Bismaleimide Modified by Allyl Novolak for Superabrasives

A novel thermosetting resin system for superabrasives based on novolak and bismaleimide （BMI） was developed. The novolak resin was allylated and then copolymerized with BMI. The structure of allyl novolak and reaction mechanism were analyzed by FFIR. Thermal and mechanical properties were characterized by using com- prehensive thermal analyzer （DSC-TG） and strength tester, respectively. The results showed that high molecular weight of novolak was advantageous for heat-resistance, but was unfavorable for the bending strength. High allyl content improved the heat-resistance but lowered the bending strength. When the molecular weight of novolak was 450 and allyl content was 50%, the best resin system with good heat-resistance and bending strength was obtained. It was suitable for the manufacturing of superabrasive tools.

Studies on Rheological Behaviors of Bismaleimide Resin System for Resin Transfer Molding

The rheological behavior of bismaleimide resin for resin transfer molding(RTM) was studied with DSC analysis and viscosity experiments A rheological model based on the dual Arrhenius equation was established and used to simulate the rheological behavior of the resin The model predictions determined from the dual Arrhenius equation were in good agreement with experimental data The processing window of the resin system can be well determined based on the developed model The rheological model is importan...

SYNTHESIS OF A NEW SILICONE-CONTAINING BISMALEIMIDE COPOLYMER RESIN

A copolymer of bismaleimide-diallylbisphenol A-diphenylsilandiol was synthesized and the copolymerisation was studied by using N-phenylmaleimide, bisphenol A and diphenyl-silandiol as model compounds. The copolymer could be well. cured around 200 degrees C, and the cured resins had good thermal stability. In the range of 170-210 degrees C, a higher curing temperature was favorable to obtain more thermal stable resin by reducing the content of diphenylsilandiol cyclo-homopolymer in resin which would spoil its-thermal stability.

STUDY ON CO-CURING REACTION IN CHAIN-PROLONGED BISMALEIMIDE-UNSATURATED POLYMER RESIN SYSTEM

The curing proces of chemical reactombetween flexible unsaturated polymer resin and diphenyl-methane bismaleimides which have been chain-prolonged by diaminodiphenylmethane is presented. also the kinetics parameters and curing technology are investigated.

Phase separation morphology and mode II interlaminar fracture toughness of bismaleimide laminates toughened by thermoplastics with triphenylphosphine oxide group

Toughness improvement of bismaleimide（BMI）resin is very important for its application in composite materials.Blending with

Thermal conductivity and dielectric properties of bismaleimide/cyanate ester copolymer

The blend was synthesised with bismaleimide(BMI)resin and bisphenol A-based cyanate ester(BADCy)resin.The BMI/BADCy copolymer showed excellent dielectric and thermal conductivity properties.The volume resistivity of the copolymer was a little lower than BADCy system.The volume resistivity of blend was 7.8×10^(15)Ω·cm when the BMI content was 20 wt%,which still showed good insulation performance.The dielectric property of modified BADCy copolymer remained the good stability from 0.1 Hz to 1 MHz.Compared to pure BADCy system,the breakdown property of BMI/BADCy blend reached the maximum value of 77.9 kV/mm when the content of BMI was 20 wt%,which was still about 1.22 times.The thermal property and thermal conductivity property of the copolymer were higher than BADCy system.

Thermal Degradation Kinetics of Structurally Diverse Poly(bispropargyl ethers-bismaleimide) Blends

