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E Baer - One of the best experts on this subject based on the ideXlab platform.

  • mechanisms of ductile tear in blown Film from blends of Polyethylene and high melt strength polypropylene
    Polymer, 2002
    Co-Authors: A C Chang, A Hiltner, S P Chum, E Baer
    Abstract:

    Deformation processes associated with ductile tear in blown Films of Polyethylene blended with up to 30 wt% high melt strength polypropylene (hmsPP) were studied. The tear resistance was determined with a reinforced trouser tear test. During stable crack growth, a crack-tip damage zone was transformed into a continuous yielded zone at the fractured edge. The relationship to lamellar morphology was probed with atomic force microscopy. Balanced tear characteristics of Polyethylene Film reflected the nearly isotropic lamellar morphology. In contrast, the highly oriented shish-kebab morphology of hmsPP domains in the blend Films resulted in increasingly anisotropic behavior as the amount of hmsPP increased. The most important manifestation was a significant reduction in machine direction (MD) tear. Good adhesion of Polyethylene and hmsPP in blend Films prevented interfacial failure and provided stress transfer to the dispersed phase at high strains. In MD tear, extension of the matrix by the normal processes of lamellar breakup and fibrillation caused rotation of hmsPP domains into the loading direction and in a later stage shear displacement of reoriented hmsPP lamellae. Locally, hmsPP domains constrained deformation of Polyethylene lamellae. Factors that increased constraint on the Polyethylene matrix such as increasing the amount of hmsPP or increasing the aspect ratio of hmsPP domains reduced the MD tear resistance. In transverse direction (TD) tear, the oriented hmsPP domains deformed by lamellar shear processes concurrently with lamellar breakup and fibrillation of the Polyethylene matrix. As a result, the blend Film preserved good TD tear resistance.

  • structure of blown Film from blends of Polyethylene and high melt strength polypropylene
    Polymer, 2002
    Co-Authors: A C Chang, A Hiltner, E Baer
    Abstract:

    Abstract The structure of blown Film processed from linear low density Polyethylene blended with up to 30 wt[percnt] of a high melt strength polypropylene (hmsPP) was examined using primarily atomic force microscopy and wide angle X-ray scattering. The study focused on two Polyethylene resins with the same density: a conventional Ziegler–Natta catalyzed linear low density Polyethylene (znPE) and a blend of a Ziegler–Natta catalyzed and a metallocene catalyzed linear low density Polyethylene (zn/mPE). Parallel characterization was performed on blown Film of the hmsPP and blown Film of each of the Polyethylene resins. In Films of the blends, the hmsPP was well-dispersed in the Polyethylene matrix as elongated domains. In the domains, the hmsPP crystallized as planar row-nucleated structures with the long axis of the lamellae perpendicular to the extrusion direction. Row-nucleated hmsPP lamellae provided a template for epitaxial crystallization of Polyethylene lamellae. The 42° angle of the lattice match imparted a characteristic herringbone texture to the Polyethylene. Blending with hmsPP increased the tensile modulus and strength of Polyethylene Film without significantly affecting the ultimate elongation.

A C Chang - One of the best experts on this subject based on the ideXlab platform.

  • mechanisms of ductile tear in blown Film from blends of Polyethylene and high melt strength polypropylene
    Polymer, 2002
    Co-Authors: A C Chang, A Hiltner, S P Chum, E Baer
    Abstract:

    Deformation processes associated with ductile tear in blown Films of Polyethylene blended with up to 30 wt% high melt strength polypropylene (hmsPP) were studied. The tear resistance was determined with a reinforced trouser tear test. During stable crack growth, a crack-tip damage zone was transformed into a continuous yielded zone at the fractured edge. The relationship to lamellar morphology was probed with atomic force microscopy. Balanced tear characteristics of Polyethylene Film reflected the nearly isotropic lamellar morphology. In contrast, the highly oriented shish-kebab morphology of hmsPP domains in the blend Films resulted in increasingly anisotropic behavior as the amount of hmsPP increased. The most important manifestation was a significant reduction in machine direction (MD) tear. Good adhesion of Polyethylene and hmsPP in blend Films prevented interfacial failure and provided stress transfer to the dispersed phase at high strains. In MD tear, extension of the matrix by the normal processes of lamellar breakup and fibrillation caused rotation of hmsPP domains into the loading direction and in a later stage shear displacement of reoriented hmsPP lamellae. Locally, hmsPP domains constrained deformation of Polyethylene lamellae. Factors that increased constraint on the Polyethylene matrix such as increasing the amount of hmsPP or increasing the aspect ratio of hmsPP domains reduced the MD tear resistance. In transverse direction (TD) tear, the oriented hmsPP domains deformed by lamellar shear processes concurrently with lamellar breakup and fibrillation of the Polyethylene matrix. As a result, the blend Film preserved good TD tear resistance.

