The melting behavior of polybutadienes

Mandelkern, L.; Tryon, Max; Quinn, F. A.

doi:10.1002/pol.1956.120199108

Cited by 28 publications

(9 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…(7) with = 1480C.18 aiid AH = 1000. 17 The upper line is a best fit for hiandelkern's data. The polymers of high trans content appear to fit the theory quite well.…”

Section: L/tml/tmo = R/ah In Xtmentioning

confidence: 99%

Structure effects and related polymer properties in polybutadiene. I. Preparation and characterization

Berger

Buckley

1963

J. Polym. Sci. A Gen. Pap.

View full text Add to dashboard Cite

SynopsisStereoregular polybutadienes, of both high trans and high cis contents, were isomerized to provide polymers of varying &-trans content. These isomeriates were used to study structural effects on physical properties. The isomerizations were carried out under photosensitized conditions in benzene solution at 25'C. The reaction was controlled to deliver polymers over the range &95% trans content. This range was selected to provide crystalline and semicrystalline polymers whose structures could be examined in terms of sequencing or blocking by established x-ray techniques. Isomer contents were measured accurately by infrared traces. Isomerizations reached an equilibrium of 77% trans regardless of whether the reaction started with high trans or high cis polybutadienes. Intrinsic viscosity was found to increase regularly with trans content in conformity with the larger size of the trans unit. 'lap/c versus c relations were observed to give a complicated form and this subject was deferred for further study. Crystallinity decreased regularly with reduced trans content m the equilibrium of 77% trans was approached. Continued isomerization a t the point of equilibrium produced a completely amorphous polymer. The melting temperatures of the crystalline polymers were studied in detail by x-ray camera and counting techniques.One form was stable up to 60°C. and invariant with cis-trans content in the range 80-95% trans. Below 80% trans the melting point of this form decreased with further reduction in trans content. The melting temperature of the other crystal form was dependent on trans content and decremed with decreased trans content until it coincided with the melting temperature of the other form. The distributions of trans and cis units and sequences of them were calculated through construction of matrices of transition probabilities. Copolymer theory was invoked to calculate pseudo reactivity ratios for the trans and cis forms. The melting temperatures of the two crystals were found to follow the predicted curves for random copolymers, although not simultaneously. This behavior is discussed. The crystallinity of the isomerizates of high trans content was found to be similar to block copolymers in spite of the fact that the method of their preparation would require that they be characterized as random. The importance of a crystal transition in this case is stressed along with the general effects due to the amount and type of the noncrystallisable unit.These polymers exhibited two crystal forms.

show abstract

“…(7) with = 1480C.18 aiid AH = 1000. 17 The upper line is a best fit for hiandelkern's data. The polymers of high trans content appear to fit the theory quite well.…”

Section: L/tml/tmo = R/ah In Xtmentioning

confidence: 99%

Structure effects and related polymer properties in polybutadiene. I. Preparation and characterization

Berger

Buckley

1963

J. Polym. Sci. A Gen. Pap.

View full text Add to dashboard Cite

show abstract

“…Oxygen (a) and carbon dioxide (b) permeability as a function of refractive index: blend polymer and triblock copolymer in this study (); other polymers with π electrons (); without π electrons () …”

Section: Resultsmentioning

confidence: 93%

Gas transport and optical properties of ABA-type triblock copolymers designed using fluorine-containing polyimide macroinitiators with methyl methacrylate

et al. 2013

View full text Add to dashboard Cite

Abstract4,4'-(Hexafluoroisopropylidene) diphthalic anhydride 2,3,5,6-tetramethyl-1,4-phenylenediamine (6FDA-TeMPD) polyimide macroinitiator was synthesized and reacted with poly(methyl methacrylate) (PMMA) to form an ABA-type triblock copolymer by atom transfer radical polymerization. The effect of the ABA-type triblock copolymer structure on solid, thermal, optical and gas transport properties was systematically investigated and compared with the physical blend polymer. The blend polymer was cloudy, whereas the triblock copolymer was colorless and transparent. The PMMA component decomposition temperature for the triblock copolymer slightly shifted to higher temperature, while its gas barrier property was higher than the blend polymer. The refractive index and the gas permeability decreased while maintaining the heat resistance by a high nanoscale distribution of both polymer components. The 6FDA-TeMPD/PMMA ABA-type triblock copolymer can be described as a polymer material with high heat resistance, high gas barrier property and low refractive index amongst existing polymers.

show abstract

“…This increases the crystallization temperature T m . An experimental study showing the validity of the foregoing equation for high-trans-1,4 polybutadienes has been carried out by Mandelkern et al [171] and by Berger and Buckley [23], and similar effects have been described in eis-1,4-polybutadienes [19,210]. A more striking and important aspect is the increased rate of crystallization caused by strains or-probably better-stresses.…”

Section: T=(h a -H C )/(S A -S C ) = Ah ( /As {mentioning

confidence: 84%

Rheological Behavior of Unvulcanized Rubber

White¹

1978

Science &Amp; Technology of Rubber

View full text Add to dashboard Cite

The melting behavior of polybutadienes

Cited by 28 publications

References 35 publications

Structure effects and related polymer properties in polybutadiene. I. Preparation and characterization

Structure effects and related polymer properties in polybutadiene. I. Preparation and characterization

Gas transport and optical properties of ABA-type triblock copolymers designed using fluorine-containing polyimide macroinitiators with methyl methacrylate

Rheological Behavior of Unvulcanized Rubber

Contact Info

Product

Resources

About