A New Benzoxazine Containing Benzoxazole-Functionalized Polyhedral Oligomeric Silsesquioxane and the Corresponding Polybenzoxazine Nanocomposites

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.

Study of a Novel Fluorine-Containing Polyether Waterborne Polyurethane with POSS as a Cross-Linking Agent

Waterborne polyurethane are more eco-friendly materials due to lower volatile organic compounds (VOCs, mainly isocyanates) content than the alternative materials. However, these rich hydrophilic groups polymers have not yet reached good mechanical properties, durability and hydrophobicity behaviors. Therefore, hydrophobic waterborne polyurethane has become a research hotspot, attracting significant attention. In this work, firstly, a novel fluorine-containing polyether P(FPO/THF) was synthesized by cationic ring-opening polymerization of 2-(2,2,3,3-tetrafluoro-propoxymethyl)-oxirane (FPO) and tetrahydrofuran (THF). Secondly, fluorinated polymer P(FPO/THF), isophorone diisocyanate (IPDI) and hydroxy-terminated polyhedral oligomeric silsesquioxane (POSS-(OH)₈) were used to prepare a new fluorinated waterborne polyurethane (FWPU). Hydroxy-terminated POSS-(OH)₈ was used as a cross-linking agent, while dimethylolpropionic acid (DMPA) and triethylamine (TEA) were used as a catalyst. Four kinds of waterborne polyurethanes (FWPU0, FWPU1, FWPU3, FWPU5) were obtained by adding different contents of POSS-(OH)₈ (0%, 1%, 3%, 5%). The structures of the monomers and polymers were verified by ¹H NMR and FT-IR, and the thermal stabilities of various waterborne polyurethanes were analyzed by thermogravimetric analyzer (TGA) and differential scanning calorimetry (DSC). As the results, the thermal analysis showed that the FWPU performed the good thermal stability and the glass transition temperature could reach at about -50 °C. The FWPU1 film exhibited that the elongation at break was 594.4 ± 3.6% and the tensile strength at break was 13.4 ± 0.7 MPa, elucidating that the FWPU1 film developed the excellent mechanical properties relative to the alternative FWPUs. Further, the FWPU5 film performed the promising properties, including the higher surface roughness of FWPU5 film (8.41 nm) obtained by the atomic force microscope (AFM) analysis, and the higher value of water contact angle (WCA) at 104.3 ± 2.7°. Those results illustrated that the novel POSS-based waterborne polyurethane FWPU containing a fluorine element could develop the excellent hydrophobicity and mechanical properties.

Supercapacitor and high k properties of CNT-PbS reinforced quinoxaline amine based polybenzoxazine composites

The new 2,3-diphenylquinoxalin-6-amine (dpqa) was designed and synthesized through an efficient and high yield condensation process. Data from FTIR and ¹H-NMR spectroscopy have been adopted to ascertain the molecular structure of benzoxazine compounds. Furthermore, the quinoxaline amine based benzoxazine (BA-dpqa) was synthesized using bisphenol-A and paraformaldehyde followed by combining different weight percentages (1, 5 and 10 wt%) of (3-glycidyloxypropyl)trimethoxysilane functionalized CNT-PbS with benzoxazine to obtain nanocomposites. The thermal and morphological properties of the quinoxaline amine based neat polybenzoxazine matrix poly(BA-dpqa) and CNT-PbS/poly(BA-dpqa) composites were analysed by XRD, TGA and SEM analysis. The values of the degradation temperature (T_d) obtained for neat poly(BA-dpqa) and 10 wt% CNT-PbS/poly(BA-dpqa) composites are 414 °C and 424 °C. Furthermore, the chair yield percentage was calculated as 33% and 35% respectively. The water contact angle of polybenzoxazine gradually increased from 89° to 127° proportional to the content of CNT-PbS. Among the composites, 10 wt% CNT-PbS reinforced poly(BA-dpqa) nanocomposites possess higher dielectric constant (k = 11.0) than other composites. The pseudocapacitor nature of the prepared electrodes is demonstrated by the good electrochemical performance according to the CV curve. Also, the prepared 10 wt% CNT-PbS/poly(BA-dpqa) (637 F g^-1 at 5 A g^-1 and 11.8 Ω) electrode shows better capacitance and lower charge transfer resistance values than 5 wt% CNT-PbS/poly(BA-dpqa) (613 F g^-1 at 5 A g^-1 and 13.2 Ω) and neat poly(BA-dpqa) (105 F g^-1 at 5 A g^-1 and 15.6 Ω) according to the charge/discharge curves and EIS spectra. 10 wt% CNT-PbS/poly(BA-dpqa) shows 99.2% cycling efficiency even at the 2000th cycle, which indicates the good electrochemical performance of the prepared electrode.

