The effect of moisture absorption on the physical properties of polyurethane shape memory polymer foams

Yu, Ya-Jen; Hearon, Keith; Wilson, Thomas S.; Maitland, Duncan J.

doi:10.1088/0964-1726/20/8/085010

Cited by 95 publications

(76 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To achieve these objectives, a new class of highly covalently crosslinked SMP foams was developed by our group [14] based on the materials proposed by Wilson et al [15] Extensive investigation of these materials has been reported in recent years. Studies critical to their embolic application in treatment of aneurysms, such as of their mechanical properties and shape memory behavior [14], the inclusion of contrast agent for enabling in vivo imaging during device delivery [16], stresses experienced on the aneurysm wall during actuation/implantation [17], the effect of moisture on the foam's actuation temperature, [18] variation in composition to control the rate of actuation of foams in presence of moisture [19], and in vivo implantation in porcine models [20] have been performed. The treated porcine animal models were observed to be healthy until the 90 day period, after which they were sacrificed to explant the aneurysmal area.…”

Section: Introductionmentioning

confidence: 99%

Low density biodegradable shape memory polyurethane foams for embolic biomedical applications

et al. 2014

View full text Add to dashboard Cite

Low density shape memory polymer foams hold significant interest in the biomaterials community for their potential use in minimally invasive embolic biomedical applications. The unique shape memory behavior of these foams allows them to be compressed to a miniaturized form, which can be delivered to an anatomical site via a transcatheter process, and thereafter actuated to embolize the desired area. Previous work in this field has described the use of a highly covalently crosslinked polymer structure for maintaining excellent mechanical and shape memory properties at the application-specific ultra low densities. This work is aimed at further expanding the utility of these biomaterials, as implantable low density shape memory polymer foams, by introducing controlled biodegradability. A highly covalently crosslinked network structure was maintained by use of low molecular weight, symmetrical and polyfunctional hydroxyl monomers such as Polycaprolactone triol (PCL-t, Mn 900 g), N,N,N0,N0-Tetrakis (hydroxypropyl) ethylenediamine (HPED), and Tris (2-hydroxyethyl) amine (TEA). Control over the degradation rate of the materials was achieved by changing the concentration of the degradable PCL-t monomer, and by varying the material hydrophobicity. These porous SMP materials exhibit a uniform cell morphology and excellent shape recovery, along with controllable actuation temperature and degradation rate. We believe that they form a new class of low density biodegradable SMP scaffolds that can potentially be used as “smart” non-permanent implants in multiple minimally invasive biomedical applications.

show abstract

Section: Introductionmentioning

confidence: 99%

Low density biodegradable shape memory polyurethane foams for embolic biomedical applications

et al. 2014

View full text Add to dashboard Cite

show abstract

“…4,5 In the medical device industry, proposed neat SMP applications such as interventional embolectomy devices or neurovascular stents also demand tailorability of various material properties and have complex geometric design requirements. 6–11 …”

Section: Introductionmentioning

confidence: 99%

A Structural Approach to Establishing a Platform Chemistry for the Tunable, Bulk Electron Beam Cross-Linking of Shape Memory Polymer Systems

et al. 2013

Self Cite

View full text Add to dashboard Cite

The synthetic design and thermomechanical characterization of shape memory polymers (SMPs) built from a new polyurethane chemistry that enables facile, bulk and tunable cross-linking of low-molecular weight thermoplastics by electron beam irradiation is reported in this study. SMPs exhibit stimuli-induced geometry changes and are being proposed for applications in numerous fields. We have previously reported a polyurethane SMP system that exhibits the complex processing capabilities of thermoplastic polymers and the mechanical robustness and tunability of thermomechanical properties that are often characteristic of thermoset materials. These previously reported polyurethanes suffer practically because the thermoplastic molecular weights needed to achieve target cross-link densities severely limit high-throughput thermoplastic processing and because thermally unstable radiation-sensitizing additives must be used to achieve high enough cross-link densities to enable desired tunable shape memory behavior. In this study, we demonstrate the ability to manipulate cross-link density in low-molecular weight aliphatic thermoplastic polyurethane SMPs (Mw as low as ~1.5 kDa) without radiation-sensitizing additives by incorporating specific structural motifs into the thermoplastic polymer side chains that we hypothesized would significantly enhance susceptibility to e-beam cross-linking. A custom diol monomer was first synthesized and then implemented in the synthesis of neat thermoplastic polyurethane SMPs that were irradiated at doses ranging from 1 to 500 kGy. Dynamic mechanical analysis (DMA) demonstrated rubbery moduli to be tailorable between 0.1 and 55 MPa, and both DMA and sol/gel analysis results provided fundamental insight into our hypothesized mechanism of electron beam cross-linking, which enables controllable bulk cross-linking to be achieved in highly processable, low-molecular weight thermoplastic shape memory polymers without sensitizing additives.

show abstract

“…However, these water molecules can also interact with functional groups of material thereby increasing swelling behaviour. This type of functional group interaction can occur when the PUs are exposed to water extensive moisture atmosphere [25]. The penetrated water molecules can involve in the hydrogen bonding and thereby increasing the chain mobility.…”

Section: Swelling Ratio Of Polymermentioning

confidence: 99%

Synthesis and characterization of MDI and functionalized polystyrene based poly(urethane-urea-amide)

Kayalvizhi

Suresh

Shunmugavelu

et al. 2016

Int J Plast Technol

View full text Add to dashboard Cite

This article describes the synthesis of 4,4 0 -methylenediphenyl diisocyanate (MDI) based polyurethane-ureas-amide using diamine-diamide chain extenders and dihydroxy polystyrene (PSt) having a weight average molecular weight of 2000 g/mol. The weight average molecular weight of the soft segment is varied from 2000 to 10,000 g/mol using MDI as a chain extender and thereby changing the hard segment content from 30 to 17 wt% in the copolymer. The inherent viscosity of the polymer is found to be in the range of 1.6-3.4 dL/g is suggesting that the polymer is of high molecular weight. FT-IR results conclude that the urea groups form monodentate assemblies. DSC data show the peaks for Tg of soft and Tm of hard segments. Depending on the amide concentration, the melting temperature of the polymer varies from 189 to 249°C. Also, at high concentration of the hard segment, the cooling curve shows crystallization exotherm peak. The entire series of polymer shows single stage decomposition temperature centered around 400°C shown by the TGA measurement. The solubility of the polymer in chloroform and swelling ratio is depending on the concentration of the hard segment. The studied polymer shows excellent solvent resistivity.

show abstract

The effect of moisture absorption on the physical properties of polyurethane shape memory polymer foams

Cited by 95 publications

References 27 publications

Low density biodegradable shape memory polyurethane foams for embolic biomedical applications

Low density biodegradable shape memory polyurethane foams for embolic biomedical applications

A Structural Approach to Establishing a Platform Chemistry for the Tunable, Bulk Electron Beam Cross-Linking of Shape Memory Polymer Systems

Synthesis and characterization of MDI and functionalized polystyrene based poly(urethane-urea-amide)

Contact Info

Product

Resources

About