Thermo-mechanical behavior and structure of melt blown shape-memory polyurethane nonwovens.
New processing methods for shape-memory polymers allow for tailoring material properties for numerous applications. Shape-memory nonwovens have been previously electrospun, but melt blow processing has yet to be evaluated. In order to determine the process parameters affecting shape-memory behavior, this study examined the effect of air pressure and collector speed on the mechanical behavior and shape-recovery of shape-memory polyurethane nonwovens. Mechanical behavior was measured by dynamic mechanical analysis and tensile testing, and shape-recovery was measured by unconstrained and constrained recovery. Microstructure changes throughout the shape-memory cycle were also investigated by micro-computed tomography. It was found that increasing collector speed increases elastic modulus, ultimate strength and recovery stress of the nonwoven, but collector speed does not affect the failure strain or unconstrained recovery. Increasing air pressure decreases the failure strain and increases rubbery modulus and unconstrained recovery, but air pressure does not influence recovery stress. It was also found that during the shape-memory cycle, the connectivity density of the fibers upon recovery does not fully return to the initial values, accounting for the incomplete shape-recovery seen in shape-memory nonwovens. With these parameter to property relationships identified, shape-memory nonwovens can be more easily manufactured and tailored for specific applications.
MedShape, Inc., 1575 Northside Drive NW Suite 440, Atlanta, GA 30318, United States. Electronic address: david.safranski@medshape.com.
David L
DL
Safranski
W.H.Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States.
Jennifer M
JM
Boothby
W.H.Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States.
Cambre N
CN
Kelly
School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States.
Kyle
K
Beatty
Department of Mechanical Engineering, University of Wyoming, Laramie, WY 82071, United States.
Nishant
N
Lakhera
Department of Mechanical Engineering, University of Wyoming, Laramie, WY 82071, United States.
Carl P
CP
Frick
Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States; Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, United States.
Angela
A
Lin
Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States; Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, United States.
Robert E
RE
Guldberg
MedShape, Inc., 1575 Northside Drive NW Suite 440, Atlanta, GA 30318, United States.
Jack C
JC
Griffis
D055119:Elastic Modulus; D008422:Materials Testing; D011108:Polymers; D011140:Polyurethanes / Q000737:chemistry*; D013696:Temperature; D055114:X-Ray Microtomography
D011108:Polymers; D011140:Polyurethanes
Mechanical behavior; Melt blown; Micro-computed tomography; Nonwoven; Shape-memory; Structure