Shape-Memory Polymer Networks from Oligo[(-hydroxycaproate)-co-glycolate]dimethacrylates and Butyl Acrylate with Adjustable
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- 作者：Steffen Kelch ; Susi Steuer ; Annette M. Schmidt ; Andreas Lendlein
- 刊名：Biomacromolecules
- 出版年：2007
- 出版时间：March 2007
- 年：2007
- 卷：8
- 期：3
- 页码：1018 - 1027
- 全文大小：126K
- 年卷期：v.8,no.3(March 2007)
- ISSN：1526-4602
文摘
Degradable shape-memory polymer networks intended for biomedical applications were synthesized from oligo[(
-hydroxycaproate)-co-glycolate]dimethacrylates with glycolate contents between 0 and 30 mol % using aphotopolymerization process. In addition AB copolymer networks were prepared by adding 60 wt % n-butylacrylate as comonomer. All synthesized polymer networks are semicrystalline at room temperature. A meltingtransition Tm between 18 and 53 
C which can be used as switching transition for the shape-memory effect canbe attributed to the crystalline poly(-hydroxycaproate) phase. At temperatures below Tm the elastic propertiesare dominated by these physical cross-links. At temperatures higher than Tm the E modulus of the amorphouspolymer networks is lowered by up to 2 orders of magnitude, depending on the chemical cross-link density.Copolymer networks based on macrodimethacrylates with a Mn of up to 13 500 g·mol-1 and a maximum glycolatecontent of 21 mol % show quantitative strain recovery rates in stress-controlled cyclic thermomechanicalexperiments. Hydrolytic degradation experiments of polymer networks performed in phosphate buffer solution at37 C show that the degradation rate can be accelerated by increasing the glycolate content and decelerated bythe incorporation of n-butyl acrylate.
-hydroxycaproate)-co-glycolate]dimethacrylates with glycolate contents between 0 and 30 mol % using aphotopolymerization process. In addition AB copolymer networks were prepared by adding 60 wt % n-butylacrylate as comonomer. All synthesized polymer networks are semicrystalline at room temperature. A meltingtransition Tm between 18 and 53 C which can be used as switching transition for the shape-memory effect canbe attributed to the crystalline poly(-hydroxycaproate) phase. At temperatures below Tm the elastic propertiesare dominated by these physical cross-links. At temperatures higher than Tm the E modulus of the amorphouspolymer networks is lowered by up to 2 orders of magnitude, depending on the chemical cross-link density.Copolymer networks based on macrodimethacrylates with a Mn of up to 13 500 g·mol-1 and a maximum glycolatecontent of 21 mol % show quantitative strain recovery rates in stress-controlled cyclic thermomechanicalexperiments. Hydrolytic degradation experiments of polymer networks performed in phosphate buffer solution at37 C show that the degradation rate can be accelerated by increasing the glycolate content and decelerated bythe incorporation of n-butyl acrylate.