Blends of liquid crystalline polyester–polyurethane and epoxy: Preparation and properties

Two novel liquid crystalline polymers, polydiethyleneglycol bis(4-hydroxybenzoate) terephthaloyl and block copolymer (PDBH), were synthesized by condensation reaction. The blends of the two liquid crystalline polymers and o-cresol formaldehyde epoxy resin were prepared by linear phenol-formaldehyde resin as curing reagent. Both mechanical and thermal properties of the blends containing liquid crystalline polymer were improved to a certain extent. By adding 5 wt % PDBH, the impact strength, bending strength, and the glass transition temperature were enhanced by 128%, 23.84%, and 28°C, respectively, compared with the unmodified version. The results of curing kinetics showed that the curing reaction active energy of the modified system by PDBH decreased from 79.70 to 70.26 kJ/mol.

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“…6 . A total of 7 g diethyleneglycol and 22 g methyl 4-hydroxybenzoate was dissolved in 40 mL 1,1,2,2-tetrachloroethane.…”

Section: Synthesis Of Monomers and Polymersmentioning

confidence: 95%

“…[2][3][4][5][6] It can not only improve the toughness and strength of epoxy resin but also modify the heat resistance. Most of the current reported liquid crystalline polymers are liquid crystalline polyester or polyurethane.…”

Section: Introductionmentioning

confidence: 99%

Modification of an o‐cresol formaldehyde epoxy resin by the thermotropic liquid crystalline polymer

Huang

Tan

Wang

2005

J of Applied Polymer Sci

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“…[10,12]; Unsaturated polyester, industrial products; glass fiber (length: 5∼6 mm, diameter: 10-13 m), industrial product, curing agent (a blend of styrene and peroxide), calcium carbonate, aluminum hydroxide and zinc stearic as inorganic fillers are industrial products kindly provided by Guangdong Fuxing Materials Plant, China. Dynamic mechanical properties are measured by DMA Q800 (TA Instruments), specimen dimension is 20 mm × 10 mm × 1.2 mm, measurement frequency is 1 Hz; Thermal expansion coefficient of the composite is measured by NETZSCH Dilatometry (model: DIL 402C); Rheological properties are measured by SHIMADZU CFT-500D capillary reometer at 160 C; The crystal behavior of UP, LCMC and UP/LCMC blend is analyzed by X-ray diffractory (XRD) (model: Panalytic X'Pert Pro, Netherlands); Optical anisotropies of UP and UP/LCMC blends are observed by Olympus BH-2 polarizing optical microscope (POM) equipped with a heating stage.…”

Section: Materials and Measurementsmentioning

confidence: 99%

Rheological, Dynamic Mechanical and Thermal Properties of Thermotropic Liquid Crystalline Polymer/Unsaturated Polyester/Glass Fiber Hybrid Composites

Wei¹,

Yu²,

Lv³

et al. 2008

Jnl of Comp & Theo Nano

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Unsaturated polyester (UP) reinforced with self-synthesized reactive thermotropic liquid crystalline polymer (TLCP)-methacryloyl copolymer (LCMC) and glass fiber (GF), the hybrid composites of UP/GF/LCMC are prepared by molding technology. The dynamic mechanical analysis (DMA) indicate that storage modulus and glass transition temperature (T g ) of hybrid composites increase significantly because of the addition of LCMC. The thermal expansion coefficient of composites containing 5% LCMC decrease by about 30% than that of composites without LCMC. Rheological performance analysis show that the composites under melting stage are non-Newton liquid of shear thinning, and the processability of composites with 5% LCMC can be improved effectively. The crystal behavior analysis of LCMC/UP blend is investigated by X-ray diffraction (XRD) and polarizing optical microscope (POM). The results show that the crystal phase and texture structure of LCMC still exist in the blends after blending with UP.

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“…The TLCP used in this work is one kind reactive polyester TLCP whose liquid crystalline polymer (LCP) phase temperature is 230-262.28C synthesized by us (The synthesis route is shown as step 1 in Scheme 1) 14,15 ; UP (molecular structure see step 2 in Scheme 1), industrial products; GF (length: 5-6 mm, diameter: 10-13 mm), industrial product, curing agent (blend of styrene and peroxide), calcium carbonate, aluminum hydroxide, and zinc stearic as inorganic fillers are industrial products kindly provided by Guangdong Fuxing Materials Plant, China.…”

Section: Materials and Measurementsmentioning

confidence: 99%

Wear and mechanical properties of reactive thermotropic liquid crystalline polymer/unsaturated polyester/glass fiber hybrid composites

Wei

et al. 2006

J of Applied Polymer Sci

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To improve the performance of unsaturated polyester (UP) under cold-heat alternate temperature, selfsynthesized reactive thermotropic liquid crystalline polymer (TLCP)-methacryloyl copolymer (LCMC), UP, and glass fiber (GF) hybrid composites was prepared by molding technology. The apparent activation energy and crystal behavior analysis of LCMC/UP blends were investigated by Differential scanning calorimetry and X-ray diffraction (XRD), respectively, the results showed that the addition of LCMC can reduce apparent activation energy and accelerate the curing reaction of UP, the XRD analysis indicated that the crystal phase of LCMC still exist in the blends after blending with UP. The effect of LCMC content on the properties of LCMC/UP/GF hybrid composites such as impact strength, bending strength, and ring-on-block wear were also investigated through static mechanical tests and wear tests. The mechanical properties of hybrid composites increased significantly because of the addition of LCMC. The wear tests showed that LCMC can improve the wear resistance of the UP/GF/LCMC hybrid composites even though the content of LCMC was at a relatively low level (5-7.5 wt %). This makes it possible to develop novel kind of UP-based materials with good wear resistance for various applications. The Worn surface was observed by scanning electron microscopy (SEM) and the mechanism for the improvement is discussed in this paper.

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Blends of liquid crystalline polyester–polyurethane and epoxy: Preparation and properties

Cited by 24 publications

References 7 publications

Modification of an o‐cresol formaldehyde epoxy resin by the thermotropic liquid crystalline polymer

Modification of an o‐cresol formaldehyde epoxy resin by the thermotropic liquid crystalline polymer

Rheological, Dynamic Mechanical and Thermal Properties of Thermotropic Liquid Crystalline Polymer/Unsaturated Polyester/Glass Fiber Hybrid Composites

Wear and mechanical properties of reactive thermotropic liquid crystalline polymer/unsaturated polyester/glass fiber hybrid composites

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