Microballoon-facilitated tunable porosity of elastomeric shape memory polymer composites

Patent metadata

Field	Value
Publication number	US-2026078279-A1
Application number	US-202519394722-A
Country	US
Kind code	A1
Filing date	Nov 19, 2025
Priority date	Jun 27, 2017
Publication date	Mar 19, 2026
Grant date	—

Abstract

A method includes extruding a mixture through a nozzle to form a structure of extruded filaments arranged in a pre-defined arrangement. The mixture includes a first ink and a second ink with each of the inks having a matrix material and a filler. The second ink includes a plurality of unexpanded gas-filled microballoons. In addition, the method includes heating the extruded filaments of the formed structure under a negative pressure system for expanding the unexpanded gas-filled microballoons to achieve intra-filament porosity and curing the matrix material of the extruded filaments to at least a pre-defined extent. A ratio of the first ink to the second ink in the mixture extruded through the nozzle is pre-defined and/or controlled.

First claim

What is claimed is:

1 . A method comprising:
extruding a mixture through a nozzle to form a structure of extruded filaments arranged in a pre-defined arrangement,
wherein the mixture comprises a first ink and a second ink, each of the inks having a matrix material and a filler,
wherein the second ink includes a plurality of unexpanded gas-filled microballoons,
wherein a ratio of the first ink to the second ink in the mixture extruded through the nozzle is pre-defined and/or controlled;
heating the extruded filaments of the formed structure under a negative pressure system for expanding the unexpanded gas-filled microballoons to achieve intra-filament porosity; and curing the matrix material of the extruded filaments to at least a pre-defined extent.

2 . The method as recited in claim 1 , wherein the first ink comprises a plurality of second unexpanded gas-filled microballoons having a composition different than a composition of the unexpanded gas-filled microballoons.

3 . The method as recited in claim 2 , wherein the second unexpanded gas-filled microballoons have a glass transition temperature that is different than a glass transition temperature of the unexpanded gas-filled microballoons.

4 . The method as recited in claim 2 , wherein an amount of the second unexpanded gas-filled microballoons in the first ink is in a range greater than 0 wt. % to about 20 wt. % of total weight of a mixture of the first ink and the second ink.

5 . The method as recited in claim 2 , wherein an amount of the second unexpanded gas-filled microballoons in the first ink is an effective amount to result in an intra-filament porosity in a range of greater than 20 vol. % to about 95 vol. % after post processing of the printed structure.

6 . The method as recited in claim 1 , wherein the extruding includes direct ink writing.

7 . The method as recited in claim 6 , wherein the mixture is extruded in a raster process based on a three-dimensional coordinate system.

8 . The method as recited in claim 1 , wherein the matrix material includes a siloxane polymer.

9 . The method as recited in claim 1 , wherein the mixture includes a polymerization inhibitor.

10 . The method as recited in claim 1 , wherein the formed structure has an inter-porosity defined by the arrangement of extruded filaments.

11 . The method as recited in claim 1 , wherein the mixture comprises a plasticizing agent.

12 . The method as recited in claim 1 , comprising applying a curing technique during extrusion of the mixture for partially curing the matrix material.

13 . The method as recited in claim 1 , wherein the mixture includes a curing agent.

14 . The method as recited in claim 1 , wherein a technique for heating of the extruded filaments for expanding the unexpanded gas-filled microballoons is selected from the group consisting of: a resistive heating technique, an infrared radiation technique, a radiative technique, a microwave radiation technique, and a thermoacoustic technique.

15 . The method as recited in claim 1 , wherein a technique for curing the matrix material of the extruded filaments is selected from the group consisting of: a resistive heating technique, an infrared radiation technique, a radiative technique, a microwave radiation technique, a thermoacoustic technique, and a photo-based technique.

Assignees

• L Livermore Nat Security Llc
• Honeywell Federal Mfg & Tech Llc

Inventors

• Rodriguez Jennifer Nicole
• Duoss Eric B
• Golobic Alexandra
• Lenhardt Jeremy M
• Perez Perez Lemuel
• Small Iv Ward
• Wilson Thomas S
• Wu Amanda
• Yee Timothy Dexter
• Schulze Stephanie

Classifications

• B33Y70/00

  Materials specially adapted for additive manufacturing · CPC title

• B33Y10/00

  Processes of additive manufacturing · CPC title

• B29C64/118

  using filamentary material being melted, e.g. fused deposition modelling [FDM] · CPC title

• B29K2083/00

  Use of polymers having silicon, with or without sulfur, nitrogen, oxygen, or carbon only, in the main chain, as moulding material · CPC title

• B33Y80/00

  Products made by additive manufacturing · CPC title