Download or read book Synthesis and Characterization of Low melting Thermotropic Liquid Crystalline Poly ester imide s written by Sunny Jacob and published by . This book was released on 1994 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Two new series of low-melting liquid crystalline poly(ester-imide)s, (PEIM(s)) containing biphenyldiimide mesogen with a high aspect ratio was prepared by the polycondensation of ll-(3,3',4,4'-biphenyltetracarboxydiimido)-bis undecanoic acid with various aliphatic diols and methyl esters of hydroquinone and 4,4'-biphenol by melt polymerization. The mesogenic diimide diacid was prepared by reacting 3,3',4,4'- biphenyltetracarboxylic dianhydride with 11 -amino undecanoic acid using the method of Augl and Wrasidlo. The synthesized polymers were characterized by Gel Permeation Chromatography (GPC), IR Spectroscopy, Dilute Solution Viscosity, Thermogravimetry (TGA), Differential Scanning Calorimetry (DSC) and Polarizing Light Microscopy (PLM). The data obtained from GPC indicated the presence of a wide distribution of molecular weights. The infrared spectra of the polymers showed multiple peaks due to the vibrational coupling of the imide carbonyl groups. The inherent viscosities ranged from 0.5 g/dL to 1.65 g/dL. Thermogravimetric analysis showed that these PEIM(s) have high thermal stability in both oxidizing and inert atmosphere. DSC and PLM studies indicated that these poly(ester-imide)s are semi-crystalline and the degree of crystallinity can be increased by annealing above glass transition. They showed all major thermal transitions. The DSC curves of these polymers showed crystal ordering exotherm(s), glass transition and melting endotherm(s). The glass transition temperature of the polymers decreased with increase in the number of methylene units. The melting point of the even polymers decreased from 136 C (n = 4) to 122 C (n = 12) and interestingly an opposite trend was noticed for 'odd' polymers. The melting point of the 'odd' PEIM(s) were lower than the 'even' ones. These polymers showed a definite odd-even effect in melting point. An additional melting endotherm was observed in the DSC heating curves obtained after annealing the samples at the crystal ordering temperature. This indicated that the title polymers exhibited an enantiotropic liquid crystalline behavior. The optical micrographs of the 'even' PEIM(s) observed between crossed polarizers after annealing indicated the presence of an ordered smectic phase below Tm2 and a less ordered smectic phase around Tm2. Formation of droplets near the clearing temperature followed by the formation of a coarse texture at a lower temperature in the case of 'odd' PEIM(s) are indicative of the presence of a nematic phase, below the isotropic transition temperature. Poly(esterimide) s containing aromatic diols showed higher transition temperatures than those containing aliphatic diols. Multiple endotherms were evident in the DSC thermograms of poly(ester-imide)s containing aromatic diols. The optical micrographs of the aromatic polymers taken at temperatures around Tm were comparable to the fine scale versions of the Schlieren texture. PLM studies and analysis of the cooling traces revealed that poly(ester-imide)s containing aliphatic diols have slow crystallization kinetics. The 'odd' PEIM(s) can be quench cooled from the isotropic melt to the isotropic glass. The rate of crystallization was found to be much faster in the case of polymers containing aromatic diols. The even and the aromatic poly(ester-imide)s were found to be more crystalline than the 'odd' ones. The poly(ester-imide) derived from aliphatic diol n = 7 showed unusual results in the DSC and PLM studies which is explained as a result of crosslinking or branching due to side reactions."--Abstract.
Download or read book Synthesis and Characterization of Thermotropic Liquid Crystalline Poly ester imide s written by Jinseo Ahn and published by . This book was released on 1996 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: "A series of novel poly(ester-imide)s were prepared by the reactions of 6,6'-(3,3',4,4'-benzophenonetetracarboxylic diimido)-bis-hexanoic acid with various aliphatic diols containing four to ten methylene groups using a melt polymerization technique. Besides these, a novel poly(esterimide) was synthesized by the reaction of 1 1, 1 1 '-(3,3', 4,4'- benzophenonetetracarboxylic diimido)-bis-undecanoic acid with 1,6-hexanediol employing the same technique. Two kinds of monomers containing diimide diacids were prepared by the reactions of 3,3',4,4'-benzophenonetetracarboxylic dianhydride with respective 6-aminocaproic acid and 1 1 -aminoundecanoic acid. A total of eight poly(ester-imide)s, PEIMs, were characterized for liquid crystalline properties. The solubility, viscosity, infrared spectroscopy, thermal analyses such TGA and DSC, and the optical studies were performed. Infrared spectra of PEIMs confirmed the formation of imide and ester groups. These poly(ester-imide)s exhibited high thermal and oxidative stability and very poor solubility corresponding to high viscosity. There were no reproducible endothermic or exothermic peaks found besides glass transition temperatures in the DSC thermograms. In addition, no PEIMs showed birefringent textures under the polarized light microscope. DSC and optical study indicated that Odd PEIMs and PEIM(6,10) are totally amorphous, while Even PEIMs are partially crystalline polymers with extremely slow crystallization rate. Two new compounds, BTDI-1 1 A/1 8-ol and BPDI-1 1 A/1 8-ol, with small molecular weight were designed and synthesized. The reaction of respective BTDI-1 1 A and BPDI-1 1 A with 1 -octadecanol was performed in boiling toluene with azeotropic removal of water by using Dean-Stark apparatus. DSC and optical study with polarized light microscopy indicated that BTDI-1 1 A/1 8-ol has a liquid crystalline phase that is very close to solid crystal state, whereas BPDI-1 1 A/1 8-ol has no liquid crystalline property."--Abstract.
