Accudyne Systems Inc. (Newark, Del., USA), a manufacturer of custom part purpose automation equipment for thermoset applications and thermoplastic insitu consolidation fiber and tape placement machines for out of autoclave processing, reported on April 18 that it and the U.S. Air Force have been awarded a U.S. patent for increasing the rate of crystallization of engineering thermoplastics.
The patent covers the development of a new and novel method for enhancing the crystallization rates of engineering thermoplastics through the use and incorporation of particulate additives with dimensions on the order of 10 to 1,000 nm. The presence of nanoparticles at concentrations of less than 10 weight percent of the composition, reduces the viscosity of the thermoplastics as compared to the respective homopolymer, thereby increasing polymer chain transport and diffusion to the crystallizing growth front.
The prescription of this technology has been shown to reduce crystallization half times of some engineering thermoplastics by as much as 40 percent at optimal crystallization temperatures, an effect that is magnified as the temperature is reduced towards the glass state of the amorphous phase. Nano-modified engineering thermoplastics with rapid crystallization kinetics and relatively low viscosities can be used in component fabrication processes that require rapid processing times.
One of the major cost drivers of fabricating parts made from composite materials is the need to finalize the cure in an autoclave. The use of thermoplastics holds the promise of fabricating a fully consolidated part without the need to finalize the cure in an autoclave. One of the limiting factors of thermoplastic resin systems has been the length of time for crystallization to occur to achieve properties that equal or exceed the properties of parts cured in an autoclave. Thermoplastic resins are also recyclable and tougher than thermoset resins, and as such are desirable for a wide variety of applications.
“This is an important technical breakthrough in the development of materials to further mature the technology to deploy insitu consolidation for thermoplastics and Accudyne Systems expresses its gratitude to the Air Force for its sponsorship of the work done to develop this technology” says John Melilli, VP of sales and marketing at Accudyne Systems Inc.