Star mold

For large-scale production, a star plate or star mold assembly is best. This consists of three flat rectangular plates of hard wood or metal, preferably aluminum. One has a perfectly smooth surface. The second, which rests upon this, has many circular holes of the size of the stars which are desired. The damp mixture is dumped upon this plate, rubbed, pressed, and packed into the holes, and the surface of the plate is then wiped clean. The third... 

For large-scale production, a star plate or star mold assembly... 

Dynamic melt viscosity studies on the star blocks and a similar triblock were carried out using a Rheometric Mechanical Spectrometer (RMS) (Rheometrics 800). Circular molded samples with -1.5 mm thickness and 2 cm diameter were subjected to forced sinusoidal oscillations (2% strain) between two parallel plates. The experiment was set in the frequency sweep mode. Data were collected at 180 and 210 °C. 

The dynamic melt viscosity measurements of select star blocks and a similar triblock were carried out on a rheometric mechanical spectrometer, RMS. Circular molded samples of 2 cm diameter and -1.5 mm thickness were subjected to forced sinusoidal oscillations. Dynamic viscosities were recorded in the frequency range of 0.01-100 rad/s at 180 °C. Figure 10 shows the complex viscosities of two select star blocks and a similar linear triblock. The plots showed characteristic behavior of thermoplastic elastomers, i.e., absence of Newtonian behavior even in the low frequency region. The complex viscosity of the star block... 

Asymmetric stars have also been used or have the potential to be used in many other applications as compatibilizers [50],impact modifiers and in sealant [100] and molding compositions etc. 

Fig. 34 Images of clear compression molded films made with linear PS (MW = 280kg mol ) blended with PS-y-CD 12-arm star molecules, (a) PS3.4-y-CD, (b) PS32-y-CD, (c) PS52-y-CD, and (d) PS90-y-CD...

Three-arm star PIB ionomers were prepared by techniques described extensively before (16-17). Some relevant parameters for the sample are shown in Table I. The 3-arm PIB ionomers neutralized by NaOH were dried at room temperature under vacuum for 1 month, while another series of Na salts were dried at 140°C for a week. Samples were then compression molded at 150°C under an applied load of 4000 lbs/ in. Typical dimensions of the rectangular specimens for stress relaxation studies were 3.0 x 6.0 x 40 (mm). 

Scheme 1. Templating steps induding both casting and coating approaches. Schematic illustration demonstrating the casting and coating of a star-shaped template. The casting technique gives a composite in which the second material fills the area around the mold so that on removal of the mold a structured material is obtained, which is an inverse replica of the initial template. In contrast, coating of the template results in a layer of the second material aroimd the mold, resulting in a hollow replica on removal of the template...

Figure 3. Images of a) the mold with starting and processed polymers, b) processed baroplastic(PEHAo.4g-b-PSo,3i)" 4-arm star-block copolymer (P6), at different pressures for 1 min at room temperature.

Optic molds - to make beads into different shapes, such as stars, etc. 

Handbook of Polypropylene and Polypropylene Composites, edited byHanitun G. Katian Polymer Blends and Alloys, edited by Gabriel 0. Shonaike and George P. Simon Star and Hyperbranched Polymers, edited by Munmaya K. Mishra and Shiro Kobayastv Practical Extrusion Blow Molding, edited by SamuelL. Belcher... 

Bregar, B., Molding Takes Stage With Rock Star Press (Rotomolder), PN, Dec. 15, 2003. 

A runner layout of pieces to be demolded by simple ejection should be achieved so that the sprue picker takes the runner easily. A row layout of the mold cavities is more favorable for sprue picking than round or star layout versions. It is often practical to form the upp>er end of the runner with an extra cone which guarantees an easy take-off. 

Fig. 21. Morphology of an injection-molded specimen of a star-block copolymer with a PS content of 74% with lamellar arrangement of PS and PB lamellae before and after deformation, (a) PS and PB lamellae before deformation (b) Plastically stretched PS and PB lamellae deformed in parallel direction to lamellar orientation (a, b tern micrc aphs of chemically stained thin sections, PB lamellae appear dark arrow shows direction of tension) Frequency distributions of thicknesses of PS lamellae (c) before and (d) after deformation. From Ref. 60.

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