Effect of expandable graphite on thermal and flammability properties of poly(lactic acid)‐starch/poly(ɛ‐caprolactone) blend systems

Abstract

The effect of expandable graphite (EG) on the flammability and thermal stability of a poly(lactic acid) (PLA)-starch/ poly(E-caprolactone) (PCL) blend was investigated. The samples were prepared by melt-mixing and characterized by thermogravimetric analysis (TGA), simultaneous TGA-Fourier transform infrared spectroscopy and cone calorimetry. The char residues of the composites after combustion in the cone calorimeter were analyzed with environmental scanning electron microscopy (ESEM). The thermal degradation stability of the composites was improved and the char content was found to be increased. The flammability performance results indicated that the PLA-starch/PCL blend was successfully modified with the EG micro-filler to obtain fire resistant composites, especially at high filler loadings, due to the formation of an intumescent carbonaceous char. This was confirmed by reductions of up to 64% in both the peak heat release rate (PHRR) and the total smoke release (TSR), and 54% in the specific extinction area (SEA). This is due to the EG acting mainly through a physical mode by cooling and fuel dilution, and through the formation of an intumescent char layer. However, the effective heat of combustion (EHC) and carbon monoxide (CO) yields did not favorably improve. POLYM. ENG. SCI., 00:000-000, 2017.Temperature at maximum weight loss from DTG. The values in parenthesis are the expected residue % (at 7008C) calculated from {residue % of the blend (e.g., 8.3%) 3 weight fraction of the blend (e.g., 0.95) 1 weight fraction of EG (e.g., 5%) 5 13%}.

Effect of different size‐modified expandable graphite and ammonium polyphosphate on the flame retardancy, thermal stability, physical, and mechanical properties of rigid polyurethane foam

“…In order to prevent burning and delay fire spread, flame retardants (FRs) are commonly used in polymers . The graphite intercalation compound (GIC), namely expandable graphite (EG), is known as a new generation of intumescent flame retardant, which is halogen‐free, nondripping, and low smoke . In the event of a fire or thermal shock, EG will instantly expand and form “worm‐like” expanded graphite.…”

Mixing‐sequence controlled selective localization of carbon nanoparticles in PLA/PCL blends

“…The biodegradable poly(lactic acid) (PLA)/poly(ε‐caprolactone) (PCL) blend is a material already used in the biomedical field . However, the addition of nanoparticles such as CNT and graphene nanoplatelets (GN) can provide it with new properties, allowing for new areas of application, since they produce fully biodegradable polymer blends combining good stiffness, strength, ductility, flammability, and electrical properties . However, as previously mentioned, the control of selective nanoparticle localization is important to define the blend's final properties.…”

Preparation and Properties of Compatible Starch‐PCL Composites: Effects of the NCO Functionality in Compatibilizer

“…Most of the decomposition process was distributed between 250 and 460 °C, leaving at least 8.5% final residue at 700 °C. This stage (250–460 °C) was mainly caused by the decomposition of starch and PCL . Moreover, it can be seen that the residual char of PS‐0 was the least, followed by PSPU‐2 and the PSTI‐3 had the largest residual amount, since there was no heat‐resistant benzene ring structure in PS‐0.…”

“…This stage (250-460°C) was mainly caused by the decomposition of starch [6,9,33] and PCL. [35] Moreover, it can be seen that the residual char of PS-0 was the least, followed by PSPU-2 and the PSTI-3 had the largest residual amount, since there was no heat-resistant benzene ring structure in PS-0. The PCLPU sample ( f = 2), did not only form a cross-linked layer to chemically interact with CS, but also had the soft segment structure that could interact with the PCL matrix through physical cross-linking to enhance the stability of the system significantly.…”