Material Innovations
Plastic tanks from DERA
 DERA's "plastic tank" (left) meets a more conventional armored fighting vehicle. |
Plastic tanks may be familiar in the home as children's toys but are less familiar on the battlefield. However, in the UK, DERA (Defense Evaluation Research Agency) has announced what it claims as the "world's first plastic tank," technically known as the Advanced Composite Armored Vehicle Platform (ACAVP) demonstrator. Developed by DERA and Vickers Defense Systems, the vehicle's technology will support the development of advanced composite materials for incorporation into future armored fighting vehicles (AFV).
Details of the materials incorporated in the plastic tank have not been released, but further advances in composite technology will be demonstrated in various planned vehicles, including a main battle tank. "Future tanks will need to be smaller and lighter than their present day counterparts while retaining or improving their survivability against anti-armor weapons, and this can only be achieved by the use of lightweight composite structures," said Mark French, DERA ACAVP Research Team Leader.
The plastic tank underwent a year-long evaluation program that included all standard British Army tests to assess conventional armored vehicles. These included speed, step-climbing, cross-country mobility, and resistance to impacts, loads, and abrasions. It showed "stealth" advantages over conventional AFVs in terms of radar, thermal, and electromagnetic signatures. Ballistic tests on representative samples of the composite materials used in ACAVP are said to have been "an outstanding success."
The use of composite materials to protect fighting vehicles is not novel, but very extensive incorporation in the manner of the plastic tank certainly is.
- Stuart Birch
Acoustical foam from E-A-R
 TUFCOTE TBK-faced acoustical foam from E-A-R Specialty Composites is suitable for applications in engine compartments, vehicle cabs, and pumps. |
E-A-R Specialty Composites has introduced a new noise-control product—TUFCOTE TBK acoustical foam—that features a durable, puncture-resistant urethane facing that is both decorative and functional. The matte, textured facing resists moisture, making the foam suitable for noise control in environments where it may be exposed to grease, oils, or engine fluids. Unlike foil facings, the non-glare surface provides a smoother appearance over irregular substrates and will not reflect or magnify adjacent surfaces.
Applications for the TBK foam include engine compartments, vehicle cabs, machinery housings, generators, pumps, and compressors. The foam is available from stock in thicknesses of 13 to 25 mm (0.5 and 1 in), and in custom-order thicknesses from 6 to 50 mm (0.25 to 2 in). The urethane facing, which coats the tiny recesses in the foam's top surface, measures 63.5 µm (2500 µin) thick. The company claims the foam readily accepts adhesive packages and is easily die cut or laminated.
- Jean L. Broge
An alloy in GE Plastics
 GE Plastics' NORYL PPX resin is suited for use in bumper fascias, front-end modules, and underhood components. Shown here is a modular front-end and bumper fascia prototype. |
GE Plastics has introduced a new alloy targeted for bumper fascias, front-end modules, and underhood components for OEMs and suppliers in need of a polyolefin-type material that can maintain shape at high temperatures.
"The automotive industry has asked for a material that gives them all the benefits of a TPO, glass-reinforced nylon, or polypropylene but opens the performance envelope to include greater rigidity at elevated temperatures as well as better creep and scratch resistance," said Keith DuPont, Product Manager, NORYL resin business. "The answer is NORYL PPX, a new family of high-performance alloy resins with a high-melt flow for thinwall injection molding of bumper fascias and the dimensional stability and chemical resistance desired in front-end modules."
The NORYL PPX portfolio presently includes four commercial grades for the automotive industry, featuring two unreinforced and two glass-reinforced grades. Additional grades are in development and will be available soon for sampling in instrument panels, wheel covers, and spoilers.
The two unreinforced grades, which are paintable using plasma and flame treating paint systems, are positioned for bumper fascias and underhood components. Both grades offer an enhanced balance of heat resistance and impact, with a 30-50% greater modulus or stiffness than TPO. The high stiffness exhibited by both grades enables molders to reduce material use and promote faster molding cycle times through thinwall technology.
The two glass-reinforced resin grades, with 30 and 40% glass content, are targeted for front-end modules, seat backs, load decks, and underhood components. Both grades offer a good balance of high elongation (how far the material will extend before breaking, as a percentage beyond its original length), and long-term heat resistance and stiffness, which enables part consolidation as well as weight and unit costs.
The NORYL PPX resin combines previously incompatible particles of polyphenylene ether with a base of polypropylene using patent-pending technology that allows balanced properties to be obtained from the alloy formulation. It is "regrind friendly" with other polypropylene-based products.
"This was a crucial product development for us," said John Carrington, Commercial Director, NORYL resin. The NORYL resin business has introduced more than 40 new grades in the past year, and more than 20 grades are scheduled for 2001, including a high-heat platable grade, a conductive grade, and special effects products.
- Jean L. Broge
