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Film Process (film + process)
Selected AbstractsRheological, morphological, mechanical, and barrier properties of PP/EVOH blendsADVANCES IN POLYMER TECHNOLOGY, Issue 3 2001Jong Ho Yeo Using the biaxially oriented film process, polypropylene (PP)/ethylene-vinyl alcohol copolymer (EVOH) blends with an improved barrier property could be obtained by generating a laminar structure of the dispersed phase in the matrix phase. This laminar morphology, induced by biaxial orientation, was found to result in a significant increase in the oxygen barrier property of PP/EVOH (85/15) blends by about 10 times relative to the pure PP. In this study, compatibility in the PP/EVOH blend system was evaluated by investigating the influence of compatibilizer on the rheological, morphological, and mechanical properties of the blends. In addition, the effects of compatibilizer content, draw ratio, and draw temperature on the oxygen permeability and morphology of biaxially drawn blend films were also studied. It was revealed that an optimum amount of compatibilizer, maleic anhydride grafted PP, should be used to improve the barrier property of the PP/EVOH blends with a well-developed laminar structure. The draw ratio and draw temperature had a significant influence on the permeability of the blends. The blend films exhibited a more pronounced laminar structure when the blends were stretched biaxially under processing conditions of higher draw ratio and draw temperature, resulting in higher barrier properties. © 2001 John Wiley & Sons, Inc. Adv Polym Techn 20: 191,201, 2001 [source] Effect of chain architecture on biaxial orientation and oxygen permeability of polypropylene filmJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2008P. Dias Abstract Films of two isotactic propylene homopolymers prepared with different catalysts and a propylene/ethylene copolymer were biaxially oriented under conditions of temperature and strain rate that were similar to those encountered in a commercial film process. The draw temperature was varied in the range between the onset of melting and the peak melting temperature. It was found that the stress response during stretching depended on the residual crystallinity in the same way for all three polymers. Biaxial orientation reduced the oxygen permeability of the oriented films, however, the reduction did not correlate with the amount of orientation as measured by birefringence, with the fraction of amorphous phase as determined by density, or with free volume hole size as determined by PALS. Rather, the decrease in permeability was attributed to reduced mobility of amorphous tie molecules. A single one-to-one correlation between the oxygen permeability and the intensity of the dynamic mechanical ,-relaxation was demonstrated for all the polymers used in the study. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] On unifying multiblock analysis with application to decentralized process monitoringJOURNAL OF CHEMOMETRICS, Issue 9 2001S. Joe Qin Abstract Westerhuis et al. (J. Chemometrics 1998; 12: 301,321) show that the scores of consensus PCA and multiblock PLS (Westerhuis and Coenegracht, J. Chemometrics 1997; 11: 379,392) can be calculated directly from the regular PCA and PLS scores respectively. In this paper we show that both the loadings and scores of consensus PCA can be calculated directly from those of regular PCA, and the multiblock PLS loadings, weights and scores can be calculated directly from those of regular PLS. The orthogonal properties of four multiblock PCA and PLS algorithms are explored. The use of multiblock PCA and PLS for decentralized monitoring and diagnosis is derived in terms of regular PCA and PLS scores and residuals. While the multiblock analysis algorithms are basically equivalent to regular PCA and PLS, blocking of process variables in a large-scale plant based on process knowledge helps to localize the root cause of the fault in a decentralized manner. New definitions of block and variable contributions to SPE and T,2 are proposed for decentralized monitoring. This decentralized monitoring method based on proper variable blocking is successfully applied to an industrial polyester film process. Copyright © 2001 John Wiley & Sons, Ltd. [source] Self-heterodyne diode mixer with GCPW using thin film process at 60 GHzMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 1 2009Seung-Woon Choi Abstract A self-heterodyne diode mixer is proposed using thin film process based on alumina substrate at 60 GHz in conjunction with grounded coplanar waveguide transition. To down-convert both very low RF and LO signals received simultaneously from transmitter for self-heterodyne communication scheme, the proposed mixer adapted with the knee voltage bias condition of 0.65 [V] improves its mixing efficiency significantly. The designed SHM shows the conversion loss of ,15.13 dB at RF and LO frequencies of 60.565 and 59.01 GHz, respectively, with both input powers of ,15 dBm and it also can defines IMD free input dynamic range as ,30 dBm. The measured return losses satisfies with more than 20 dB and 9 dB for RF/LO input and IF output port, respectively. