Chin-Lung Chiang

In this study, the carbon-rich cellulose architecture derived from discarded bamboo chopsticks was successfully valorized as a sustainable bio-carbon source, completely replacing traditional petroleum-based pentaerythritol (PER), to produce an intumescent flame retardant. A biomass-based intumescent flame retardant thermoplastic TPU composite material with P/N synergistic effects was prepared and compared with a conventional intumescent flame retardant, namely a PER/melamine (MEL)/ammonium polyphosphate (APP) composite. The biomass-based composite exhibited superior flame retardancy, smoke suppression, and toxicity reduction effects compared with the PER-based composite. Specifically, the TPU composite incorporating 30 wt% of the bamboo/MEL/APP intumescent system exhibited an elevated limiting oxygen index (LOI) of 29%, surpassing the 26% observed in the TPU/PER/MEL/APP system at the same loading. In addition, the biomass-derived formulation achieved a UL-94 vertical rating improvement from failure to V-0. The peak heat release rate, total heat release, and total smoke output were reduced by 45.18%, 37.98%, and 37.68%, respectively.

This study, based on the concept of a circular economy, utilizes cellulose from water bamboo shoot shell to synthesize a phosphorus-nitrogen flame retardant. This material is then used to improve the thermal properties of epoxy resin, resulting in a flame-retardant composite material with wider application potential. First, the husks were ground into powder, boiled, and dried. The powder was then reacted with phenyl phosphine (phenyl phosphinic acid), followed by the addition of triglycidyl isocyanurate (TGIC). Finally, epoxy resin and a hardener (DDM) were added to form the flame-retardant composite material. Thermogravimetric analysis (TGA) showed that the residual char rate increased from 15.3% to 25.5%, and the integrated programmed decomposition temperature (IPDT) increased from 659°C to 1058°C, demonstrating the composite's excellent thermal properties. The LOI value of pure epoxy resin was only 23%, but with the addition of a 40% flame retardant, the composite's LOI reached 26%. While epoxy resin does not achieve any UL-94 rating, the addition of a 40% flame retardant resulted in a V-0 rating with no dripping. This is because the phosphorus-based flame retardant forms a char layer upon high-temperature combustion, protecting the substrate from dripping. SEM was also used to observe the composite's surface morphology.

This study involves the surface modification of rice husk (RH) using phosphoric acid, and successfully synthesizing a novel bio-based intumescent flame retardant (ADP-RH) by combining ammonia water. ADP-RH serves as a source of acid, carbon, and gas. When incorporated at only 15[ ]wt.% into bio-based thermoplastic polyurethane (TPU) without the use of petrochemical flame retardants, the limiting oxygen index (LOI) of the composite material reaches 29%, and it achieves a V0 flame retardant rating in the UL 94 test. ADP-RH enhances the compatibility between the flame retardant and bio-based TPU, achieving excellent flame retardancy at low concentrations. This work provides valuable insights for the development of bio-based TPU composite materials suitable for various applications.