BMI Resin Research Articles

Grafting Carbon Fibers with Graphene via a One-Pot Aryl Diazonium Reaction to Refine the Interface Performance of T1100-Grade CF/BMI Composites.

In this study, a one-pot aryl diazonium reaction was used as a simple and mild method to graft graphene onto the smooth and inert surface of T1100-grade carbon fiber (CF) through covalent bonding without any damage on CF, to refine the interface performance of CF/bismaleimide (BMI) composites. XPS, SEM, AFM, and dynamic contact angle testing (DCAT) were used to characterize chemical activity, morphologies, and wettability on untreated and grafted CF surfaces. Meanwhile, the impact of the graft method on the tensile strength of CF was also examined using the monofilament tensile test. IFSS between CF grafted with graphene and BMI resin achieved 104.2 MPa after modification, increasing from 85.5 MPa by 21.8%, while the tensile strength did not decrease compared to the pristine CF. The mechanism of this interface enhancement might be better chemical bonding and mechanical interlock between CF grafted with graphene and BMI resin, which is generated from the high surface chemical activity and rough structure of graphene. This study may propose a simple and mild method to functionalize the CF surface and enhance the interface performance of composites without compromising the tensile properties of T1100-grade CF.

Controlling degradation and recycling of carbon fiber reinforced bismaleimide resin composites via selective cleavage of imide bonds

Carbon fiber reinforced bismaleimide resin (CF/BMI) composites are widely used in aerospace field due to their high thermal stability, chemical resistance and excellent mechanical properties. With the large-scale application of CF/BMI composites, it is inevitable to produce a lot of solid wastes, which have a serious impact on the environment, so people have to recycle waste CF/BMI composites. In view of the physical and chemical properties of BMI resin, we developed a green and friendly chemical recovery method of CF/BMI composites by selectively breaking imide bonds for controlled chemical degradation of BMI resin. In 5 wt% NaOH/H2O reaction system, the controlled chemical degradation of CF/BMI composites can be realized by selective cleavage of imide bonds, and the 4,4′-Diaminodiphenyl methane (DDM) and 2,2′,2″,2‴-((methylenebis(4,1-phenylene))bis(azanetriyl))tetrasuccinic acid (MBTA) can be recovered, and the carbon fiber (CF) can be recycled at the same time. Under the optimal reaction conditions, the yields of DDM and MBTA reached 6.7 wt% and 27.9 wt% at 180 °C for 8 h, respectively. Meanwhile, CF in CF/BMI composites can be completely recovered, and the tensile strength of recovered carbon fiber (rCF) is about 97.6% of that of virgin carbon fiber (vCF). This work provides a very promising strategy for the recycling of CF/BMI composites. The high value-added CF and chemicals (DDM and MBTA) can be recovered by controlled degradation of CF/BMI composites via selective cleavage of imide bonds.

Construction of carbon nanotubes/bismaleimide composite films with superior tensile strength and toughness

Carbon nanotubes (CNTs) have been considered as promising reinforcements for various composites due to their excellent mechanical properties. However, preparation of high-performance CNT/resin composites still suffers from bad dispersion, low fraction, and poor alignment of CNTs and their weak bonding with the resin matrix. Herein, we report an effective strategy towards preparing CNT/Bismaleimide (BMI) composite films with excellent mechanical properties. Firstly, from floating catalytic spray pyrolysis, CNTs are deposited on a water soluble substrate as a thin film to maintain their original microstructures. The films are then stacked layer by layer and pulled in tension with the substrate dissolved in water. The pristine stacked films are immersed in BMI solutions of different concentrations and stretched to different strains for simultaneous CNT reorientation and resin infiltration. The films are finally pressed at low temperature for resin permeation and redistribution and high temperature for resin curing. The determining factors such as the alignment and mass fraction of CNTs and the distribution of BMI resin in the composite film can be easily tailored. Benefiting from the resultant excellent CNT alignment, high CNT content (61.4 wt%), and uniform distribution of the resin between CNTs, the composite film can achieve excellent mechanical properties, including a tensile strength of 4.18 GPa, elongation at break of 4.35%, Young's modulus of 145 GPa, and toughness of 94.2 J cm−3. Such a strength and toughness are superior to those for the CNT composites published in the literature so far.