Download or read book Synthesis and Characterization of Novel Poly ester imide ether s Exhibiting Liquid Crystallinity written by Randy T. Pike and published by . This book was released on 1996 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: "A series of novel thermotropic poly(ester-imide-ether)s were synthesized by melt polymerization techniques. The imide dimethyl ester: N-[(carbomethoxy) phenyl]-4-(carbomethoxy) phthalimide, prepared in a series of reactions, was reacted with varying ratios of poly(tetramethylene ether) glycol and 1,6 hexane diol to give the copolymers in 56% to 96% yield. The polymers were characterized by differential scanning calorimetry, dilute solution viscosity, gel permeation chromatography, infrared spectroscopy, thermogravimetric analysis, and polarized optical microscopy. Inherent viscosity values range from 0.40 dl/g to 1.14 dl/g. Gel permeation chromatographic analysis of the initial polymer series showed number average molecular weights ranging from 32,000 g/mol to 100,000 g/mol. Glass transition temperatures range from -46 C to 44 C. The polymer series exhibit moderate thermal stability with thermal decomposition temperatures exceeding 360 C. Copolymers PEI-1-ET-9 (650) and PEI-3-ET-7 (650) showed no mesophase formation. Copolymers PEI-5-ET-5 (650), PEI-7-ET-3 (650), PEI-9-ET-1 (650), PEI-7-ET-3 (2000), PEI-9-ET-1 (2000), PEI-7-ET-3 (2900), and PEI-9-ET-1 (2900) displayed birefringent monotropic liquid-crystalline behavior."--Abstract.
Download or read book Synthesis and Characterization of Poly ester imide s written by Fei Nie and published by . This book was released on 1989 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: "A series of novel ordered poly(ester-imide)s were synthesized using both solution and melt polymerization techniques and their liquid crystal properties studied. Commercially available 6-aminohexanoic acid and 11-aminoundecanoic acid were reacted with 1,2,4,5-benzenetetracarboxylic anhydride (PMDA) by a melt reactions to give -pyromellitimide dicarboxylic acid derivatives. These derivatives were treated with thionyl chloride to give -pyromellitimide dicarboxylic dichloride derivatives which were reacted with a series of diols having six, eight, nine, ten and twelve methylene units in their structural units by a solution polymerization technique, using refluxing 1,2,4-trichlorobenzene as solvent. These same diols were treated with acetic anhydride to produce a series of diacetates. Using a melt polymerization technique, the diacetates were treated with -pyromellitimide dicarboxylic acids to give the same series of poly(ester-imide)s as prepared by the solution method. The polymers obtained were characterized using infrared spectroscopy (IR), differential scanning calorimetry (DSC), polarizing light microscopy (PLM) and dilute solution viscosity. Inherent viscosities of the prepared polymers ranged from 0.07 to 0.25 dL/gram for solution polymerization and from 0.67 to 1.00 dL/gram for melt polymerization. Phase transition temperatures, determined by differential scanning calorimetry, ranged from 67 to 140C for solution polymerization; from 129 to 232C for melt polymerization. Solution and melt polymerization poly(ester-imide)s showed nematic and smectic liquid crystal bifringence textures using a hot stage under polarizing light microscopy."--Abstract.