  • structure of blown Film from blends of Polyethylene and high melt strength polypropylene
    Polymer, 2002
    Co-Authors: A C Chang, A Hiltner, E Baer
    Abstract:

    Abstract The structure of blown Film processed from linear low density Polyethylene blended with up to 30 wt[percnt] of a high melt strength polypropylene (hmsPP) was examined using primarily atomic force microscopy and wide angle X-ray scattering. The study focused on two Polyethylene resins with the same density: a conventional Ziegler–Natta catalyzed linear low density Polyethylene (znPE) and a blend of a Ziegler–Natta catalyzed and a metallocene catalyzed linear low density Polyethylene (zn/mPE). Parallel characterization was performed on blown Film of the hmsPP and blown Film of each of the Polyethylene resins. In Films of the blends, the hmsPP was well-dispersed in the Polyethylene matrix as elongated domains. In the domains, the hmsPP crystallized as planar row-nucleated structures with the long axis of the lamellae perpendicular to the extrusion direction. Row-nucleated hmsPP lamellae provided a template for epitaxial crystallization of Polyethylene lamellae. The 42° angle of the lattice match imparted a characteristic herringbone texture to the Polyethylene. Blending with hmsPP increased the tensile modulus and strength of Polyethylene Film without significantly affecting the ultimate elongation.

Miroslaw Zukowski - One of the best experts on this subject based on the ideXlab platform.

Lavinia Balan - One of the best experts on this subject based on the ideXlab platform.

  • a photochemical approach designed to improve the coating of nanoscale silver Films onto food plastic wrappings intended to control bacterial hazards
    Journal of Nanoparticle Research, 2015
    Co-Authors: Gabriel Mustatea, Loic Vidal, Ioan Calinescu, Alina Dobre, Mariana Ionescu, Lavinia Balan
    Abstract:

    Plasmonic silver Film was directly generated on a variety of substrates through a facile and environmentally friendly method, which involves a UV-photoreduction process without any reducing or stabilizing agent and requiring no thermal step. Top-coated Films of unprotected silver nanoparticles (3–11 nm) were generated from hydroalcoholic AgNO3 solution and directly on glass substrates or food packaging plastic wraps, low density Polyethylene Film, and polyvinyl chloride. The natural antibacterial activity of the material was evaluated. The correlation between silver migration and antimicrobial activity of silver-functionalized substrates against pure strains of gram-negative bacteria (Escherichia coli) and gram-positive bacteria (Staphylococcus aureus) was demonstrated. By way of illustration, food plastic wraps top-coated in this way exhibited a high antibacterial activity. The metal nanoparticle Film obtained in this way was characterized and the influence of several parameters (fluence, exposure, silver nitrate concentration, and nature of the free radicals generator) on their formation was studied. Moreover, by shaping the actinic beam with an appropriate device, it is very easy to pattern the brown yellow silver nanoFilm or to print messages in plain text.

Claudio Cocozza - One of the best experts on this subject based on the ideXlab platform.

  • effect of hydrolyzed protein based mulching coatings on the soil properties and productivity in a tunnel greenhouse crop system
    Science of The Total Environment, 2018
    Co-Authors: Luciana Sartore, Evelia Schettini, Laura De Palma, Gennaro Brunetti, Claudio Cocozza
    Abstract:

    : Polymeric protein-based biocomposites were used in this work as water dispersions to generate, in situ, biobased mulching coatings by spray technique, as alternative to low density Polyethylene Films for soil mulching. At the end of their lifetime, these biodegradable coatings degrade in soil thank to the microbial community that mineralizes them. Protein hydrolysates (PH) were derived from waste products of the leather industry, while poly(ethylene glycol) diglycidyl ether (PEG) and epoxidized soybean oil (ESO) were used to make the biodegradable spray coatings. A study under greenhouse condition was carried out using seedling test plots in order to investigate the performance of the spray coatings and their possible influence on some aspects of leaf growth, functionality and nutritional quality of lettuce (Lactuca sativa L., Mortarella selection Romanella variety Duende) and on soil properties. The biodegradable coatings showed the same good agronomic performances comparable with the ones of a commercial low density Polyethylene mulching Film, maintaining the mulching effect for the requested cultivation period and ensuring at the same time a similar rate of plant growth and dry matter accumulation. The research showed that 2 months after the tillage carried out at the end of the cultivation the amount of coating residues present in the soil was <5% of the initial weight of the biodegradable coatings. At the end of the field test, the soil mulched with the Polyethylene Film recorded an electrical conductivity value lower with respect to the soil mulched with the sprayed coatings, which release nutrients in the soil during their decomposition.