Enhancing the mechanical properties of bismaleimide resin with montmorillonite modified by two intercalators (amino-terminated polyoxypropylene and octadecyl trimethyl ammonium chloride)

PurposeBismaleimide (BMI) is a kind of thermosetting resin and its application is usually limited by low toughness. In this paper, two kinds of reinforcement intercalator amino-terminated polyoxypropylene (POP) and octadecyl trimethyl ammonium chloride (OTAC) were designed and synthesized to toughen BMI resin and the toughening effect was compared and analyzed. The purpose of this paper is to toughen BMI resin and analyze the toughening effect of two reinforcements intercalator amino-terminated polyoxypropylene (POP) and octadecyl trimethyl ammonium chloride (OTAC).Design/methodology/approachSodium-based montmorillonite (Na-MMT) was modified by POP and OTAC, and the ion-exchange reaction obtained organic montmorillonite (POP-MMT and OTAC-MMT). The polymer matrix (MBAE) was synthesized, in which 4,4’-diamino diphenyl methane BMI was used as the monomer and 3,3’-diallyl bisphenol A and bisphenol A diallyl ether were used as active diluents. And then, POP-MMT/MBAE and OTAC-MMT/MBAE composites were prepared using MBAE as matrix and POP-MMT or OTAC-MMT as reinforcement. The Fourier-transform infrared, X-ray diffraction and scanning electron microscope (SEM) of the filler and microstructure and mechanical properties of the composite were characterized to the better reinforcement.FindingsPOP-MMT and OTAC-MMT enhanced BMI-cured products’ toughness by generating microcracks in the polymer to absorb more fracture energy. Meanwhile, POP-MMT and OTAC-MMT were the main stress components and the enhancement of the interface interaction was beneficial to transfer the external force from the matrix to the reinforcement and improved the mechanical properties of the composite. Furthermore, with the intercalation rate increasing, the compatibility of the two phases was increased and the performance of MBAE was also elevated.Research limitations/implicationsBMI is generally used as aerospace structural materials, functional materials, impregnating paint and other fields. However, high crosslinking density leads to moulding material’s brittleness and limits a wider range of applications. Therefore, it has become an urgent priority to explore and improve the mechanical properties of BMI resin.Originality/valuePOP and OTAC have successfully intercalated Na-MMT layers to get POP-MMT and OTAC-MMT, and the interplanar crystal spacing and the intercalation rate were calculated, respectively. The results were corresponding with the SEM images of POP-MMT and OTAC-MMT. After that, the morphology of composites illustrated the compatibility was related to the intercalation rate. According to the mechanism of modified MMT toughening epoxy resin, when they were dispersed uniformly in the matrix, the composite’s mechanical properties had been significantly improved. Additionally, OTAC-MMT with a higher intercalation rate had better compatibility and interfacial force with the matrix, so that the mechanical properties of OTAC-MMT/MBAE were the best.

Influence of DBD-grafted multi-carboxyl polyurethane on interfacial properties of PBO fibre-reinforced BMI resin composites

The poor adhesion between polybenzoxazole (PBO) fibre and resin can lead to limitations in the composites formed for practical applications. Air atmospheric dielectric barrier discharge was applied to graft multi-carboxyl polyurethane (C-PU) designed and synthesised by introducing polar functional groups on the PBO fibre surface to enhance interfacial bonding. The effects of power density and C-PU concentration on the composites formed, as well as the surface ageing time of post-grafted fibres, were studied. The surface chemical composition and morphologies of the grafted PBO fibre were characterised by X-ray photoelectron spectroscopy, attenuated total reflection Fourier transformed infrared spectroscopy, and scanning electron microscopy. Mechanical performance testing showed that the interlaminar shear strength of the PBO/BMI composites is significantly improved and that the fibre surface activity can be maintained for up to 15 days. More importantly, the transition temperature of the as-prepared C-PU graft matched with the curing temperature of the BMI resin.

Effects of plasma treatment of carbon fibers on interfacial properties of BMI resin composites

High performance continuous fiber surface modification by inductively coupled RF plasma (ICP) and dielectric barrier discharge (DBD) low temperature plasma were conducted. X‐ray photoelectron spectroscopy (XPS) and other analytical testing methods systematically studied plasma treatment time, discharge power, discharge pressure, etc, on fiber surface state, surface composition, and surface shape changes in the appearance and wetting properties. The results show that after plasma treatment the surface of the fiber is grafted with a large number of polar functional groups such as carboxyl groups and hydroxyl groups. The surface roughness increases, the surface free energy increases, and the fiber wetting property is significantly improved, resulting in improvement in interlaminar shear strength (ILSS) between the fiber and the resin matrix. Finally, the surfaces of the fibers and its relationship with interfacial properties of fiber reinforced bismaleimide composites are also discussed.