Download or read book Preparation and Characterization of Semi Flexible Thermotropic Poly ester imide s written by John V. Facinelli and published by . This book was released on 1989 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: "A series of novel poly(ester-imide)s were prepared by the reaction of meta- and para-substituted trlmellltimide dicarboxylic diacid chlorides with various diols containing four, five, six, seven, eight, nine, ten and twelve methylene groups by a solution polymerization technique utilizing refluxing 1,2,4-trichlorobenzene as a solvent. The poly(ester-imide)s were characterized by dilute solution viscosity, infrared spectroscopy, differential scanning calorimetry and polarized light microscopy. The inherent viscosities of the meta-substituted poly(ester-imide)s ranged from 0.06 to 0.25 dL/g while those of the para-substituted poly(ester-imide)s ranged from 0. 1 0 to 0.65 dL/g and were obviously of higher molecular weight. The meta series were amorphous and showed no mesophase formation. The para-substituted poly(ester-imide)s having four, six, eight or ten methylene spacers showed birefringent liquid-crystalline behavior."--Abstract.
Download or read book Thermotropic Liquid Crystalline Poly amide imide s written by Bidan Zhang and published by . This book was released on 1996 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in Thermotropic Liquid Crystal Polymers written by Tai-shung Chung and published by . This book was released on 2001 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt: Annotation Liquid crystal polymers are sometimes called super polymers--with good reason. Their wide range of exceptional properties and ease of processing make them design candidates for many demanding applications. This new book provides a thorough review of LCP technology with the emphasis on the chemistry, synthesis and characterization of the material in its many variants. Additional chapters cover processing and applications. From the Editor's Preface The field of thermotropic liquid crystalline polymers has grown substantially in the last two decades, with fundamental research, publications, commercial products, and patents. In the 1980's, Dr. Ralph Miano led my colleagues and me at Hoechst Celanese in commercializing the first thermotropic liquid crystalline polymers, based on Dr. Gordon Calundann's composition patents. Today, more than seven companies have produced thermotropic liquid crystalline polymer materials, with at least 50 variants available. Hence, it is timely to compile a comprehensive review on the nature of this type of material and the ongoing progress in this field€. The goals of this book are to summarize previous work, provide new insights into this class of polymers, and add to the understanding of the formation of liquid crystallinity. This book covers a wide range of topics and addresses different disciplines in the field. The chapters are arranged as a learning scheme for the professional, from basic science to applied engineering. The first few chapters summarize the syntheses of various polyester, polyester-amid, and polyimide liquid crystalline polymers. The science and origins of liquid crystal formation are revealed. Next, we introduce the characterizations of these materials by their different chemical and physical aspects. Because most commercially available thermotropic liquid crystalline polymers have been used in the form of composites, we have also incorporated a chapter on polymer blends, detailing blending mechanisms and resultant properties. Two chapters on thermosetting liquid crystalline polymers integrate them with other topics, because of their unique importance and their applications for microelectronics and packaging. The final chapter deals with the engineering and processing aspects of thermoplastic liquid crystalline polymers for a variety of applications.
Download or read book Synthesis and Characterization of Novel Poly ester imide s Containing Chiral Centers written by T. Edwin Freeman and published by . This book was released on 1993 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Characterization of Thermotropic Liquid Crystalline Polyesters for Use in Molecular Composites written by Sridevi Narayan-Sarathy and published by . This book was released on 1995 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Characterization of Thermotropic Liquid Crystalline Main chain Viologen Polymers written by Weihong Xu and published by . This book was released on 1996 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Synthesis Characterization and Mechanical Testing of Novel Liquid Crystalline Poly ester amide s and Their Blends with Nylon 6 6 written by Thomas F. McCarthy and published by . This book was released on 1993 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Characterization of Glassy Main Chain Thermotropic Liquid Crystalline Polyesters Based Upon a Highly Substituted Phenylene terephthalate Mesogenic Unit with Flexible Spacers written by Ann Marie Delvin and published by . This book was released on 1988 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Characterization of Polyether ester Liquid Crystalline Polyesters and Poly arylene Ether Ketone lcp Segmented Copolymers written by Wae-asae Waehamad and published by . This book was released on 1991 with total page 582 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Synthesis and Characterization of Thermotropic Liquid Crystal Compounds as Models for Reaction Injection Molded RIM type Polymers written by Guerry Leonard Grune and published by . This book was released on 1982 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Characterization of Thermotropic Liquid Crystalline Polyurethane Based on a Mesogenic Diol and Aliphatic Diisocyanates written by Syed Zafar Mahdi and published by . This book was released on 1996 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Maro Polymer Notes written by and published by . This book was released on 1997 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Papers Presented at the Meeting written by American Chemical Society. Division of Polymer Chemistry and published by . This book was released on 1997 with total page 732 pages. Available in PDF, EPUB and Kindle. Book excerpt:
