SBIR-STTR Award

A hybrid buoyancy foam is proposed, consisting of new technology lightweight macrospheres in a matrix of closed-cell blown foam. The hybrid composite, with a target density of 0.05 g/cm3, will combine the compressive strength and stiffness of macrospheres with the resilience of a blown foam to meet the specified threshold performance properties. The macrospheres will be manufactured using thin film UV-curable core-shell rubber modified vinyl ester technology for damage tolerance, with milled carbon fiber reinforcement. These will be closely packed in highly ordered binary arrays using additive layering techniques for maximum volume packing factor in virtually net shapes. The macrospheres will be encapsulated with carbon reinforced rigid poly-DCPD, polyurethane or BPA/BPF epoxy blown foam as a binder, engineered for high modulus and resilience in the ocean temperature range. Phase I will develop macrosphere manufacturing, grading and assembly processes and blown foam formulation, resulting in a laboratory-scale composite for property testing. Phase I Option will work on refining properties and scaling up processes for full-scale production in a Phase II. Potential technology offshoots include a high-performance syntactic foam with unprecedented strength and moduli for given density, as well as a pure blown foam of high stiffness and resilience for shallow water.

Benefit:
The foam could be commercialized for high-performance nonmilitary applications such as cable buoyancy for windmills, lightweight core material for fabricating windmill blades, as well as shallow water pipeline buoyancy

Keywords:
lightweight macrospheres, lightweight macrospheres, additive layering techniques., core-shell rubber modified vinyl ester, UV curable, hybrid buoyancy foam, closed-cell blown foam, hybrid composite, milled carbon fiber reinforcement

A hybrid buoyancy foam is proposed, consisting of new technology lightweight macrospheres in a matrix of closed-cell blown foam. The hybrid composite, with a target density of 0.05 g/cm3, will combine the compressive strength and stiffness of macrospheres with the resilience of a blown foam to meet the specified threshold performance properties. The macrospheres will be manufactured using thin film UV-curable core- shell rubber modified vinyl ester technology for damage tolerance, with Boron Nitride Nanotubes reinforcement. These will be closely packed in highly ordered binary arrays using additive layering techniques for maximum volume packing factor in virtually net shapes. The macrospheres will be encapsulated with BNNT or carbon reinforced rigid polyurethane or BPA/BPF epoxy blown foam as a binder, engineered for high modulus and resilience in the ocean temperature range. Phase I will develop macrosphere manufacturing, grading and assembly processes and blown foam formulation, resulting in a laboratory-scale composite for property testing. Phase I Option will work on refining properties and scaling up processes for full-scale production in a Phase II. Potential technology offshoots include a high-performance syntactic foam with unprecedented strength and moduli for given density, as well as a pure blown foam of high stiffness and resilience

Benefit:
An improved compressive/shear strength-to-weight ratio and/or high temperature resistant, low density insulating foam has great potential for use in many commercial engineering areas. Target markets cover the spectrum of performance requirements and justifiable cost, ranging from highly engineered applications which are only made possible by the technology development, and have extensive quality control/quality assurance (QC/QA) requirements, to near-commodities. The technical development gives several options to offer, ranging from nanotube reinforced composites for the highest strength/density performance, through carbon fiber and graphene to glass reinforcement, to unreinforced foam at the commodity end.

Keywords:
additive layering techniques., lightweight macrospheres, core-shell rubber modified vinyl ester, milled carbon fiber reinforcement, closed-cell blown foam, UV curable, hybrid composite, hybrid buoyancy foam