Crystallizing crazes: The probable source of solvent stress cracking resistance in a polyester/polycarbonate blend

Kambour, R. P.; Chu, Chaoqun; Avakian, Roger

doi:10.1002/polb.1986.090240918

Cited by 13 publications

(10 citation statements)

References 6 publications

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“…In simulations, an exponential force distribution was found in the crazes of a glassy polymer, which would favor covalent bond scission . Permanent cross-links make disentanglement more difficult and therefore usually inhibit crazing, but local reductions in T g as a result of solvent sorption can dramatically lower the stress required for crazing. − The void channels of existing crazes also provide pathways for the solvent to reach the highly stressed polymer chains at the tip of the craze, and the fibrils themselves, being relatively thin, are readily plasticized, favoring craze (and crack) propagation. A second, competing mode of local plastic deformation in polymer glasses is the orientation of short chain segments to form shear deformation zones, which proceeds without the creation of voids and therefore does not necessarily require the breakdown of entanglements or bond scission .…”

Section: Discussionmentioning

confidence: 99%

Mechanoluminescent Imaging of Osmotic Stress-Induced Damage in a Glassy Polymer Network

2017

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A chemiluminescent mechanophore, bis(adamantyl-1,2-dioxetane), is used to investigate the covalent bond scission resulting from the sorption of chloroform by glassy poly(methyl methacrylate) (PMMA) networks. Bis(adamantyl)-1,2-dioxetane units incorporated as cross-linkers underwent mechanoluminescent scission, demonstrating that solvent ingress caused covalent bond scission. At higher cross-linking densities, the light emission took the form of hundreds of discrete bursts, widely varying in intensity, with each burst composed of 107–109 photons. Camera imaging indicated a relatively slow propagation of bursts through the material and permitted analysis of the spatial correlation between the discrete bond-breaking events. The implications of these observations for the mechanism of sorption and fracture are discussed.

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Section: Discussionmentioning

confidence: 99%

Mechanoluminescent Imaging of Osmotic Stress-Induced Damage in a Glassy Polymer Network

2017

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“…7 for the miscible blend of amorphous PEI with the crystalline PEEK. The improvement of PC ESCR was shown with the addition of a miscible crystallizable cyclohexane dimethanol tere/iso phthalate polyester [82]. Improvement in the ESCR for PMMA with the addition of crystalline and miscible poly(vinylidene fluoride) was noted for both critical strain and critical stress measurements [83].…”

Section: Polymer Blend Technologymentioning

confidence: 99%

Environmental stress cracking: A review

Robeson

2012

Polymer Engineering & Sci

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Environmental stress failure of polymers (specifically glassy thermoplastics) is a major failure mode in application end use. The environmental stress failure discussion will primarily be limited to non‐reactive environments. Crystalline polymers and even lightly crosslinked polymers can exhibit similar failure to glassy polymers but often require a much higher external applied stress. The mechanisms of environmental stress cracking proposed in the literature will be discussed in detail along with testing methods commonly employed. Approaches to resolve environmental stress failure have limited discussion in the open literature although a significant number of references can be found in the patent literature. Polymer blend approaches, fiberglass reinforcement, and impact modification are areas where industry has solved the environmental stress failure problems. An additional unique mode of failure with water exposure in glassy engineering polymers yielding microcavity formation will also be discussed. Environmental stress failure is an area of considerable concern to the utilization of polymers in a myriad of applications and the unsolved problems existing in the area will be detailed suggesting the need for additional research attention. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers

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“…This possible stabilizing action of the crystallization of a polymer or a crystallizable component of a blend to fibrils formed in crazes was mentioned by Kambour. 66…”

Section: Resultsmentioning

confidence: 99%

Cold Crystallization of Glassy Polylactide during Solvent Crazing

Трофимчук

Efimov

Grokhovskaya

et al. 2017

ACS Appl. Mater. Interfaces

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Uniaxial tension accompanied by the orientation and crystallization of polymer chains is one of the powerful methods for the improvement of mechanical properties. Crystallization of amorphous isotropic polylactide (PLA) at room temperature is studied for the first time during the drawing of films in the presence of liquid adsorption-active media (ethanol, water-ethanol mixtures, and n-heptane) by the solvent crazing mechanism. The crystalline structure arises only under simultaneous actions of a liquid medium and a tensile stress and does not depend on the nature of the environment. The degree of polymer crystallinity increases nearly linearly with the growth in the fraction of the fibrillar material and reaches a maximum value of 42-45%. It has been stated that polymer crystallization happens in crazes involving nanofibrils with a diameter of about 10-20 nm without affecting the bulk polymer parts. Wide-angle X-ray scattering has been used to confirm that the crazing-induced crystallization is accompanied by the formation of the α'-crystalline phase with crystallite sizes (X-ray coherent scattering region) of 3-5 nm, depending on the nature of the liquid medium. After stretching in liquid media to a high tensile strain, the strength of a PLA film has increased to 200 MPa.

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Crystallizing crazes: The probable source of solvent stress cracking resistance in a polyester/polycarbonate blend

Cited by 13 publications

References 6 publications

Mechanoluminescent Imaging of Osmotic Stress-Induced Damage in a Glassy Polymer Network

Mechanoluminescent Imaging of Osmotic Stress-Induced Damage in a Glassy Polymer Network

Environmental stress cracking: A review

Cold Crystallization of Glassy Polylactide during Solvent Crazing

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