INTERPENETRATING POLYMER NETWORKS AS HIGH PERFORMANCE DIELECTRIC ELASTOMERS

Author(s):  
Soon Mok Ha ◽  
Wei Yuan ◽  
Qibing Pei ◽  
Ronald Pelrine ◽  
Scott Stanford
Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 862 ◽  
Author(s):  
Jingfeng Liu ◽  
Weifeng Fan ◽  
Gewu Lu ◽  
Defeng Zhou ◽  
Zhen Wang ◽  
...  

Thermoplastic polyimide (TPI) was synthesized via a traditional one-step method using 2,3,3′,4′-biphenyltetracarboxylic dianhydride (3,4′-BPDA), 4,4′-oxydianiline (4,4′-ODA), and 2,2′-bis(trifluoromethyl)benzidine (TFMB) as the monomers. A series of semi-interpenetrating polymer networks (semi-IPNs) were produced by dissolving TPI in bisphenol A dicyanate (BADCy), followed by curing at elevated temperatures. The curing reactions of BADCy were accelerated by TPI in the blends, reflected by lower curing temperatures and shorter gelation time determined by differential scanning calorimetry (DSC) and rheological measurements. As evidenced by scanning electron microscopy (SEM) images, phase separation occurred and continuous TPI phases were formed in semi-IPNs with a TPI content of 15% and 20%. The properties of semi-IPNs were systematically investigated according to their glass transition temperatures (Tg), thermo-oxidative stability, and dielectric and mechanical properties. The results revealed that these semi-IPNs possessed improved mechanical and dielectric properties compared with pure polycyanurate. Notably, the impact strength of semi-IPNs was 47%–320% greater than that of polycyanurate. Meanwhile, semi-IPNs maintained comparable or even slightly higher thermal resistance in comparison with polycyanurate. The favorable processability and material properties make TPI/BADCy blends promising matrix resins for high-performance composites and adhesives.


2016 ◽  
Vol 23 (6) ◽  
pp. 579-588
Author(s):  
Zhiran Chen ◽  
Yajie Lei ◽  
Hailong Tang ◽  
Xiaobo Liu

AbstractThe 2,2-bis[4-(3,4)-dicyanophenoxy phenyl]propane (BAPh)/polyarylene ether nitrile (PEN-OH) prepolymers and polymers were prepared by heat polymerization. Firstly, BAPh/PEN-OH systems were characterized using differential scanning calorimetry, dynamic rheological analysis, and thermal gravimetric analysis. The results revealed that the polymerization reaction can be controlled by various concentrations of PEN-OH and postcuring temperatures, and BAPh/PEN-OH prepolymers had low curing temperatures (229.3–300.4°C), large processing windows (∼106.5°C) with low melt viscosities, and excellent thermal stabilities. Then, the polymerization reaction and surface structures of BAPh/PEN-OH systems were investigated using Fourier transform infrared and scanning electron microscopy, respectively. The interpenetrating polymer networks were found in BAPh/PEN-OH polymers, suggesting that the addition of PEN-OH can not only promote the curing behaviors of BAPh but also increase the toughness of the polymers. The flexure strength and modulus of BAPh/PEN-OH polymers increased with the introduction of PEN-OH. The dielectric properties of BAPh/PEN-OH polymers were investigated, which had little dependence on the frequency. BAPh/PEN-OH systems can be used as a good candidate for high-performance polymeric materials.


2006 ◽  
Author(s):  
Soon Mok Ha ◽  
Wei Yuan ◽  
Qibing Pei ◽  
Ron Pelrine ◽  
Scott Stanford

2020 ◽  
Vol 42 (4) ◽  
pp. 245-253
Author(s):  
A.M. Fainleib ◽  

In a short review the effective methods of optimization of structure and properties of high-performance polymers obtained from thermoreactive nitrogen-containing resins such as benzoxazines, bismaleimides, cyanate esters have been analysed. High crosslinked density copolymer thermosets are synthesized through chemical interactions between reactive functional groups, which belong to the monomers/oligomers used. The different possible processes such as copolymerization or formation of interpenetrating polymer networks are discussed. The high-performance polymers and composites from thermoreactive nitrogen-containing resins are effectively used in aerospace industry and microelectronics as materials possessing high thermal and thermooxidative stability, radiation and chemical resistance, low water absorption, low dielectric loss, high dimension stability and high adhesion to different substrate. The performance characteristics of this kind of materials can be controlled by changing their composition, temperature-time curing schedule, using catalytic systems. Keywords: copolymers, IPNs, thermoreactive resins, benzoxazine, bismaleimide, cyanate ester resins.


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