Dual-shape properties of triple-shape polymer networks with crystallizable network segments and grafted side chains

Bellin, Ingo; Kelch, Steffen; Lendlein, Andreas

doi:10.1039/b702524f

Cited by 137 publications

(132 citation statements)

References 23 publications

(28 reference statements)

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“…This difference in H sw,1 (A(B) can be related to the difference in the two programming procedures. In SMCP-2s-I shape (A) was fixed by PEG crystallites and 'low' melting PCL crystallites resulting in higher values for H sw,1 (A(B), whereas during SMCP-2s-II only PEG crystallites are responsible for fixation of shape (A), as previously reported for photocrosslinked CLEG polymer networks [8,43,44]. For samples programmed by SMCP-2s-I H sw,2 (B(C) $ 25 kA·m -1 could be determined, while slightly lower values for H sw,2 (B(C) were obtained when SMCP-2s-II was applied.…”

Section: Recovery By Inductive Magnetic Heatingsupporting

confidence: 56%

“…Here, the lower values observed for SMCP-2s-II programmed samples can be related to the contribution of 'low' melting PCL crystallites to the fixation of shape (B) at T low = 0°C. When one-step programming SMCP-1s was used for programming, a single transition, which is characteristic for a dual-shape effect, was achieved for all nanocomposites in the "% rec -H curves with H sw $ 23 kA·m -1 , because the temporary shape is predominantly fixed by PCL crystallites during SMCP-1s, while crystallization of the grafted PEG chains did contribute to the fixation of shape (A) [43,44].…”

Section: Recovery By Inductive Magnetic Heatingmentioning

confidence: 99%

“…[10]. As it was demonstrated that a triple-shape effect could be achieved for multiphase AB polymer networks programmed by a one-step or two-step SMCP [44], here we want to investigate the influence of different SMCPs on the shapememory properties of polymer network nanocomposites with grafted polymer network architecture.…”

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confidence: 99%

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Shape-memory properties of magnetically active triple-shape nanocomposites based on a grafted polymer network with two crystallizable switching segments

Kumar¹,

Kratz²,

Behl³

et al. 2012

Express Polym. Lett.

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Shape-memory polymers (SMP) and composites thereof belong to the class of actively moving polymers, which have the capability of storing one (dualshape) [1][2][3][4][5][6], two (triple-shape) [7][8][9][10][11][12][13] or multiple (multiple-shape) [14] stable temporary shapes and recover their original or other temporary shapes when exposed to an external stimulus. The field of SMP research has developed rapidly over the last years [6,[15][16][17][18][19][20][21][22][23][24][25] and it has become apparent that these functional polymers are motivating novel applications. Thermo-sensitive SMP contain physical or chemical network-points, which determine their original shape, while each temporary shape is fixed by switching domains associated to a thermal transition temperature T trans , that can be a glass transition (T g ) or a melting transition (T m ) [16,17]. The process for programming of a temporary shape is called 'shapememory creation procedure' (SMCP) and can be realized e.g. by deforming the material to an extension of ! m at T > T trans and cooling to T < T trans while keeping the deformation, which then is fixed temporarily by solidification of the related set of switching domains [26]. The recovery of the original shape is named shape-memory effect (SME), which is typically induced by increasing the environmental temperature (T env ) [3,5,27,28] Abstract. Thermo-sensitive shape-memory polymers (SMP), which are capable of memorizing two or more different shapes, have generated significant research and technological interest. A triple-shape effect (TSE) of SMP can be activated e.g. by increasing the environmental temperature (T env ), whereby two switching temperatures (T sw ) have to be exceeded to enable the subsequent shape changes from shape (A) to shape (B) and finally the original shape (C). In this work, we explored the thermally and magnetically initiated shape-memory properties of triple-shape nanocomposites with various compositions and particle contents using different shape-memory creation procedures (SMCP). The nanocomposites were prepared by the incorporation of magnetite nanoparticles into a multiphase polymer network matrix with grafted polymer network architecture containing crystallizable poly(ethylene glycol) (PEG) side chains and poly(!-caprolactone) (PCL) crosslinks named CLEGC. Excellent triple-shape properties were achieved for nanocomposites with high PEG weight fraction when two-step programming procedures were applied. In contrast, single-step programming resulted in dual-shape properties for all investigated materials as here the temporary shape (A) was predominantly fixed by PCL crystallites.

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Section: Recovery By Inductive Magnetic Heatingsupporting

confidence: 56%

Section: Recovery By Inductive Magnetic Heatingmentioning

confidence: 99%

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Shape-memory properties of magnetically active triple-shape nanocomposites based on a grafted polymer network with two crystallizable switching segments

Kumar¹,

Kratz²,

Behl³

et al. 2012

Express Polym. Lett.