Structurally diverse bispropargyl ethers using resorcinol,quinol,4,4￠-dihydroxy biphenyl,bisphenol-A,4,4￠-dihydroxy diphenyl ketone,4,4￠-dihydroxy diphenylsulphone,trimethyl indane bisphenol and tetramethyl spirobiindane bisphenol were prepared by using phase transfer catalyst.Synthesized materials were separately blended with 4,4￠-bismaleimido diphenyl methane（BMIM）in mole ratios（0.5：0.5）.The materials were thermally cured and the structural characterisation and the thermal properties of these cross-linked materials are investigated using Fourier-transform infrared（FTIR）spectrophotometer and thermogravimetric analyzer（TGA）.Among the different materials investigated poly MRPE,poly MBPEBPA and poly MSPE show higher onset degradation temperature of 300°C indicating higher thermal stability.The degradation kinetics is investigated using Flynn-Wall-Ozawa（FWO）,Vyazovkin（VYZ）and Friedman（FRD）methods.Amongst the various cured materials investigated,the activation energy（Ea-D）values obtained for poly MRPE and poly MKPE were observed to increase continuously froma=0.2 to 0.8 and the values range from 199 kJ/mol to 245 k J/mol and 153 k J/mol to 295 k J/mol respectively.The crosslinked materials resulting from these bispropargyl monomers definitely need more energy for bond cleavage due to the presence of more aromatic units.The volatile products obtained during the thermal degradation of the polymers were analyzed using thermogravimetric-Fourier transform infrared analyses（TG-FTIR）.The phenols,substituted phenols,carbon monoxide,carbon dioxide and small amount of aniline were found to be the major products during thermal degradation of these cured blends.

Synthesis and fluorescence behavior of 2,5-diphenyl-l,3,4- oxadiazole-containing bismaleimides and bissuccinimides

Bismaleimides bearing 2,5-diphenyl-l,3,4- oxadiazole chromophores at para, meta, ortho position and corresponding saturated bissuccinimides were synthe- sized. Several synthetic strategies for these bismaleimides were discussed in detail. Almost no or very weak fluorescence was observed for these bismaleimides, however, the bissuccinimides show a strong fluorescence. The effect of molecular geometry on optical behavior and fluorescence quenching mechanism were investigated by UV-vis absorption and fluorescence emission spectro- scopy. The electron coupling of ground state of p- bismaleimide is stronger than those of m- and o- bismaleimides.p-Bissuccinimide displays increasing fluor- escence quantum yields with red shifts of 22-24 nm, compared to m-bissuccinimide. Polymerizable C=C bonds play a key role in the intramolecular fluorescence quenching.

高强度环氧-酰亚胺粘合剂的研制

选用双马来酰亚胺(BMI)对环氧树脂进行改性,制得一种高强度环氧-酰亚胺体系的ET粘合剂,并对ET粘合剂进行了一系列性能研究。结果表明:ET粘合剂的拉伸剪切强度最高达28.4 MPa,吸水率小于1%,并具有良好的电学性能和工艺性能。

Preparation and Properties of Nano-SiO_2/TDE-85/BMI/BAD Cy Composites

A new type of the nanometer particles and epoxy/bismaleimide-triazine nanocomposites were prepared using a nanometer silica （nano-SiO2）, a 4,5-epoxycyclohexane 1,2-dicarboxylic acid dilycidyl （TDE-85） epoxy resin, a 4,4＇-bismaleimidodiphenymethane （BMI） and a bisphenol a dicyanate （BADCy）. The properties of nano-SiOJTDE-85/BMI/BADCy composites, such as mechanical and thermal properties, were systemically investigated in detail by mechanical measurement, scanning electron microscope （SEM）, dynamic mechanical analysis （DMA） and thermogravimetric analysis （TGA）. The experimental results showed that the addition of the appropriate amount of nano-SiO： could improve the impact strength and the flexural strength of the nano- SiO2/TDE-85/BMI/BADCy composites. Simultaneously, the thermal stability of the blends was found to be higher than that of the TDE-85/BMI/BADCy copolymers.

Research on the Fire Resistance of BMI/DDM Resin Toughened by CTBN

Many factors that affect the flame resistance of the modified BMIsystem were studied, including the effect of different content ofP_4, C_24H_29Cl_21/ZnO_3B_2o_3·5H_2O and C_24H_29Cl_21/MoO_3 onOxygen Index of the modified Bismaleimide resin. The thermalstability and mechanical properties of the cured BMI resin were alsomeasured. It showed that this new kind of modified bismaleimide resinhad nice fire resistance, excellent thermal stability and mechanicalproperties.

