Rheological behavior of a semirigid liquid crystal polymer

Mantia, F. P. La; Valenza, A.; Paci, Massimo; Magagnini, Pier Luigi; Pedretti, U.; Roggero, A.

doi:10.1002/pen.760331503

Cited by 19 publications

(22 citation statements)

References 14 publications

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“…The semirigid LCP is a semirigid copolyester made from sebacic acid, 4.4'dihydroxybiphenyl, and 4-hydroxybenzoic acid in the molar ratio 1 : 1 : 2. Synthesis and properties of this copolyster are presented elsewhere (29)(30)(31)(32).…”

Section: Methodsmentioning

confidence: 99%

“…7, is lower than that of PP only at temperatures above 220°C: at lower temperatures it becomes larger. The viscosity of the blend with 20% SBH is intermediate at high temperatures, lower than that of both components at intermediate temperatures, and then overcomes that of the PP at low temperatures when the SBH is crystallized (Tc 170°C) (31). It is worth mentioning that the crystallization temperatures of the LCPs is lower than the melting temperature.…”

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confidence: 93%

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Nonisothermal elongational behavior of blends with liquid crystalline polymers

Mantia

Valenza

Scargiali

1994

Polymer Engineering & Sci

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a l e m 901 28 P a l e m , Italy Measurements of melt strength and breaking stretching ratio of several blends of thermoplastic polymers with liquid crystalline polymers are presented. The melt strength behavior depends not only on the viscosity of the blends but also on the temperature dependence of the viscosity. In particular, even if the viscosities of the blends are, at the extrusion temperature, lower than that of the thermoplastic matrices, the melt strength can be larger than that of the pure thermoplastics if its viscosity-temperature curve exceeds that of the matrices far from the solidification temperature. This behavior allows one to spin or film blow these blends despite the low viscosity.

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 93%

Nonisothermal elongational behavior of blends with liquid crystalline polymers

Mantia

Valenza

Scargiali

1994

Polymer Engineering & Sci

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“…The semiflexible LCP, referred to as SBH, was a laboratory sample (LCPlB/024) kindly supplied by Eniricerche S.p.A., Milan. This copolyester was synthesized as described elsewhere (32)(33)(34)(35) Phase Behavior of Blends of PET with JXPs no1 at 60°C with a concentration of 0.1 g/dL, was 1.20 dL/g. The chemical structures of all the investigated polymers are shown in Scheme 1.…”

Section: Materialamentioning

confidence: 99%

Phase behavior of blends of poly(ethylene terephthalate) with liquid‐crystalline polymers

Magagnini

Tonti

Masseti

et al. 1998

Polymer Engineering & Sci

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Poly(ethy1ene terephthalate) (PET) was melt blended with several liquid-crystalline polymers (LCPs), both with and without Ti(OBu), catalyst. The LCPs, referred to as VA, LC5, LC3, and SBH, respectively, were Vectra-A950, Rodrun LC-5000, Rodrun LC-3000, and a laboratory copolyester of sebacic acid (S), 4.4'-diacetoxybiphenyl (B), and 4-acetoxybenzoic acid (H). Their degree of aromaticity decreases in that order. The phase behavior and the morphology of the blends were studied by diEerential scanning calorimetry and scanning electron microscopy. All the LCPs retard the dynamic crystallization of PET. The lower the LCPs degree of aromaticity, the more pronounced was the effect. It was not possible to obtain any evidence of ester exchange reactions by the reactive blending of PET with VA. On the contrary, appreciable changes of phase behavior and morphology were observed under comparable conditions for the other blends. With LC5 and LC3, the transesterification process predominantly involved the ET-rich phase of those polymers. Extensive transesterification occurred between PET and SBH, as proven by the gradual formation of a quasi homogeneous material, with lowered temperatures and enthalpies of fusion and crystallization. For blends with more than 25% SBH, homogenization is followed by the segregation of a new, highly aromatic phase.

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“…Semirigid polymers often require more energy during processing and modification compared with flexible polymers. [6d,7]…”

Section: Introductionmentioning

confidence: 99%

Grafting Polymers from Poly(2,6-dimethyl-1,4-phenylene oxide) as New Thermoplastics

Zhang

2017

Macromol. Chem. Phys.

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Graft polymers with poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) as backbones are successfully prepared via two convenient steps. The utilization of semiflexible PPO as backbones offers unique properties for the graft polymers. Thermal, rheological, and phase behaviors of these new graft polymers are well controlled via the precise design of architectural parameters. The disordered microphase separation in melt state and the proper composition of side grafts provide the ease of thermal processing for these graft polymers. The graft density shows impact on the relaxation and mechanical properties of the thermoplastics. This work shows the possibility to use lots of semiflexible engineering polymers as backbones to construct new thermoplastics.

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Rheological behavior of a semirigid liquid crystal polymer

Cited by 19 publications

References 14 publications

Nonisothermal elongational behavior of blends with liquid crystalline polymers

Nonisothermal elongational behavior of blends with liquid crystalline polymers

Phase behavior of blends of poly(ethylene terephthalate) with liquid‐crystalline polymers

Grafting Polymers from Poly(2,6-dimethyl-1,4-phenylene oxide) as New Thermoplastics

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