Properties and Flammability of Electrospun PVA and PVA/Laponite® Membranes

Physical and mechanical properties of electrospun polyvinyl alcohol (PVA) were related to electrospinning process parameters through fabricated structures, fiber morphology, and diameters. The effects of electrospinning voltage, flow rate and distance between needle tip and collector on tensile strength, strain at maximum load, burst strength, and air permeability were investigated. The results showed that higher applied voltage, lower flow rate, and shorter distance gave higher tensile strength. However, burst strength had critical points during the changes of the above three parameters while all the measured data were in a narrow range. Higher voltage and longer distance caused the lower air permeability. PVA/Laponite (R) nanocomposites were produced by electrospinning and tensile strength and flammability of electrospun PVA/Laponite (R) structures were studied. The results indicated that introduction of Laponite (R) nanoclay to electrospun PVA structure decreased the tensile strength and strain at maximum load. The low orientation of Laponite (R) nanoclay along the fibers due to the low aspect ratio of Laponite (R) resulted in lower tensile strength of electrospun PVA webs. The flammability of electrospun webs was characterized by burning rate. Electrospun PVA/Laponite (R) had slower burning rate than that of pure PVA and thus flame resistance of PVA webs was improved by adding Laponite (R) nanoclay. The increase in flame retardation is attributed to slower decomposition of PVA/Laponite (R) membranes.