Thermomechanical characterization of shape memory polymers using high temperature nanoindentation

Fulcher, J. T.; Yang, Lih-Mei; Tandon, G. P.; Foster, D. C.

doi:10.1016/j.polymertesting.2010.02.001

Cited by 37 publications

(23 citation statements)

References 26 publications

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“…For example, Wornyo, et al 23 investigated the deformation behavior of diethylene glycol dimethacrylate and polyethylene glycol dimethacrylate shape memory copolymer networks with various organic components based on the nanoindentation results. Fulcher, et al 24 provided a detailed approach on the thermomechanical characterization of a thermosetting epoxy based SMPs by nanoindentation tests at different temperatures. Nelson, et al 25 reported a temperature-dependent nano-scale recovery of a thermosetting epoxy based SMPs using the tip of atomic force microscopy (AFM).…”

Section: Introductionmentioning

confidence: 99%

Micro-mechanics of nanostructured carbon/shape memory polymer hybrid thin film

Lei

Pei

et al. 2016

Soft Matter

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This paper investigates the mechanics of hybrid shape memory polymer polystrene (PS) based nanocomposites with skeletal structures of CNFs/MWCNTs formed inside. Experimental results showed an increase of glass transition temperature (Tg) with CNF/MWCNT concentrations instead of a decrease of Tg in nanocomposites filled by spherical particles, and an increase in mechanical properties on both macro- and μm-scales. Compared with CNFs, MWCNTs showed a better mechanical enhancement for PS nanocomposites due to their uniform distribution in the nanocomposites. In nanoindentation tests using the Berkovich tips, indentation size effects and pile-up effects appeared obviously for the nanocomposites, but not for pure PS. Experimental results revealed the enhancement mechanisms of CNFs/MWCNTs related to the secondary structures formed by nanofillers, including two aspects, i.e., filler-polymer interfacial connections and geometrical factors of nanofillers. The filler-polymer interfacial connections were strongly dependent on temperature, thus leading to the opposite changing trend of loss tangent with nanofiller concentrations, respectively, at low and high temperature. The geometrical factors of nanofillers were related to testing scales, further leading to the appearance of pile-up effects for nanocomposites in the nanoindentation tests, in which the size of indents was close to the size of the nanofiller skeleton.

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Section: Introductionmentioning

confidence: 99%

Micro-mechanics of nanostructured carbon/shape memory polymer hybrid thin film

Lei

Pei

et al. 2016

Soft Matter

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“…SMPs consist of dual‐segment; one part is highly elastic and other part is able to vary its stiffness upon a particular stimulus . SMPs have advantages such as light weight, low cost, good processability, high shape deformability, high shape recoverability, superior molding properties, potential biocompatibility, biodegradability, etc., over the shape memory alloys those possess lesser recovery strain . Such additional advantages of shape memory polymers suggest their use in deployable space structure, morphing aircraft, and micro‐system .…”

Section: Introductionmentioning

confidence: 99%

Improved shape memory effects in multiwalled‐carbon‐nano‐tube reinforced thermosetting polyurethane composites

Prasad

Hashmi

Naik

et al. 2016

J of Applied Polymer Sci

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Shape memory thermosetting polyurethane (SMPU) composites containing different amount of multiwalled carbon nanotube (MWCNT) ranging from 0 to 0.250 phr were prepared. The shape memory behavior, tensile stress, and recovery stress were determined by using conventional thermomechanical cycle; however, the modified thermomechanical cycle designated as progressive stretch-relax-stretch (PSRS) cycle was also employed to create shape memory effects in studied composites. The test was carried out in water bath which was equipped with an electric heater, temperature controller, and tensile stress and strain measuring setup. The recovery and tensile stresses both were showing higher values for PSRS samples as compared with conventional samples. Loading of MWCNT improved the recovery stress of SMPU, thereby confirming reinforcing effect. The maximum recovery stress of 2.17 MPa for 0.188 phr MWCNT loading was observed as compared with 1.09 MPa of unreinforced SMPU specimen. The recovery time was also improved on reinforcement as demonstrated in this article. The morphology of fractured surface and degree of dispersion of MWCNT was studied using Field Emission Scanning Electron Microscope. The impact on glass transition temperature was also observed for MWCNT reinforcement on SMPU, which depends on the degree of dispersion and loading of MWCNT in the specimen.

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“…This confirms the softening of the polymer and is in accordance with other studies. [11,13,18,32] To further investigate the effects of temperature on the mechanical properties of PPV, high-temperature dynamic nanoindentations studies were conducted. The results were analyzed using Eqs.…”

Section: Quasi-static and Dynamic Nanoindentation Resultsmentioning

confidence: 99%

Elevated temperature nanoindentation characterization of poly(para-phenylene vinylene) conjugated polymer films

et al. 2015

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a b s t r a c tTemperature dependent mechanical properties of poly(p-phenylene vinylene) (PPV) were investigated using quasi-static (QS) and dynamic nanoindentation (NI) at temperatures over the range of 25 to 100 C. The reduced modulus decreased from about 4.40 GPa to 3.64 GPa over this temperature range. The plasticity indices at all measurement temperatures were lower than the critical value of 0.875, characterizing material "sink-in", rather than "pile-up" during measurements. The plasticity index showed a non-monotonic trend, with a minimum value at around 70 C. Analysis of indentation stress relaxation data, obtained at different temperatures, was also performed using generalized Maxwell viscoelastic models. From these analyses, a relaxation mode, with a characteristic relaxation time of approximately 0.5 s, was evident. The characteristic time remained relatively unchanged over the temperature range of 25 to 100 C. However, the relaxation modulus associated with this mode showed the expected decrease with increase in temperature.

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Thermomechanical characterization of shape memory polymers using high temperature nanoindentation

Cited by 37 publications

References 26 publications

Micro-mechanics of nanostructured carbon/shape memory polymer hybrid thin film

Micro-mechanics of nanostructured carbon/shape memory polymer hybrid thin film

Improved shape memory effects in multiwalled‐carbon‐nano‐tube reinforced thermosetting polyurethane composites

Elevated temperature nanoindentation characterization of poly(para-phenylene vinylene) conjugated polymer films

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