Modification of traditional benzoxazine by blending with polyfunctional benzoxazines containing aromatic group and fluorene group

A series of polyfunctional benzoxazine monomers containing aromatic and fluorene group (AMFB) were used as modified agents to improve the performance of typical bifunctional bisphenol-A-aniline-based (BA-a) benzoxazine resins. The polymerization behaviors of BA-a/AMFB blends were investigated by using the differential scanning calorimetry (DSC), while the dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) were used to analyze the thermomechanical and thermal properties of BA-a/AMFB copolymers [poly(BA-a/AMFB)]. Moreover, the cross-section morphologies of poly(BA-a/AMFB) were observed by scanning electron microscope (SEM). The experimental results showed that BA-a monomer has good catalytic activity for AMFB monomers during the curing process. Compared with BA-a polymer [poly(BA-a)], due to the introduction of heat-resistant fluorene ring and the increase of the crosslinking degree of copolymers, the copolymers showed higher glass transition temperature and better thermal properties. For poly(BA-a/AMFB), the T5, T10, and Yc were higher than those of poly(BA-a). With the increase of the alkyl chain length of AMFB monomers, the cross-section creases gradually changed from linear to dendritic, and the number of creases increased significantly, which indicated that the toughness of the copolymers was significantly improved.

Preparation of TiO2-modified Biochar and its Characteristics of Photo-catalysis Degradation for Enrofloxacin

In order to solve the problem that the traditional biochar(BC) has insufficient removal ability of enrofloxacin and TiO₂ is difficult to recycle. In this study, TiO₂-modified biochar composites were prepared by impregnation method. Through characterization analysis, The BET specific surface area results indicated that after loading TiO₂, the specific surface area of TiO₂-biochar(Ti-BC), TiO₂-ironized biochar(Ti-FBC) and TiO₂-alkaline biochar(Ti-KBC) increased by 4.34, 10.43 and 11.52 times, respectively. The analysis results of SEM, EDS, FT-IR, XRD and XPS showed that TiO₂ was supported on biochar in the anatase state. The UV-vis DRS measurement showed that the band width of Ti-KBC was the smallest and the best catalytic activity. Under 15 W UV lamp (254 nm) irradiation, the photocatalytic degradation process of enrofloxacin by different biochar accords with the first-order kinetic equation. Ti-KBC showed best degradation effect under different initial concentrations of enrofloxacin. When the pH of the solution was 5.0 and the dosage of Ti-KBC was at 2.5 g·L⁻¹, the enrofloxacin degradation rate of 100 mg·L⁻¹ reached 85.25%. The quenching test confirmed that the active substance O₂•^— played a major role in the photocatalytic degradation process. After five cycles of the test, the degradation rate of Ti-KBC for enrofloxacin was 77.14%, which was still better than that of BC, Ti-BC and Ti-FBC.

A New Sight into Bio-Based Polybenzoxazine: From Tunable Thermal and Mechanical Properties to Excellent Marine Antifouling Performance

With the rapid development of bio-based polymers, polybenzoxazine derived from renewable resources has been widely investigated. However, there are few reports on the functional application of bio-based polybenzoxazine based on the special chemical structures of renewable compounds. In this work, an easy approach to prepare the polybenzoxazines with varied thermomechanical properties and excellent marine antifouling performance from renewable resources is presented. After a variety of main-chain-type benzoxazine polymers (MCBPs) were synthesized from the renewable daidzein, furfurylamine, polyetheramine, and paraformaldehyde, their chemical structures were identified by Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy (¹H NMR). Then, their curing behaviors were monitored by differential scanning calorimetry and rheological tests. Results revealed that the cross-linked MCBPs with varied thermomechanical properties could be easily prepared by adjusting the molar ratio of polyetheramine and furfuramine. Notably, these cured MCBP films demonstrated excellent antibacterial and algaecidal properties due to the presence of daidzein and furan units. This work first presents the new application prospect of bio-based MCBPs, for example, in marine antifouling coatings.