Synthesis and properties of bismaleimide resins containing phthalide cardo and cyano groups

Two novel n ≈ 1 oligomeric bismaleimide monomers containing phthalide cardo and cyano groups (PCBMI and MCBMI) were designed and synthesized. The chemical structures of the monomers were confirmed from proton nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy. Both BMIs exhibit good solubility in common organic solvents, enabling easy solution processing. Thermal curing behaviors of the monomers were investigated by differential scanning calorimetry, displaying broad exothermic peaks and large thermal processing windows. Furthermore, PCBMI/carbon fiber composites were prepared, with their thermal stability and mechanical properties investigated. Thermogravimetric analysis and test of interlaminar shear strength indicated that the thermal polymerization of cyano groups improved the heat resistance of BMI resins and enhanced the interfacial adhesion at higher temperature.

Cure mechanism of novel bismaleimide resins based on fluorene cardo moiety and their thermal properties

ABSTRACTIn this paper, two novel bismaleimide resins based on 9, 9-bis[4-(4-maleimidophenoxy) phenyl] fluorene (PFBMI), 9, 9-bis[4-(4-maleimidophenoxy)-3-methylphenyl]fluorene (MFBMI), and 2, 2’-diallyl bisphenol A (DABPA) were prepared. Their curing mechanism and curing kinetic were carefully investigated by Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The thermal mechanical properties of the composites based on these BMI resins and the glass cloth were obtained by Dynamic mechanical analysis (DMA), displaying that the novel resins whose Tg were 296°C and 289°C had excellent thermal performance. In addition, Thermogravimetric analysis (TGA) results showed that both the cured PD and MD resins possessed good thermal stability, and their T5% were all higher than 410°C.

Bismaleimide-diamine copolymers containing phthalide cardo structure and their modified BMI resins

3,3-Bis[4-(4-aminophenoxy)phenyl]phthalide (PPDA) and 4,4′-bimaleimidodiphenyl-methane (BDM) were prepared via a Michael-type addition using molar ratio 1:2(PM2), 1:3(PM3) and 1:4(PM4) in acetone a...

A study of co-reaction mechanism and properties of propenyl-substituted monomer/bismaleimide system

A practical modifier, 4,4′-bis[2-(1-propenyl)phenoxy]benzophenone (MT), has been synthesized and copolymerized with 4,4′-bismaleimidodiphenylmethyene (4,4′-BMI) to yield a low-temperature cure bismaleimide resin. Structural information of MT was obtained using Fourier transform infrared spectroscopy and nuclear magnetic resonance (proton and carbon) spectroscopy, elemental, and mass spectrometry analyses. The differential scanning calorimetric curve of the MT/4,4′-BMI system shows two exothermic peaks at 164°C and 210°C, respectively. This value was compared with other polymerization reactions involving diallyl bisphenol A (DP) and diallyl bismaleimide (DBMI), with an exothermic peak at around 257°C. Unlike normal bismaleimide resins with DP postcured at 250°C for about 4–8 h, the MT/4,4′-BMI resin was cured at 230°C for a total of 6 h (i.e. MBMI-230) or at 200°C for 6 h (i.e. MBMI-200). Furthermore, the resins exhibit high thermal resistance, excellent mechanical properties, and exceptionally low dielectric loss. For MBMI-230 and MBMI-200, the dielectric loss values are all in the range of 0.0024–0.0054 from 7 GHz to 18 GHz and feature excellent thermal stabilities (5% weight loss temperature ( Td5) > 415°C under nitrogen atmosphere) and thermo-oxidative stabilities ( Td5 > 425°C in air atmosphere). Additionally, the cured resins also display a high bending modulus (>3.2 GPa) at room temperature and an excellent mechanical stability at high temperature.

Tribology Property of Benzoxazine–Bismaleimide Composites with Hyperbranched Polysilane-Grafted Multi-Walled Carbon Nanotubes

To reveal the wear mechanism of hyperbranched polysilane (HBPSi) grafted multi-walled carbon nanotubes (HBPSi–MWCNTs) modified benzoxazine–bismaleimide (BOZ–BMI) resin (HBPSi–MWCNTs/BOZ–BMI), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) were employed. The results indicated that the suitable addition of HBPSi–MWCNTs could largely enhance the tribological properties of BOZ–BMI composites. The worn surface of the composites showed that the severe wear of the BOZ–BMI resin was converted from adhesive wear to abrasive wear with the addition of HBPSi–MWCNTs. The excellent tribological properties can be attributed to the improved interfacial adhesion between HBPSi–MWCNTs and the BOZ–BMI resin matrix. The TGA demonstrated that the composite with 0.8[Formula: see text]wt.% HBPSi–MWCNTs exhibits better thermal resistance; thus, it can inhibit adhesive wear during the friction process. The XPS spectra and the surface energy showed that the HBPSi–MWCNTs could be exposed on the worn surface of the composite to improve the anti-wear capacity of the composites further.

