A positron annihilation study on the microstructure of cyanate ester resin toughened by carboxyl‐terminated butadiene‐acrylonitrile rubber system

Zeng, Minfeng; Sun, Xudong; Wang, Yun; Zhang, Mingzhu; Shen, Yong‐Miao; Wang, Baoyi; Qi, Chenze

doi:10.1002/pat.1185

Cited by 30 publications

(13 citation statements)

References 29 publications

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“…PALS is an effective method to calculate the free volume of polymers, by which o‐Ps lifetime (τ 3 ) and o‐Ps intensity ( I 3 ), as summarized in Table 1, can be obtained. Thus useful parameters related to the free volume, such as the average volume of free cavities ( V h ) can be calculated:45, 46 where R is the average radius of a free volume cavity and R 0 is an empirical parameter ( R 0 = R + δ R , where δ R is 0.166 nm). In addition, the apparent free volume fraction ( f app ), which is concerned with the microstructure of modified CE resin, can be calculated: …”

Section: Resultsmentioning

confidence: 99%

Novel hyperbranched polyphenylsilsesquioxane‐modified cyanate ester resins with improved toughness and stiffness

Zhuo

Liang

et al. 2011

Polymer International

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High-performance thermosetting resins should have good toughness and stiffness, so simultaneously toughening and stiffening is the main target in developing high-performance resins. A novel modified cyanate ester resin with improved toughness and stiffness was developed by copolymerizing 2,2 -bis(4-cyanatophenyl)isopropylidene (CE) with hyperbranched polyphenylsilsesquioxane (HBPPSi). The mechanical properties and their nature were systematically investigated from the viewpoint of structure-property relations using positron annihilation lifetime spectroscopy and spectral analyses. It is found that a suitable content of HBPPSi in CE resin can effectively improve toughness and stiffness. In the case of the CE resin modified with 10 wt% HBPPSi, its impact and flexural strengths are 21 kJ m −2 and 148 MPa, respectively, about 2.6 and 1.4 times of those of neat CE resin. The flexural modulus increases from 3.0 (for neat CE resin) to 3.4 GPa. The results of dynamic mechanical analyses also corroborate the static mechanical properties. The improved toughness and stiffness of CE resin can be attributed to the synergistic effect resulting from changes of both polymer chain structure and aggregation state structure. These attractive features of HBPPSi/CE resins suggest that the method proposed herein may be a new approach for the development of high-performance resins for cutting-edge industries.

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Section: Resultsmentioning

confidence: 99%

Novel hyperbranched polyphenylsilsesquioxane‐modified cyanate ester resins with improved toughness and stiffness

Zhuo

Liang

et al. 2011

Polymer International

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“…The apparent fraction free volume ( f v ) was estimated by eq. :

f_{v} = I_{3} V_{normal3} + I_{normal4} V_{normal4},

where V 3 and V 4 are the mean free volumes of spheres with radiuses r 3 and r 4 , respectively, according to eq. :

V_{j} = \frac{4 π r_{j}^{normal3}}{3} .

…”

Section: Methodsmentioning

confidence: 99%

High‐performance PDMS membranes for pervaporative removal of VOCs from water: The role of alkyl grafting

Zhou

Chen

et al. 2016

J of Applied Polymer Sci

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To improve the pervaporation performance of PDMS membrane, alkyl groups with different chain length were grafted into PDMS matrix. The prepared membranes were characterized by ATR-IR, DSC, TGA, PALS, and tensile testing. The effects of alkyl grafting on pervaporation performance of PDMS membrane were investigated in separation of ethyl acetate/water mixture. Experimental results show that the separation factor of PDMS membrane is largely improved by alkyl grafting because of the enhanced preferential sorption of ethyl acetate, and this improvement depends on alkyl grafting ratio and alkyl chain length. The total flux of PDMS membrane reduces after alkyl grafting owing to the decreased free volume. When grafting ratio is above 6.9%, membrane grafted with shorter alkyl groups is preferred for pervaporation. The best pervaporation performance is achieved by 9% octyl grafted PDMS membranes with a separation factor of 592 and a total flux of 188 gm 22 h 21 in separation of 1% ethyl acetate/water mixture at 40 8C. Moreover, this octyl grafted PDMS membrane also exhibits excellent separation performance in removal of butyl acetate, methyl-tert-butyl ether, and n-butanol from water.

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“…33 Figure 8 shows the calculated V h and f app values of cured EA and EA/mSiO 2 resins. EA/mSiO 2 resins have lower V h and f app values than EA resin.…”

Section: Industrial and Engineering Chemistry Researchmentioning

confidence: 99%

Tough Silica-Hybridized Epoxy Resin/Anhydride System with Good Corona Resistance and Thermal Stability for Permanent Magnet Synchronous Wind-Driven Generators through Vacuum Pressure Impregnation

Zhou

Liang

et al. 2015

Ind. Eng. Chem. Res.

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The biggest obstacle to fabricate permanent magnet synchronous wind-driven generators (PMSWG) is lack of high-performance resins for vacuum pressure impregnation (VPI) technique. A novel resin system was developed by hybridizing epoxy resin/anhydride (EA) with specially modified silica (mSiO 2 ) and grinding technology. EA/mSiO 2 resins have good processing features for VPI technique reflected by suitably low viscosity and very long work life (≥24 months), and they also show much higher impact and flexural strengths, corona resistance, and thermal stability than EA resin. For the EA/mSiO 2 resin with 9 wt % mSiO 2 , its impact strength and corona resistant life are 25.2 kJ/m 2 and 806 min, more than 3.4 and 16.1 times those of EA resin, respectively. Simulation stator coils impregnated with EA/mSiO 2 resins exhibit much better electrical insulation than those with EA resin, demonstrating that EA/mSiO 2 resins are the right candidate for fabricating PMSWG and other high-voltage motors, generators, and transformers.

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A positron annihilation study on the microstructure of cyanate ester resin toughened by carboxyl‐terminated butadiene‐acrylonitrile rubber system

Cited by 30 publications

References 29 publications

Novel hyperbranched polyphenylsilsesquioxane‐modified cyanate ester resins with improved toughness and stiffness

Novel hyperbranched polyphenylsilsesquioxane‐modified cyanate ester resins with improved toughness and stiffness

High‐performance PDMS membranes for pervaporative removal of VOCs from water: The role of alkyl grafting

Tough Silica-Hybridized Epoxy Resin/Anhydride System with Good Corona Resistance and Thermal Stability for Permanent Magnet Synchronous Wind-Driven Generators through Vacuum Pressure Impregnation

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