Biaxial tensile drawing of poly(ethylene terephthalate) via environmental crazing as a method for creating a porous structure

Streltsov

Малахов

et al. 2020

Polymer International

This work addresses the phenomenon of the development of a patterned surface relief on polymer films via different modes of environmental crazing. Commercial films of semicrystalline poly(tetrafluoroethylene) (PTFE) and amorphous glassy poly(ethylene terephthalate) (PET) were subjected to tensile drawing in the presence of physically active liquid environments (carbon tetrachloride or aliphatic alcohols). The structure parameters and wettability of the modified films were studied by AFM, SEM, profilometer measurements and contact angle measurements. Environmental intercrystallite crazing of PTFE is accompanied by the development of an unstable structure with a high free surface, which experiences marked strain recovery upon unloading. As a result of the relief formation, PTFE hydrophobicity is enhanced (the water contact angle increases by 25°). Classical environmental crazing of PET films is accompanied by the formation of an anisotropic surface relief which is an assembly of crazes oriented perpendicular to the direction of tensile drawing, thus leading to the phenomenon of anisotropic wetting. The proposed approach for structural surface modification makes it possible to use the advantages of surface instability and spontaneous self-organization of the polymer towards the development of a unique surface microrelief.

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Surface modification of poly(tetrafluoroethylene) and poly(ethylene terephthalate) films via environmental crazing

Streltsov

Малахов

et al. 2020

Polymer International

“…[ 23–26 ] At present, it has been revealed that crazed polymers are permeable for gases, water vapor, and liquids. [ 27,28 ] Moreover, the formed porous structure enables one to use crazed polymers as matrices for incorporating low‐ and high‐molecular weight compounds, that is, for the preparation of nanocomposites (NCs). [ 29–31 ]…”

Section: Introductionmentioning

confidence: 99%

Breathable Materials and Hybrid Nanocomposites with Antimicrobial Activity Based on Porous Poly(ε‐Caprolactone) Obtained via Environmental Crazing

Khavpachev

Bagrov

et al. 2020

Macro Materials & Eng

Structural modification of poly(ε‐caprolactone) (PCL) allows the fabrication of new functional materials obtained via the PCL films/fibers stretching in ethanol by the crazing mechanism. Atomic force microscopy, X‐ray scattering, and differential scanning calorimetry are employed to study the evolution of PCL structure. It is shown that ethanol plasticizes the polymer being deformed, and the stretching of PCL films/fibers occurs with formation of a fibrillar‐porous structure in the interlamellar space. The obtained porous matrices have pore size below 50 nm and bulk porosities of 28% and 48% for fibers and films, respectively. Thermal stabilization of the PCL films’ porous structure made it possible to obtain breathable materials with a vapor permeability of 625–652 g m−2 per day. The resulting porous PCL fibers and films can be used as matrices for the incorporation of useful additives and preparation of functional nanocomposites (NCs), biodegradable surgical suture, packaging, covering, and textile vapor‐permeable materials. Hybrid NCs with antibacterial and fungicidal activities are obtained on the basis of the porous PCL matrices and functional components (5% silver, 1% brilliant green, 28% Betadine, etc.) incorporated into them.

Breathable polymeric materials based on high‐density polyethylene prepared by environmental crazing

J of Applied Polymer Sci

Rukhlya

Grokhovskaya

et al. 2019

This work addresses the preparation of breathable materials based on high‐density polyethylene (HDPE) and characterization of their performance. The sustainable HDPE mesoporous materials were prepared by the tensile drawing of the HDPE films in the presence of physically active liquids (PALEs) via the mechanism of environmental intercrystallite crazing (EIC). The prepared mesoporous materials were characterized by the different physicochemical methods such as differential scanning calorimetry (DSC), atomic force microscopy (AFM), low‐temperature nitrogen adsorption (LTNA), and so forth. Water vapor transmission rate (WVTR) of the breathable materials can be tailored by varying the tensile strain upon the EIC and is found to be equal to 597–1345 g m−2 day−1. The breathable HDPE‐based materials are characterized by good mechanical and insulating properties as well as by high water entry pressure (~43–47 bar). Hence, the deformation of HDPE films via the EIC mechanism provides an efficient route for the preparation of mesoporous breathable materials based on the low‐cost commercial polymers, which can be used as waterproof, protective, subroof, gas storage, and packaging materials. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48567.