High-performance polymer composites with enhanced mechanical and thermal properties from cyanate ester/benzoxazine resin and short Kevlar/glass hybrid fibers

The investigation and design of new polymeric materials with an astonishing combination of properties are nowadays of great importance to facilitate the manufacturing process of high-quality products intended to be utilized in different applications and technical fields. For this intent, novel high-performance blend composites composed of the cyanate ester/benzoxazine resin blend reinforced by different proportions of silane-surface modified Kevlar and glass fibers were successfully fabricated by a compression molding technique and characterized by different experimental tests. The mechanical test results revealed that the bending and impact strength properties were considerably improved when increasing the amount of the hybrid fibers. The studied materials also presented excellent thermal stabilities as compared to the unfilled blend’s properties. With respect to the properties of the reinforcing systems, these improvements seen in either the mechanical or thermal properties could be due to the good dispersion as well as excellent adhesion of the reinforcing fibers inside the resin matrix, which were further evidenced by the Fourier transform infrared spectroscopy and scanning electron microscopy results. Consequently, the improved mechanical and thermal properties promote the use of the fabricated hybrid composites in domestic and industrial applications requiring functional materials with advanced properties for aerospace and military applications.

Improving the flame retardancy and thermal property of organotitanate-modified epoxy resin for electronic application via a simple method

The development of halogen-free epoxy resins (EPs) has become a major concern in the field of electronic packaging materials because flame retardants containing halogen release toxic chemicals during combustion. In this article, a type of modified EP possessing multiple functionalities, including high flame retardancy and thermal property as well as low hygroscopicity, was prepared via a simple method by taking advantage of synergistic effects of organotitanate and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO). The mechanical and thermal properties of the as-prepared EP/titanium (Ti)/DOPO system were characterized by dynamic mechanical analysis, glass transition temperature, differential scanning calorimetry, and so on. The results showed that the incorporation of organotitanate and DOPO into EP can not only enhance the decomposition temperature and residual char but also increase the glass transition temperature and limiting oxygen index (LOI) value. The EP/Ti/DOPO system reached UL94 V-0 rating with an LOI of 34.7%. Compared to pure epoxy, the peak heat release rate, heat release capacity, and total heat release of EP/Ti/DOPO were decreased by 33.3%, 35.1%, and 16.7%, respectively.