Synthesis of a benzoxazine monomer contained hyperbranched polysiloxane and the characteristics of its polymer alloys blend with bismaleimides

A novel benzoxazine monomer contained hyperbranched polysiloxane structure (HBPSi-BOZ) was synthesized via a solvent process based on the polyformaldehyde, aniline, and a new hyperbranched polysiloxane with terminal amino groups (HBPSi-NH2). The HBPSi-BOZ was then used as modified phase to blend with bismaleimides (BMIs) resin, and a polymer alloy HBPSi-BOZ/BMI was successfully prepared. The thermal resistant properties, mechanical properties, and tribological properties of HBPSi-BOZ/BMI resins with different contents of HBPSi-BOZ prepared were researched to get an optimal ratio. The thermogravimetric analysis was also carried out to study the polymerization process and stability of HBPSi-BOZ/BMI resins. The results showed that as the thermal resistance increased, the wear resistance and mechanical properties of HBPSi-BOZ/BMI resins were also enhanced.

Cardanol based benzoxazine blends and bio-silica reinforced composites: thermal and dielectric properties

In the present work, a novel cardanol based benzoxazine was synthesised by reacting three different amines (aniline (CrAb), N,N-dimethylaminopropylamine (CrDb) and caprolactam modified N,N-dimethylaminopropylamine (CrCb)) with cardanol in the presence of formaldehyde under appropriate experimental conditions.

POSS-benzocyclobutene (POSS-BCB) resin

Organic-inorganic hybrid materials with a high thermal stability and a low dielectric constant show great potential in the microelectronics industry. In this work, polyhedral oligomeric silsesquioxane-benzocyclobutenes (POSS-BCBs) were synthesized by a hydrosilylation reaction of octavinyloctasilasesquioxane (OVPOSS) and 4-(1,1-dimethyl-1-hydro)-silyl-benzocyclobutene with H2PtCl6 as a catalyst. The ring-opening reaction of BCB on POSS-BCBs resulted in POSS-BCB resins with a highly cross-linked network structure. This resin exhibited good thermal stability (T5% is 495°C in N2), low dielectric constants (<2.1 at 20 MHz) and low water absorption.

Achieving low dielectric, surface free energy and UV shielding green nanocomposites via reinforcing bio-silica aerogel with polybenzoxazine

Silica aerogel (SA) derived from rice husk ash was functionalized using benzoxazine terminated silane (FSA) and was used as a nanoreinforcement for industrial valuable resin polybenzoxazine (PBZ) in order to achieve low dielectric, to improve the surface as hydrophobic and to enhance the UV shielding behavior of the resulting nanocomposites.

A new mechanism for the low dielectric property of POSS nanocomposites: the key role of interfacial effect

The low dielectric constant (ε) of polyhedral oligomeric silsesquioxanes (POSS) nanocomposites was also attributed to its interfacial structure.

Polybenzoxazine/Polyhedral Oligomeric Silsesquioxane (POSS) Nanocomposites

The organic/inorganic hybrid materials from polyhedral oligomeric silsesquioxane (POSS, inorganic nanoparticles) and polybenzoxazine (PBZ) have received much interesting recently due to their excellent thermal and mechanical properties, flame retardance, low dielectric constant, well-defined inorganic framework at nanosized scale level, and higher performance relative to those of non-hybrid PBZs. This review describes the synthesis, dielectric constants, and thermal, rheological, and mechanical properties of covalently bonded mono- and multifunctionalized benzoxazine POSS hybrids, other functionalized benzoxazine POSS derivatives, and non-covalently (hydrogen) bonded benzoxazine POSS composites.

An aggregation-induced emission enhancement fluorescent benzoxazine-derived macromolecule: catalyst-free synthesis and its preliminary application for the determination of aqueous picric acid

An aggregation-induced emission enhancement macromolecular benzoxazine derivative was synthesized by a catalyst-free Mannich reaction and showed a fluorescence quenching response towards nitro compounds.