azo-peroxyesters by Arrhenius-type and three-parameter equations

Hefczyc

Siudyga

Zawadiak

et al. 2011

J Therm Anal Calorim

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Thermogravimetric analysis of azo-peroxyesters revealed two decomposition stages on TG curves. Molecular nitrogen is released in the first stage and carbon dioxide in the second. Fitting the thermogravimetric data by means of the three-parameter model and a classic one based on an Arrhenius-type kinetic equation showed that the former approach satisfactorily describes the process within the wide range of the extent of decomposition. It was found that two coefficients of the three-parameter equation are related to the temperature of maximum reaction rate. One of the coefficients of the three-parameter equation is also related to the activation energy. The compounds investigated can be grouped with respect to their kinetic characteristics, structure and stage of decomposition.

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