Scalable Synthesis of Thymol-Based Bisphenol E Epoxy Monomer and Related Thermosets with Low Dielectric Constant and Density and Improved Resistance to Hygrothermal Aging
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引用次数: 0
Abstract
Epoxy resins coming from biobased bisphenols have received significant attention; however, thymol-derived bisphenol epoxies are still essentially unknown so far. Here, a biobased bisphenol E (DHPF) intermediate was obtained from thymol and acetaldehyde via a highly efficient approach, followed by O-glycidylation to afford a bisphenol E epoxy monomer (DHEP) with a viscosity of only 3.5 Pa·s at 60 °C identical to that of a bisphenol A epoxy (DGEBA). Using 4,4′-diaminodiphenyl sulfone (44DDS) and methyltetrahydrophthalic anhydride (MTHPA) as curatives, cured DHEP thermosets were prepared through cast molding, and their properties are systematically studied and compared with DGEBA thermosets. DHEP delivers a lower dielectric constant to the resulting thermosets, especially for DHEP/MTHPA (1.9, 10 MHz). The DHEP-based thermoset also exhibits decreased water absorption, density, and thermal diffusivity and improved resistance to hygrothermal aging as indicated by storage modulus and Tg retention, and good bulk mechanical properties. Moreover, when formulated into an epoxy adhesive for bonding stainless steel sheets, DHEP endows the glue joint with a rather high lap shear strength up to 12.7 MPa. Overall, DHPF can be readily prepared in large quantities, and DHEP is potentially 100% biobased with good processability; the finalized DHEP thermosets have advantages in many properties of high interest, thereby illustrating its good prospects for real applications.
期刊介绍:
ACS Applied Polymer Materials is an interdisciplinary journal publishing original research covering all aspects of engineering, chemistry, physics, and biology relevant to applications of polymers.
The journal is devoted to reports of new and original experimental and theoretical research of an applied nature that integrates fundamental knowledge in the areas of materials, engineering, physics, bioscience, polymer science and chemistry into important polymer applications. The journal is specifically interested in work that addresses relationships among structure, processing, morphology, chemistry, properties, and function as well as work that provide insights into mechanisms critical to the performance of the polymer for applications.