Synthesis of novel bismaleimide monomers based on fluorene cardo moiety and ester bond: Characterization and thermal properties

ABSTRACTTwo novel bismaleimide monomers based on fluorene cardo moiety and ester bonds, namely 9, 9-bis[4-(4-maleimidobenzoate) phenyl]fluorene (PEFBMI) and 9,9-bis[4-(4-maleimidobenzoate)-3-methylphenyl]fluorene (MEFBMI) were designed and synthesized. Their structures were confirmed by FTIR, 1H-NMR, 13C-NMR spectroscopy and Elemental analysis. Both monomers obtained have excellent solubility in some organic solvents with low boiling point, including acetone, chloroform and dichloromethane. The curing process of the monomers were investigated by DSC, displaying that the melting point of the monomers were 157.1°C and 193.6°C respectively, and all processing windows exceed 30°C. DMA results showed the glass transition temperature of the cured PEFBMI/glass cloth composite was higher than 390°C while that of the cured PEFBMI composite was 349.2°C. TGA results indicated that the cured BMI resins have good thermal stability and their 5% weight loss temperatures were both higher than 410°C.

A multifunctional silicon-containing hyperbranched epoxy: controlled synthesis, toughening bismaleimide and fluorescent properties

A multifunctional silicon-containing hyperbranched epoxy is explored. The polymer can not only toughen BMI resins, but also emit blue photoluminescence.

Improved mechanical and tribological properties of bismaleimide composites by surface-functionalized reduced graphene oxide and MoS2 coated with cyclotriphosphazene polymer

PZD/rGO/MoS2 hybrid nanoparticles were prepared by a one-pot noncovalent method, and then were incorporated into BMI resin as additive to fabricate PZD/rGO/MoS2/BMI composites.

Multi-functional ladderlike polysiloxane: synthesis, characterization and its high performance flame retarding bismaleimide resins with simultaneously improved thermal resistance, dimensional stability and dielectric properties

The development of high-performance flame-retardant polymers with simultaneously increased integrated performance, especially thermal resistance, dimensional stability and dielectric properties, is a challenge. Progress in this field depends greatly on the development of high-performance flame retardants. In the work reported here, a unique ladder-like multi-functional polysiloxane (PN-PSQ), with a large number of amine groups and a phosphaphenanthrene structure, was synthesized through the controlled hydrolysis of self-made phosphorus-containing triethoxysilane and γ-aminopropyl triethoxysilane. A series of PN-PSQ/bismaleimide (BMI) resins was then prepared and their structure and integrated properties investigated. The results show that a small addition of PN-PSQ effectively gives BMI resins an improved curing process, outstanding flame retardant properties, remarkably improved thermal and dimensional stability as well as a decreased dielectric constant and dielectric loss, completely overcoming the critical disadvantages of currently available flame retardants for thermally resistant polymers. For example, for the PN-PSQ5/BMI resin with 5 wt% PN-PSQ, its limited oxygen index and average heat release rate are about, respectively, 1.6 times and 58% of that of BMI resin alone. Compared with BMI resin alone, the glass transition temperature of the PN-PSQ5/BMI resin is increased by about 10 °C. The coefficient of thermal expansion of the former in a glassy or rubbery state and the dielectric constant and loss at 1 MHz decrease by about 10–20%. These attractive performances are attributed to the special structure of PN-PSQ/BMI resins induced by the unique nature of PN-PSQ. This investigation provides a new approach to synthesizing multi-functional polysiloxane and related high-performance resins.

Modification of carbon fiber by air plasma and its adhesion with BMI resin

Carbon fiber (CF) was modified by air plasma at 30 Pa and 200 W with different treatment times. Interlaminar shear strength (ILSS) of CF/BMI composites suggested that air plasma-treated CFs showed better adhesion with BMI resins than the untreated resins; the maximum increment was 20.4% after plasma treatment for 900 s. Meanwhile, we investigated the surface changes of CFs using X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The results indicated that air plasma treatment roughened the CF surfaces and improved the polarity of CFs by enhancing the polar group content. These changes were believed to be the major reasons for the improvement of interfacial adhesion. The fracture morphology observed by scanning electron microscopy (SEM) indicated that the fracture failure mode changed from adhesive failure to cohesive failure. After boiling in water for 48 h, the water absorption of the composites was low while the ILSS of the composites retained about 90%, which implied that the CF/BMI composites had good humidity resistance properties.

