Synthesis of Renewable Furan-Based Benzoxazines and Polybenzoxazines: Recent Advances

The burgeoning field of materials science is currently witnessing a paradigm shift toward the utilization of renewable plant biomass as a viable chemical source for the production of sustainable materials. This trend is substantiated by a significant corpus of recent experimental and theoretical research focused on the synthesis and property analysis of such polymers. Within this context, polybenzoxazines stand out as a pioneering class of thermosetting polymers, distinguished by their exceptional thermal and mechanical characteristics, coupled with the feasibility of synthesizing their precursor monomers from eco-friendly, renewable resources, including plant phenols and furfurylamine. Opting for furfurylamine over traditional aniline and its petroleum-derived counterparts in the synthesis of benzoxazines not only increases the eco-compatibility of the resultant materials but also imparts a significant alteration to their properties. This short review, spanning the last three years, delves into the principal advancements achieved in the realm of novel furan-bearing benzoxazines and polybenzoxazines from 2021 to present, accentuating both the triumphs and challenges encountered in this burgeoning domain.

Recent Progress of Low Dielectric and High-Performance Polybenzoxazine-Based Composites

With the rapid advancement of intelligent electronics, big data platforms, and other cutting-edge technologies, traditional low dielectric polymer matrix composites are no longer sufficient to satisfy the application requirements of high-end electronic information materials, particularly in the realm of high integration and high-frequency, high-speed electronic communication device manufacturing. Consequently, resin-based composites with exceptional low dielectric properties have garnered unprecedented attention. In recent years, benzoxazine-based composites have piqued the interest of scholars in the fields of high-temperature-resistant, low dielectric electronic materials due to their remarkable attributes such as high strength, high modulus, high heat resistance, low curing shrinkage, low thermal expansion coefficient, and excellent flame retardancy. This article focuses on the design and development of modification of polybenzoxazine based on low dielectric polybenzoxazine modification methods. Studies on manufacturing polybenzoxazine co-polymers and benzoxazine-based nanocomposites have also been reviewed.

Flame-retardant poly(L-lactic acid) with enhanced UV protection and well-preserved mechanical properties by a furan-containing polyphosphoramide

Despite good biodegradability and mechanical strength, the intrinsic flammability of poly(L-lactic acid) (PLA) impede its practical application. Introducing phosphoramide is an effective method to enhance the flame retardancy of PLA. However, most of the reported phosphoramides derive from petroleum resources, and their addition tends to deteriorate the mechanical properties, especially toughness, of PLA. Herein, a bio-based, furan-containing polyphosphoramide (DFDP) with high flame-retardant efficiency was synthesized for PLA. Our study found that 2 wt% DFDP enabled PLA to pass a UL-94 V-0 rating, and 4 wt% DFDP increased the limiting oxygen index (LOI) to 30.8 %. DFDP effectively maintained the mechanical strength and toughness of PLA. The tensile strength of PLA with 2 wt% DFDP reached 59.9 MPa, and its elongation at break and impact strength were increased by 15.8 % and 34.3 %, respectively, relative to those of virgin PLA. The UV protection of PLA was significantly enhanced by introducing DFDP. Hence, this work provides a sustainable and comprehensive strategy for the creation of flame-retardant biomaterials with improved UV protection and well-preserved mechanical properties, which possess a broad prospect in industrial application.

Recent advances in the development of green furan ring-containing polymeric materials based on renewable plant biomass

Fossil resources are rapidly depleting, forcing researchers in various fields of chemistry and materials science to switch to the use of renewable sources and the development of corresponding technologies. In this regard, the field of sustainable materials science is experiencing an extraordinary surge of interest in recent times due to the significant advances made in the development of new polymers with desired and controllable properties. This review summarizes important scientific reports in recent times dedicated to the synthesis, construction and computational studies of novel sustainable polymeric materials containing unchanged (pseudo)aromatic furan cores in their structure. Linear polymers for thermoplastics, branched polymers for thermosets and other crosslinked materials are emerging materials to highlight. Various polymer blends and composites based on sustainable polyfurans are also considered as pathways to achieve high-value-added products.

Metal Ion-Catalyzed Low-Temperature Curing of Urushiol-Based Polybenzoxazine

In this work, urushiol-based polybenzoxazine is cured by the Lewis acid (FeCl₃, AlCl_3, and CuCl₂) at low temperature instead of high thermal curing temperature. The effect of the Lewis acid on structures and properties of the polymers is revealed. The relating urushiol-based benzoxazine monomer (BZ) was synthesized by natural urushiol, formaldehyde, and n-octylamine. The monomer was reacted with the Lewis acid with a molar ratio of 6:1 (N_monomer: N_Metal) at 80°C to obtain films that can be cured at room temperature. The chemical structures of benzoxazine monomers were identified by Fourier-transform infrared spectroscopy (FTIR) and ¹H nuclear magnetic resonance spectroscopy (¹H-NMR). The interaction between the metal ion and the polymers is revealed by X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance-FTIR (ATR-FTIR). The effect of the Lewis acid on the mechanical properties, wettability, and thermal stability was investigated. The results show that the benzoxazine cured by Cu²⁺ has a better performance than that cured by Al³⁺ and Fe³⁺.

Synthesis of a triptycene-containing dioxazine benzoxazine monomer and a main-chain triptycene-polydimethysiloxane-benzoxazine copolymer with excellent comprehensive properties

A novel triptycene-containing dioxazine benzoxazine monomer and a main-chain benzoxazine copolymer have been synthesized and their corresponding thermosets exhibit excellent thermal stability, low flammability and low dielectric constants.