Polystyrene foam containing a modifier-free nanoclay and having improved fire protection performance
View Patent ↗Polymer extruded or expanded foams that contain modifier-free nanoclays are provided. The addition of modifier-free nano-clays to extruded or expanded foam products improves the thermal properties, mechanical properties, and fire performance properties. Water or a water-containing compound is used as a carrier for the modifier-free nanoclays. The final foamed products may be utilized in building application such as foamed insulation products and in underground applications such as highway insulation. A preferred modifier-free nanoclay is Na + MMT. Modifier-free nanoclay particles may be injected into a polymer during an extrusion foaming process. In another embodiment of the invention, polymer beads containing water/nanoclay particles are formed using inverse emulsion/suspension polymerizations and expanded or extruded into a foamed product. In a further embodiment, a modifier-free nanoclay particle is encapsulated in a super-absorbent material, which may be used in an expanding or extruding process.
1. Expandable polystyrene beads used to form foamed insulation products comprising:
a polystyrene matrix; and
particles positioned within said polystyrene matrix, wherein the particles each comprise an inverse emulsified water phase and modifier-free nanoclay substantially uniformly dispersed in the inverse emulsified water phase;
wherein the expandable polystyrene beads exhibit an increase of expansion ratio when foamed of more than 100% in comparison with polystyrene beads lacking the substantially uniform distribution of modifier-free nanoclay,
wherein the modifier-free nanoclay is sodium montmorillonite.
2. The expandable polystyrene beads according to claim 1 , wherein said polystyrene matrix is spherical in shape and has a diameter from about 0.01 to about 5 mm.
3. The expandable polystyrene beads according to claim 1 , wherein the modifier-free nanoclay is substantially exfoliated.
4. The expandable polystyrene beads according to claim 1 , wherein the beads include about 1-15% by weight of the modifier-free nanoclay.
5. The expandable polystyrene beads according to claim 1 , wherein a polymer foam prepared by expanding the polymer beads exhibits bimodal foam morphology.
6. The expandable polystyrene beads according to claim 1 , wherein a polystyrene foam prepared by expanding the polystyrene beads exhibits improved fire resistance compared to a polystyrene foam prepared from expandable polystyrene beads including nanoclay and a modifier.
7. Expandable polystyrene beads used to form foamed insulation products comprising:
a polystyrene matrix; and
particles positioned within said polystyrene matrix, wherein the particles each comprise a water phase and modifier-free nanoclay;
wherein the expandable polystyrene beads exhibit an increase of expansion ratio when foamed of more than 100% in comparison with polystyrene beads lacking the modifier-free nanoclay,
wherein the modifier-free nanoclay is sodium montmorillonite.