Paper Number
PO78                         My Program 

Session
Poster Session

Title
Influence of rheology on melt blowing of nonwoven mats with applications to biodegradable polymers

Presentation Date and Time
October 16, 2024 (Wednesday) 6:30

Track / Room
Poster Session / Waterloo 3 & 4

Authors (Click on name to view author profile)

  1. Roy, Omkar (University of Michigan, Chemical Engineering)
  2. Zhang, Zhaokun (University of Michigan, Mechanical Engineering)
  3. Song, Chunlei (University of Michigan, Mechanical Engineering)
  4. Shih, Albert (University of Michigan, Mechanical Engineering)
  5. Larson, Ronald (University of Michigan, Chemical Engineering)

Author and Affiliation Lines (in printed abstract book)
Omkar Roy1, Zhaokun Zhang2, Chunlei Song2, Albert Shih2 and Ronald Larson1
1Chemical Engineering, University of Michigan, Ann Arbor, MI 48105; 2Mechanical Engineering, University of Michigan, Ann Arbor, MI 48105

Speaker / Presenter 
Roy, Omkar

Keywords
advanced manufacturing; non-Newtonian fluids; polymer melts; real-world rheology

Text of Abstract
Commercial respiratory personal protective equipment, usually made of polypropylene (PP), are very challenging to sustainably recycle, motivating exploration of alternative biodegradable polymers for melt blowing. To determine which polymers can be melt blown into nonwoven mats suitable for filtration of fine airborne particles, we measure the viscosity of melt, melt-blown fiber diameter and mat’s filtration efficiency for polypropylene-PP, polylactic acid-PLA, polyethylene-PE, polyamide-PA blown from a commercial-scale melt blowing machine. We have identified a correlation between the aerosol filtration efficiency of meltblown mats and mean fiber diameter irrespective of melt material. A double-layer filtration efficiency of more than 95% is achieved for a mean fiber diameter of 1-2 micrometers, while filtration efficiency drops to less than 10% for a mean fiber diameter of 8 micrometers and above. In particular, the production-scale meltblown nonwovens using low molecular weight PLA can achieve filtration efficiency beyond the current standards for N95 respirators. For the first time, we also report the effect on PLA melts of commercial additives that reduce viscosity leading to smaller melt-blown fiber diameter, but which can lead to deteriorated mechanical properties. Our computational modeling of the commercial melt blowing shows that the stresses delivered to the extruded melt are too low to generate significant viscoelasticity, and so a simple Newtonian constitutive equation should be sufficient to describe the material during the melt blown process.