scholarly journals Shape-Memory Polymer Networks from Oligo[(ε-hydroxycaproate)-co-glycolate]dimethacrylates and Butyl Acrylate with Adjustable Hydrolytic Degradation Rate

2007 ◽  
Vol 8 (3) ◽  
pp. 1018-1027 ◽  
Author(s):  
Steffen Kelch ◽  
Susi Steuer ◽  
Annette M. Schmidt ◽  
Andreas Lendlein
Keyword(s):  
Shape Memory ◽  
Butyl Acrylate ◽  
Degradation Rate ◽  
Shape Memory Polymer ◽  
Polymer Networks ◽  
Hydrolytic Degradation

Hydrolytic Degradation of Actuators Based on Copolymer Networks From Oligo(ε-caprolactone) Dimethacrylate and n-Butyl Acrylate

MRS Advances ◽  
2019 ◽  
Vol 4 (21) ◽  
pp. 1193-1205 ◽  
Author(s):  
M. Balk ◽  
M. Behl ◽  
A. Lendlein
Keyword(s):  
Shape Memory ◽  
Alkaline Hydrolysis ◽  
Butyl Acrylate ◽  
Network Architecture ◽  
Degradation Products ◽  
Sodium Hydroxide Solution ◽  
Shape Memory Polymer ◽  
Hydrolytic Degradation ◽  
Solution Ph ◽  
Polymer Actuators

ABSTRACTShape-memory polymer actuators often contain crystallizable polyester segments. Here, the influence of accelerated hydrolytic degradation on the actuation performance in copolymer networks based on oligo(ε-caprolactone) dimethacrylate (OCL) and n-butyl acrylate is studied. The semi-crystalline OCL was utilized as crosslinker with molecular weights of 2.3 and 15.2 kg∙mol−1 (ratio: 1:1 wt%) and n-butyl acrylate (25 wt% relative to OCL content) acted as softening agent creating the polymer main chain segments within the network architecture. The copolymer networks were programmed by 50% elongation and were degraded by means of alkaline hydrolysis utilizing sodium hydroxide solution (pH = 13). Experiments were performed in the range of the broad melting range of the actuators at 40 °C. The degradation of test specimen was monitored by the sample mass, which was reduced by 25 wt% within 105 d. As degradation products, fragments of OCL with molecular masses ranging from 400 to 50.000 g·mol-1 could be detected by NMR spectroscopy and GPC measurements. The cleavage of ester groups included in OCL segments resulted in a decrease of the melting temperature (Tm) related to the actuator domains (amorphous at the temperature of degradation) and simultaneously, the Tm associated to the skeleton domain was increased (semi-crystalline at the temperature of degradation).The alkaline hydrolysis decreased the polymer chain orientation of OCL domains until a random alignment of crystalline domains was obtained. This result was confirmed by cyclic thermomechanical actuation tests. The performance of directed movements decreased almost linearly as function of degradation time resulting in the loss of functionality when the orientation of polymer chains disappeared. Here, actuators were able to provide reversible movements until 91 d when the accelerated bulk degradation procedure using alkaline hydrolysis (pH = 13) was applied. Accordingly, a lifetime of more than one year can be guaranteed under physiological conditions (pH = 7.4) when, e.g., artificial muscles for biomimetic robots as potential application for these kind of shape-memory polymer actuators will be addressed.

Actuators Based on Oligo[(ε-caprolactone)-co-glycolide] with Accelerated Hydrolytic Degradation

MRS Advances ◽  
2019 ◽  
Vol 5 (12-13) ◽  
pp. 655-666
Author(s):  
Maria Balk ◽  
Marc Behl ◽  
Andreas Lendlein
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer ◽  
Hydrolytic Degradation ◽  
Life Time ◽  
Melting Transition ◽  
Multifunctional Materials ◽  
Degradation Behaviour ◽  
Molecular Weights ◽  
Function Relationship ◽  
Macroscopic Shape

ABSTRACTPolyester-based shape-memory polymer actuators are multifunctional materials providing reversible macroscopic shape shifts as well as hydrolytic degradability. Here, the function-function interdependencies (between shape shifts and degradation behaviour) will determine actuation performance and its life time.In this work, glycolide units were incorporated in poly(ε-caprolactone) based actuator materials in order to achieve an accelerated hydrolytic degradation and to explore the function-function relationship. Three different oligo[(ε-caprolactone)-co-glycolide] copolymers (OCGs) with similar molecular weights (10.5 ± 0.5 kg∙mol−1) including a glycolide content of 8, 16, and 26 mol% (ratio 1:1:1 wt%) terminated with methacrylated moieties were crosslinked. The obtained actuators provided a broad melting transition in the range from 27 to 44 °C. The hydrolytic degradation of programmed OCG actuators (200% of elongation) resulted in a reduction of sample mass to 51 wt% within 21 days at pH = 7.4 and 40 °C. Degradation results in a decrease of Tm associated to the actuating units and increasing Tm associated to the skeleton forming units. The actuation capability decreased almost linear as function of time. After 11 days of hydrolytic degradation the shape-memory functionality was lost. Accordingly, a fast degradation behaviour as required, e.g., for actuator materials intended as implant material can be realized.

