PDF Publication Title:
Text from PDF Page: 043
5.4.1.2 Polystyrene Foams Although polystyrene foams are used extensively in sail and surf board manufacture, where their light weight (40kg/m3), low cost and easy to sand characteristics are of prime importance, they are rarely employed in high performance component construc- tion because of their low mechanical properties. They cannot be used in conjunction with polyester resin systems because they will be dissolved by the styrene present in the resin. 5.4.1.3 Polyurethane Foams Polyurethane foams exhibit only moderate mechanical properties and have a tendency for the foam surface at the resin/core interface to deteriorate with age, leading to skin delamination. Their structural applications are therefore normally limited to the pro- duction of formers to create frames or stringers for stiffening components. However, polyurethane foams can be used in lightly loaded sandwich panels, with these panels being widely used for thermal insulation.The foam also has reasonable elevated service temperature properties (150°C/300°F), and good acoustic absorption. The foam can readily be cut and machined to required shapes or profiles. 5.4.1.4 Polymethyl methacrylamide Foams For a given density, polymethyl methacrylamide (acrylic) foams such as Rohacell of- fer some of the highest overall strengths and stiffnesses of foam cores. Their high dimensional stability also makes them unique in that they can readily be used with conventional elevated temperature curing prepregs. However, they are expensive, which means that their use tends to be limited to aerospace composite parts such as helicopter rotor blades, and aircraft flaps. 5.4.1.5 Styrene acrylonitrile (SAN) co-polymer Foams SAN foams behave in a similar way to toughened cross-linked PVC foams. They have most of the static properties of cross-linked PVC cores, yet have much higher elonga- tions and toughness. They are therefore able to absorb impact levels that would fracture both conventional and even the toughened PVC foams. However, unlike the toughened PVC’s, which use plasticizers to toughen the polymer, the toughness properties of SAN are inherent in the polymer itself, and so do not change appreciably with age. SAN foams are replacing linear PVC foams in many applications since they have much of the linear PVC’s toughness and elongation, yet have a higher temperature perform- ance and better static properties. However, they are still thermoformable, which helps in the manufacture of curved parts. Heat-stabilised grades of SAN foams can also be more simply used with low-temperature curing prepregs, since they do not have the interfering chemistry inherent in the PVC’s. Typical SAN products include Gurit’s Corecell® A-series foams. GTC-6-0417 - 41PDF Image | GUIDE TO COMPOSITES
PDF Search Title:
GUIDE TO COMPOSITESOriginal File Name Searched:
guide-to-composites.pdfDIY PDF Search: Google It | Yahoo | Bing
5,000 BF Shipping Container Lumber Dry Kiln For Quality Lumber The 5,000 BF container kiln consists of one 40 foot high-cube aluminum shipping container... More Info
Shipping Container Lumber Dry Kilns by Global Energy Global Energy designed and developed the container kiln back in 1991. The purpose is to give access to portable sawmill owners, furniture makers, and small business the value added profit of dry kiln lumber and quality hardwoods... More Info
Vacuum Kiln Conversion Kit for Lumber and Wood Dry Kilns Convert your existing conventional dry kiln into a fast drying vacuum kiln. Similar to vacuum bagging in the boat building and aircraft industry, we have come up with a proprietary process which allows you to build a very simple vacuum kiln at a fraction of the price, and without the intensive conventional metal chamber structure... More Info
Vacuum Pump Cart System for Bagging Clamping Wood Drying and more Vacuum Cart with 2HP Pump and Dual Pistons with multiple multiplex vacuum ports and liquid reservoir... More Info
Vacuum Bagging Basics Vacuum bagging is a method of clamping, which has traditionally been used in the composites industry, but can also be used for vacuum drying materials, including wood products... More Info
CONTACT TEL: 608-238-6001 Email: greg@globalmicroturbine.com (Standard Web Page)