Molecular Dynamics Simulation of a Phenylene Polymer. 1. Poly(phenylene oxide)

Chen, C. L.; Chen, H. L.; Lee, C. L.; Shih, J. H.

doi:10.1021/ma00086a017

Cited by 25 publications

(5 citation statements)

References 3 publications

(3 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…East/south to north/west motions, of two adjacent phenyl rings correspond to “gearwheels” (i.e. “disrotatory” 20 or “in phase”). Starting from the minimum energy conformation, no high intramolecular energetic barrier has to be overcome in this direction.…”

Section: Resultsmentioning

confidence: 99%

Molecular Mobility in Para-Substituted Polyaryls. 3. Low-Temperature Dynamics

David¹,

Girard²,

Dolmazon³

et al. 1996

Macromolecules

View full text Add to dashboard Cite

The low-temperature mechanical relaxations in poly(oxy-1,4-phenyleneoxy-1,4-phenylenecarbonyl-1,4-phenylene [poly(aryl ether ether ketone, PEEK], poly(thio-1,4-phenylene) [poly(phenylene sulfide), PPS], and poly(oxy-1,4-phenylenesulfonyl-1,4-phenylene), [poly(aryl ether sulfone), PES] are investigated. All three polymers exhibit a low-temperature γ relaxation, in the temperature range from 40 to 100 K at 1 Hz. The apparent activation energies for the γ relaxations (15−25 kJ/mol) are close to the values derived from empirical force field molecular mechanics calculations of the “crankshaft motion” in an isolated chain portion. Only polymers with a polar interaromatic bridge (PEEK and PES) exhibit another secondary β relaxation, in the temperature range from 100 to 250 K at 1 Hz. Moreover, the apparent activation energies of the β processes are significantly higher than the activation energies of the γ relaxations. Therefore, it is concluded that polar intermolecular interactions play an important role in the molecular events leading to the β relaxation, whereas the γ relaxation is due to conformational changes mostly controlled by an intramolecular energy.

show abstract

Section: Resultsmentioning

confidence: 99%

Molecular Mobility in Para-Substituted Polyaryls. 3. Low-Temperature Dynamics

David¹,

Girard²,

Dolmazon³

et al. 1996

Macromolecules

View full text Add to dashboard Cite

show abstract

“…The rotational barriers of the ether linkage, which is the most rotatable linkage in the PIs, were calculated by the Dreiding force field. 35,36 Bis(phthalimide)s of ( 1), (2), and (3), which are shown in Figure 7, were used as model compounds of PI1x, PI2x, and PI3x, respectively, and density functional theory calculations in the gas phase were carried out as implemented in the Gaussian09W package of quantum chemical programs. The rotational barriers of the ether linkage in the model compounds of PI1x, PI2x, and PI3x were 0.92, 0.64, and 0.77 kcal mol À1 , respectively.…”

Section: Polymer Propertiesmentioning

confidence: 99%

Synthesis and properties of polyimides having a hexaphenylbenzene unit

Nabeshima

Morikawa

2014

High Performance Polymers

View full text Add to dashboard Cite

Aromatic polyimides (PIs) with a hexaphenylbenzene unit were synthesized from 1,4-bis[4-(4-aminophenoxy)phenyl]-2,3,5,6-tetraphenylbenzene (1) and various tetracarboxylic dianhydrides by a conventional two-step procedure that included ring-opening polymerization in N-methyl-2-pyrrolidone and subsequent thermal cyclic dehydration. The PIs were characterized by X-ray diffraction, differential scanning calorimetry, thermogravimetry, and dynamic mechanical analysis. The PIs had glass transition temperatures in the range of 289–352°C, and all the polymers were amorphous. The structure–property relationships of these PIs were examined and compared with those of the previously prepared analogous PIs from 4,4′-bis(4-aminophenoxy)biphenyl (2) and 4,4′-bis(4-amino-2-phenylphenoxy)biphenyl (3). Water absorption and dielectric constants of the PIs were also compared and discussed on the basis of imide content per repeating unit.

show abstract

“…As shown in Fig. , two peak values of the equivalent shear‐rate were 0.835 ps −1 and 0.695 ps −1 , respectively, which were on the same order as the shear‐rate in molecular dynamic simulations .…”

Section: Introductionmentioning

confidence: 52%

The chain scission extent of polystyrene in different shear flow fields

Chen

Zhang

et al. 2017

Polymer Engineering & Sci

View full text Add to dashboard Cite

A mechanochemical reactor providing strong shear-force has been developed in order to graft the polar groups onto the polymers. The extent of polymers' chain scission is a key factor in grafting process. In order to evaluate the scission extent, the shearing experiments were carried out for GPPS152P, which were produced by SECCO Petrochemical Company, Shanghai, China, at different revolving speeds, and temperatures. The decrease in molecular weight of GPPS152P was evaluated through gel permeation chromatography method and was estimated to be 13.8%. Additionally, the molecular weight distribution (MWD) of this sample became narrower. The chain scission theory and the shear rate, simulated through POLYFLOW software, were simultaneously employed to conduct quantitative analysis of molten PS' chain scission process. According to this method, the decrease in molecular weight was estimated to be 12.88%. Therefore, this method can be taken as a guideline for estimating molecular weight and MWD of products in manufacturing industry. POLYM. ENG. SCI., 58:913-919, 2018.

show abstract

Molecular Dynamics Simulation of a Phenylene Polymer. 1. Poly(phenylene oxide)

Cited by 25 publications

References 3 publications

Molecular Mobility in Para-Substituted Polyaryls. 3. Low-Temperature Dynamics

Molecular Mobility in Para-Substituted Polyaryls. 3. Low-Temperature Dynamics

Synthesis and properties of polyimides having a hexaphenylbenzene unit

The chain scission extent of polystyrene in different shear flow fields

Contact Info

Product

Resources

About