A high-performance matrix is the key base for the fabrication of high-frequency copper-clad laminates. A high-performance resin system based on commercial poly(phenylene oxide) (PPO) and 2,2 0 -bis(4-cyanatophenyl) isopropylidene (BADCy), coded as PPO-n/ BADCy (where n is the weight parts of PPO per 100 weight parts of BADCy), was developed. The effect of PPO on the key properties, including the dielectric and thermal properties, water resistance, and toughness, of the cured resins was investigated extensively. The results show that PPO not only catalyzed the curing reaction of BADCy but also reacted with BADCy to form a singlephase structure. Furthermore, compared with the cured BADCy resin with 1 phr epoxy resin as a catalyst, the cured PPO-n/BADCy resins had significantly increased impact strengths and decreased dielectric constants, loss, and water resistance. The reasons behind these desirable improvements are discussed from the view of structureproperty relationships. These results suggest that the PPO-n/BADCy system has great potential to be used as a matrix for high-frequency copper-clad laminates or other advanced composites.
Novel modified cyanate ester resins (EPMPS-n/BADCy), with significantly decreased dielectric loss and improved toughness, were developed by copolymerizing the cyanate ester resin, 2, 2(-bis (4-cyanatophenyl) isopropylidene resin) (BADCy), with an epoxidized methyl phenyl silicone resin (EPMPS). The curing behavior of EPMPS-n/BADCy and the typical properties of the corresponding cured EPMPS-n/BADCy were systematically investigated. The results show that the addition of EPMPS into BADCy can not only accelerate the curing reaction of BADCy, but also decrease dielectric loss and enhance the impact strength as well as water resistance. For example, in the case of the modified BADCy resin with 15 wt%EPMPS, its impact strength is 17.8 kJ/m 2 , about 3 times of that of pure BADCy resin and its water absorption is only 0.25%, about one-half of that of pure BADCy resin. In addition, while the dielectric loss is only 79% of that of pure BADCy resin, while its dielectric constant remains constant over the frequency range of 1KHz-1 MHz. The above results suggest that EPMPS-n/BADCy have great potential to be used as the matrix or adhesive for advanced composites.View this article online at wileyonlinelibrary.com PROPERTIES OF CYANATE ESTER/POLYORGANOSILOXANE Scheme 3. The formation of oxazolidinone rings.Scheme 2. Formation of triazine rings.Scheme 4. Self-polymerization of EPMPS.
High curing temperature is the key disadvantage of cyanate esters. A novel catalyst system was developed, which is a hybrid catalyst system (HC) consisting of UV activated tricarbonyl cyclopentadienyl manganese (Catalyst I) and Catalyst II derived from dibutyl tin dilaurate. The effect of HC on the reactivity of 2, 2 0 -bis(4-cyanatophenyl) isopropylidene (BADCy) monomer, and that on the dielectric and thermal properties of cured resin were investigated. Results show that HC displays an attractive synergy effect on catalyzing BADCy over its two components. Compared with the curing exothermic peak of BADCy, that of BADCy/HC system appears at significantly lower temperature (which is at least 1208C lower than the former). In addition, cured BADCy/HC resin also exhibits interesting synergy effect in integrated performance, that is, it has much better thermal resistance and dielectric properties than cured BADCy, BADCy/Catalyst I, and BADCy/Catalyst II resins. The BADCy/HC resin can be used as high performance matrices for advanced composites and adhesives. POLYM. ENG. SCI., 51:2236-2244
Advanced wave-transparent composites are the key materials for many cutting-edge industries including aviation and aerospace, which should have outstanding heat resistance, low dielectric constant and loss as well as good mechanical properties. A novel kind of high-performance wave-transparent composites based on surface-modified aluminum phosphate AlPO 4 (KH-550) and cyanate ester (CE) was first developed. The dielectric and dynamic mechanical properties of AlPO 4 (KH-550)/CE composites were investigated intensively. Results show that AlPO 4 (KH-550)/ CE composites have decreased dielectric loss and higher storage moduli than pure CE resin; in addition, the composites with suitable AlPO 4 (KH-550) concentration remain the outstanding thermal property and low dielectric constant of pure CE resin. The reasons attributing to these results are discussed from the effects of AlPO 4 (KH-550) on the key aspects such as morphology, curing mechanism, and interfacial adhesion of composites.
Thermodegradation behaviors of novel aluminum phosphate/cyanate ester (AlPO 4 (KH550)/CE) composites were studied in detail. Results show that thermodegradation behaviors and kinetic parameters of AlPO 4 (KH550)/CE composites are greatly dependent on the AlPO 4 (KH550) loading. The addition of AlPO 4 (KH550) into CE resin changes the thermodegradation mechanism (mainly at the temperature lower than 450 C) and degradation process from two steps to three steps. Comparing with CE resin, AlPO 4 (KH550)/CE composites have lower initial degradation temperature and greatly higher char yield. Besides, for each thermodegradation step, the more the AlPO 4 content, the smaller the activation energy value is. All reasons leading to these outcomes are investigated intensively.
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