Polyolefin Films Research Articles

Why do People use KEMAMIDE E in Polyolefin Films in place of ordinary amides?

RETURN TO ISSUEPREVAdvertisementNEXTWhy do People use KEMAMIDE E in Polyolefin Films in place of ordinary amides?Cite this: Chem. Eng. News 1968, 46, 2, 4Publication Date (Print):January 8, 1968Publication History Published online6 November 2010Published inissue 8 January 1968https://doi.org/10.1021/cen-v046n002.p004Copyright © 1968 AMERICAN CHEMICAL SOCIETYArticle Views83Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (314 KB) SUBJECTS:Amides Get e-Alerts

Electron paramagnetic resonance of ultraviolet‐irradiated polyolefins

AbstractIf films of polyolefins are ultraviolet‐irradiated at liquid nitrogen temperature, alkyl radicals which can be examined by EPR are produced. No EPR spectra are observed from polyolefins irradiated at room temperature in air. Ultraviolet irradiation of polyolefins containing small alkyl side chains generally produces radicals corresponding to the pendant group or methyl radicals if the side chains contain a methyl branch. For some polymers the radical species could not be identified with certainty. Stabilization studies indicate that an optimum concentration of ultraviolet stabilizer is necessary for maximum stabilization of polyolefins. Preliminary results of EPR studies of the ultraviolet irradiation of various polyolefins are given, and some possible radical species are discussed.

A method of rapid determination of thermal expansion and apparent second‐order transition temperature of polymer films

AbstractAn Instron tensile tester has been modified to measure the thermal expansion of polymer films. The method greatly simplifies the experimental procedure necessary for the standard ASTM dilatometric thermal expansion measurement, particularly for thin films. Thermal expansion measurements were made for films of polyester, polycarbonates, vinyls, cellulosies, and polyolefins from room temperature up to 300°F. Second‐order transition temperatures were determined by plotting thermal elongation vs temperature; the transition temperature is indicated by a change in slope. Both expansion coeffcients and transition temperatures as determined by this method give excellent agreement with values reported in the literature.

Determination of polyolefin film properties from refractive index measurements

AbstractA technique is described for determining the density of polyolefin film from refractive index measurements. The procedure involves the measurement of the refractive indexes (nx, ny, and nz) along the three major axes of a film sample and conversion of the arithmetic average refractive index to a density value. The refractive index data are also used to calculate the per cent crystallinity and birefringence in the film.

Apparatus for measuring the dynamic tensile modulus of thin polymeric films

AbstractA method and apparatus have been developed specifically for the determination of the dynamic tensile modulus of thin polymeric films. A weight is attached to a 2 × 60‐mm. strip of film, the upper end of which is clamped to a phonograph recording head. The recording head is used to set the system into either longitudinal or transverse vibration. The cross‐sectional area of the film is determined in place from the length, the density, and the transverse resonant frequency (the Vibroscope principle). The modulus is found from the dimensions of the specimen and the longitudinal resonant frequency. The apparatus has been used to study the moduli of a series of polymeric packaging films, the dependence of the modulus of polyethylene film on the angle between the long axis of the specimen and the machine direction, the gage dependence of the stiffness of polyolefin films, and the relationship between the modulus and the moisture and glycerol contents of cellophane.

Relationship between dynamic modulus of thin films and stiffness, as determined by the Handle‐O‐Meter

AbstractA series of thirteen polyethylene and ten polypropylene packaging films was studied by both the Handle‐O‐Meter and the dynamic tensile modulus apparatus, to discover how the stiffness of polyolefin films determined with the Handle‐O‐Meter depended on the modulus of the material and the thickness of the film. The polyethylene films included low‐, medium‐, and high‐density resins and ranged in thickness from 0.7 to 4 mils. The moduli of these films ranged from 2.5 X 109 to 18 X 109 dynes/cm.2 The polypropylene films were made from several types of resins with moduli varying from 73 x 109 to 54 X 109, and the thicknesses of these films ranged from 0.5 to 4 mils. When the logarithm of the ratio of stiffness to modulus was plotted as a function of the logarithm of the thickness of the film, as determined from unit weights and densities, a straight line was obtained with a slope of 2.5. This means that over a wide range of gauge and modulus the Handle‐O‐Meter stiffness of these materials, S (in grams), is related to the modulus, E (in dynes per square centimeter), and the thickness, t (in mils), by the equation S = 1.41 X 10‐9Et2.5. This result, which shows that the Handle‐O‐Meter stiffness of polyolefin films may be represented as a function of the thickness and the modulus as given by the dynamic tensile modulus apparatus, may be used to calculate a modulus value from any single Handle‐O‐Meter stiffness value or, alternatively, to reduce Handle‐O‐Meter stiffness measurements to a standard thickness. Conversely, this relationship may be used to predict the Handle‐O‐Meter stiffness of a film made from a polymer whose modulus is known.

Orientation studies on drawn polyolefins

AbstractThe effect of different thermal treatments on the degree and type of orientation produced by cold drawing three polyolefin films: polyethylene, polypropylene, and polybutene‐1, was studied by two complementary techniques: x‐ray diffraction for the measurement of crystal orientation and birefringence for the measurement of the total film orientation. Variations in the texture of these polymer films were characterized by these techniques as well as by density, tensile stress measurements and photomicrographs. The birefringence–strain data showed a decrease in birefringence values at a given strain as the polymer side group size increased. This decrease appears to be associated with a more symmetrical polarizability ellipsoid and hence a decrease in crystal birefringence. The birefringence–strain curves for the same polymer system showed a decrease in birefringence value at a constant strain with increased annealing. X‐ray diffraction data indicate that the a and b axes in both polyethylene and polybutene‐1 film orient by different amounts at a given strain. Polypropylene, on the other hand, shows equal amounts orientation of the a and b axes. The different orientation behavior for these polymer systems is discussed in terms of variation in the ease with which polymer crystals may be deformed.