scholarly journals Using the group contribution method and molecular dynamics to predict the glass transition temperatures and mechanical properties of poly-(p-phenylenediamine-alt-2, 6-diformyl multiphenyl)

2021 ◽  
pp. 174751982110116
Author(s):  
Duan Li ◽  
Hui-Ting Li ◽  
Hongmei Wu ◽  
Yuyuan Wang
Keyword(s):  
Molecular Dynamics ◽  
Glass Transition ◽  
Degree Of Polymerization ◽  
Group Contribution ◽  
Side Chain ◽  
Transition Temperatures ◽  
Group Contribution Method ◽  
Free Volume Theory ◽  
Glass Transition Temperatures ◽  
Benzene Rings

This article reports the glass transition temperatures of poly-( p-phenylenediamine-alt-2,6-diformyl multiphenyl) predicted by both the group contribution method and the molecular dynamics simulations. The related modeling method and the degree of polymerization, density, specific volume, radius of volume, radius of rotation, and non-bonding energy terms with temperature are analyzed in depth. The bulk modulus, shear modulus, compressibility, Young’s modulus, and Poisson’s ratio of poly-( p-phenylenediamine-alt-2,6-diformyl multiphenyl) at room temperature are simulated by molecular dynamics. The results show that the simulated glass transition temperatures of poly-( p-phenylenediamine-alt-2,6-diformyl multiphenyl) are greater than 480 K, which indicates that poly-( p-phenylenediamine-alt-2,6-diformyl multiphenyl) can be expected to be used as a high-temperature-resistant material. As the number of rigid benzene rings on the molecular side chain increases, the glass transition temperature decreases, with an average decrease of 10 K for each additional benzene ring. The free volume theory can explain the glass transitions of poly-( p-phenylenediamine-alt-2,6-diformyl multiphenyl). The modulus and density of poly-( p-phenylenediamine-alt-2,6-diformyl multiphenyl) change accordingly with an increase of rigid benzene rings on the side chain, probably due to the fact that the flexibility of the polymers changes accordingly as the number of benzene rings on the side chain increases.

Properties and Structure of Elastomers

1966 ◽  
Vol 39 (4) ◽  
pp. 881-896 ◽  
Author(s):  
Joginder Lal ◽  
Kenneth W. Scott
Keyword(s):  
Tensile Strength ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Alkyl Group ◽  
Side Chain ◽  
Transition Temperatures ◽  
Glass Transition Temperatures ◽  
Dynamic Mechanical ◽  
Alkyl Ethers

Abstract The glass transition temperatures of high molecular weight poly (vinyl n-alkyl ethers) decrease with increasing length of the n-alkyl group. On lengthening the n-alkyl group, 14 per cent of the specific volume increase is free volume. Branching or substitution in the alkyl group of the polymer increases the Tg value. A comparison of poly (vinyl n-alkyl ethers) and polymers of normal α-olefins shows that an ether group and a methylene group in the side chain are equivalent in influencing the glass transition temperature. We have varied systematically the side chain alkyl group in poly (vinyl alkyl ethers) and evaluated at 3 different temperatures the influence of these variations on the dynamic properties of the vulcanizates of these polymers. The relative position of the curves, relating dynamic resilience to dynamic modulus of these polymers, is generally in the order of their glass transition temperatures. The dynamic mechanical property data on poly (vinyl n-pentyl ether) and poly (vinyl 2-ethylhexyl ether), which have the same glass transition temperature, fall on a common curve characteristic of the temperature of measurement. Apparently, the Tg is a major factor in correlating the dynamic mechanical behavior of these elastomers. The size and shape of the alkyl group appear to be reflected primarily in their effect on the Tg. Polysulfidic crosslinks are not essential for the attainment of high tensile strength in natural rubber vulcanizates cured with a sulfur-diphenylguanidine system. Data for the samples which had lost significant amounts of polysulfidic crosslinks by reaction with triphenylphosphine fitted a curve of tensile strength as a function of 300 per cent modulus for the control samples.

Copolymerization of 2,3:4,5-Di-O-isopropylidene-1-vinylbenzyl-β-D-fructopyranose with styrene: Preparation of polymers containing carbohydrate side chain residues and effect of composition on glass transition temperatures

1978 ◽  
Vol 31 (11) ◽  
pp. 2559 ◽  
Author(s):  
WK Busfield ◽  
FP Franke ◽  
RD Guthrie
Keyword(s):  
Glass Transition ◽  
Specific Rotation ◽  
Solution Viscosity ◽  
Side Chain ◽  
Transition Temperatures ◽  
Radical Initiation ◽  
Glass Transition Temperatures ◽  
A Value ◽  
Free Radical Initiation ◽  
Styrene Content

A range of copolymers of styrene and 2,3:4,5-di-O-isopropylidene-1- vinylbenzyl-β-D-fructopyranose (A) were prepared by free-radical initiation and characterized by i.r., N.M.R., microanalysis and solution viscosity. Reactivity ratios were derived. The specific rotation of the copolymers was linearly related to the molar composition. The glass transition temperatures of the copolymers decreased almost linearly with decreasing styrene content to a value of 73°C for the homopolymer of monomer (A). A method of releasing the isopropylidene blocking groups was developed; the glass transition temperatures of the resultant fructopyranose copolymers increased with decreasing styrene content to a value of 132°C for a copolymer containing 45 mole % styrene.

Effect of the side chain structure on the glass transition temperatures of some poly(thiocarbonate)S

1986 ◽  
Vol 105 ◽  
pp. 149-160 ◽  
Author(s):  
M. Yazdani-Pedram ◽  
E. Soto ◽  
L.H. Tagle ◽  
F.R. Diaz ◽  
L. Gargallo ◽  
...  
Keyword(s):  
Glass Transition ◽  
Chain Structure ◽  
Side Chain ◽  
Transition Temperatures ◽  
Glass Transition Temperatures
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