Papers by Author: Wei Jen Chen

Abstract: Polypropylene (PP) has the disadvantage of flammability and easy dripping, flame retardant was incorporated into polymer to improve the thermal and flame retardant property. Conventional flame retardant containing halogen would release toxic gases when the materials got fire and let the people died in the fire and destroy the environment. Intumenscent flame retardant consists of three key components: acid source, carbon source and blowing agent. Acid source is phosphoric acid, which can dehydrate the materials. Carbon source can form char layer to prevent further thermal degradation. The blowing agent can swell the carbon layer to avoid heat and mass transfer during material get fire. Novel intumenscent flame retardant which contains phosphorus and nitrogen was successfully prepared. FTIR, TGA, LOI and UL-94 were used to characterize the structure, flame retardant mechanism and thermal property of the composites. LOI and UL-94 data showed the composites possess excellent flame retardant property. For kinetic of thermal degradation.

Abstract: The composites of mechanical and thermal properties of modified and unmodified Carbon nanotube /epoxy resin nanocomposites tested under various circumstances is a major investigation in this study. Identification of functional groups of CNT surface using Fourier transforms infrared spectroscopy (FTIR) was done to male sure if the means of modification adopted in this study is successfully. The tensile and flexural strengths of modified CNT-containing nanocomposites with the amount of modified CNT around 0.75 Phr tested under room temperature circumstance increase 10.96 % and 21.44 % respectively. These two strengths of nanocomposites tested under high temperature circumstance increase 14.55 % and 10.80 % respectively. Additionally, both strengths of nanocomposites tested under high temp.-high humidity circumstance increase 11.65 % and 23.53 % respectively. According to the test results using pyris diamond thermomechanical analyzer (TMA) coefficient decreases 39.81 % with increasing the content of modified CNT and meanwhile glass transition temperature increases 4.15 %. Because of above-mentioned effect, a modified CNs-containing nanocomposite possesses great thermo stability. Overall, No matter what circumstance (high temperature or high temp.-high humidity circumstances) nanocomposites expose to, and no matter whether CNT are modified or not, CNT do significantly enhance mechanical and physical properties of composite.

Abstract: In recent years, the influence of surface modification of carbon nanotubes (CNTs ) on CNT’s dispersion among epoxy resin, mechanical properties and electrical conductivities of CNTs has been observed. On account of above-mentioned effects, that CNTs treated with oxidizing in organic acids, a kind of surface modification, generates functional groups on the surface of CNTs is a major investigation in this study to enhance mechanical properties and electrical conductivities of CNTs. In this study, CNTs dispersed among epoxy resin well by adopting ultrasonication method and then the nano-prepreg was fabricated by mixing CNTs/Epoxy resin into carbon fiber. The influence of the different proportion contents of CNTs added into Epoxy resin on mechanical properties and electrical conductivities of composites is investigated. The strength of material tested under different circumstance is also observed. Furthermore, the creep behavior of carbon fiber/epoxy resin thermosetting composites tested under different circumstance and stress is also concerned to be analyzed.