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RTM resins offer low cycle time
Materials news
RTM resins offer low cycle time
Crack detection system promises safer structures
UK COMPANY Scott Bader has extended its Crystic Crestapol high performance resins range with the products Crestapol 1210 and 1210A. Crestapol 1210 is designed for use in resin transfer moulding (RTM) and pultrusion applications; 1210A is a partially accelerated pregrade. These low viscosity resins are said to be suitable for the production of railway furniture, domestic household doors and garage doors, general building and construction projects, as well as modular buildings. Fire resistance or other specific properties can be incorporated with the use of selective fillers. Production can be optimised to achieve a cycle time of six to seven minutes for RTM. According to the company, rapid mould fill and de-mould
A TECHNIQUE for identifying and repairing stress induced micro-cracks in highperformance aircraft wings could increase the lifetime, safety and cost effectiveness of structures made from polymer composites. The system has been invented by a research team led by Associate Professor Nikhil Koratkar, at Rensselaer Polytechnic’s Department of Mechanical, Aerospace and Nuclear Engineering, Troy, New York, USA. The technique works by infusing a polymer with electrically conductive carbon nanotubes, sending a small amount of electricity through them and monitoring the electrical resistance between
can also be attained with large composite parts. The resins require the addition of a catalyst plus two accelerators (only one for Crestapol 1210A) to start the curing reaction. The recommended catalyst is Akzo Trigonox 44B used with Scott Bader Accelerator G, with dimethyl aniline (DMA) required in addition only for use with Crestapol 1210 resin. The levels of catalyst and accelerators used are dependent upon the gel times. Both resins can be used with a variety of fillers, including aluminium trihydrate (ATH) for fire retardant applications. The company offers technical advice regarding suitable fillers, additives and gel times. Scott Bader; www.scottbader.com
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REINFORCEDplastics
both performance and value in single-end roving applications, such as filament winding. The company says mechanical tests on glass fibre reinforced epoxy laminates have indicated excellent performance in both tension and elongation values. It claims outstanding mechanical properties are measured when Vinamul 8868 is included in epoxy and polyester matrices. In September, Celanese opened its new emulsions facility in Nanjing, China. It will supply customers throughout Asia. Celanese; www.connectcelanese.com
December 2007
Rensselaer Polytechnic Institute; www.rpi.edu
Polyamide turns up the heat
Direct roving sizing lowers costs CELANESE is introducing a vinyl acetate sizing emulsion for direct roving applications. According to Celanese Global Segment Manager, Paolo Bavaj, Vinamul 8868 will lower the system costs for manufacturing direct rovings while retaining very good performance. This product is said to be compatible with epoxy resins and dispersions and can be added up to 50-70% to these systems in well established sizing formulations. Vinamul 8868 has a fine particle size and is highly compatible with sizing additives, like organosilanes and lubricants. Celanese says it offers
any two points. Fatigue-induced damage shows up because the longer the crack, the higher the electrical resistance. With the location and length of a crack pinpointed engineers can then send a short electrical charge to the area to heat up the carbon nanotubes and melt an embedded healing agent which melts into and seals the crack with a claimed 70% recovery in strength. The system was tested on a structure made from epoxy but Koratkar is confident the method will be just as effective with much larger structures and in real time situations.
Technyl HP: breakage occured in the weld line at 180°C and 200°C.
PA 6 at 180°C: the material failed, not the weld line.
