Design and In-Depth Characterization of Liquid Crystalline Polyesters for Lower Melting Points and Wider Processing Windows

Design and In-Depth Characterization of Liquid Crystalline Polyesters for Lower Melting Points and Wider Processing Windows | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Design and In-Depth Characterization of Liquid Crystalline Polyesters for Lower Melting Points and Wider Processing Windows Selahattin Erdoğan This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6523141/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 09 Oct, 2025 Read the published version in Journal of Polymer Research → Version 1 posted 5 You are reading this latest preprint version Abstract This paper presents a thorough examination of thermotropic liquid crystalline polyesters (LCPs) designed to achieve lower melting points and wider nematic windows without sacrificing their strength or stability. The work begins by synthesizing fully aromatic LCPs and then systematically introducing aliphatic segments or partially crystalline polyesters—such as PET, PEN, PBT, PBN, and PHN—to modify melting temperatures (Tₘ) and phase-transition behavior. Comprehensive characterization was conducted using techniques such as differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), polarized light microscopy (PLM), wide-angle X-ray scattering (WAXS), and nuclear magnetic resonance (NMR). These results indicate that incorporating flexible or semicrystalline domains broadens the temperature range in which the polymers exhibit a nematic phase, thereby improving processability. In particular, formulations containing longer aliphatic diacids, such as octanedioic or decanedioic acid, showed lower Tₘ values and significantly expanded the temperature windows for nematic ordering. TGA measurements confirmed that an elevated fraction of aromatic units enhances thermal stability, whereas aliphatic constituents support easier processing. WAXS and fiber diffraction analyses revealed a higher degree of crystallinity in the LCPs enriched with PET, correlating with a stronger mechanical performance. Blending these modified LCPs with common thermoplastics (for instance, PET, PP, and ABS) resulted in improvements in tensile strength and overall mechanical behavior, suggesting that these materials are promising candidates for advanced composites. Moreover, detailed analyses of the reaction times and catalysts highlighted the delicate balance between achieving a sufficiently high molecular weight and maintaining tractable melt viscosities. Altogether, this study offers a roadmap for tuning LCP architectures to produce materials with optimized thermal, mechanical, and processing characteristics, thereby widening their suitability for applications ranging from high-performance fibers to industrial-scale thermoplastic composites. Liquid Crystalline Polyesters (LCPs) Thermal Processing Window Aromatic–Aliphatic Copolymer Design Thermotropic Polymer Composites Nematic–Isotropic Transition Full Text Cite Share Download PDF Status: Published Journal Publication published 09 Oct, 2025 Read the published version in Journal of Polymer Research → Version 1 posted Reviewers agreed at journal 06 May, 2025 Reviewers invited by journal 06 May, 2025 Editor invited by journal 25 Apr, 2025 Editor assigned by journal 24 Apr, 2025 First submitted to journal 24 Apr, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6523141","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":452413926,"identity":"3023ee33-e25d-4679-9674-091ddfea9b26","order_by":0,"name":"Selahattin Erdoğan","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA50lEQVRIiWNgGAWjYJACCRDBz8DYAOEeIFaLZANCC4xFQIsB3HBCWuTbex/e+PDLLs/4/OG2Bx93MMjx3Uhgf1yBR4vBmePGljP7kovNbiS2G848w2AseSOBsfEMPi0SaWzSvD3MidtuMLZJ87YxJG4AacHnMvn5z0Ba6hM39x8Ea6knqIXhBhubNM+Pw4kbGBLBWhIMCGkxOJPGbDmz4XjijBuJbZIzz0gA/fOwcSZeh7UfY7zx4U91Yn//8WcSH3fYyPMdTz7wEa/DQICxDcZokACThDQAwR+4FiIUj4JRMApGwYgDAB85VBG2RF3wAAAAAElFTkSuQmCC","orcid":"https://orcid.org/0000-0002-3937-577X","institution":"Sinop Üniversitesi: Sinop Universitesi","correspondingAuthor":true,"prefix":"","firstName":"Selahattin","middleName":"","lastName":"Erdoğan","suffix":""}],"badges":[],"createdAt":"2025-04-24 18:28:16","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6523141/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6523141/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s10965-025-04508-8","type":"published","date":"2025-10-09T15:57:39+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":93419836,"identity":"c097e5c3-ab84-4359-82f0-b53c1eb35957","added_by":"auto","created_at":"2025-10-13 16:08:17","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1341830,"visible":true,"origin":"","legend":"","description":"","filename":"SelahattinErdoganManuscript1042025.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6523141/v1_covered_6ad73d1d-c9bb-4970-8a15-091f3ffa87b6.pdf"}],"financialInterests":"","formattedTitle":"Design and In-Depth Characterization of Liquid Crystalline Polyesters for Lower Melting Points and Wider Processing Windows","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"journal-of-polymer-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jpol","sideBox":"Learn more about [Journal of Polymer Research](https://www.springer.com/journal/10965)","snPcode":"10965","submissionUrl":"https://www.editorialmanager.com/jpol/","title":"Journal of Polymer Research","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Liquid Crystalline Polyesters (LCPs), Thermal Processing Window, Aromatic–Aliphatic Copolymer Design, Thermotropic Polymer Composites, Nematic–Isotropic Transition","lastPublishedDoi":"10.21203/rs.3.rs-6523141/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6523141/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"This paper presents a thorough examination of thermotropic liquid crystalline polyesters (LCPs) designed to achieve lower melting points and wider nematic windows without sacrificing their strength or stability. The work begins by synthesizing fully aromatic LCPs and then systematically introducing aliphatic segments or partially crystalline polyesters—such as PET, PEN, PBT, PBN, and PHN—to modify melting temperatures (Tₘ) and phase-transition behavior. Comprehensive characterization was conducted using techniques such as differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), polarized light microscopy (PLM), wide-angle X-ray scattering (WAXS), and nuclear magnetic resonance (NMR).\nThese results indicate that incorporating flexible or semicrystalline domains broadens the temperature range in which the polymers exhibit a nematic phase, thereby improving processability. In particular, formulations containing longer aliphatic diacids, such as octanedioic or decanedioic acid, showed lower Tₘ values and significantly expanded the temperature windows for nematic ordering. TGA measurements confirmed that an elevated fraction of aromatic units enhances thermal stability, whereas aliphatic constituents support easier processing. WAXS and fiber diffraction analyses revealed a higher degree of crystallinity in the LCPs enriched with PET, correlating with a stronger mechanical performance.\nBlending these modified LCPs with common thermoplastics (for instance, PET, PP, and ABS) resulted in improvements in tensile strength and overall mechanical behavior, suggesting that these materials are promising candidates for advanced composites. Moreover, detailed analyses of the reaction times and catalysts highlighted the delicate balance between achieving a sufficiently high molecular weight and maintaining tractable melt viscosities. 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