Interpenetrating polymer networks formed by cyanate esters and phenylethynyl-terminated imides

2016 ◽  
Vol 29 (5) ◽  
pp. 556-568 ◽  
Author(s):  
Christoph Meier ◽  
Patricia P Parlevliet ◽  
Manfred Döring

An oligomeric phenylethynyl-terminated imide (PETI) has been formulated with a cyanate ester (CE) with and without the addition of a compatibilizer 2,2′-diallylbisphenol A (DABPA) forming interpenetrating polymer networks (IPNs). Modulated differential scanning calorimetry (mDSC) was used to monitor the curing of the resin mixtures. The formation of various resulting IPNs was verified using mDSC, dynamical mechanical thermoanalysis (DMTA), thermal gravimetry analysis and scanning electron microscopy. Furthermore, it could be shown by mDSC and DMTA that a covalent bond of the separated CE and PETI networks could be achieved by the addition of DABPA. In this regard, a reaction mechanism is proposed for the cross-linking reaction between the allylic pendent group of DABPA and the phenylethynyl end-group of the PETI resin. The cured resin specimens showed to have very high heat resistance and very high glass transition temperatures up to 330°C.

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.


e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Mehdi Ghafghazi ◽  
Masoud Esfandeh ◽  
Jalil Morshedian

AbstractThis paper describes the preparation of Epoxy/Urethane (EP/PU) graft interpenetrating polymer networks (g-IPNs) and investigates the effect of EP/PU weight ratio and urethane's prepolymer molecular weight on the mechanical, morphological and thermal properties of the IPN system. Here, g-IPN was prepared by thorough mixing of an isocyanate-terminated urethane prepolymer with an epoxy resin followed by simultaneous curing of the resins. Polytetra hydrofuranate (PTHF), molecular weights (Mw) 1000, 2000 and 3000 g/gmol, was used to prepare urethane prepolymers. EP/PU weight ratios were 75/25, 50/50, 30/70 and 15/85. Disappearance of epoxide and isocyanate functional groups was followed by Fourier Transform Infrared spectroscopy (FT-IR), showing curing of the resins. Differential Scanning Calorimetry (DSC) was used to investigate the glass transition temperature (Tg) of the IPNs. Thermal Gravimetric Analysis (TGA), Dynamic Mechanical Thermal Analysis (DMTA), tensile measurements and Scanning Electron Microscopy (SEM) were used to study thermal, mechanical and morphological properties of the prepared systems. The best mechanical properties were obtained at EP/PU weight ratio 75/25 which also shows a fine and uniformly dispersed morphology. Moreover, at this ratio, with increasing PTHF Mw in the urethane prepolymer, the mechanical properties were improved whereas a decrease was observed in Tg and thermal degradation temperature of g-IPNs.


2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Kuan-Liang Liu ◽  
Pei-Yu Kuo ◽  
Jin-Lin Han ◽  
Kuo-Huang Hsieh

To achieve a sustainable bioeconomy, various bioderived additives have been developed to produce biocomposites, but only a handful of research on biocomposites focuses on the effect of bioderived additives on interpenetrating polymer networks (IPNs). This study is aimed at understanding the interaction between bioadditives and interpenetrating polymer networks and is the first study to build the relationship between bioadditive ratio and damping factor based on dynamic mechanical analysis. The IPNs were prepolymerized in bulk by isocyanate and poly(oxypropylene) polyol (PPG) with two different molecular weights (PPG 700 and PPG 1000), and then, they were grafted with bisphenol A diglycidyl ether epoxy. The bioadditives were prepared from agricultural waste, sugarcane bagasse, and the effect of the coupling agent 3-glycidoxypropyltrimethoxysilane on a bioadditive surface was also discussed in this study. The results show that modified bioadditives have significant enhancement on tensile strength and tensile modulus of polyurethane-grafted epoxy resin interpenetrating polymer networks (PU(PPG)-EP graft-IPNs). However, the enhancement is not from a strong covalent bond between matrix and additives, that is, due to the well-dispersed bioadditives which provide stiff segments. The static and dynamic mechanical performance, water absorption ratio, and morphology of the (PU(PPG)-EP graft-IPNs) elastomers were also thoroughly discussed in this study.


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.


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