Diazonium functionalization of graphene nanosheets and impact response of aniline modified graphene/bismaleimide nanocomposites

For developing high performance of graphene-based nanocomposites, dispersibility of graphene sheets in matrices and interfacial interaction are challenging due to the strong tendency of agglomeration and surface inertia of graphene. Here we report an efficient way to functionalize graphene nanosheets with aniline groups on their surfaces, to attain the functionalized graphene nanosheets (FGS) by diazonium treatment following reduction of graphene oxide with hydrazine hydrate. Two kinds of nanocomposites based on diallyl bisphenol A modified bismaleimide (BMI-BA) resin which was filled with functionalized graphene and reduced graphene oxide nanosheets were prepared, and the FGS were linked with BMI resin by chemical bonds. The FGS/BMI-BA composite at a loading of 0.3wt% revealed a 39% increase in impact strength and a slightly improvement in flexural strength, and the resulting composite remains stable at high temperature. This work provides more possibilities for incorporation of graphene into polymer matrices and an efficient method to toughening the BMI resin.

Preparation and properties of modified bismaleimide resins based on phthalide‐containing monomer

ABSTRACTA series of bismaleimide resins based on phthalide‐containing monomer have been prepared by the copolymerization reaction of 3,3‐bis[4‐(4‐maleimidophenoxy)phenyl] ‐phthalide (PPBMI), 4, 4'‐dimaleimido diphenylmethane (MBMI) and 2, 2'‐diallyl bisphenol A (DABPA) in different feed ratios. The curing behavior, thermal, mechanical and physical properties and compatibility of all resultant resins were carefully characterized using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), notched Izod impact test, water absorption test and scanning electron microscopy (SEM). DSC investigations showed that with an increase of the weight ratio of PPBMI, the dominating exothermic polymerization temperature (Tp) increased. The glass transitions were observed from DMA thermograms for the cured BMI resins in the temperature range from 277°C to 311°C and decreased with increasing PPBMI content. The TGA results indicated the thermal stability was improved as PPBMI content increased. The investigations of the mechanical properties showed a complicated trend with an increase in PPBMI content. In addition, the equilibrium water uptake of the modified resins was reduced as PPBMI content increased. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1084‐1091, 2013

The interfacial adhesion of poly-p-phenylene benzobisoxazole/bismaleimide composites improved by oxygen/argon plasma treatment and surface aging effects

In this work, the interfacial adhesion of poly-p-phenylene benzobisoxazole/bismaleimide (PBO/BMI) composites improved by oxygen/argon plasma treatment and surface aging effects were investigated. The surface chemical compositions and the topography of the PBO fibers were analyzed using X-ray photoelectron spectroscopy and atomic force microscopy, respectively. The results showed that some active groups (e.g. carboxyl, hydroxyl and amide groups) were introduced onto the surface, and a noticeable alteration of the topography was also observed. After the PBO fibers were treated for 7min, the interlaminar shear strength was increased to 61.6MPa, an increase of 38.1%. Comparing the results with oxygen-only, argon-only and oxygen/argon plasma treatments, it can be inferred that the mechanical interlocking played a major role in the adhesion between the PBO fibers and the BMI resin. Through scanning electron microscopy, we found that the failure mode of the composite changed from adhesive failure to partial cohesive failure after the oxygen/argon plasma treatment. However, due to the surface aging effects, the interlaminar shear strength decreased sharply in the first few days and then, after 10days, remained substantially constant.

A multi-scale analysis of local stresses development during the cure of a composite tooling material

This paper is dedicated to the cure of an in-plane isotropic carbon-epoxy tooling material presenting a specific mesostructure. Eshelby-Kroner self-consistent model (EKSC) is used to achieve a two-steps scale transition procedure, allowing relating microscopic to macroscopic properties of the material, and estimating its multi-scale mechanical states. This procedure is used to predict the local residual stresses due to thermal and chemical shrinkage of the resin, depending on the manufacturing process conditions. An experimental investigation provides the BMI resin cure kinetics and mechanical properties as a function of the temperature and conversion degree. The consequences of these evolutions on the local mechanical states are investigated and discussed.