All-polymer hybrid electret fibers for high-efficiency and low-resistance filter media

Abstract

A one-step and controllable strategy to prepare all-polymer hybrid electret fibers is reported based on the coupling of polystyrene and polyvinylidene fluoride in electric response. The complementary dielectric properties between PS and PVDF generate dual-system electret charges within PS/PVDF fibers, thereby improving the electret effect. The bi-component all-polymer electret fibers show enhanced electret property and structural continuity, contributing to a N95 protective respirator with high filtration efficiency (99.752%), low air resistance (72 Pa) and long service life. The fabrication of all-polymer electret fibers solves the challenge of nanoparticle toxicity for existing polymer/nanoparticle electret fibers.

Research on Regularities of Cyclic Air Motion through a Respirator Filter

“…where β 2 is density of sediment on the surface of the filter fibre, kg/m 3 ; M=β 2 h 1 is dust holding capacity, kg/m 2 ; h 1 is dust sediment height, m; V p is dust particle volume, m 3 The process of settling the aerosol particles on a cylinder can be expressed by the well-known equation:…”

“…The resistance of filters to air flow is one of the most important indicators of filter respirators [1][2][3]. The protective power time of filters and the user's working capacity depend on its level, which both defines the selection of respiratory protective equipment (RPE) and estimates their protective efficiency [4][5][6][7].…”

“…where p(y,t) is the pressure drop, Pa; Rf is the initial resistance value of a clean filter, (H•s)/m 3 ; V b is the air volume when breathed in and out, m 3 ; ω is the ripple frequency, 1/s; k is the parameter which characterizes the permeability of the porous medium, (m −1 ); y is a coordinate, m; t is time, s. The results of calculating the value of pressure drop for respirator filters by formula (1) show its dependence only on the volume of the inhaled and exhaled air, which fluctuates according to the harmonic law as a material particle, which does not allow the estimation of the influence of the air velocity on the respirator filter resistance under different breathing modes as a result of an increase in the load on the worker when performing the production functions. The model conditions a significant error in the result obtained as compared with the experimental data [19], because it does not consider the change in the filtering velocity, which is related to the area of the filter under consideration, which will have an impact on the initial filter resistance, particularly with increasing load on workers, when structural changes occur in the breathing process: the phase of inhalation decreases in time, while the phase of exhalation, on the contrary, increases, which leads to significant differences between the values of pressure drop in a respirator filter.…”

Polymer electrets and their applications

“…One serious problem is that the air we breathe today has been heavily polluted by various pollutants (particles) in the environment, including, black carbon, coal dust, tobacco smoke, dust, pollen, and bacteria. It is thereby very imperative to prevent the human respiratory system from these pollutants, an important issue in occupational hygiene 196 . Filtration is considered as one valid way to do that, in addition to wet scrubbing and electrostatic precipitation.…”

Self-Supporting Three-Dimensional Electrospun Nanofibrous Membrane for Highly Efficient Air Filtration

“…The spiral whipping motion of the electrospinning jet plays the key role in the formation of curled nanofibrous patterns [20][21][22], which can be produced easily by adjusting the process parameters. PVDF is an excellent candidate material for air filters for its properties of light weight, chemical stability and ease of processing [23][24][25]. Xiao [8] et al produced a unique tree-like structure PVDF nanofiber by adding the silver nanoparticles with good filtration performance and high antibacterial activity.…”