Revealing of process–structure–property relationships of fine polypropylene fiber mats generated via melt blowing

Abstract

In this study, we presented systematic and comparative investigations on the structure of polypropylene fibers generated using different processing conditions via melt blowing. Increasing air pressure, die-to-collector distance, and air temperature reduced the average fiber diameter nearly 3-fold, 2-fold, and 1.75-fold, respectively.An average of 1.4 μm Feret-diameter was observed as the smallest pore size, while the fiber mat solidities ranged from 8 to 13%. Differential scanning calorimetry results showed single melting peaks in the 1st heating cycle and double melting peaks in the second one, due to the phase transition at melt blowing. The fiber crystallinities varied between 43 and 52% by changing the processing conditions. The X-ray diffraction study revealed that the MB fibers exhibited α and mesomorphic crystals depending on the processing parameters. The reference polypropylene sheet made of the same fiber grade polypropylene resin, on the other hand, exhibited a mix of α and γ crystalline forms. The polypropylene fiber mat tensile strength improved by 48% and by 13% with increasing air pressure and air temperature, respectively.Decreasing fiber collection distances resulted in 2.5-fold higher tensile strength while strain at break reduced eightfold. A new factor, mat consolidation coefficient, was introduced and used to efficiently summarize melt-blown fiber mats' process-property-structure relationships. This study details how to control the melt blowing parameters to tailor the polypropylene fiber mat features for the respective application field. It also presents an insight into fiber formation mechanisms during melt blowing for generating self-bonded, defect-free, fine fiber mats.

A review of processing strategies to generate melt-blown nano/microfiber mats for high-efficiency filtration applications

“…These features may include but not limited to: hydrophobicity/hydrophilicity, piezoelectric or antistatic properties, biocompatibility or biodegradability, high filtration efficiency or absorbency of liquid matters, possess a high modulus and strength, etc. Often a combination of multiple properties is desired, and that can be achieved with precisely engineered equipment operated within a rather narrow processing window, accurately designed processing parameters, or combination of two or more synthetic materials [24,25].…”

Development of single‐polypropylene composites interleaved with MWCNT‐doped melt‐blown fine fiber mats

“…The mesophase can form at cooling rates high enough to prevent the crystallization of the more stable monoclinic α form. [ 11,31 ] Results implied that the CNT addition suppressed the crystalline phase transition and resulted in monoclinic α crystalline form.…”

“…where ΔH m is the experimental heat of fusion obtained by the DSC scans. For the heat of fusion of the 100% crystalline h-PP (ΔH 0 m ) 207 J/g was considered [11] in the analysis. To characterize the PP/MWCNT nanocomposite fiber mat thermal characteristics, TGA was performed using a The shear viscosity of the pristine (0 wt%) and CNTdoped (0.1, 0.25 and 0.5 wt%) PP nanocomposites were measured with a capillary rheometer (Instron 13 Ceast SR20).…”

“…[8] The melt-blown (MB) fibers have several remarkable advantages, including but not limited to small diameter, high aspect ratio, large specific surface area, networked pore structure, unique physicochemical properties, and design flexibility for chemical/physical surface functionalization. [11,12] Up to date, various types of nanofillers (graphene oxide, CNTs, nanoclay, etc.) have been incorporated within a polymer matrix to improve the mechanical, thermal and electrical characteristics of fine fiber mats and related composite structures.…”

Large-scale preparation of polylactic acid/polyethylene glycol micro/nanofiber fabrics with aligned fibers via a post-drafting melt blown process

“…The melt blown process, one of the most widespread technologies for micro/nanofiber fabrics, has a series of attractive characteristics, such as large scale, no potential solvent toxicity, and abundant resources [ 1 , 2 ]. In addition, melt blown fabrics composed of petroleum-based polymers, i.e., polypropylene (PP), polyethylene (PE), and polyester (PET) [ 3 ], have been widely used in personal hygiene, medical protection, packaging, filtration, separation, and other industries due to the cooperative advantages between the properties of micro/nanofibers and polymers [ 4 – 6 ].…”