Promoted polymerization of Phthalonitrile containing benzoxazine (BA-ph) was designed on basis of the catalysis performance of a type of aniline curing agent (2,6-bis(4-aminophenoxy)benzonitrile ...(BAB)). The curing processes and curing behaviors of BA-ph with BAB were investigated by differential scanning calorimetry (DSC) and gelatin time. With the assistance of orthogonal test analysis method, main factors that affected the pre-polymerization of BA-ph were studied and the appropriate pre-polymerization conditions were determined. According to the results of dynamic rheological analysis (DRA) and Fourier transform infrared spectroscopy (FTIR), possible curing mechanism of BA-ph with BAB were proposed. The results show that BAB could reduce the prepolymerization temperature of BA-ph resin, and increase its polymerization rate and crosslinking degree, and the BA-ph/BAB polymer mainly formed the aromatic heterocyclic structure of triazine rings, phthalocyanine rings and polyisoindoline rings. Then, thermal stability of BA-ph (BAB15%) polymers pretreated at different temperatures and prepared at 200 °C was analyzed to understand the cross-linked structures. Results indicated that BA-ph (BAB15%) polymers exhibit outstanding thermal properties (T5%>410 °C and integral program decomposition temperature (IPDT) reached 3342 °C). Mechanical properties and thermomechanical properties of glass fiber reinforced BA-ph composites were also investigated and exhibited excellent mechanical properties, to further reveal the effects of BAB on the polymerization of BA-ph resin and expand the application of high-performance resin-based composites.
The polymerization process is the key factor affecting the forming process of phthalonitrile-based composites. A novel curing agent was introduced into phthalonitrile resin, and then, catalytic polymerization process and mechanism of phthalonitrile-based resin were analyzed and revealed by kinetic analysis method. Since then, high-performance phthalonitrile-based composites were designed and obtained. Display omitted
•A novel curing agent for phthalonitrile containing benzoxazine was designed.•Acceleration effects of polymerization was verified with Kinetic analysis.•Polymerization mechanisms were proposed.•High-performance composites with outstanding thermal stability were obtained.
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.
Poly (arylene ether nitrile) (PEN) is a kind of high-performance engineering plastic and their properties can be tuned by the copolymerization of various structural diphenols and dichloro ...(fluoro)-benzonitrile. In this work, a series of phenolphthalein and bisphenol AF based PEN (PP/BPAF-PEN) copolymers were designed and synthesized. Structures, molar weights, mechanical and thermal properties were studied. Results showed that PP/BPAF-PEN copolymers were successfully synthesized and exhibited good compatibility, outstanding thermal and mechanical properties. Besides, PP/BPAF-PEN exhibited excellent Tg up to 260 °C (DSC), tensile strength of 120 MPa, high Td5% and char yields (>70%). With incorporation of –CF3 into molecular chains, dielectric constant of PP-PEN (3.41 at 1 MHz) was decreased to 3.05 of PP/BPAF-PEN and dielectric loss was around 0.01. Hence, the obtained PP/BPAF-PEN copolymers possessing excellent properties could be applied as the candidates in flexible printed circuit (FPC) substrate.
•PP/BPAF-PEN copolymers were synthesized and results showed that the copolymers exhibited well compatibility.•PP-PEN possessed excellent Tg (260 °C) and mechanical properties (tensile strength > 120 MPa, tensile modulus > 3434.6 MPa).•PP/BPAF-PEN gained dielectric constant of 3.05 at 1 MHz and all of PP/BPAF-PENs exhibited Tg > 200 °C (by DSC).•Thermal stability was enhanced with incorporation of BPAF into molecular chains.
In order to solve the problem of high methanol crossover for direct methanol fuel cells, a series of cross-linkable sulfonated poly(arylene ether nitrile)s with pendent nitrile groups as ...cross-linkable groups have been synthesized through direct condensation polymerization. As far as we know, there are no detailed reports connected with nitrile groups being used as cross-linkable groups. The chemical structures of the sulfonated poly(arylene ether nitrile)s were confirmed by Fourier transform infrared (FT-IR) spectroscopy. The introduction of cross-linking network structure caused significant enhancement in thermal property and dimensional stability. Meanwhile, methanol permeability, swelling ratio and water uptake of the membranes substantially decreased after cross-linking. For instance, the water uptake and swelling ratio of SPEN-CN-70 are 1985.3% and 157% at 80°C, while those of CSPEN-CN-70 decrease to 64.9% and 16.9%, respectively. The SPEN-CN membranes showed the methanol permeability range from 0.838×10−7 to 8.24×10−7cm2s−1, while the CSPEN-CN membranes showed the lower permeability range from 0.156×10−7 to 1.64×10−7cm2s−1, respectively. Most importantly, after cross-linking, CSPEN-CN-60 showed the highest selectivity of 5.37×105Sscm−3, which was 11.9 times higher than that of Nafion 117. Although the conductivity of the CSPEN-CN was lower than that of the SPEN-CN, the higher selectivity makes the CSPEN-CN as potential candidate for applications in fuel cells.
•Cross-linkable sulfonated poly(arylene ether nitrile)s have been synthesized.•CSPEN-CN-60 showed the highest selectivity of 5.37×105Sscm-3.•Methanol permeability, swelling ratio and water uptake of the membranes decreased after cross-linking.•The crosslinking reaction was performed at 240 °C.
