This Small Business Innovation Research (SBIR) Phase I project aims to develop a layer-by-layer spray technology capable of integrating commercially-available nanoparticles, including multiwall carbon nanotubes (CNT), carbon nanofibers (CNF) and nanoclays into stable and strong nanopapers by electrostatic bonding, offering superior surface wear resistance and electrical conductivity properties at much lower cost and higher production rate than existing methods.
The broader/commercial impact of this project will be the potential to provide light-weight, high-strength and low-cost nanopapers with superior Electromagnetic Interference (EMI) shielding capability and wear resistance. The nanopapers are expected to form strong bonding with the matrix resin such as epoxy. The resulting nanocomposite materials can be used as structural composites for a broad range of applications including aerospace industry, wind energy generators and so on.
This Phase I and IB study has led to very fruitful findings and achievements. The developed new technology will deliver significant benefits in the green energy (wind mill, and Li-battery), aerospace, military, electronics, consumer goods and automobile industries. However, based on Ohio’s local business and our domestic and international industrial supply chains, NIL would like to stay focus on the automobile market in the US and wind energy and aerospace markets in China with near-term commercialization targets of several under-hood automotive parts for EMI shielding and erosion resistance in the US and protective wind blade coating for sand erosion resistance, de-icing and possibly lightening protection in China. Our Phase I project objective was to prove the technology feasibility of surface modification of carbon nanoparticles and using functionalized nanoparticles to form high strength nanopapers for erosion resistant and EMI shielding applications in near-term wind energy, consumer goods and automotive markets and long-term aerospace markets. To realize this goal, NIL worked closely with The Ohio State University (OSU) faculty, post-doc researchers and students over the last fifteen months. We have successfully synthesized polyaniline functionalized nanoparticles including carbon nanofibers (CNF), multiwall carbon nanotubes (MWNT), nanoclays (MMT) and graphene (from graphite). We have also worked out agreements with a small Ohio company, Capital Resin Corporation (CRC) and a large chemical company, LCY Group to scale up the nanoparticle functionalization process. NIL and OSU also built a pilot scale batch equipment capable of producing large nanopapers from functionalized nanoparticles using the layer-by-layer spraying for customer evaluation. The major achievements in Phase I and IB are highlighted in the following: Polyaniline surface modified nanoparticles such as, carbon nanofibers (CNF), multiwall carbon nanotubes (MWNT), nanoclays (MMT) and graphene were successfully synthesized. The polyaniline modified carbon nanopapers showed much better mechanical strength and electric conductivity than nanopapers prepared by non-treated, acid treated and PEI treated carbon nanoparticles. For example, the polyaniline modified CNF nanopapers showed >100X improvement in tensile strength and >10X improvement in electrical conductivity than pristine CNF nanopapers, which is very attractive to our customers in regard to nanopaper processibility and EMI shielding performance. CNF nanopapers. TEM and CV electric scan measurements revealed strong bonding of polyaniline to carbon nanofibers. A pilot scale high pressure layer-by-layer coating machine was designed and built to apply the aforementioned nanoparticles to make large nanopaper samples for customer evaluation. The aforementioned nanopapers could be easily applied to the conventional Vacuum Assisted RTM (VARTM) process and Seeman Composite Resin Infusion Molding Process (SCRIMP) without any process changes (i.e. "drop-in" process). The polyaniline surface modified nanopapers could result in faster curing for epoxy resins based composites, which is significant for the fabrication of large infrastructures at low temperatures, such as wind blade molding, in terms of reduced energy consumption, tooling cost and operation time, and improved composite strength due to less residual resins. CNF nanopaper (~20 vol.% CNF) coated epoxy composites showed >7X improvement of sand erosion resistance than epoxy/unidirectional glass fiber (>40 vol.% glass fiber) composites typically for wind blades, and >3X improvement of sand erosion resistance than epoxy/woven carbon fiber (>50 vol.% carbon fiber) composites typically for helicopter applications. Furthermore, CNF nanopaper coated epoxy/glass fiber composites showed good de-icing performance, another important advantage for wind energy applications. Our preliminary economic analysis showed that our functionalized carbon nanopapers, particularly the polyaniline modified CNF nanopapers and benzenesulfonic functionalized graphene nanopapers are cost competitive comparing to the commercially available carbon nanopapers, but with much better mechanical and physical performance expect for the extremely expensive Nanocomp CNT sheets made from the CVD process (i.e. ~$5,000/ft2 vs. <$100/ft2). We have successful established a strong Phase II team with NIL and TAI serving as the co-leader of the project to collaborate with US industrial partners- OmnovaSolution and CK Technologies for thermoplastics based automotive applications and Asia industrial partners-Han Jiang and LCY Group for thermoset composites based wind blade and aerospace applications in China. In summary, Nanomaterial Innovation Ltd. (NIL) has successfully finished all proposed Phase I and IB tasks by working closely with our OSU and industrial partners. Based on excellent results and some new findings from Phase I and IB, we would like to continue working with our partners to complete the development our proposed nanomaterials and nanotechnologies for commercialization. Contributions within Discipline: This nanopaper project combined new nanomaterials and nanotechnology with traditional polymer materials and polymer/composite processing techniques. The activity proved our Phase I feasibility and improved our understanding of nanomaterials and nanotechnology. It will further the development of nanomaterials and nanotechnology for commercialization. Students and post-doc researchers involved also received training of nanotechnology.
