Influence of Chemical Structure on the Properties of Polymers

Аскадский, А.А.

doi:10.1016/b978-0-08-020953-1.50006-5

Cited by 24 publications

(46 citation statements)

References 3 publications

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“…Solubility parameter and cohesion energy density were calculated by Fedor`s group contribution method [14], van der Waals volume by Askadskii [15,16]. The results are shown in Table II.…”

Section: Resultsmentioning

confidence: 99%

Rapeseed Oil as Renewable Resource for Polyol Synthesis

Stirna¹,

Fridrihsone²,

Misane³

et al. 2011

Scientific Journal of Riga Technical University. Environmental and Climate Technologies

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-Vegetable oils are one of the most important platform chemicals due to their accessibility, specific structure of oils and low price.Rapeseed oil (RO) polyols were prepared by amidization of RO with diethanolamine (DEA). To determine the kinetics of amidization reaction, experiments were carried out. Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), amine (NH) value was determined. Group contribution method by Fedor`s was used to calculate solubility parameters, van der Waals volume was calculated by Askadskii. Obtained polyol`s OH and NH value are from 304 up to 415 mg KOH/g. RO polyols synthesis meets the criteria of "green chemistry".In the present study, reaction of RO amidization with DEA was investigated, as well as optimum conditions for polyol synthesis was established to obtain polyols for polyurethane production. Calculations of solubility parameter and cohesion energy density were calculated, as RO polyols will be used as side chains in polymers, and solubility parameter will be used to explain properties of polymers.

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“…Solubility parameter and cohesion energy density were calculated by Fedor`s group contribution method [14], van der Waals volume by Askadskii [15,16]. The results are shown in Table II.…”

Section: Resultsmentioning

confidence: 99%

Rapeseed Oil as Renewable Resource for Polyol Synthesis

Stirna¹,

Fridrihsone²,

Misane³

et al. 2011

Scientific Journal of Riga Technical University. Environmental and Climate Technologies

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“…However, we will assume that the value of the integral heat of sorption Qaint, equal to the heat of wetting, in conversion to the amorphous constituent of the FFP is a more informative characteristic reflecting the entire sorption isotherm. This characteristic can be obtained experimentally in calorimetric measurements [ 10,11 ] (1) and CA (2). Points: experimental data; solid line: calculation with Eq.…”

Section: It Was Shown That the Hygroscopicity And Characteristic Enermentioning

confidence: 98%

“…These characteristics are of theoretical and practical interest, since they first allow assessing the contribution of some structural element to the resulting properties of FFP [1][2][3] and second, they make it possible to interpolate missing or insufficiently reliable data for a sample with sufficient reliability if these characteristics are known for its homologs. Examples of this approach are the diffusion coefficients of water vapors in aliphatic polyamides [4], hygroscopic properties of aliphatic polyamides [5] and polyimides [6] in 65% relative humidity, and glass transition temperature (T) ofpolyimides as a function of chain rigidity [7].…”

Section: It Was Shown That the Hygroscopicity And Characteristic Enermentioning

confidence: 99%

Alteration of the hygroscopic properties in systematic (homologous) series of fibre-forming polymers

2000

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It was shown that the hygroscopicity and characteristic energy of sorption of water vapor by fibre-forming polymers with a systematically varied molecular composition change nonlinearly with an increase in the concentration of functional groups. Equations are proposed for calculating the sorption isotherms as a function of the molecular structure (concentration offunctional groups) and supermolecular structure (degree of crystallinity) of the polymer.The present article is a continuation of the publications on analyzing the characteristics of alteration of the physicochemical properties of fibre-forming polymers (FFP) as a function of their molecular composition. These characteristics are of theoretical and practical interest, since they first allow assessing the contribution of some structural element to the resulting properties of FFP [ 1-3] and second, they make it possible to interpolate missing or insufficiently reliable data for a sample with sufficient reliability if these characteristics are known for its homologs. Examples of this approach are the diffusion coefficients of water vapors in aliphatic polyamides [4], hygroscopic properties of aliphatic polyamides [5] and polyimides [6] in 65% relative humidity, and glass transition temperature (T) ofpolyimides as a function of chain rigidity [7]. g We previously investigated the changes in the temperature characteristics [8] and density of FFP [9].The hygroscopic properties are examined here as a function of the molecular composition for homologous series of aliphatic polyamides (APA) and cellulose acetates (CA) with different degrees of substitution. We analyzed the experimental data and the results obtained by different investigators. The relative concentrations of functional groups (FG), expressed in mole FG/g of polymer unit, were used as the characteristic of FFP. Amide groups for APA and hydroxyl groups for CA are such groups. Polymers not containing these groups were selected as the saturated homologs with a zero concentration of FG. Polyethylene (PE), which can arbitrarily be considered as a polyamide with a zero content of amide groups, was selected as the homolog for APA. For polycaproamide PA6 with a [--(CH2)5--CONH--] unit molecular structure, there is one amide group per elementary polymer unit with a weight of 113 g. In this case, the concentration of functional groups is 0.00885 mole/g. For comparison, we used data on the hygroscopicity of collagen [5] in which the concentration of amide groups is 47.4 wt. %, i.e., 0.011087 mole/g. Cellulose tfiacetate (CTA) with a zero concentration of hydroxyl groups was selected as the homolog for CA. Data for cellulose (C) were also used.The equilibrium moisture content of FFP in standard conditions (temperature of 20~ relative humidity of 65%) was considered the hygroscopicity index. However, we will assume that the value of the integral heat of sorption Qaint, equal to the heat of wetting, in conversion to the amorphous constituent of the FFP is a more informative characteristic reflecting the entire so...

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“…However, the motion of rings bonded to SO 2 continued. This enabled the probe with the smallest activation volume to experience conformational transitions down to a temperature of 195 K. The fact that a C arom -S chemical bond is longer than a C arom -C aliph bond [5] argues in favor of this assignment for relaxation transitions in PSF. Therefore, the mobility of benzene rings around a C arom -S bond is less hindered and can occur at lower temperatures than the mobility of the first type of benzene rings.…”

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confidence: 94%

“…The freezing temperatures of probe conformational equilibria T f were determined from these functions ( Table 2). The temperatures T f could be related to the probe activation volumes V p ≠ in order to analyze the relaxation transitions in the polymers [5]. The quantity V p ≠ characterized the minimum volume required for the conformational transition of the corresponding probe in the polymer.…”

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confidence: 99%