Hydrodynamic and conformational properties of a phenyl-substituted para-aromatic polyester in dioxane and dichloroacetic acid

Bushin, S. V.; Smirnov, K.P.; Андреева, Л. Н.; Belyaeva, Ye.V; Bilibin, A. Yu.; Stepanova, A.R.; Tsvetkov, V.N.

doi:10.1016/0032-3950(90)90241-w

Cited by 5 publications

(2 citation statements)

References 5 publications

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“…The Mark‐Houwink‐Sakurada equation relates the intrinsic viscosity (

([], η)

) to the number average molecular weight ( M n ).

([], η) goodbreak= K goodbreak\times {M_{n}}^{α}

For poly( p ‐phenylene phenyl terephthalate) (LC‐ref), the values of

K

and

α

were reported to be 1.06 × 10 −2 and 1.0, respectively 21 . The

K

and

α

values at a low molecular weight range (25 ≤

([], η)

≤ 257cm 3 /g) for poly(phenyl‐ p ‐phenylene phenyl terephthalate) (AM‐ref) were reported to be 4.00 × 10 −3 and 1.11, respectively 22 …”

Section: Methodsmentioning

confidence: 99%

All‐aromatic ester‐based thermosets: The effect of crosslinking in the nematic or isotropic state

Bijleveld

Dingemans

2021

J of Applied Polymer Sci

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We'll report on two series all‐aromatic main‐chain reactive oligomers that can be crosslinked in either the nematic phase or in the isotropic phase. This series is unique in that both model systems have an identical backbone geometry, comprised of hydroquinone with or without a phenyl substituent and phenyl substituted terephthalic acid. Crosslinking the oligomers (Mn of 1–9 kg/mol) via maleimide end‐groups in the nematic or isotropic phase yields networks with similar crosslink densities (Mc) and similar thermal properties. Crosslinked films exhibit high decomposition temperatures (>395°C) and amorphous thermoset films exhibit Tg's in the 141–190°C range whereas nematic thermoset films give Tg's that range from 143 to 176°C, as measured by DMTA. However, the phase type appears to have a major effect on the stress–strain behavior of the films. All films prepared by crosslinking un‐aligned nematic oligomers show poor stress–strain behavior (σ = 20–63 MPa, ε = 0.5%–5.4%), whereas crosslinking the amorphous oligomers results in films with excellent stress–strain properties (σ = 94–97 MPa, ε = 7.1%–13.3%). The superior toughness of the cured amorphous films can be attributed to the larger free volume induced by steric crowding of the phenyl substituents in the polymer repeat unit.

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“…The Mark‐Houwink‐Sakurada equation relates the intrinsic viscosity (

([], η)

) to the number average molecular weight ( M n ).

([], η) goodbreak= K goodbreak\times {M_{n}}^{α}

For poly( p ‐phenylene phenyl terephthalate) (LC‐ref), the values of

K

and

α

were reported to be 1.06 × 10 −2 and 1.0, respectively 21 . The

K

and

α

values at a low molecular weight range (25 ≤

([], η)

≤ 257cm 3 /g) for poly(phenyl‐ p ‐phenylene phenyl terephthalate) (AM‐ref) were reported to be 4.00 × 10 −3 and 1.11, respectively 22 …”

Section: Methodsmentioning

confidence: 99%

All‐aromatic ester‐based thermosets: The effect of crosslinking in the nematic or isotropic state

Bijleveld

Dingemans

2021

J of Applied Polymer Sci

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“…Such structures are characterized by the so-called "crankshaft" conformation [11], which provides high equilibrium rigidity. For example, the Kuhn segment length of a para-aromatic polyester (pAPE) (Figure 9) is 26 nm according to hydrodynamic data [80] and 20 nm according to flow birefringence data [81]. As seen in Figures 1 and 9, the APEr.ch.…”

Section: Synthesis Of the Polyester Multifunctional Macroinitiatormentioning

confidence: 98%

Thermoresponsive Molecular Brushes with a Rigid-Chain Aromatic Polyester Backbone and Poly-2-alkyl-2-oxazoline Side Chains

Тарабукина

Fatullaev

Krasova

et al. 2021

IJMS

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A new polycondensation aromatic rigid-chain polyester macroinitiator was synthesized and used to graft linear poly-2-ethyl-2-oxazoline as well as poly-2-isopropyl-2-oxazoline by cationic polymerization. The prepared copolymers and the macroinitiator were characterized by NMR, GPC, AFM, turbidimetry, static, and dynamic light scattering. The molar masses of the polyester main chain and the grafted copolymers with poly-2-ethyl-2-oxazoline and poly-2-isopropyl-2-oxazoline side chains were 26,500, 208,000, and 67,900, respectively. The molar masses of the side chains of poly-2-ethyl-2-oxazoline and poly-2-isopropyl-2-oxazoline and their grafting densities were 7400 and 3400 and 0.53 and 0.27, respectively. In chloroform, the copolymers conformation can be considered as a cylinder wormlike chain, the diameter of which depends on the side chain length. In water at low temperatures, the macromolecules of the poly-2-ethyl-2-oxazoline copolymer assume a wormlike conformation because their backbones are well shielded by side chains, whereas the copolymer with short side chains and low grafting density strongly aggregates, which was visualized by AFM. The phase separation temperatures of the copolymers were lower than those of linear analogs of the side chains and decreased with the concentration for both samples. The LCST were estimated to be around 45 °C for the poly-2-ethyl-2-oxazoline graft copolymer, and below 20 °C for the poly-2-isopropyl-2-oxazoline graft copolymer.

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Hydrodynamic, Dynamo-optical and conformational properties of A para-Aromatic polyester containing a small amount of meta-phenylene moiety

Андреева

Bushin

Mashoshin

et al. 1990

Polymer Science U.S.S.R.

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Hydrodynamic and conformational properties of a phenyl-substituted para-aromatic polyester in dioxane and dichloroacetic acid

Cited by 5 publications

References 5 publications

All‐aromatic ester‐based thermosets: The effect of crosslinking in the nematic or isotropic state

All‐aromatic ester‐based thermosets: The effect of crosslinking in the nematic or isotropic state

Thermoresponsive Molecular Brushes with a Rigid-Chain Aromatic Polyester Backbone and Poly-2-alkyl-2-oxazoline Side Chains

Hydrodynamic, Dynamo-optical and conformational properties of A para-Aromatic polyester containing a small amount of meta-phenylene moiety

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