List of articles (by subject)
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Open Access Article
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Mohammad Azadi -
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zahra daneshfar -
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امیر کرمی -
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hamidreza heidari -
Open Access Article
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mina alizade -
Open Access Article
6 - Semi-Experimental Methods for Determination of Flory-Huggins Interaction Parameter in Polymeric Mixtures: A Review
Zahra Khoubi-AraniThe Flory-Huggins interaction parameter (χ) is a crucial factor affecting the miscibility and morphology of components in polymer mixtures and their final properties and applications. The reliable measurement of the interaction parameter is worthwhile in fundamental und MoreThe Flory-Huggins interaction parameter (χ) is a crucial factor affecting the miscibility and morphology of components in polymer mixtures and their final properties and applications. The reliable measurement of the interaction parameter is worthwhile in fundamental understanding and quantitative determination of structure-performance relation and finally in practical applications of polymers in different fields. Different methods are used for evaluation of this parameter. In this study, six semi-experimental methods are reviewed: measurement of melting point depression, equilibrium swelling, contact angle, phase separation points, vapor pressure, and inverse gas chromatography. In these methods, equilibrium melting temperatures of pure polymer and its mixtures, degree of equilibrium swelling of the cross-linked polymer in the presence of swelling agent, surface energy of components in the polymeric mixtures, equilibrium components composition in the two-phase system, the ratio of partial vapor pressure of solvent to its saturated one and retention volume are experimentally measured, respectively. Then a proper equation is fitted on the data and the interaction parameter is obtained. In some methods, such as measurement of contact angle, only a positive interaction parameter at temperature of the test is obtained. But in some others, such as measurement of melting point depression, there is no constraint for the sign of interaction parameter. In addition, some methods can determine the composition dependency of the interaction parameter, such as determination of phase separation points. Manuscript profile -
Open Access Article
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Amirhosein Yazdanbakhsh -
Open Access Article
8 - Crystallinity of polymers determined by differential scanning calorimetry (II)
Mina AlizadehaghdamDifferential scanning calorimetry (DSC) is widely used to determine the crystallinity of semicrystalline polymers. In the two-phase model, the measured heat of fusion is compared to the melting enthalpy of a completely crystalline polymer to get the crystallinity degree MoreDifferential scanning calorimetry (DSC) is widely used to determine the crystallinity of semicrystalline polymers. In the two-phase model, the measured heat of fusion is compared to the melting enthalpy of a completely crystalline polymer to get the crystallinity degree. Fusion heat of a polymeric sample is identified by area under the melting endotherm and a baseline. A correct baseline is heat capacity of the semicrystalline sample. It varies with both temperature and crystallinity and is difficult to evaluate. Enthalpy of a process is a state-function quantity and is independent of the process path. In polymer melting, temperature increase and fusion process occur simultaneously. This makes evaluation of the fusion heat challenging. Herein, alternative paths are supposed in which temperature increase and fusion process occur separately and sequentially. This leads to a convenient enthalpy evaluation. Two alternative paths can be defined: first, polymer melts at a constant temperature which is followed by temperature increase of the melt; second, polymer temperature increases without any change in crystallinity degree which is followed by polymer melting at a constant temperature. Lastly, an enthalpy deficiency due to the amorphous-crystalline interface and an excess enthalpy due to the defects present in crystalline regions are investigated how to affect the crystallinity. Manuscript profile -
Open Access Article
9 - Studying structural properties of polyethylene waxes with infrared spectroscopy
Mina AlizadehaghdamPolyethylene waxes are ethylene oligomers with unique properties, high crystallinity, linearity and low solubility in the solvents which provides a variety of applications in different industries such as electrotechnique, rubber, textile, fertilizer production, etc. Inf MorePolyethylene waxes are ethylene oligomers with unique properties, high crystallinity, linearity and low solubility in the solvents which provides a variety of applications in different industries such as electrotechnique, rubber, textile, fertilizer production, etc. Infrared spectroscopy (FTIR) is a simple and common analysis to examine the chemical and physical properties of polyethylene such as structure identification, chemical composition and crystallinity evaluation. Physical properties of a polyethylene wax largely depends on its branching degree. Absorption at the wavelength 1378 cm-1 associated with methyl groups symmetric deformation is used for determining the number of branches. Rocking vibration of methyl and methylene groups in the wavelength ranges of 800-1200 cm-1 and 720-770 cm-1 respectively are applied for identification of the branch type. Absorption of vinyl, trans vinylene and vinylidene unsaturation and carbonyl groups introduced into the structure by wax oxidation, were investigated. Absorption intensity was related to the number of absorbing species by molar absorption parameter or absorption coefficient based on the Beer-Lambert law. Some experimental relations were also introduced based on nuclear magnetic resonance spectroscopy. Deconvolution of the double absorption in the range 720-730 cm-1, associated with rocking vibration of methylene groups, to the crystalline and amorphous bands led to the crystallinity estimation. Manuscript profile -
Open Access Article
10 - Platform for manufacturing and intelligent production of polymers: genome engineering of polymer materials
Zeinab Sadat HosseiniHigh-performance polymer materials are the foundation of high-level technology development and advanced manufacturing. Recently, polymeric material genome engineering (PMGE) has been proposed as a basic platform for the intelligent production of polymeric materials. Po MoreHigh-performance polymer materials are the foundation of high-level technology development and advanced manufacturing. Recently, polymeric material genome engineering (PMGE) has been proposed as a basic platform for the intelligent production of polymeric materials. Polymeric Material Genome Engineering (PMGE) is an emerging field that combines the principles of the Materials Genome Initiative with polymer science to accelerate the discovery and development of new polymeric materials. The concept of PMGE is to create a comprehensive database of polymer properties obtained from both computational and experimental methods. This database can then be used to train machine learning models that can predict the properties of new polymers. However, the development of PMGE is still in its infancy and many issues remain to be addressed. Overall, PMGE represents a significant step towards the intelligent manufacturing of polymeric materials, with the potential to revolutionize the field by enabling faster and more efficient development of new materials. In this review are presented the fundamental concepts of PMGE and a summary of recent research and achievements, then are investigated the most important challenges and the future prospects. Specifically, this study focuses on the property prediction approaches, including of the proxy approach and the machine learning, and discusses the potential applications of PMGE, i.e. the advanced composites, the polymer materials used in the communication systems, and electrical integrated circuit manufacturing. Manuscript profile