Thermal, mechanical and shape memory properties of shape memory epoxy resin

Liu, Yuyan; Han, Chunmiao; Tan, Huifeng; Du, Xi

doi:10.1016/j.msea.2009.12.014

Cited by 158 publications

(115 citation statements)

References 17 publications

Supporting

Mentioning

112

Contrasting

Order By: Relevance

“…This implied that the movement of the molecular chain segment of the NGDE/PBA-a shape memory samples could be more restricted with increasing BA-a content since an increasing of storage modulus at rubbery plateau was observed in the DMA results. The recovery times of our SMPs were in the same range as that of epoxy resin E-51 (WSR 618) cured by aromatic amine curing agent [37]. Therefore, the incorporation of the BA-a into the NGDE/PBA-a SMPs can prolong the shape recovery time thus broadening the range of application of these SMPs.…”

Section: Effect Of Ba-a Contents On Shape Fixity Ofmentioning

confidence: 59%

“…After a step curing at 130°C/12 h, 140°C/4 h, 150°C/4 h and 160°C/2 h, the values decreased to 245.6, 236.7, 231.7 and 101.4 J/g, respectively, which corresponded to the degree of conversion of 9.7, 12.9, 14.8 and 62.7%. Liu et al [37] suggested that the degree of conversion about 60% of shape memory epoxy provided samples with good balance properties between shape memory performance and thermomechanical properties. The fully cured samples, i.e.…”

Section: Characterization Methodsmentioning

confidence: 99%

“…After that, fraction force reduced under the gradual adjustment of segments results in the slopes of recovery angle is sharply as named the transition stage. At the terminal stage, the shape recovery rate becomes slower than the transition stage because the constrained force of the sample had been released due to a little of it remaining [7,37,51]. In addition, the shape recovery time of the samples tended to decrease with increasing the active temperature from T g to T g + 20°C.…”

Section: Effect Of Ba-a Contents On Shape Fixity Ofmentioning

confidence: 99%

See 2 more Smart Citations

Effects of benzoxazine resin on property enhancement of shape memory epoxy: A dual function of benzoxazine resin as a curing agent and a stable network segment

Tanpitaksit¹,

Jubsilp²,

Rimdusit³

2015

Express Polym. Lett.

View full text Add to dashboard Cite

Abstract. An ability of bisphenol-A/aniline based benzoxazine resin (BA-a) to simultaneously acts as a curing agent and a stable or rigid network segment for shape memory epoxy, i.e. a two component system, is demonstrated. This significantly simplifies a formulation of present shape memory epoxy systems, i.e. a three or four component system. A suitable content of BA-a in the aliphatic epoxy (NGDE)/polybenzoxazine (PBA-a) samples for good shape memory performance is in a range of 30 to 50 mol%. The storage modulus of the obtained NGDE/PBA-a shape memory polymers (SMPs) was increased from 3.57 GPa for 30 mol% BA-a content to 4.50 GPa for 50 mol% BA-a content. Glass transition temperature of the sample was also substantially increased with increasing BA-a fraction, i.e. from 51°C to 140°C. Flexural modulus and strength at room temperature of the samples at 50 mol% BA-a were found to be as high as 3.97 GPa and 132 MPa compared to the maximum values of 2.54 GPa and 100 MPa of SMP based on cyanate ester-epoxy. All samples exhibited a high value of shape fixity close to 100%. A presence of the BA-a in the samples also imparted a greater recovery stress ranging from 0.25 to 1.59 MPa. Consequently, the obtained NGDE/PBA-a copolymers are highly attractive for shape memory materials to be used in a broader range of applications particularly at elevated temperature and a higher recovery stress value.

show abstract

Section: Effect Of Ba-a Contents On Shape Fixity Ofmentioning

confidence: 59%

Section: Characterization Methodsmentioning

confidence: 99%

Section: Effect Of Ba-a Contents On Shape Fixity Ofmentioning

confidence: 99%

See 1 more Smart Citation

Effects of benzoxazine resin on property enhancement of shape memory epoxy: A dual function of benzoxazine resin as a curing agent and a stable network segment

Tanpitaksit¹,

Jubsilp²,

Rimdusit³

2015

Express Polym. Lett.

