scholarly journals Connection of water permeability with a number of physical properties of polymers

2021 ◽  
Vol 263 ◽  
pp. 01022
Author(s):  
A.A. Askadskii ◽  
T.V. Zhdanova ◽  
I.F. Andreev ◽  
S.V. Matseevich ◽  
T.A. Matseevich
Keyword(s):  
Inverse Problem ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Water Permeability ◽  
Chemical Structure ◽  
Cohesion Energy ◽  
Vinyl Polymers ◽  
Cohesion Energy Density ◽  
Polymer Unit

Currently, methods for predicting the properties of polymers are very popular, since they simplify the work of synthetic chemists. Instead of lengthy and time-consuming experiments, many properties of polymers can be predicted in advance based on their chemical structure. Naturally, such tasks must be computerized so that the properties are predicted after the chemical structure of the repeating polymer unit is displayed on the display screen. This is the so-called direct task. The inverse problem is more complex and interesting. It consists in entering the intervals of the desired characteristics into the computer. Then computer synthesis of polymers possessing these characteristics are realized. The work consists in writing a computer program that allows the computer synthesis of polymers of different classes with specified intervals of water permeability. These classes include polyurethanes, polysulfones, polysulfides, polyethers and polyesters, polyamides, polyketones and polyethyrketones, polycarbonates, polyolefins, vinyl polymers, polystyrene, acrylic and methacrylic polymers. On the basis of this program, water permeability compatibility diagrams are constructed with various physical characteristics of polymers – glass transition temperature, temperature of the onset of intensive thermal degradation, cohesion energy, density, solubility parameter (Hildebrand parameter).

Citric acid grafting onto polyurethane for the control of molecular interactions and water compatibility

2016 ◽  
Vol 48 (8) ◽  
pp. 691-710
Author(s):  
Yong-Chan Chung ◽  
Hyeryoung Yoon ◽  
Jae Won Choi ◽  
Byoung Chul Chun
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Citric Acid ◽  
Low Temperature ◽  
Molecular Interactions ◽  
Water Permeability ◽  
Enthalpy Change ◽  
Low Temperature Flexibility ◽  
Grafting Onto

Citric acid (CA) was used as a grafted group onto polyurethane (PU) to form a CA-grafted PU series, with a control PU series containing free CA prepared for comparison. With an increase in the CA content, the enthalpy change during the melting increased for the PU and CPU series, and the glass transition temperature increased with the increase in CA content for the PU series but not for the CPU series. The tensile strengths of the PU series sharply increased with the CA content, whereas those of the CPU series did not. The PU series demonstrated better low-temperature flexibility and water permeability than the unmodified PU.

scholarly journals Glass transition temperature from the chemical structure of conjugated polymers

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Renxuan Xie ◽  
Albree R. Weisen ◽  
Youngmin Lee ◽  
Melissa A. Aplan ◽  
Abigail M. Fenton ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Conjugated Polymers ◽  
Chemical Structure

MODELING AND PREDICTING THE GLASS TRANSITION TEMPERATURE OF VINYL POLYMERS BY USING HYBRID PSO-SVR METHOD

2013 ◽  
Vol 12 (03) ◽  
pp. 1350002 ◽  
Author(s):  
J. F. PEI ◽  
C. Z. CAI ◽  
Y. M. ZHU
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Independent Set ◽  
Percentage Error ◽  
Support Vector ◽  
Ann Model ◽  
Prediction Ability ◽  
Vinyl Polymers ◽  
Sar Model

Based on four physicochemical descriptors (the rigidness descriptor R OM resulted by hydrogen-bonding moieties group and/or rings, the chain mobility n, the molecular average polarizability α and the net charge of the most negative atom q-) derived from the polymers' monomers structure, the support vector regression (SVR) approach combined with particle swarm optimization (PSO), is proposed to construct a model for prediction of the glass transition temperature T g of three classes of vinyl polymers, including polystyrenes, polyacrylates and polymethacrylates. The mean absolute error (MAE = 13.68 K), mean absolute percentage error (MAPE = 4.22%) and correlation coefficient (R2 = 0.9252) calculated by SVR are superior to those (MAE = 16.74 K, MAPE = 5.30% and R2 = 0.9059) achieved by S-SAR model, and (MAE = 16.83 K, MAPE = 5.27% and R2 = 0.9057) achieved by ANN model for the identical training set (124 vinyl polymers), whereas the MAE = 15.09 K, MAPE = 4.82% and R2 = 0.9253 calculated by SVR are also better than those of MAE = 17.96 K, MAPE = 5.94% and R2 = 0.8952 achieved by S-SAR, and MAE = 16.603 K, MAPE = 5.4% and R2 = 0.9120 achieved by ANN for the same 68 test samples. Furthermore, the MAE, MAPE and R2 for an independent set (10 vinyl polymers) predicted by SVR also reached 14.132 K, 4.25% and 0.9475, respectively. The results strongly support that the comprehensive modeling and prediction ability of SVR model surpass those of S-SAR and ANN models by applying identical training, test and independent samples. It is demonstrated that the established SVR model is more suitable to be used for prediction of the T g values for unknown vinyl polymers possessing similar structure than S-SAR model or ANN model.

Effect of polymers chemical structure on the membrane characteristics

2016 ◽  
Vol 30 (1) ◽  
pp. 58-66 ◽  
Author(s):  
Inga A Ronova ◽  
Svetlana V Kryuchkova ◽  
Marina Y Yablokova ◽  
Alexander Y Alentiev ◽  
Lyudmila G Gasanova ◽  
...  
Keyword(s):  
Glass Transition ◽  
Comparative Analysis ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Permeability Coefficient ◽  
Chemical Structure ◽  
Gas Transport ◽  
Polymer Membranes ◽  
Gas Transport Properties ◽  
Methylene Group

The comparative analysis of gas transport properties and conformational parameters of membranes obtained from two polyimides and polysulfone was made. It was shown that the introduction of a sulfone group instead of a methylene group in the amine component of polyimide leads to an increase in glass transition temperature and of polymer membrane permeability coefficient and a reduction in selectivity. Also it was demonstrated that the solvent used during the preparation of polymer membranes had a significant influence on their gas transport characteristics.

Chemical structure and physical properties of cyclic olefin copolymers (IUPAC Technical Report)

2005 ◽  
Vol 77 (5) ◽  
pp. 801-814 ◽  
Author(s):  
Ju Young Shin ◽  
Ji Yong Park ◽  
Chenyang Liu ◽  
Jiasong He ◽  
Sung Chul Kim
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Chemical Structure ◽  
Moisture Absorption ◽  
High Surface ◽  
Polymeric Materials ◽  
Surface Characteristics ◽  
Cyclic Olefin ◽  
Cyclic Olefin Copolymers

Cyclic olefin copolymers comprise a new class of polymeric materials showing properties of high glass-transition temperature, optical clarity, low shrinkage, low moisture absorption, and low birefringence. There are several types of cyclic olefin copolymers based on different types of cyclic monomers and polymerization methods. In this work, we have analyzed the chemical structure of the currently commercialized cyclic olefin copolymers by 13C NMR, and investigated their glass-transition temperatures and surface characteristics. It was observed that the glass-transition temperature, Tg, of cyclic olefin copolymers depended on the bulkiness of the main chain, and the number of rings had an important role in increasing the bulkiness of cyclic olefin copolymers. Cyclic olefin copolymers with polar substituents such as ester or ether groups showed high surface energy per area and peel strength.

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