Puncture strength

Blending with LLDPE is used to upgrade the properties and improve the processing of conventional LDPE. For example, by adding 25% of ethylene—1-butene LLDPE resin with I2 of 0.5 to conventional LDPE resin, the dart impact strength of 75 p.m film is increased from 490 to 560 g, the puncture strength from 41 to 49 J /mm (770-920 ft-lbf/in.), and the tear strength from 43 to 63 N /mm (246—360 ppi). CompositionaHy uniform VLDPE resins are used in blends with HDPE, commodity LLDPE, and polypropylene (PP) (70,71,89). 

For problem-free processing, high tensile and puncture strengths are desirable. Especially when using expanded metal... 

Brand name Backweb thickness (mm) Electrical resistance ( mficnr) Oil content (%) Porosity (%) Puncture strength (N) Supplier... 

Mechanical strength Tensile properties, puncture strength ... 

Metallocene enhanced toughness, impact and puncture strengths, better cold behaviour and optical properties. 

Yamamura, Y. Ooizumi, S. Yamamoto, K. Separator for rechargeable lithium ion batteries with high puncture strength and high melt rupture temperature. Nltto Denko Technol. Rep. (http /Mww.nitto.com/rd/rd6 l.html), 2001, 39, 39. 

Membrane puncture strength measurements were performed on plasticized samples of Aldrich VHMW and Occidental 410 PVC s. Samples were 33.3 wt% PVC, and 66.7 wt%. dioctylsebacate (DOS) plasticizer. Thicknesses were calculated from densities using weights and areas. Results are given in Figure 3. Membranes were hydrated for 24 hours to duplicate conditions of use. Smaller membranes are stronger per unit thickness. 

Polymer Film Thickness pm Tensile Strength (MPa) Tension at Break (MPa) Elongation % Puncture Strength (N)... 

Thin film with high tensile and puncture strength, low color difference, and low water vapor permeability is more suitable for application as coating, the carriers of antimicrobials, and nutraceuticals than thick film produced by pouring fihn-forming solution. 

Table 3 shows the thickness and tensile and puncture strength, tension at break, and percent elongation of soy, whey and wheat protein, and carboxymethyl cellulose hlms (40). Wheat gluten him showed higher tensile (23.28 MPa) and puncture strengths (3.54 N). Micard et al. (47) reported a very low tensile strength (2.1 MPa)... 

Polymer dispersion (film thickness, pm) Puncture strength (MPa) Elongation (%) ... 

Different sizes of films were formed. The samples were cut to measure film properties and to establish a film thickness control equation. The small-diameter films were used for the water vapor permeability (WVP) and puncture strength (PS) large ones for tensile strength and elongation at break (%) measurement. The volume of solution was added over PVC plates at volume constant using a thin layer chromatography spreader. The plates were placed on a leveled surface to achieve uniform films and dried at room condition (25 2°C and 58 3% HR) for 24 to 48 h. Films used for each property measurement were manufactured and stored under the same temperature but at different relative humidity conditions. 

The puncture test was realized as described previously by Gontard et al. (1992). To avoid any thickness variation, the puncture strength values were divided by the thickness of the film. Three replicates of each film type were tested. 

Effect puncture strength in sodium caseinate films. The puncture strength was calculated considering the thickness. 

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