Photo-Cross-Linkable Coumarin-Based Poly(ε-caprolactone) for Light-Controlled Design and Reconfiguration of Shape-Memory Polymer Networks

2018 ◽  
Vol 52 (2) ◽  
pp. 444-456 ◽  
Author(s):  
Thomas Defize ◽  
Jean-Michel Thomassin ◽  
Heidi Ottevaere ◽  
Cédric Malherbe ◽  
Gauthier Eppe ◽  
...  
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer ◽  
Polymer Networks

Shape memory polymer networks from styrene copolymer

2007 ◽  
Author(s):  
Dawei Zhang ◽  
Xiaoguang Wang ◽  
Wuyi Zhang ◽  
Yanju Liu ◽  
Jinsong Leng
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer ◽  
Polymer Networks ◽  
Styrene Copolymer

Shape-memory polymer networks from oligo(?-caprolactone)dimethacrylates

2005 ◽  
Vol 43 (7) ◽  
pp. 1369-1381 ◽  
Author(s):  
Andreas Lendlein ◽  
Annette M. Schmidt ◽  
Michael Schroeter ◽  
Robert Langer
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer ◽  
Polymer Networks

Thermo-mechanical Behavior of (Meth)Acrylate Shape-Memory Polymer Networks

2011 ◽  
Vol 1312 ◽  
Author(s):  
Carl P. Frick ◽  
Nishant Lakhera ◽  
Christopher M. Yakacki
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer ◽  
Polymer Network ◽  
Polymer Networks ◽  
Weight Fraction ◽  
Crosslinking Density ◽  
Mechanical Stiffness ◽  
Actuation Force ◽  
Order Of Magnitude ◽  
Cross Linker

ABSTRACTOur overall approach is based on developing a photocrosslinkable polymer network with a favorable shape-memory response, using polymer chemistry and crosslinking density to control thermo-mechanical properties. Three polymer networks were created and thermo-mechanically tested, each from tert-Butyl acrylate linear builder co-polymerized with a poly(ethylene glycol) dimethacrylate cross-linker. By systematically altering the molecular weight and the weight fraction of the cross-linker, it was possible to create three polymers that exhibited the same glass transition temperature, but varied by almost an order of magnitude in rubbery modulus. Therefore, the mechanical stiffness could be tailored to suit a given application. Recovery behavior of the polymers was characterized over a range of deformation temperatures. It has been implicitly assumed a linear relationship between Free-Strain (i.e. no actuation force) and Fixed-Stress (i.e. maximum actuation force), however, this has never been confirmed experimentally. The energy per unit volume performed by the shape-memory polymer was quantified, and observed to be a function of strain recovered. The maximum recoverable work was shown to increase with cross-linking density, although the overall efficiency is similar for all materials tested.

Body temperature-responsive two-way and moisture-responsive one-way shape memory behaviors of poly(ethylene glycol)-based networks

2017 ◽  
Vol 8 (25) ◽  
pp. 3833-3840 ◽  
Author(s):  
Guang Yang ◽  
Xueyang Liu ◽  
Alfred Iing Yoong Tok ◽  
Vitali Lipik
Keyword(s):  
Free Radical ◽  
Ethylene Glycol ◽  
Shape Memory ◽  
Shape Memory Polymer ◽  
Polymer Networks ◽  
Poly Ethylene Glycol ◽  
Thermally Induced ◽  
Temperature Responsive ◽  
Shape Memory Effects ◽  
Poly Ethylene

In this work, crosslinked shape-memory polymer networks were prepared by thermally induced free-radical polymerizations of methacrylate-terminated poly(ethylene glycol) (PEG) and n-butyl acrylate (BA), which integrate thermal-responsive two-way and moisture-responsive one-way shape memory effects (SME).

scholarly journals Shape memory polymer networks based on methacrylated fatty acids

2019 ◽  
Vol 116 ◽  
pp. 321-329 ◽  
Author(s):  
Guillermina Capiel ◽  
Norma E. Marcovich ◽  
Mirna A. Mosiewicki
Keyword(s):  
Fatty Acids ◽  
Shape Memory ◽  
Shape Memory Polymer ◽  
Polymer Networks

Cytotoxicity and thermomechanical behavior of biomedical shape-memory polymer networks post-sterilization

2008 ◽  
Vol 3 (1) ◽  
pp. 015010 ◽  
Author(s):  
C M Yakacki ◽  
M B Lyons ◽  
B Rech ◽  
K Gall ◽  
R Shandas
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer ◽  
Polymer Networks ◽  
Thermomechanical Behavior
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