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Film Extrusion (film + extrusion)

Distribution by Scientific Domains
Polymers and Materials Science100%

Selected Abstracts

Film extrusion of sunflower protein isolate

POLYMER ENGINEERING & SCIENCE, Issue 11 2006
Antoine Rouilly
Film extrusion of sunflower protein isolate (SFPI) was studied. The influence of die temperature (85,160°C), water and glycerol contents were investigated through appearance, mechanical and thermomechanical properties, and swelling behavior in water of films. It was demonstrated that highest temperature, well above SFPI denaturation temperature in the compound, highest glycerol content (70 parts for 100 parts of SFPI), and medium water content (20 parts for 100 parts of SFPI) gave the most regular and smoothest film (as seen on SEM micrographs). Its ultimate tensile strength, Young's modulus, and strain at break were, respectively, 3.2 MPa, 17.7 MPa, and 73%. Soaked in water, its swelling was about 186% w/w but the film was quiet insoluble. Effect of temperature and plasticizer content were discussed in relation to the kinetic of SFPI denaturation. These first results are very promising for the development of biodegradable protein-based films. POLYM. ENG. SCI. 46:1635,1640, 2006. © 2006 Society of Plastics Engineers. [source]

Effect of flow history on poly(vinylidine fluoride) crystalline phase transformation

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2007
Hadi Sobhani
Abstract This study was devoted to the effect of extensional flow during film extrusion on the formation of the ,-crystalline phase and on the piezoelectric properties of the extruded poly(vinylidine fluoride) (PVDF) films after cold drawing. The PVDF films were extruded at different draw ratios with two different dies, a conventional slit die and a two-channel die, of which the latter was capable of applying high extensional flow to the PVDF melt. The PVDF films prepared with the two-channel die were drawn at different temperatures, strain rates, and strains. The optimum stretching conditions for the achievement of the maximum ,-phase content were determined as follows: temperature = 90°C, strain = 500%, and strain rate = 0.083 s,1. The samples prepared from the dies were then drawn under optimum stretching conditions, and their ,-phase content and piezoelectric strain coefficient (d33) values were compared at equal draw ratios. Measured by the Fourier transform infrared technique, a maximum of 82% ,-phase content was obtained for the samples prepared with the two-channel die, which was 7% higher than that of the samples prepared by the slit die. The d33 value of the two-channel die was 35 pC/N, which was also 5 pC/N higher than that of the samples prepared with the slit die. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 [source]

Molecular, rheological, and crystalline properties of low-density polyethylene in blown film extrusion

POLYMER ENGINEERING & SCIENCE, Issue 12 2007
Khokan 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]