{"title":"改善含有内酰胺衍生段单元的热致性液晶聚(酯酰胺)的热性能、机械性能和介电性能","authors":"","doi":"10.1016/j.molliq.2024.126253","DOIUrl":null,"url":null,"abstract":"<div><div>We prepared two different series of thermotropic liquid crystalline poly(ester amide)s (TPEAs) via bulk polycondensation reactions of 4-hydroxybenzoic acid (HBA, 75.0 mol %) and 6-hydroxy-2-naphthoic acid (HNA, 25.0–17.5 mol %) with ε-caprolactam (CL, 0.0–7.5 mol %) or γ-butyrolactam (BL, 0.0–7.5 mol %). Our investigation aimed to explore the impact of lactam-derived aliphatic amide units’ length and content on the liquid crystalline feature, microstructure, thermal transition, thermal stability, mechanical/relaxational/rheological behavior, and dielectric characteristics of TPEAs. The molecular structure and fibrillar formation of TPEAs containing aliphatic amide units were confirmed through FT-IR and SEM analysis. With increasing CL or BL-derived units from 1.0 mol % to 5.0 mol %, we observed an increase in crystallinity, glass transition temperature, melting temperature, complex melt viscosity, and storage modulus of TPEAs, attributed to the enhanced intermolecular hydrogen bonding interactions. However, at 7.5 mol % CL or BL-derived unit content, these properties decreased due to increased chain irregularity as well as lowered crystallinity. Notably, the dielectric constants (3.31–3.04 at 2 MHz) of TPEAs decreased with the increase of lactam-derived aliphatic amide units owing to the restricted chain mobility by intermolecular hydrogen bonding interactions. We believe that the TPEAs synthesized in this study hold significant potential for applications in technical plastics, superfibers, and printed circuit board materials.</div></div>","PeriodicalId":371,"journal":{"name":"Journal of Molecular Liquids","volume":null,"pages":null},"PeriodicalIF":5.3000,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Improved thermal, mechanical, and dielectric properties of thermotropic liquid crystalline poly(ester amide)s containing lactam-derived segmental units\",\"authors\":\"\",\"doi\":\"10.1016/j.molliq.2024.126253\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>We prepared two different series of thermotropic liquid crystalline poly(ester amide)s (TPEAs) via bulk polycondensation reactions of 4-hydroxybenzoic acid (HBA, 75.0 mol %) and 6-hydroxy-2-naphthoic acid (HNA, 25.0–17.5 mol %) with ε-caprolactam (CL, 0.0–7.5 mol %) or γ-butyrolactam (BL, 0.0–7.5 mol %). Our investigation aimed to explore the impact of lactam-derived aliphatic amide units’ length and content on the liquid crystalline feature, microstructure, thermal transition, thermal stability, mechanical/relaxational/rheological behavior, and dielectric characteristics of TPEAs. The molecular structure and fibrillar formation of TPEAs containing aliphatic amide units were confirmed through FT-IR and SEM analysis. With increasing CL or BL-derived units from 1.0 mol % to 5.0 mol %, we observed an increase in crystallinity, glass transition temperature, melting temperature, complex melt viscosity, and storage modulus of TPEAs, attributed to the enhanced intermolecular hydrogen bonding interactions. However, at 7.5 mol % CL or BL-derived unit content, these properties decreased due to increased chain irregularity as well as lowered crystallinity. Notably, the dielectric constants (3.31–3.04 at 2 MHz) of TPEAs decreased with the increase of lactam-derived aliphatic amide units owing to the restricted chain mobility by intermolecular hydrogen bonding interactions. We believe that the TPEAs synthesized in this study hold significant potential for applications in technical plastics, superfibers, and printed circuit board materials.</div></div>\",\"PeriodicalId\":371,\"journal\":{\"name\":\"Journal of Molecular Liquids\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":5.3000,\"publicationDate\":\"2024-10-14\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Molecular Liquids\",\"FirstCategoryId\":\"92\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0167732224023122\",\"RegionNum\":2,\"RegionCategory\":\"化学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"CHEMISTRY, PHYSICAL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Molecular Liquids","FirstCategoryId":"92","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0167732224023122","RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
Improved thermal, mechanical, and dielectric properties of thermotropic liquid crystalline poly(ester amide)s containing lactam-derived segmental units
We prepared two different series of thermotropic liquid crystalline poly(ester amide)s (TPEAs) via bulk polycondensation reactions of 4-hydroxybenzoic acid (HBA, 75.0 mol %) and 6-hydroxy-2-naphthoic acid (HNA, 25.0–17.5 mol %) with ε-caprolactam (CL, 0.0–7.5 mol %) or γ-butyrolactam (BL, 0.0–7.5 mol %). Our investigation aimed to explore the impact of lactam-derived aliphatic amide units’ length and content on the liquid crystalline feature, microstructure, thermal transition, thermal stability, mechanical/relaxational/rheological behavior, and dielectric characteristics of TPEAs. The molecular structure and fibrillar formation of TPEAs containing aliphatic amide units were confirmed through FT-IR and SEM analysis. With increasing CL or BL-derived units from 1.0 mol % to 5.0 mol %, we observed an increase in crystallinity, glass transition temperature, melting temperature, complex melt viscosity, and storage modulus of TPEAs, attributed to the enhanced intermolecular hydrogen bonding interactions. However, at 7.5 mol % CL or BL-derived unit content, these properties decreased due to increased chain irregularity as well as lowered crystallinity. Notably, the dielectric constants (3.31–3.04 at 2 MHz) of TPEAs decreased with the increase of lactam-derived aliphatic amide units owing to the restricted chain mobility by intermolecular hydrogen bonding interactions. We believe that the TPEAs synthesized in this study hold significant potential for applications in technical plastics, superfibers, and printed circuit board materials.
期刊介绍:
The journal includes papers in the following areas:
– Simple organic liquids and mixtures
– Ionic liquids
– Surfactant solutions (including micelles and vesicles) and liquid interfaces
– Colloidal solutions and nanoparticles
– Thermotropic and lyotropic liquid crystals
– Ferrofluids
– Water, aqueous solutions and other hydrogen-bonded liquids
– Lubricants, polymer solutions and melts
– Molten metals and salts
– Phase transitions and critical phenomena in liquids and confined fluids
– Self assembly in complex liquids.– Biomolecules in solution
The emphasis is on the molecular (or microscopic) understanding of particular liquids or liquid systems, especially concerning structure, dynamics and intermolecular forces. The experimental techniques used may include:
– Conventional spectroscopy (mid-IR and far-IR, Raman, NMR, etc.)
– Non-linear optics and time resolved spectroscopy (psec, fsec, asec, ISRS, etc.)
– Light scattering (Rayleigh, Brillouin, PCS, etc.)
– Dielectric relaxation
– X-ray and neutron scattering and diffraction.
Experimental studies, computer simulations (MD or MC) and analytical theory will be considered for publication; papers just reporting experimental results that do not contribute to the understanding of the fundamentals of molecular and ionic liquids will not be accepted. Only papers of a non-routine nature and advancing the field will be considered for publication.