Reusable expandable media with flexible skin for composite manufacturing and methods thereof
A material system including a plurality of expandable pellets or a monolithic flexible carrier is disclosed, each of which may include a polymer matrix configured to hold an expandable core, and a flexible skin configured to encapsulate the polymer matrix, and where the flexible skin is at least partially permeable with respect to the expandable core or a gas released by the expandable core. Implementations of the material system may include where the polymer matrix may include a thermoplastic polymer. The material system may include a charging source configured to introduce blowing agent. A method of curing a composite part is also described.
1 . A method of curing a composite part, comprising:
introducing a blowing agent into an expandable material to place the expandable material in a charged state;
contacting the expandable material with an uncured composite part;
subjecting the expandable material and the uncured composite part to a first temperature such that the expandable material transitions from a charged state to an activated state;
maintaining the expandable material at the first temperature and in the charged state until the uncured composite part is a cured composite part;
cooling the expandable material and the cured composite part to a second temperature;
separating the expandable material from the cured composite material; and
exposing the expandable material to a recovery condition; and
wherein the expandable material comprises a polymer matrix configured to hold the blowing agent, and a flexible skin configured to:
encapsulate the polymer matrix; and
restrict escape of the blowing agent to control an expansion of the expandable material.
2 . The method of claim 1 , wherein:
the recovery condition comprises a third temperature and a period of from about 0.5 hours to about 48 hours;
the first temperature is from about 150° C. to about 300° C.;
the second temperature is from about 25° C. to about 90° C.; and
the third temperature is from about 25° C. to about 300° C.
3 . The method of claim 1 , further comprising storing the expandable material in the charged state after introducing a blowing agent into the expandable material.
4 . The method of claim 1 , wherein storing the expandable material in a charged state comprises a fourth temperature of from about 25° C. to about 35° C. for a time from about 24 hours to about 72 hours.
5 . The method of claim 1 , further comprising re-charging the expandable material after exposing the expandable material to the recovery condition.
6 . The method of claim 1 , wherein re-charging the expandable material comprises exposing the expandable material to a re-charging temperature for about 0.5 hours to about 2 hours.
7 . The method of claim 1 , wherein the expandable material comprises a plurality of pellets.
8 . The method of claim 1 , wherein the expandable material comprises a flexible carrier.
9 . A method of curing a composite part, comprising:
introducing a blowing agent into an expandable material to place the expandable material in a charged state;
contacting the expandable material with an internal cavity of an uncured composite part;
subjecting the expandable material and the internal cavity of the uncured composite part to a first temperature such that the expandable material transitions from a charged state to an activated state;
maintaining the expandable material at the first temperature and in the charged state until the uncured composite part is a cured composite part;
cooling the expandable material and the cured composite part to a second temperature; and
wherein the expandable material comprises a polymer matrix configured to hold the blowing agent, and a flexible skin configured to:
encapsulate the polymer matrix; and
restrict escape of the blowing agent to control an expansion of the expandable material.
10 . The method of claim 9 , further comprising:
separating the expandable material from the cured composite material; and
exposing the expandable material to a recovery condition.
11 . The method of claim 9 , wherein:
a recovery condition comprises a third temperature and a period of from about 0.5 hours to about 48 hours;
the first temperature is from about 150° C. to about 300° C.;
the second temperature is from about 25° C. to about 90° C.; and
the third temperature is from about 25° C. to about 300° C.
12 . The method of claim 9 , further comprising storing the expandable material in the charged state after introducing a blowing agent into the expandable material.
13 . The method of claim 9 , wherein storing the expandable material in a charged state comprises a fourth temperature of from about 25° C. to about 35° C. for a time from about 24 hours to about 72 hours.
14 . The method of claim 9 , further comprising re-charging the expandable material after exposing the expandable material to a recovery condition.
15 . The method of claim 9 , wherein re-charging the expandable material comprises exposing the expandable material to a re-charging temperature for about 0.5 hours to about 2 hours.
16 . The method of claim 9 , wherein the expandable material comprises a plurality of pellets.
17 . A method of curing a composite part, comprising:
introducing a blowing agent into an expandable material to place the expandable material in a charged state;
contacting the expandable material with an uncured composite part, wherein the uncured composite part is contained in a mold;
subjecting the expandable material and the uncured composite part to a first temperature such that the expandable material transitions from the charged state to an activated state;
maintaining the expandable material at the first temperature and in a charged state until the uncured composite part is a cured composite part;
cooling the expandable material and the cured composite part to a second temperature;
separating the expandable material from the cured composite material; and
exposing the expandable material to a recovery condition; and
wherein:
the expandable material comprises a polymer matrix configured to hold the blowing agent, and a flexible skin configured to:
encapsulate the polymer matrix; and
restrict escape of the blowing agent to control an expansion of the expandable material.
18 . The method of claim 17 , wherein the expandable material is in contact with an internal cavity of the uncured composite part.
19 . The method of claim 17 , wherein:
the recovery condition comprises a third temperature and a period of from about 0.5 hours to about 48 hours;
the first temperature is from about 150° C. to about 300° C.;
the second temperature is from about 25° C. to about 90° C.; and
the third temperature is from about 25° C. to about 300° C.
20 . The method of claim 17 , wherein the expandable material comprises a plurality of pellets.