The essential work of fracture of a thermoplastic elastomer

Maspoch, M. Ll.; Santana, Oliverio J.; Grando, J.; Ferrer, D.; Martínez, Alejandro Rosillo

doi:10.1007/s002890050145

Cited by 20 publications

(8 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…During the second and third thermal mending steps, there was no indication of crack reopening, but rather a necking effect that is apparent in ductile thermoplastic materials. 33 Figure 6b shows the force vs displacement curve for a notched l-PCL 50 :n-PCL 50 sample that was stretched in its damaged state, showing stereo micrographs of the sample in its prestretched, initial crack opening, crack transition, and partial crack propagated state. We observe in Figure 6b the sample after damage and before uniaxial stretching followed by the sample's yield point of initial crack opening (transition from the elastic to plastic deformation state).…”

Section: ' Results and Discussionmentioning

confidence: 99%

“…Self Healing (SH) experiments were conducted using the deeply double-edge notched tensile (DDEN-T) geometry employed for fracture testing of polymeric films. − Cured l-PCL:n-PCL blend samples were first cut into a dogbone geometry (ASTM D638−03 Type 1, scaled down by a factor of 3), with an average thickness of 0.56 ± 0.08 mm and a width of 4.3 mm, using a custom-made dogbone cutting die (TestResources, Inc., Shakopee, MN). For such specimens, the gauge length is 16.67 mm.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Linear/Network Poly(ε-caprolactone) Blends Exhibiting Shape Memory Assisted Self-Healing (SMASH)

Rodriguez

Luo

Mather

2011

ACS Appl. Mater. Interfaces

366

290

View full text Add to dashboard Cite

Self-healing (SH) polymers are responsive polymeric materials that can repair mechanical damage such as cracks in an autonomous fashion. In most SH polymers studies reported to date, crack closure was either unaddressed or achieved by manual intervention. Here, we report a new strategy that utilizes shape memory (SM) to prepare novel SH polymers that are capable of simultaneously closing and rebonding cracks with a simple thermal trigger. This strategy, termed "shape memory assisted self-healing (SMASH)", is demonstrated in a blend system consisting of cross-linked poly(ε-caprolactone) network (n-PCL) with linear poly(ε-caprolactone) (l-PCL) interpenetrating the network, and exhibits a combination of SM response from the network component and SH capacity from the linear component. Thermomechanical analysis revealed that the thermoset, n-PCL, demonstrates reversible plasticity -a form of shape memory where large plastic deformation at room temperature is fully recoverable upon heating. This SM action assists to close any cracks formed during deformation and/or damage while l-PCL chains tackify the crack surfaces by diffusion to the free surface and ultimately across the area of damage during the same heating step as used for SM. In our study, we investigated the controlled damage and SMASH healing of blends with varying composition using tensile testing of essential work of fracture film specimens. The healing component, l-PCL used had a high M(w) (M(w) ∼65k g/mol) to enable re-entanglement after diffusion across the interface while the shape memory component, n-PCL was prepared from PCL telechelic diacrylates and a tetrathiol cross-linker, yielding excellent shape memory. We found excellent self-healing of films by the SMASH mechanism, with near complete healing for l-PCL contents exceeding 25 wt %. Applications are envisioned in the area of self-healing bladders, inflated structure membranes, and architectural building envelopes.

show abstract

Section: ' Results and Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Linear/Network Poly(ε-caprolactone) Blends Exhibiting Shape Memory Assisted Self-Healing (SMASH)

Rodriguez

Luo

Mather

2011

ACS Appl. Mater. Interfaces

366

290

View full text Add to dashboard Cite

show abstract

“…The EWF method was initially developed by Cotterell and Reddel,6 following Broberg's work,7 for the characterization of ductile fracture in metal sheets. Afterwards, it was applied with success to plastic film and sheets,8 and in the last decade multiple works have shown the convenience of employing the EWF method to characterize fracture properties of polymer thin sheets and films 9–14. Also, there have been many contributions to develop the technique in their experimental details15–20 as well as to understand the influence among the fracture parameters thus obtained and the microstructure and morphology of the fractured materials 5, 10, 21…”

