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Project TitleComposite Foam made from Polymer Microspheres Reinforced with Long Fibers
Track Code3313
Short Description
Abstract
 
TagsComposite foam, PVC foam, crack resistance, polymer microspheres, reinforced foam, thermal expansion
 
Posted DateApr 1, 2014 6:18 PM

USC Solution

A new technological process was developed for the synthesis of fiber-reinforced foam to overcome the limitation of the use of long fibers in low-density reinforced foams. This approach does not have viscous flow and fiber arrangement limitations that are the inherent peculiarities of existing fiber-reinforced foam technology. This novel process for making foam is based on thermoplastic expandable hollow microspheres. Dry microspheres are combined with long randomly arranged fibers or fiber webs to achieve a composite foam. This approach for fiber-reinforcement of foam should work for all types of hollow polymer microspheres, both expandable and non-expandable, thermoplastic and non-thermoplastic. The long fiber architecture may be woven or non-woven. The permeability of fiber network should allow for penetration of the microspheres between fibers or yarns.

Value Proposition

The mechanical properties of composite foam based on PVC microspheres using this approach have already reached 90+% of those of commercial PVC foam. The results show superior properties:

  • Excellent crack resistance, fracture toughness, fatigue resistance. Calculated strain energy density values were several times higher than commercial PVC foam and unreinforced foam, indicating improved crack resistance and damage tolerance;
  • Improved adhesion between core and skin in sandwich structures;
  • Adjustable range of densities: 4 -25 pcf;
  • Adjustable coefficient of thermal expansion (CTE) by adjustment of fiber loading;
  • Improved mechanical properties; and
  • Excellent dielectric properties: low dielectric coefficient and low loss tangent

Applications

  • Core materials for sandwich structures that are used in a wide range of engineering applications, including transportation vehicles, civil infrastructure, wind energy applications, high-performance boats, electronic circuit boards, radomes with controlled CTE, and recreational equipment
  • Foams in military or civilian aircraft, where the mechanical properties and crack resistance of foam cores will be improved by fiber reinforcement

Stage of Development

  • Preliminary tests completed indicating the foam composite with this approach can match the performance of some of the best foams commercially available. For example, it compares favorably with DIAB's PVC structural foam (Divinycell┬«), widely used in transportation vehicles, building construction, and wind energy structures

Contact information

Patrick Maloney, Licensing Associate, Physical Sciences

USC Stevens Center for Innovation

(213) 821-3552

pmaloney@usc.edu