Preparation,Morphology, and Structure of Thermotropic Liquid Crystalline Polyester-imide/Phenol-formaldehyde Resin Blends |
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Authors: | Xiaodong Dang Chun Wei Hongxia Liu Jian Lv Dongming Pan Xiaojian Li |
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Institution: | 1. Key Laboratory of New Processing Technology for Nonferrous Metals and Materials, Ministry of Education , Guilin University of Technology , Guilin , China;2. College of Material Science &3. Engineering , Guilin University of Technology , Guilin , China |
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Abstract: | As a novel toughening agent, thermotropic liquid crystalline polymers (TLCPs) possess excellent properties of high strength, high modulus, low expanding coefficient, and high thermal stability. In this study, a thermotropic liquid crystalline poly(ester-imide) derived from N,N’-hexane-1,6-diylbis(tri-millitimide) (IA6), p-hydroxylbenzoic acid (PHB), and 4,4’-dihydroxybenzophenone (DHBP) was synthesized by the Higashi's direct polycondensation method. The structure and properties of the TLCP were studied using Fourier transformed infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), thermogravimetic analyses (TGA), polarized light microscopy (POM), and wide angle X-ray diffraction (WAXD). The results revealed that the synthesized polyester-imide is a nematic TLCP with good thermal stability and its starting decomposition temperature is up to 439°C. Additionally, polymer blends of phenol-formaldehyde (PF) resin with different contents of polyester-imide were prepared and characterized by POM and WAXD. POM results demonstrated that two-step blending is an ideal method for blending TLCP and PF resin. By this method, continuous filamentous stripes can be clearly observed at 230°C for TLCP/PF blend of 10 wt% poly(ester-imide). |
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Keywords: | Liquid crystalline polyester-imides morphology two-step blending method phenol formaldehyde resin |
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