Self-polymerization epoxy/phthalonitrile (APPEN) pre-polymers were studied systematically, and then, gelation time and differential scanning calorimetry (DSC) were employed to investigate their ...curing behaviors. Taking advantage of orthogonal test analysis, the key factors that affected the co-polymerization of APPEN were defined and the appropriate pre-polymerization conditions were analyzed. A possible curing mechanism of APPEN was proposed. Then, the thermomechanical and mechanical properties of glass-fiber-reinforced APPEN laminates (APPEN/GF) prepared at 180 °C were analyzed to understand the cross-linked and aggregation structures. Fracture surface of the composite laminates was also investigated to reveal the copolymerization degree and the interfacial binding. The results indicated that APPEN/GF composites exhibit outstanding mechanical and thermomechanical properties (flexural strength, 712 MPa, flexural modulus, 38 GPa, and Tg > 185 °C). The thermal stability (T5% > 334 °C and IPDT reached 1482 °C) of APPEN/GF composites was also investigated to further reveal the copolymerization between epoxy resin and aminophthalonitrile, which may be beneficial to the application of epoxy-matrix-based composites in the field of high-performance polymer composites.
Apple Replant Disease (ARD) is common in major apple-growing regions worldwide, but the role of rhizosphere microbiota in conferring ARD resistance and promoting plant growth remains unclear. In this ...study, a synthetic microbial community (SynCom) was developed to enhance apple plant growth and combat apple pathogens. Eight unique bacteria selected via microbial culture were used to construct the antagonistic synthetic community, which was then inoculated into apple seedlings in greenhouse experiments. Changes in the rhizomicroflora and the growth of aboveground plants were monitored. The eight strains, belonging to the genera Bacillus and Streptomyces, have the ability to antagonize pathogens such as Fusarium oxysporum, Rhizoctonia solani, Botryosphaeria ribis, and Physalospora piricola. Additionally, these eight strains can stably colonize in apple rhizosphere and some of them can produce siderophores, ACC deaminase, and IAA. Greenhouse experiments with Malus hupehensis Rehd indicated that SynCom promotes plant growth (5.23%) and increases the nutrient content of the soil, including soil organic matter (9.25%) and available K (1.99%), P (7.89%), and N (0.19%), and increases bacterial richness and the relative abundance of potentially beneficial bacteria. SynCom also increased the stability of the rhizosphere microbial community, the assembly of which was dominated by deterministic processes (|beta NTI| > 2). Our results provide insights into the contribution of the microbiome to pathogen inhibition and host growth. The formulation and manipulation of similar SynComs may be a beneficial strategy for promoting plant growth and controlling soil-borne disease.
Copolymerization is the typical method to obtain the high-performance resin composites, due to its universality and regulation performance. It can be employed among various resin matrices with active ...groups to obtain the desired structures, and subsequently, the outstanding properties. In this work, the copolymerization between the allyl-functional phthalonitrile-containing benzoxazine resin (DABA-Ph) and 4,4'-bis(Maleimidodiphenyl)methane (BMI) were monitored. The interactions among the active groups including allyl moieties, maleimide, benzoxazine rings and nitrile groups were investigated. Differential scanning calorimetry (DSC) and dynamic rheological analysis (DRA) were used to study the curing behaviors and the processing properties. The possible curing processes were proposed and confirmed by Fourier transform infrared spectroscopy (FTIR). Then, glass fiber-reinforced DABA-Ph/BMI composites were designed, and their thermal-mechanical properties were studied. Results indicated that all the composites exhibited outstanding flexural strength, flexural modulus, and high glass-transition temperatures (
> 450 °C). The thermal stability of the composites was studied by thermogravimetry (TGA) and evaluated by the integral program decomposition temperature (IPDT). it is believed that the excellent thermal mechanical properties and outstanding
as well as good thermal stability would enable the reinforced copolymer-based laminates to be applied in wider fields.
The thermal conductive cyanate ester/epoxy (CE/AG80) composites with hexagonal boron nitride (h-BN) reinforced were manufactured and investigated. The low and stable dielectric constant/loss of the ...composites with respect to both frequency (500 Hz-100 kHz) and temperature (50-350 °C) were discussed as functions of the content of h-BN. It was found that the low and stable dielectric constant/ loss of the composites can be maintained in the whole frequency range at room temperature, and the mutations of constant/loss at the frequency of 1 kHz occurred above 280 °C for all of the samples. Moreover, a remarkable enhancement of the thermal conductivity (0.54 W/mK a 1.8-fold enhancement) was achieved with the introduction of h-BN and significantly outperformed traditional thermal conductive fillers. The significant improvements of the thermal conductivity of the composites were analyzed by the Agari’s model and the parameters of
C
1
and
C
2
were also calculated.
Dye pollution is a serious problem in modern society. We desired to develop an efficient adsorbent for the decontamination of discharged dyes. In this work, the polymeric microspheres derived from a ...kind of amphiphilic block of co-poly(arylene ether nitrile) (B-b-S-P) were prepared on the basis of “oil-in-water” (O/W) microemulsion method. The B-b-S-P microspheres were found competent to remove the cationic dye, methylene blue (MB); and various influential factors, such as contact time, initial concentration, solution pH and temperature were investigated. Results indicated that the maximum adsorption capacity of B-b-S-P microspheres for MB was 119.84 mg/g at 25 °C in neutral conditions. Adsorption kinetics and isotherm dates were well fitted to a pseudo-second-order kinetic model and the Langmuir isotherm model, and thermodynamic parameters implied that the adsorption process was endothermic. The B-b-S-P microspheres also exhibited a highly selective adsorption for cationic dye MB, even in the presence of anionic dye methyl orange (MO). In addition, the possible adsorption mechanism was studied, suggesting that the electrostatic interaction and π–π interaction could be the main force in the adsorption process.
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