A HIGH temperature polyamide (PA) 66, available with 35% or 50% glass fibre reinforcement, has been launched by Rhodia. TECHNYL® Heat Performance
(HP) is designed for automotive applications such as air intake manifolds and air ducts. Rhodia claims that this product broadens the range of PA use to high heat environments where it was only possible to use polyphthalamide (PPA) the past. As temperatures under the car hood continue to rise, excluding the use of PA 6 and PA 66, the company says that Technyl HP will become the only economic solution. A study showed that after 1000 hours ageing at 200°C, Technyl HP showed no cracking, while standard PA 66 and current high performance PA 66 did. Rhodia; www.rhodia.com
RTM resins offer low cycle time
Crack detection system promises safer structures
UK COMPANY Scott Bader has extended its Crystic Crestapol high performance resins range with the products Crestapol 1210 and 1210A. Crestapol 1210 is designed for use in resin transfer moulding (RTM) and pultrusion applications; 1210A is a partially accelerated pregrade. These low viscosity resins are said to be suitable for the production of railway furniture, domestic household doors and garage doors, general building and construction projects, as well as modular buildings. Fire resistance or other specific properties can be incorporated with the use of selective fillers. Production can be optimised to achieve a cycle time of six to seven minutes for RTM. According to the company, rapid mould fill and de-mould
A TECHNIQUE for identifying and repairing stress induced micro-cracks in highperformance aircraft wings could increase the lifetime, safety and cost effectiveness of structures made from polymer composites. The system has been invented by a research team led by Associate Professor Nikhil Koratkar, at Rensselaer Polytechnic’s Department of Mechanical, Aerospace and Nuclear Engineering, Troy, New York, USA. The technique works by infusing a polymer with electrically conductive carbon nanotubes, sending a small amount of electricity through them and monitoring the electrical resistance between
can also be attained with large composite parts. The resins require the addition of a catalyst plus two accelerators (only one for Crestapol 1210A) to start the curing reaction. The recommended catalyst is Akzo Trigonox 44B used with Scott Bader Accelerator G, with dimethyl aniline (DMA) required in addition only for use with Crestapol 1210 resin. The levels of catalyst and accelerators used are dependent upon the gel times. Both resins can be used with a variety of fillers, including aluminium trihydrate (ATH) for fire retardant applications. The company offers technical advice regarding suitable fillers, additives and gel times. Scott Bader; www.scottbader.com
14
REINFORCEDplastics
both performance and value in single-end roving applications, such as filament winding. The company says mechanical tests on glass fibre reinforced epoxy laminates have indicated excellent performance in both tension and elongation values. It claims outstanding mechanical properties are measured when Vinamul 8868 is included in epoxy and polyester matrices. In September, Celanese opened its new emulsions facility in Nanjing, China. It will supply customers throughout Asia. Celanese; www.connectcelanese.com
December 2007
Rensselaer Polytechnic Institute; www.rpi.edu
Polyamide turns up the heat
Direct roving sizing lowers costs CELANESE is introducing a vinyl acetate sizing emulsion for direct roving applications. According to Celanese Global Segment Manager, Paolo Bavaj, Vinamul 8868 will lower the system costs for manufacturing direct rovings while retaining very good performance. This product is said to be compatible with epoxy resins and dispersions and can be added up to 50-70% to these systems in well established sizing formulations. Vinamul 8868 has a fine particle size and is highly compatible with sizing additives, like organosilanes and lubricants. Celanese says it offers
any two points. Fatigue-induced damage shows up because the longer the crack, the higher the electrical resistance. With the location and length of a crack pinpointed engineers can then send a short electrical charge to the area to heat up the carbon nanotubes and melt an embedded healing agent which melts into and seals the crack with a claimed 70% recovery in strength. The system was tested on a structure made from epoxy but Koratkar is confident the method will be just as effective with much larger structures and in real time situations.
Technyl HP: breakage occured in the weld line at 180°C and 200°C.
PA 6 at 180°C: the material failed, not the weld line.
A HIGH temperature polyamide (PA) 66, available with 35% or 50% glass fibre reinforcement, has been launched by Rhodia. TECHNYL® Heat Performance
(HP) is designed for automotive applications such as air intake manifolds and air ducts. Rhodia claims that this product broadens the range of PA use to high heat environments where it was only possible to use polyphthalamide (PPA) the past. As temperatures under the car hood continue to rise, excluding the use of PA 6 and PA 66, the company says that Technyl HP will become the only economic solution. A study showed that after 1000 hours ageing at 200°C, Technyl HP showed no cracking, while standard PA 66 and current high performance PA 66 did. Rhodia; www.rhodia.com