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Effect of soft segment crystallization and hard segment physical crosslink on shape memory function in antibacterial segmented polyurethane ionomers

Paper ID Volume ID Publish Year Pages File Format Full-Text
1863 93 2009 12 PDF Available
Title
Effect of soft segment crystallization and hard segment physical crosslink on shape memory function in antibacterial segmented polyurethane ionomers
Abstract

Shape memory polyurethane (SMPU) ionomers containing constant 75 wt.% soft segment content were synthesized using poly(ε-caprolactone)diol, 4,4′-diphenylmethane diisocyanate, 1,4-butanediol and/or N,N-bis(2-hydroxyethyl)-isonicotinamide. To introduce substrate bonding antibacterial activity, pyridinium was prepared through a neutralization reaction using 1-iodooctane as neutralization agent. For the SMPU ionomer film obtained, tensile testing at 70 °C and dynamic mechanical analysis suggests that, at temperatures > Tms (the melting point of soft segments), 6.72 and 29.55 mol.% pyridinium within hard segments significantly decreased the mechanical properties such as the stress at 100% elongation (70 °C), the initial modulus (70 °C) and the elastic modulus (75–110 °C). Cyclic tensile investigation demonstrated that the two factors, soft segment crystallization and hard segment physical crosslink, play a very important role in shape memory function in SMPU ionomers. For the each individual specimen, the fixity ratio increased, and the recovery ratio decreased with the extension of cooling time. After sufficient cooling time, the fixity ratio of all specimens can reach a high value (∼95%). Owing to the disrupted physical crosslink in the sample containing 29.55 mol.% pyridinium, the crystallization rate of soft segments has less effect on shape fixity. Therefore, a high fixity ratio (93.8%) can be achieved in a short cooling time (30 s). In the control sample, the fixity ratio is only 73.7% after 30 s cooling. In addition, the admirable substrate bonding antibacterial activity of prepared SMPU ionomers was verified using standards AACTT 147 and ASTM E2149 in comparison with the control sample. The antibacterial activity of SMPU ionomers on Gram-positive bacteria (Staphylococcus aureus) is significant, and the rate of reduction of bacteria is 100%; the antibacterial activity on Gram-negative bacteria (Klebsiella pneumoniae) increases from 83.6% to 90.7% with increase in pyridinium content from 6.72 to 29.55 mol.%.

Keywords
Antibacterial; Polyurethane; Shape memory; Immobilization; Crystallization
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Effect of soft segment crystallization and hard segment physical crosslink on shape memory function in antibacterial segmented polyurethane ionomers
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Publisher
Database: Elsevier - ScienceDirect
Journal: Acta Biomaterialia - Volume 5, Issue 9, November 2009, Pages 3346–3357
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us