View full text Add to dashboard Cite

show abstract

“…However, some non-idealities appear for both 3thiol and 4thiol formulations with increasing iso content and, consequently, ve. It must be taken into account that the increase in the content of iso also changes the type of network structure, introducing crosslinks with a non-negligible In general, the formulations with 3thiol have lower Tg than those with 4thiol because of the reduction of free volume and hindrance of the molecular motion caused by the presence of crosslink junctions [36], which becomes more relevant with increasing crosslink functionality [33], as seen for other shape-memory materials [37,38]. On the other hand, adding the iso compound to the different systems tend to increase the Tg.…”

Section: Thermo-mechanical and Network Structure Propertiesmentioning

confidence: 99%

Effect of the Network Structure and Programming Temperature on the Shape-Memory Response of Thiol-Epoxy “Click” Systems

et al. 2015

View full text Add to dashboard Cite

This paper presents a new methodology to develop "thiol-epoxy" shape-memory polymers (SMPs) with enhanced mechanical properties in a simple and efficient manner via "click" chemistry by using thermal latent initiators. The shape-memory response (SMR), defined by the mechanical capabilities of the SMP (high ultimate strength and strain), the shape-fixation and the recovery of the original shape (shape-recovery), was analyzed on thiol-epoxy systems by varying the network structure and programming temperature. The glass transition temperature (T g ) and crosslinking density were modified using 3-or 4-functional thiol curing agents and different amounts of a rigid triglycidyl isocyanurate compound. The relationship between the thermo-mechanical properties, network structure and the SMR was evidenced by means of qualitative and quantitative analysis. The influence of the programming temperature (T prog ) on the SMR was also analyzed in detail. The results demonstrate the possibility of tailoring SMPs with enhanced mechanical capabilities and excellent SMR, and intend to provide a better insight into the relationship between the network structure properties, programming temperature and the SMR of unconstrained (stress-free) systems; thus, making it easier to decide between different SMP and to define the operative parameters in the useful life.

show abstract

“…Versatility means that the thermomechanical behaviour of EPs can be tailored upon request. The related tools for shape memory thermosets, including epoxies, are: resin type, type and thus curing mechanism of the hardener, stoichiometry and deviation from that [6][7][8][9][10], hybridization of hardeners [11], mixing of differently curable resins (i.e. generation of interpenetrating and semiinterpenetrating structures [12]), and last but not least filling and reinforcing with different additives.…”

mentioning

confidence: 99%

Shape memory performance of asymmetrically reinforced epoxy/carbon fibre fabric composites in flexure

Fejős¹,

Karger‐Kocsis

2013

Express Polym. Lett.

View full text Add to dashboard Cite

Shape memory polymers (SMPs) belong to an emerging and fast developing branch of smart materials. SMPs can fix temporary shapes and recover their original one upon exposure to external stimuli. According to the latter SMPs can be grouped in thermal-, electro-, magnetic-, light-, solution (water)-activated versions. Other categorizations consider the chemical structure, the number of shapes SMP can memorize in one cycle and the possibility to repeat temporary/original shaping just upon external stimulus [1][2][3]. Nowadays, exhaustive reviews are available on the structure, properties and applications of SMPs [2][3][4][5]. SMPs consist of permanent netpoints and molecular switches of reversible nature. The latter are exploited for setting the temporary shape whereas the former memorize the original shape. For cured thermosets the netpoints are given by covalent crosslinks of the chemical network. This network architecture enables keeping the stable (original) shape also after recovery. The segments between the crosslinks act as molecular switches. They undergo a reversible phase transition at the glass transition temperature (T g ) range upon heating, where heating is the external stimulus. The transition between the glassy and rubbery states is associated with a large drop in the modulus of SMPs (covering almost 3 orders of magnitude). Temporary shaping, performed in the rubbery state, yields a conformational rearrangement in the segments of the chemically crosslinked structure. This causes a prominent entropy reduction. The shape is fixed upon cooling to the glassy state whereby energy is stored via 'freezing in' the related network deformation. When the material is heated above the T g again, the stored energy is released by Abstract. In this study asymmetrically reinforced epoxy (EP)/carbon fibre (CF) fabric composites were prepared and their shape memory properties were quantified in both unconstrained and fully constrained flexural tests performed in a dynamic mechanical analyser (DMA). Asymmetric layering was achieved by incorporating two and four CF fabric layers whereby setting a resin-and reinforcement-rich layer ratio of 1/4 and 1/2, respectively. The recovery stress was markedly increased with increasing CF content. The related stress was always higher when the CF-rich layer experienced tension load locally. Specimens with CF-rich layers on the tension side yielded better shape fixity ratio, than those with reinforcement layering on the compression side. Cyclic unconstrained shape memory tests were also run up to five cycles on specimens having the CF-rich layer under local tension. This resulted in marginal changes in the shape fixity and recovery ratios.

show abstract

Thermal, mechanical and shape memory properties of shape memory epoxy resin

Cited by 158 publications

References 17 publications

Effects of benzoxazine resin on property enhancement of shape memory epoxy: A dual function of benzoxazine resin as a curing agent and a stable network segment

Effects of benzoxazine resin on property enhancement of shape memory epoxy: A dual function of benzoxazine resin as a curing agent and a stable network segment

Effect of the Network Structure and Programming Temperature on the Shape-Memory Response of Thiol-Epoxy “Click” Systems

Shape memory performance of asymmetrically reinforced epoxy/carbon fibre fabric composites in flexure

Contact Info

Product

Resources

About