The heat resistance of polyhetero-arylenes as a function of chemical composition and of structure

Krasnov, Ye.P.; Aksenova, V.P.; Khar'kov, S. N.

doi:10.1016/0032-3950(73)90107-x

Cited by 7 publications

(3 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the case of the present polymers, T g values increased while increasing the value of the conformational rigidity parameter. Previously [34], it was shown that there was a relationship between glass transition temperature and initial decomposition temperature for several polymers: T d = aT g .…”

Section: Properties Of the Polymers IV And Vmentioning

confidence: 99%

Poly(1,3,4-oxadiazole-amide)s with pendant acetoxybenzamide or imide groups

Sava¹,

Hamciuc²

2005

Designed Monomers and Polymers

View full text Add to dashboard Cite

Two series of aromatic poly(1,3,4-oxadiazole-amide)s containing various pendant groups were synthesized by solution polycondensation of aromatic diamines having preformed 1,3,4-oxadiazole rings with diacid chlorides incorporating acetoxybenzamide, phthalimide or tetrachlorophthalimide side units. These polymers were soluble in polar amidic solvents and gave transparent flexible films. They showed good thermal stability, with initial decomposition temperature being about 300 • C for polyamides with pendant acetoxybenzamide units and 400 • C for the polyamides having pendant phthalimide or tetrachlorophthalimide groups. The glass transition temperatures of the polymers were in the range of 245-327 • C. The polymer films showed the dielectric constant in the range of 3.32-4.90 and good mechanical properties with tensile strength in the range of 35-86 MPa, tensile modulus in the range of 0.235-2.66 GPa and elongation to break in the range of 15-24%. Conformational parameters of the polymers were calculated by using the Monte Carlo method with allowance for hindered rotation. Several physical properties of these polymers such as solubility, glass transition temperature and initial decomposition temperature were measured and discussed in relation with the rigidity of their chains.

show abstract

Section: Properties Of the Polymers IV And Vmentioning

confidence: 99%

Poly(1,3,4-oxadiazole-amide)s with pendant acetoxybenzamide or imide groups

Sava¹,

Hamciuc²

2005

Designed Monomers and Polymers

View full text Add to dashboard Cite

show abstract

“…In the case of the present polymers we have found that the Kuhn segment values calculated under the assumption of free rotation (A fr ) and under the assumption of hindered rotation (A hin ) are equal. 29 It means that the ester or oxadiazole groups do not cause a significant hindrance, since they allow rotation around virtual bond going through phenyl ring in meta-position despite the narrow distance between the hydrogen of phenyl and hydrogen of amide group.…”

Section: Iiia Iiiementioning

confidence: 99%

“…In the case of the present polymers, T g values increased while increasing the value of the conformational rigidity parameter. Previously, 29 it was shown that there was a relationship between glass transition temperature and initial decomposition temperature for several polymers: T d ¼ aT g . The value of a for polyamides and polyimides lies in the range of 1.15-1.25 depending on the structure of the polymer repeating unit.…”

Section: Iiia Iiiementioning

confidence: 99%

Synthesis of Poly(1,3,4-oxadiazole-amide-ester)s and Study of the Influence of Conformational Parameters on their Physical Properties

Sava¹,

Ronova

Brumă³

2006

Polym J

View full text Add to dashboard Cite

ABSTRACT:Aromatic poly(1,3,4-oxadiazole-amide-ester)s have been synthesized by low temperature solution polycondensation reaction of equimolar amounts of aromatic diamines containing preformed 1,3,4-oxadiazole rings with diacid chlorides containing preformed ester linkages. The polymers showed high thermal stability with initial decomposition temperature being above 365 C and glass transition temperature in the range of 215-260 C. The weight average molecular weight was in the range of 91,000-257,000 and polydispersity is in the range of 1.64-5. The polymer films showed good mechanical properties with tensile strength in the range of 40-91 MPa, elastic modulus in the range of 2.22-3.98 GPa and elongation at break in the range of 1.85-7.37%. Conformational parameters of polymers have been calculated by Monte Carlo method with allowance for hindered rotation and discussed in relation with some physical properties. 1,2 High performances include electronic properties, electric conduction, optical properties, good hydrolytic stability, highly ordered systems, mechanical resistance and high thermal stability. But the applicability of these polymers is limited because they have rigid molecules due to the delocalization of -electrons along the polymer chain, which makes them insoluble in organic solvents and without glass transition or with too high glass transition temperature, and therefore their processing is very difficult. Research of poly(1,3,4-oxadiazole)s has considerably extended in the last years as can be seen from the large number of publications. Most of this research aims to improving solubility and processability of aromatic polyoxadiazoles by introduction of certain substituents on aromatic rings, flexible bridges in the chain like ether, amide, ester, isopropylidene, hexafluoroisopropylidene or voluminous units pendent to the chain, provided that the conjugation is not disturbed. 3-10We considered that the incorporation of ester together with amide groups in the macromolecular chain of aromatic poly(1,3,4-oxadiazole)s would result in products with enhanced solubility in organic solvents and reasonable glass transition temperature values, while maintaining a high thermal stability. Here we report the synthesis of poly(1,3,4-oxadiazole-amideester)s by solution polycondensation reaction of various aromatic diamines containing 1,3,4-oxadiazole ring with diacid chlorides containing preformed ester groups. We studied their thermal stability, glass transition, mechanical properties, weight average molecular weight, solubility, and film forming ability and have been compared these properties with those of related polymers. Also, some physical properties of these polymers such as solubility, glass transition temperature and initial decomposition temperature have been discussed in relation with the conformational rigidity of their chains and some relationships have been shown. EXPERIMENTAL Starting MaterialsN-methylpyrrolidinone (NMP) (Merck) was dried over phosphorous pentoxide and distilled under reduced pressu...

show abstract