ENERGY ABSORBING FOAM MATERIAL AND METHOD OF USING THEREOF
The present invention provides an energy absorbing foam material includes at least one shape memory polymer foam having a non-impact resistant configuration in a first force-application time, an impact resistant configuration in a second force-application time at a working temperature, a first glass transition temperature equal to or lower than a working temperature in the first force-application time, and a second glass transition temperature higher than a working temperature in the second force-application time. A second elastic modulus of the shape memory polymer foam in the second force-application time is at least 10 times than a first elastic modulus of the shape memory polymer form in the first force-application time at the working temperature.
1 . An energy absorbing foam material comprising:
at least one shape memory polymer foam comprising a non-impact resistant configuration in a first force-application time at a working temperature ranging from 15° C. to 55° C., an impact resistant configuration in a second force-application time at the working temperature, a first glass transition temperature equal to or lower than the working temperature in the first force-application time, and a second glass transition temperature higher than the working temperature in the second force-application time;
wherein the non-impact resistant configuration comprises a deformed configuration and an original configuration;
wherein a second elastic modulus of the shape memory polymer foam in the second force-application time is at least 10 times than a first elastic modulus of the shape memory polymer form in the first force-application time at the working temperature;
wherein the first force-application time is approximately from 0.1 second to 1000 seconds;
wherein the second force-application time is approximately below 0.1 second,
wherein the at least one shape memory polymer foam is a polyurethane foam formed by a reaction between polyol and a mixture of 4 4′-methylenebis(phenyl isocyanate) and 2,4-methylenebis(phenyl isocyanate).
2 . The energy absorbing foam material of claim 1 , wherein the yield point of the at least one shape memory polymer foam is approximately from 0.5 kPa to 1 MPa.
3 . The energy absorbing foam material of claim 1 , wherein the polyol content constitutes 55-70% of the total weight, and the mixture of 4,4′-methylenebis(phenyl isocyanate) and 2,4-methylenebis(phenyl isocyanate) content constitutes 25-45% of the total weight.
4 . The energy absorbing foam material of claim 3 , wherein the polyol and the mixture of 4,4′-methylenebis(phenyl isocyanate) and 2,4-methylenebis(phenyl isocyanate) have a weight ratio of 10:7.
5 . The energy absorbing foam material of claim 1 , wherein the mixture of 4,4′-methylenebis(phenyl isocyanate) and 2,4-methylenebis(phenyl isocyanate) constitute 40-45% of the total weight of the polyurethane foam, and wherein the content of 4,4′-methylenebis(phenyl isocyanate) constitutes 40-60% of the total weight of the mixture and the content of 2,4-methylenebis(phenyl isocyanate) constitutes 40-60% of the total weight of the mixture.
6 . The energy absorbing foam material of claim 1 , wherein the 4,4′-methylenebis(phenyl isocyanate), and the 2,4-methylenebis(phenyl isocyanate) have a weight ratio of 1:1.
7 . The energy absorbing foam material of claim 1 , wherein the second elastic modulus of the shape memory polymer foam in the second force-application time is 100 times than the first elastic modulus of the shape memory polymer form in the first force-application time at 45° C.
8 . An impact-resistant article comprising the energy absorbing foam material of claim 1 .
9 . A method of molding the energy absorbing foam material of claim 1 , comprising:
providing the energy absorbing foam material having an original shape, wherein the energy absorbing foam material is a polyurethane foam formed by a reaction between polyol and a mixture of 4 4′-methylenebis(phenyl isocyanate) and 2,4-methylenebis(phenyl isocyanate);
at a force-application time more than approximately 0.1 second to 1000 seconds and at a working temperature range approximately from 15 to 55° C., molding the energy absorbing foam material around a shape to be protected by the energy absorbing foam material;
using the molded energy absorbing foam material at a temperature range approximately from 15° C. to 55° C.;
self-recovering the original shape of the energy absorbing foam material without the application of force or heat.
10 . The method of molding the energy absorbing foam material of claim 9 , wherein the polyol content constitutes 55-70% of the total weight, and the mixture of 4,4′-methylenebis(phenyl isocyanate) and 2,4-methylenebis(phenyl isocyanate) content constitutes 25-45% of the total weight.
11 . The method of molding the energy absorbing foam material of claim 9 , wherein the polyol and the mixture of 4,4′-methylenebis(phenyl isocyanate) and 2,4-methylenebis(phenyl isocyanate) have a weight ratio of 10:7.
12 . The method of molding the energy absorbing foam material of claim 9 , wherein the mixture of 4,4′-methylenebis(phenyl isocyanate) and 2,4-methylenebis(phenyl isocyanate) constitute 40-45% of the total weight of the polyurethane foam, and wherein the content of 4,4′-methylenebis(phenyl isocyanate) constitutes 40-60% of the total weight of the mixture and the content of 2,4-methylenebis(phenyl isocyanate) constitutes 40-60% of the total weight of the mixture.
13 . The method of molding the energy absorbing foam material of claim 9 , wherein the 4,4′-methylenebis(phenyl isocyanate) and the 2,4-methylenebis(phenyl isocyanate) have a weight ratio of 1:1.
14 . The method of molding the energy absorbing foam material of claim 9 , wherein the yield point of the energy absorbing foam material is approximately from 25 kPa to 0.23 MPa.