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 13,15, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23959 [source] A neck-in model in extrusion lamination processPOLYMER ENGINEERING & SCIENCE, Issue 1 2010Seiji Shiromoto In this study, the experiment of the extrusion lamination process using high-pressure process low-density polyethylene (LDPE) was performed. The nonisothermal viscoelastic simulation of the extrusion lamination experiment was also carried out. The simulation results were in good agreement with the experimental data within wide range of take up velocity and air gap length. We developed the theoretical model based on force balance and deformation type of a film to predict the neck-in behavior in the extrusion lamination or cast film process. It was suggested from the neck-in model that the neck-in correlates with the ratio of planar to uniaxial elongational viscosity. It was confirmed that the neck-in model could predict the film edge shape and neck-in properly for conventional LDPE. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers [source] Oxygen permeability of biaxially oriented polypropylene filmsPOLYMER ENGINEERING & SCIENCE, Issue 4 2008Y.J. Lin The effect of thermal history on the oxygen permeability of biaxially oriented polypropylene (BOPP) films was investigated. Compression-molded sheets prepared with different cooling rates were biaxially oriented at several temperatures in the range between the onset of melting and the peak melting temperature and at a strain rate similar to that encountered in a commercial film process. The stress response during stretching was found to depend on the residual crystallinity in the same way regardless of the thermal history of the compression-molded sheet. Biaxial orientation reduced the oxygen permeability measured at 23°C; however, the reduction did not correlate with the amount of orientation as measured by birefringence or with the fraction of amorphous phase as determined by density. Rather, the decrease in permeability was attributed to reduced mobility of amorphous tie molecules. A single one-to-one correlation between the oxygen permeability and the intensity of the dynamic mechanical ,-relaxation was demonstrated for all the films used in the study. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers [source] Molecular, rheological, and crystalline properties of low-density polyethylene in blown film extrusionPOLYMER ENGINEERING & SCIENCE, Issue 12 2007Khokan Kanti Majumder The molecular weight and its distribution, degree of long chain branching and cooling rate strongly influence crystallinity during processing, which in turn determines the processability and the ultimate properties of the blown film. Generally a decrease in the number of branches and molecular weight of the polymer and the cooling rate results in an increase of the crystallinity. Length of the main chain and extent of branching in low-density polyethylene (LDPE) are also factors that affect melt rheology and film crystallinity. Long chain branched polyethylene is suitable in the blown film process due to its better melt strength for bubble stability. The objective of this article is to describe the effect of molecular properties (e.g. molecular weight and its distribution, degree of long chain branching etc) of LDPE on film crystallinity at different cooling rates of blown film extrusion. Two different grades of LDPE were selected to investigate molecular characteristics, crystallinity, and rheology. The resins were processed in a blown film extrusion pilot plant using four different cooling rates. Molecular, rheological, and crystalline properties of the resins were key parameters considered in this study. POLYM. ENG. SCI., 47:1983,1991, 2007. © 2007 Society of Plastics Engineers [source] Progress in Nanoengineered Microstructures for Tunable High-Current, High-Temperature Superconducting Wires,ADVANCED MATERIALS, Issue 3 2008G. Holesinger Abstract High critical current densities (Jc) in thick films of the Y1Ba2Cu3O7,, (YBCO, Tc , 92 K) superconductor directly depend upon the types of nanoscale defects and their densities within the films. A major challenge for developing a viable wire technology is to introduce nanoscale defect structures into the YBCO grains of the thick film suitable for flux pinning and the tailoring of the superconducting properties to specific, application-dependent, temperature and magnetic field conditions. Concurrently, the YBCO film needs to be integrated into a macroscopically defect-free conductor in which the grain-to-grain connectivity maintains levels of inter-grain Jc that are comparable to the intra-grain Jc. That is, high critical current (Ic) YBCO coated conductors must contain engineered inhomogeneities on the nanoscale, while being homogeneous on the macroscale. An analysis is presented of the advances in high-performance YBCO coated-conductors using chemical solution deposition (CSD) based on metal trifluoroacetates and the subsequent processing to nano-engineer the microstructure for tuneable superconducting wires. Multi-scale structural, chemical, and electrical investigations of the CSD film processes, thick film development, key microstructural features, and wire properties are presented. Prospects for further development of much higher Ic wires for large-scale, commercial application are discussed within the context of these recent advances. [source] | |||||||||||||