NanoStitch update: 60-inch wide sheet, industrial capacity, dramatic test results

Since I first blogged about N12 Technologies in 2015, it has progressed, step by step, in the  commercialization of its NanoStitch film products, which use vertically-aligned carbon nanotubes (VACNTs) to boost composite laminate properties, prevent delamination and enable thinner, lighter structures.

2017 was a big year for NanoStitch:

• N12 Technologies added a new 30,000-ft² facility in Somerville, MA.
• Signed an agreement with the University of Dayton Research Institute (UDRI, Dayton, OH, US) to incorporate its 60-in wide CNT film production line.
• Completed further testing of NanoStitch in composite products including hockey sticks, prosthetics and aerospace components

NanoStitch being trialed in 2017 on the 60-in wide continuous sheet production line previously operated by UDRI in the NCC in Kettering, Ohio outside of Dayton. 
SOURCE: N12 Technologies.

 

Scaling to industrial capacity

“The new facility in Somerville has enabled us to scale up from laboratory production and also to widen our continuous sheet production to 15 inches,” says N12 Technologies director of science and technology Ryan Williams. The company will maintain its development center on Bolton Street, with the new facility offering room to grow and expand in both product width and formats, as directed by current development programs.

The company’s second facility is in Ohio. Williams explains that UDRI was producing CNT-enhanced fibers, a.k.a. “fuzzy fibers” and also 60-inch wide CNT films. “We have worked with UDRI to transfer their production line to our VACNT process,” says Williams. “We have tested the products and they conform to our specifications.” The line is actually located in the National Composites Center (NCC) in the Dayton suburb of Kettering, Ohio. “We are in discussions with local authorities about how to tailor the facility there to meet our needs and grow jobs in the area.” The new 60-in wide NanoStitch production line there is up and running with plenty of capacity for growth, including the possibility to increase speed by a factor of six as the market grows.

 

Products for prepreggers

“We are making products that prepreggers can readily use,” notes Williams, explaining that the NanoStitch sheets are produced in a continuous process and then wound up onto rolls. “Those rolls can then be fed into a prepreg production line,” he explains. As the film contacts the prepreg, the NanoStitch is transferred from its substrate onto the prepreg, passed through the nip roller and finished into the prepregger’s product types.

However, NanoStitch can also be modified to adhere tightly to its substrate. “We can adjust the adhesive properties of the VACNTs on the substrate so that it can transfer cleanly or only partially transfer or not transfer at all, staying on its substrate. For example, in applications like batteries, developers may want to keep the VACNTs on a copper substrate.”

 

Applications knowledge

“Our focus now is on supplying orders,” Williams continues. “By working with a wide range of potential customers over the past several years, we have learned where NanoStitch adds value. For example, we are primarily focused on high-performance unidirectional epoxy laminates.”  He explains, “We typically see the largest performance increases in intermediate modulus fiber systems that are especially prone to delamination failure.”

Another insight from product development testing is how NanoStitch behaves in different applications.  “By working with customers to explore the wide variety of fiber and resin systems on the market, we have gained an understanding of the applications where we offer the highest performance improvements.  Many of the lessons we learned in aerospace testing offered us insight into consumer products,” he says.

Williams gives an example in hockey sticks, “We saw performance increases across a spectrum of impact energies.  At energy levels typical of gameplay, we saw that NanoStitch raised the threshold for detectable damage. Repeated low-energy impact damage can accumulate, resulting in later catastrophic failure.  Adding NanoStitch results in a stick that is both more durable and which maintains the snap and feel that players prefer.” At higher energy levels, like those seen in standardized aerospace testing, NanoStitch both reduced the damage area from impacts and increased the residual strength by 10-20%.
 

 

The ability of NanoStitch to prevent delamination in CFRP laminates is illustrated
 in this design-phase testing. SOURCE: N12 Technologies.

During design-phase testing with a customer, the benefits of using NanoStitch were a bit more dramatic. Carbon fiber reinforced plastic (CFRP) laminates made with NanoStitch (left) and without (right) were impacted with a high-velocity gelatin projectile.  “The NanoStitch-reinforced laminate withstood the impact with zero damage,” says Williams. “The baseline CFRP laminate, however, delaminated catastrophically during the impact. The performance difference between the two is clear.”

I explained this ability for NanoStitch to overcome delamination in my 2015 blog, “The end of delamination?”.

For more information on NanoStitch, visit N12 Technologies at JEC World 2018 (Mar 6-8, Paris, France) in Hall 6, Booth K28.