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“…On the other hand, a few new shape memory phenomena have been discovered [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47], which not only enhance the flexibility of the current shape memory technology, but also add in new dimensions for extended versatility and adoptability. Consequently, a number of novel concepts have been proposed for a range of engineering applications [45,[48][49][50][51][52][53][54], in particular in the field of biomedical engineering as of the last couple of years [24,43,[55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][70].…”

Section: Figurementioning

confidence: 99%

Mechanisms of the Shape Memory Effect in Polymeric Materials

et al. 2013

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Abstract:This review paper summarizes the recent research progress in the underlying mechanisms behind the shape memory effect (SME) and some newly discovered shape memory phenomena in polymeric materials. It is revealed that most polymeric materials, if not all, intrinsically have the thermo/chemo-responsive SME. It is demonstrated that a good understanding of the fundamentals behind various types of shape memory phenomena in polymeric materials is not only useful in design/synthesis of new polymeric shape memory materials (SMMs) with tailored performance, but also helpful in optimization of the existing ones, and thus remarkably widens the application field of polymeric SMMs.

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“…These polymer network systems are formed from two types of chain sections/ domains of different chemical constitution which connect network nodes and exhibit either melting process for both section/domain types or melting and glass transition, respectively, at two different temperatures. However, triple-shape memory effect appears only after programming in two-step process, i.e., at two temperatures agreeing with temperatures of melting or glass transition, whereas the suitable programming strains must be adjusted [11,12]. Such polymeric materials with multiple SM behavior (mSMP) could certainly offer new interesting applications for SM polymers, e.g.…”

mentioning

confidence: 99%

Multiple shape-memory behavior and thermal-mechanical properties of peroxide cross-linked blends of linear and short-chain branched polyethylenes

Kolesov

Radusch²

2008

Express Polym. Lett.

125

127

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Abstract. Thermally induced shape-memory effect (SME) in tensile mode was investigated in binary and ternary blends of two ethylene-1-octene copolymers with a degree of branching of 30 and 60 CH3/1000C and/or nearly linear polyethylene cross-linked after melt mixing with 2 wt% of liquid peroxide 2,5-dimethyl-2,5-di-(tert.butylperoxy)-hexane at 190°C. The average cross-link density estimated by means of the Mooney-Rivlin equation on the basis of tensile test data was characterized between 130 and 170 mol·m -3 depending on the blend composition. Thermal analysis points out multiple crystallization and melting behavior of blends caused by the existence of several polyethylene crystal populations with different perfection, size and correspondingly different melting temperature of crystallites. That agrees well with the diversity of blends phase morphology characterized by atomic force microscopy. However, triple-and quadruple-SME could be observed only after two-and accordingly three-step programming of binary and tertiary blends, respectively, at suitable temperatures and strains. Compared to performances obtained for the same blend after single-step programming above the maximal melting temperature the significantly poorer characteristics of SME like strain fixity and strain recovery ratio as well as recovery strain rate occurred after multi-step programming. Vol.2, No.7 (2008) [461][462][463][464][465][466][467][468][469][470][471][472][473] Available online at www.expresspolymlett.com DOI: 10.3144/expresspolymlett.2008.56 Strain fixity (R f ) and strain recovery ratios (R r ) are defined according to [4] by Equations (1): (1) where ε p is the strain caused by programming, ε v is the strain that remains after programming, cooling and unloading of specimen and ε rec,m is the residual strain that resides after thermal induced recovery (shrinkage) at maximum temperature of experiment. The investigation of the SM effect of covalent cross-linked semicrystalline polymers and in particular of peroxidic cross-linked ethylene copolymers [7][8][9][10] showed a strong correlation between the melting temperature T m ≡ T trans of the crystalline phase and the response temperature T res , namely T res ≈ T m . Thus, it may be assumed that the existence of several 'n' crystalline phases or/and crystal populations with different perfection, size and correspondingly with distinctly different melting temperatures T m.i in one polymeric material results presumably in a multiple SM behavior, i.e. in the appearance of the same or lower number of recovery strain ε rec (T) steps and accordingly dε rec (T)/dt maxima with response temperatures T res.i ≈ T m.i where 1 ≤ i ≤ n (i is an even number). The triple-shape memory behavior for two different complex polymer network systems which were prepared by photoinduced copolymerization of a methacrylate-monomer and poly(ε-caprolactone) dimethacrylate was already recently described by Bellin et al. [11]. These polymer network systems are formed from two types of chain sections/ domains of ...

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Dual-shape properties of triple-shape polymer networks with crystallizable network segments and grafted side chains

Cited by 137 publications

References 23 publications

Shape-memory properties of magnetically active triple-shape nanocomposites based on a grafted polymer network with two crystallizable switching segments

Shape-memory properties of magnetically active triple-shape nanocomposites based on a grafted polymer network with two crystallizable switching segments

Mechanisms of the Shape Memory Effect in Polymeric Materials

Multiple shape-memory behavior and thermal-mechanical properties of peroxide cross-linked blends of linear and short-chain branched polyethylenes

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