http://jpf.sagepub.com Journal of Plastic Film and Sheeting RSS feed -- current issue July/October 2008 Journal of Plastic Film and Sheeting 8756-0879 http://jpf.sagepub.com:80/icons/banner/title.gif http://jpf.sagepub.com http://jpf.sagepub.com/cgi/reprint/24/3-4/163?rss=1 2009-02-09 info:doi/10.1177/8756087908101405 3-4 24 163 2008-07-01 163 Article http://jpf.sagepub.com/cgi/reprint/24/3-4/165?rss=1 2009-02-09 info:doi/10.1177/8756087908101406 3-4 24 179 2008-07-01 165 Article http://jpf.sagepub.com/cgi/content/abstract/24/3-4/181?rss=1 Polyethylene is characterized by molecular weight (MW), molecular weight distribution (MWD), and density. Melt index (MI₂) is measured in the quality control (QC) lab and is used as an indication of resin MW. Melt flow ratio (MFR or MI₂₀/MI₂) is a calculated QC lab number, which is used as an indication of MWD. Density is a measure of crystallinity. This article shows that a capillary rheometer can provide a fast and reliable method on a production line to control MW and MWD by predicting MI₂ and MI₂₀ for a resin within specific ranges of density, melt index and equipment/catalysts.

]]> 2009-02-09 info:doi/10.1177/8756087908096625 3-4 24 192 2008-07-01 181 Article http://jpf.sagepub.com/cgi/content/abstract/24/3-4/193?rss=1 The thickness distribution of blown film is conventionally controlled by either changing the temperature or the velocity of the cooling air. This technique cannot be used for the double bubble process, where the film is cooled by water before being reheated and blown up in a second step. A new technique to alter the localized gap of the flow channel at the exit of the die has been developed. It can be used to control the thickness over the circumference of the blown film for both the conventional and double bubble process. The technology is explained and initial test results achieved are presented herein.

]]> 2009-02-09 info:doi/10.1177/8756087908099557 3-4 24 201 2008-07-01 193 Article http://jpf.sagepub.com/cgi/content/abstract/24/3-4/203?rss=1 A vacuum metallizer process study was performed and the results in terms of optical density uniformity, metal adhesion, and barrier uniformity were evaluated. Gas barrier was found to be a complex function of the process parameters studied while adhesion was determined to be sensitive to testing materials as well as process parameters. Visual uniformity was found to depend primarily on metallization pressure.

]]> 2009-02-09 info:doi/10.1177/8756087908100485 3-4 24 211 2008-07-01 203 Article http://jpf.sagepub.com/cgi/content/abstract/24/3-4/213?rss=1 The purpose of this study was to evaluate the physical and mechanical properties of environmentally-friendly films for fresh-cut lettuce. This objective was achieved by determining the gas transmission rates for oxygen, water vapor, carbon dioxide, and the thermal and mechanical properties of the films following ASTM standards D3985, F1249, F2476-05, D3418-03, and D882-02, respectively. Electromechanical testing and thermal analysis determined that biodegradable polypropylene (BPP) possessed similar mechanical and thermal properties when compared to the industry standard. This study suggests that BPP films may be used in place of traditional petroleum-based films currently used to package fresh-cut produce.

]]> 2009-02-09 info:doi/10.1177/8756087908100836 3-4 24 226 2008-07-01 213 Article http://jpf.sagepub.com/cgi/content/abstract/24/3-4/227?rss=1 ``UVA S-Pack'' is a new UV absorber additive designed to protect PET packaging content from the damaging effects of UV radiation. Compared to conventional UV absorbers that have been used for this purpose, this new product offers broader UV protection with less discoloration. The performance of this new UV absorber in content protection was demonstrated in exposure tests with vitamins and colorants. The product is also FDA-cleared for use in PET for food-contact applications. Due to this product's unique absorption and emission profile, it is expected to also offer suitable performance in polyester-based films and sheets.

]]> 2009-02-09 info:doi/10.1177/8756087908101216 3-4 24 238 2008-07-01 227 Article http://jpf.sagepub.com/cgi/content/abstract/24/3-4/239?rss=1 It is well-known that the nanocomposites technology can significantly enhance, among others, the thermal, mechanical, and barrier properties of plastics. It is also known that most bioplastics, including the thermoplastic biopolymers, have lower than desired levels for certain properties which makes their use in certain packaging applications problematic. The combination of active technologies such as antimicrobials and nanotechnologies such as nanocomposites can synergistically lead to bioplastic formulations with balanced properties and functionalities for their implementation in packaging applications. The present work presents the development and characterization of novel nanocomposites of polycaprolactone with enhanced barrier properties and with controlled-release of the biocide natural extract thymol. The antimicrobial nanocomposites of biodegradable materials were prepared in solution by a casting method. The morphology of the biocomposites was visualized by transmission electron microscopy and by atomic force microscopy, the thermal properties were investigated by differential scanning calorimetry and the relative uptake (solubility) and kinetics (diffusion) of the released biocide were determined by Attenuated Total Reflection Fourier Transformed Infrared spectroscopy. Water, oxygen, and limonene barrier properties were also enhanced in the biocomposites.

]]> 2009-02-09 info:doi/10.1177/8756087908101539 3-4 24 251 2008-07-01 239 Article http://jpf.sagepub.com/cgi/reprint/24/3-4/252?rss=1 2009-02-09 info:doi/10.1177/8756087909102519 3-4 24 253 2008-07-01 252 Article