CHEMORHEOLOGY OF MODIFIED BISMALEINIDE RESIN SYSTEM

The chemorheology of bismaleimide (BMI) resin system comprised of 4,4'-bismaleimidodiphenyl-methane, 4,4'-diaminodiphenyl-methane, phenoltype epoxy resin, and carboxyl-terminated butadiene-acrylonitrile rubber was investigated. Thermal analysis techniques were employed to obtain Kinetic and network parameters which is necessary for the development of a phenomenological viscosity model based on a modified version of the Wiliams-Landel-Ferry (WLF) equation. The model predictions agreed well with experimental value of viscosity.

THE SYNTHESIS OF MODIFIED DIPHENYL OXIDE RESIN

Modified diphenyl oxide resin was synthesized by co-polymerization of unsaturated acid and diphenyl oxide derivants. And then modified bismaleimide resin and expoxide linear phenolic resin were added into modified diphenyl oxide resin to co-polymerize and modify once more. The system was applied in composites. Their properties were investigated and found that they met the requirements as a heat-resisting adhesive.

Morphological and Spatial Effects on Toughness and Impact Damage Resistance of PAEK-toughened BMI and Graphite Fiber Composite Laminates

The microstructure property relationships have been studied in terms of glass transition behavior,phase morphology,and fracture toughness on thermoplastic polyetherketone with a phenolphthalein side group (PAEK) toughened bismaleimdes (BMI) resins,and in terms of interlaminar morphology and compression after impact (CAI) on the graphite fiber (T700SC),the rein-forced BMI matrix composites that are toughened with a so-called ex-situ concept,respectively. The characteristic morphology spectrum has been found ...

Influence of processing temperature on interfacial behavior of HKT800 carbon fiber with BMI and epoxy matrices

This paper aims to study the effect of processing temperature on interfacial behavior of HKT800 carbon fiber composites with epoxy and Bismaleimide（BMI） matrix.Referring to the processing conditions of the composite, various processing-heat treatments were conducted on HKT800 and the extracted sizing content declines with increasing temperature.Chemical analysis shows that the HKT800 sizing is epoxy-type and reactive at 200 C.The interfacial shear strength（IFSS） of HKT800/epoxy and HKT800/BMI was investigated by micro-droplet method, for which the composites were fabricated with modeling temperature schemes referring to different diffusion, cure and post-cure stages.It shows that diffusion temperature and conversion degree of the resin both enhance the interfacial adhesion of HKT800/epoxy composite.For the HKT800/BMI composite,the diffusion temperature shows a insignificant effect on the IFSS.FTIR analysis indicates that sufficient reactions are achieved between HKT800-sizing and epoxy resin, however only partial reactions are observed between the sizing and BMI.Moreover, the presence of the sizing can evidently improve the wettability of HKT800 with epoxy resin but is unfavorable for HKT800 with BMI.

Preform-based toughening technology for RTMable high-temperature aerospace composites

This article describes the efforts that led to the development of surface-loaded preforms that may be used to significantly improve the compression-after-impact strength of high-temperature composites and correspondingly to dramatically reduce the area of damage because of impact.Moreover,by matching the toughening polymer surface-loaded and design of the surface pattern,in-plane mechanical properties are unaffected or even improved over laminates made from the identical materials.The proprietary preforms,so-called ESTM-Fabrics,may be handled and infused with the high-temperature RTMable resins such as bismaleimide and polyimide in exactly the same manner as traditional fabrics without surface modification.The RTM conditions for the preform-based toughening is fully compatible with the traditional process procedure,making the technology cost-effective in production.This technology represents a key enabler for the use of low-cost RTM processes for high-temperature resins to supplant prepreg as the building-block material of choice for aeronautical composite structures.