Section: Methodsmentioning

confidence: 99%

Influence of processing on ethylene propylene block copolymers (II): Fracture behavior

Gámez‐Pérez¹,

Muñoz²,

Santana³

et al. 2006

J of Applied Polymer Sci

Self Cite

View full text Add to dashboard Cite

ABSTRACT:The present work investigates the relationships between the microstructural state and fracture properties in commercial polypropylene-based materials. In this case an isopolypropylene homopolymer and three ethylene propylene block copolymers (EPBC) with different ethylene content (EC) have been studied. A variety of morphologies were obtained by a combination of several processing methods (injection molding, injection molding-annealing, and compression molding) and thickness. Fracture behavior of deeply double-edged notched specimens was evaluated by scanning electron microscopy (SEM) and by the essential work of fracture (EWF) method, analyzing the influence of processing, thickness (t), EC, and orientation respect to melt flow direction (MD and TD). The testing direction and EC are the most relevant variables that affect the ability of the crack tip to deform plastically during the crack propagation, determining the final fracture behavior. The fracture parameters obtained with the EWF method, specific EWF, w e , and plastic item, ␤w p , have proved to be very sensitive to the processing induced morphology, finding interesting relationships between such morphologies (characterized by crystallinity index, orientation level, and skin/core ratio) and the fracture parameters of the plaques.

show abstract

“…This method was initially developed by Cotterell and Reddel [13] for metals, after Broberg's work on stable crack growth [14]. During the lasts 20 years it has been successfully applied to many different polymeric films and sheets [15][16][17][18][19]. The EWF theory states that the energy involved during the ductile fracture, W f , of a yielded region (postyielding fracture mechanics) can be treated as a two-term contribution: an essential term (W e ), proportional to the ligament section, and a second one called nonessential (W p ) proportional to the volume deformed plastically.…”

Section: Mechanical and Fracture Behaviormentioning

confidence: 99%

Evaluation of the fracture behavior of multilayered polypropylene sheets obtained by coextrusion

Gámez‐Pérez¹,

Santana²,

Gordillo³

et al. 2007

Polymer Engineering & Sci

View full text Add to dashboard Cite

The mechanical and fracture behavior of multilayered sheets (up to three layers) is presented. The sheets were processed by plane coextrusion-calendering using two polypropylene-based materials, isotactic polypropylene homopolymer (H0), and an ethylene-propylene block copolymer (C1) with 5.5% ethylene content in weight. Combining these materials five different sheets were produced, (H0, C1, H0-C1, H0-C1-H0, and C1-H0-C1), with an overall thickness of 0.5 mm. The processing variables (temperature, extrusion rate, calendering speed, etc.) were set constant among the different structures to facilitate the evaluation of the results. The structure of the sheets was characterized with wide angle X-ray scattering (WAXS). The mechanical behavior was determined from dumbbell tensile specimens in the melt flow (MD) and transverse to the melt flow (TD) directions. The fracture parameters were determined by the essential work of fracture (EWF) technique in mode I in both MD and TD directions. The results show variations on the induced orientation of the sheets, with remarkable differences on the fracture properties. The poor fracture resistance of the homopolymer (H0) film in TD is improved through coextrusion with C1, obtaining the best results for toughness in the case of the three-layered sheets. POLYM. ENG.

show abstract

The essential work of fracture of a thermoplastic elastomer

Cited by 20 publications

References 7 publications

Linear/Network Poly(ε-caprolactone) Blends Exhibiting Shape Memory Assisted Self-Healing (SMASH)

Linear/Network Poly(ε-caprolactone) Blends Exhibiting Shape Memory Assisted Self-Healing (SMASH)

Influence of processing on ethylene propylene block copolymers (II): Fracture behavior

Evaluation of the fracture behavior of multilayered polypropylene sheets obtained by coextrusion

Contact Info

Product

Resources

About