Polymeric films stretched

Lower-density E-plastomers have found alternate use in cast film processes to make elastic film laminates with good breathability which contain laminates of liquid impermeable extensible polymeric films with extensible-thermoplastic-polymer-fiber nonwovens and nonwoven webs of polyethylene-elastomer fibers as the intermediate layers. The development relates to a breathable film including an E-plastomer and filler that contributes to pore formation after fabrication and distension of the film. The method and extent of distension is designed to produce a breathable film by stretching the film to form micropores by separation of the film of the E-plastomer from the particulate solids. This film is useful for manufacture of absorbent personal-care articles, such as disposable diapers and sanitary napkins and medical garments. In detail, these constructions comprise a liquid impermeable extensible film comprising polyolefins. The outer layer contains extensible-thermoplastic-polymer-fiber nonwovens, and an elastic intermediate layer contains nonwoven webs of fiber E-plastomers. The intermediate layer is bonded to the film layer and the outer... 

ETEROAROMATics FURAN AND THIOPHENE. The chemical transformation of thiophene at high pressure has not been studied in detail. However, an infrared [441,445] study has placed the onset of the reaction at 16 GPa when the sample becomes yellow-orange and the C—H stretching modes involving sp carbon atoms are observed. This reaction threshold is lower than in benzene, as expected for the lower stability of thiophene. The infrared spectrum of the recovered sample differs from that of polythiophene, and the spectral characteristics indicate that it is probably amorphous. Also, the thiophene reaction is extremely sensitive to photochemical effects as reported by Shimizu and Matsunami [446]. Thiophene was observed to transform into a dark red material above 8 GPa when irradiated with 50 mW of the 514.5-nm Ar+ laser line. The reaction was not observed without irradiation. This material was hypothesized to be polythiophene because the same coloration is reported for polymeric films prepared by electrochemical methods, but no further characterization was carried out. 

Tentering frame A machine used to stretch textiles and polymeric films and sheets. 

Other techniques for membrane formation include stretching the polymeric film, commonly polytetra-fluoroethylene (PTFE), while it is still in a flexible state and then annealing the membrane to lock in and strengthen the pores in the stretched membrane. The stretching process results into a distinctive membrane structure of PTFE nodes, which are interconnected by fibrils (Fig. 5). 

Uniaxially Oriented A state of material such as polymeric film or composite characterized by the permanent orientation of its components such as polymer molecules or reinforcing fibers in one direction. The orientation is achieved by a number of different processes, e.g., stretching, and is intended to improve the mechanical properties of the material. 

The stretch-mode dynamic viscoelasticity of polymeric films was measured using Rhcometrics RSA-II (Rhcomctrics Far East, Japan) at a frequency of 10 Hz... 

Biaxially oriented film n. Polymeric film (i.e., polyethylene) which as been strained or stretched in one direction which produces optical and physical birefringence or most importantly, high strength one the axial or long direction. 

Generally, the physical properties of a polymeric film differ depending on the direction of stretching. This is caused by the orientation of the molecular chain in the streching direction. Figure 4.57 shows the TMA curves for the PE... 

A related study on the spectroelectrochemical behaviour of a copper electrode in [C4mim] [BF4] containing benzotriazole (BTAH) has been investigated by cyclic voltammetry and SERS [64]. A considerable decrease in the anodic currents in the presence of BTAH, as seen in the cyclic voltammograms, suggests that BTAH inhibits the oxidation of copper in the ionic liquid. The SERS results have shown that at potentials positive to the PZC for copper in the ionic liquid, a [Cu(I)(BTA)] polymeric film is formed as BTAH interacts with the copper(I). The polymeric film is responsible for the corrosion inhibition process. However, at potentials negative to the PZC, BTAH is found to adsorb chemically on the copper surface. This phenomenon is determined by the observation of the v(Cu—N) stretching mode and by the... 

Figure 2.60. The sample pan developed by Clough (1970a) for measuring melting of stretched polymeric films in constrained state (Clough 1970a). (Reprinted with permission of Taylor Francis)...

Identification of hydroxyl (OH)/hydroperoxy (OOH) groups in photo-oxidized polymeric films is based on their combined absorption in the region 3600-3300 cm (the stretching vibration of O—H). Sharp absorption at 3550 cm can be attributed to non-hydrogen-bonded OH groups, whereas a broad absorption at 3450-3300 cm may be due to hydrogen-bonded... 

An oriented sample, such as a drawn polymer film, exhibits different vibrational spectra when the orientation of the sample relative to the direction of linear polarised electromagnetic radiation is altered. In other words, it should be borne in mind that, in the presence of polarised radiation, the relative intensities of bands may be affected. The interaction between the polarised electric field of the radiation and the dipole moment associated with the vibration becomes a maximum or minimum depending on the angle between these two vectors, 0° or 90°. Hence, in polarised light, the spectra of stretch-oriented polymers exhibit dichroism." Dichroism may also be observed in the stressed areas of a polymeric sample. The dichroic behaviour of a sample can provide information on (a) the direction of the vibrational modes, (b) the orientation of the functional group in the crystalline lattice and (c) the fraction of the perfect orientation in the oriented sample. The monitoring of the dichroism can be used to monitor the production of oriented polymeric films. This is commercially important as the physical properties of drawn samples are related to the degree of orientation. 

Figures VII.3 and VII.4 show the experimental values of the Young s modulus and the tensile strength, respectively, for thick films of undoped trans-polyacetylene as a function of draw ratio (all samples were derived from the same polymerization batch). Although there is some scatter in the data, the modulus and tenacity increase approximately linearly with the draw ratio, as is commonly observed for most polymers drawn to moderate draw ratios. The modulus and tensile strength of trans-polyacetylene films stretched up to 15 times are 50 GPa and 0.9 GPa, respectively. These values are essentially equivalent to those observed for ultra-high molecular weight polyethylene [83] drawn to the same draw ratio. Recently, Akagi et al.[78] reported remarkable mechanical properties for drawn polyacetylene films prepared by non-solvent polymerization (100 GPa and 0.9 GPa for the modulus and tensile strength, respectively). The origin of difference in the modulus (in the two studies) is unknown.

The polymeric film used in the experiment was biaxially stretched polystyrene film obtained from... 

Much effort has been expended toward the improvement of the properties of polyacetylenes made by the direct polymerization of acetylene. Variation of the type of initiator systems (17—19), annealing or aging of the catalyst (20,21), and stretch orientation of the films (22,23) has resulted in increases in conductivity and improvement in the oxidative stabiHty of the material. The improvement in properties is likely the result of a polymer with fewer defects. 

Fig.2 shows the infrared absorption spectrum of the tin oxide film. In order to analyze the molecular structure of the deposited film, we deposited the tin oxide film on a KBr disc with thickness of 1 mm and diameter of 13 mm. Various peaks formed by surface reaction are observed including O-H stretching mode at 3400 cm, C=C stretching mode at 1648 cm, and Sn02 vibration mode at 530 cm. The formation of sp structure with graphite-like is due to ion bombardment with hydrogen ions at the surface and plasma polymerization of methyl group with sp -CHa. 

In recent years, much attention has been paid to the use of controlled/ living polymerizations from flat and spherical surfaces [121,122],because this allows better control over the MW and MWD of the target polymer. By using these techniques, a high grafting density and a controlled film thickness can be obtained, as such brushes consist of end-grafted, strictly linear chains of the same length and the chains are forced to stretch away from the flat surface. Several research... 

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