Dielectric and thermal properties of polymer network based on bismaleimide resin and cyanate ester containing dicyclopentadiene or dipentene. III

Octa(maleimidophenyl)silsesquioxane (OMPS) was synthesized, characterized, and employed to modify the BT resin which composed of 4,4 0 -bismaleimidodiphenylmethane (BMI) and 2,2 0 -bis(4-cyanatophenyl)propane (BCE). The curing reaction between OMPS and BT resin was first investigated. It was found that OMPS accelerate the curing reaction of BCE, and the onset temperature of the cyclotrimerization was reduced up to 95.58C (by DSC). As demonstrated by DSC and FTIR, there was no evidence that indicated the coreaction between maleimide and cyanate ester. 2,2 0 -diallyl bisphenol A (DBA) and diglycidyl ether of bisphenol A (E-51) (Wuxi Resin Factory, Jiangsu Province, China) were also used to enhance the toughness of BT resin, and the formulated BTA (containing DBA) and BTE (containing E-51) resins were obtained. The thermal properties of BT, BTA, and BTE resins incorporated with OMPS were then investigated. The results of DMA and TG showed that the BT, BTA, and BTE resins containing 1 wt % of OMPS exhibit enhanced thermal properties in comparison with their pristine resins respectively, while more contents of OMPS may impair the thermal properties of the polymer matrix, though the effect of OMPS was slight. Finally, the dielectric constant of these hybrid materials were detected, and their dielectric constant were distinctly reduced by the incorporation of OMPS, while overmuch contents of OMPS were disadvantageous for dielectric constant because of the aggregation of OMPS.

Section: Resultsmentioning

confidence: 97%

Thermal and dielectric properties of bismaleimide‐triazine resins containing octa(maleimidophenyl)silsesquioxane

Cao

2008

“…Furthermore, the dielectric properties were also promoted by the noncoplanar structures of HHPZ and BTPF, which disarranged the large conjugated system. The PB41/QF laminate had a lower dielectric constant than PPEBF‐Ph/QF due to higher crosslinking density with a higher content of triazine linkages …”

Section: Resultsmentioning

confidence: 99%

Low‐viscosity and soluble phthalonitrile resin with improved thermostability for organic wave‐transparent composites

Han

et al. 2017

High processing viscosity and poor solubility limit the application of heterocyclic polymers for fabricating organic wavetransparent composites for aerospace applications. In this paper, a novel resin, poly(phthalazinone ether bisphenol fluorene) encapped with phthalonitrile (PPEBF-Ph), was synthesized and used as the matrix. Biphenol-based phthalonitrile monomer BP-Ph was also synthesized and blended with PPEBF-Ph to further lower the processing viscosity. Solubility tests showed that the resin was soluble in dimethylformamide, N,N-dimethyl acetamide, N-methylpyrrolidone, dimethyl sulfoxide, chloroform, and other solvents. Differential scanning calorimetry and rheological studies revealed that the mixed resins exhibited low processing viscosity and a wide processing window below the gel temperature. Thermogravimetric analysis indicated that the cured resins were stable below 510-530 8C under nitrogen atmosphere after 6 h of curing (decreased by 40-60% compared with previous reports on phthalonitrile resin). In air, the char yields of the resins reached 20-30% when heated at 800 8C. The composites were reinforced by a quartz fiber cloth and exhibited a dielectric constant of 2.94-3.27 in an electromagnetic field with frequency ranging from 8 to 18 GHz. Retention of the bending modulus exceeded 70% at 400 8C according to dynamic mechanical analysis, indicating excellent mechanical stability was obtained.

“…The moisture absorption of CE resins is a function of inherent polarity of CE resins and crosslinking density. Although the introduction of p ‐xylene moiety and four methyl groups lowers the crosslinking density, the hydrophobic effect of p ‐xylene and four methyl groups will lower the water absorption effectively 26. Therefore, the water absorption of cured BBZCy is much lower than that of cured BADCy.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and properties of novel dicyanate with low dielectric and water absorption performance

Zhang

Wang

et al. 2011

The 1,4‐bis (3,5‐dimethyl‐4‐cyanatobenzyl) benzene (BBZCy) was synthesized successfully by the reaction of 1,4‐bis (3,5‐dimethyl‐4‐hydroxybenzyl)benzene(BBZ) with cyanogen chloride in the presence of triethylamine at −5–0°C. Its structure was confirmed by means of FTIR, elemental analysis, MS, and 1H NMR spectra. The monomer of BBZCy was cured by itself or cured with catalysts to form sym‐triazine structure. Thermal properties of cured BBZCy were studied using DSC, DMA, TMA, and TGA. Compared with the commercial bisphenol A dicyanate resin (BADCy), the cured BBZCy resin exhibited a lower dielectric constant (2.66 at 1 GHz), a lower dissipation factor (0.0054 at 1 GHz), lower water absorption (0.8% at 100 h), less thermal stability, and lower glass transition temperature. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011