Method To Produce Polymer Matrix Composites

Abstract

This patent describes a new, simple, and low-cost method to produce aromatic thermosetting copolyester (ATSP) based polymer matrix composites. For this method, the ATSP based composites are directly produced from the blended mixtures of the ATSP oligomer powders with the composite fillers through a high temperature and high pressure curing process. In addition, the fully cured ATSP composite laminates can be bonded together to form thicker multi-material composites. The characterization showed that these ATSP based composites are fully condensed, they have excellent tribological performance (low friction and low wear rate), and they have excellent thermal stability, indicating utility in high performance bearing applications, structural materials, and as an ablative composite material.

Claims

1. A method of producing aromatic thermosetting copolyester (ATSP) based composites, comprising: preparing mixtures of ATSP oligomer powders and fillers; curing the mixture of ATSP oligomer powders and fillers at an elevated temperature, ranged between 270 C. and 400 C. to create a cured mixture; consolidating the cured mixture in a high pressure, ranged between 0.1 MPa and 20 MPa; and wherein the ATSP oligomer powders consist of pairs of carboxylic acid-capped and acetoxy-capped oligomers, and wherein the fillers consist of discontinuous fillers and continuous fillers; and wherein the discontinuous fillers consist of milled carbon fiber, chopped carbon fiber, chopped glass fiber, milled glass fiber, ceramic powder, graphite, carbon nano tubes, graphene, and polytetrafluorethylene (PTFE) powder; and wherein the continuous fillers consist of continuous carbon fiber and continuous glass fiber, in the formats of weave sheet, unidirectional fabric sheet, unidirectional tow.

2. The method of claim 1, wherein the step of preparing mixtures of ATSP oligomer powders and fillers are achieved by adding of ATSP oligomer powders and discontinuous fillers in a predetermined weight ratios and then blending together in a blender.

3. The method of claim 1, wherein the step of preparing mixtures of ATSP oligomer powders and fillers are achieved by depositing of ATSP oligomer powders on continuous fillers with a solvent free method, and wherein the solvent free method consists of one of the following: dry powder bath, dry powder spray, and wet slurry.

4. The method of claim 1, wherein the step of curing the mixture of ATSP oligomer powders includes a temperature between 270 C. and 400 C., and wherein the ATSP oligomer powders are formed by crosslinking the carboxylic acid-capped oligomer and the acetoxy-capped oligomer.

5. The method of claim 1, wherein the consolidation of cured mixture is achieved by setting a pressure 0.1 MPa and 20 MPa during a temperature range of 270 C. and 400 C.

6. A method of producing aromatic thermosetting copolyester (ATSP) based composites attached on metal substrate, comprising: preparing mixtures of ATSP oligomer powders and fillers; preparing a metal substrate; curing the mixture of ATSP oligomer powders and fillers between a temperature range of 270 C. and 400 C. with the metal substrate as a backing plate to create a cured mixture; consolidating the cured mixture in a pressure range between 0.1 MPa and 20 MPa; and wherein the ATSP oligomer powders consist of pairs of carboxylic acid-capped and acetoxy-capped oligomers, and wherein fillers consist of discontinuous fillers and continuous fillers, and wherein the discontinuous fillers consist of milled carbon fiber, chopped carbon fiber, chopped glass fiber, milled glass fiber, ceramic powder, graphite, carbon nano tubes, graphene, and polytetrafluorethylene (PTFE) powder, and wherein the continuous fillers consist of continuous carbon fiber and continuous glass fiber, in the formats of weave sheet, unidirectional fabric sheet, unidirectional tow.

7. The method of claim 6, wherein the step of preparing mixtures of ATSP oligomer powders and fillers are achieved by adding of ATSP oligomer powders and discontinuous fillers in a predetermined weight ratio and then blending together in a blender.

8. The method of claim 6, wherein the metal substrate is prepared by a surface treatment, wherein the surface treatment is achieved with one of the following: particle blast roughening, dovetail shape machining, and particle (bronze) sintering.

9. The method of claim 6, wherein the step of curing the mixture of ATSP oligomer powders includes a temperature between 270 C. and 400 C., and wherein the ATSP oligomer powders are formed by crosslinking the carboxylic acid-capped oligomer and the acetoxy-capped oligomer.

10. The method of claim 6, wherein the step of preparing mixtures of ATSP oligomer powders and fillers are achieved by depositing of ATSP oligomer powders on continuous fillers with a solvent free method, and wherein the solvent free method consists of one of the following: dry powder bath, dry powder spray, and wet slurry.

11. The method of claim 6, wherein the consolidation of cured mixture is achieved by setting a pressure between 0.1 MPa and 20 MPa during a temperature range of between 270 C. and 400 C.

12. A method of producing aromatic thermosetting copolyester (ATSP) based composites attached with each other to form multilayer composite, comprising: preparing mixtures of ATSP oligomer powders and fillers; preparing metal plates; curing the mixture of ATSP oligomer powders and fillers between a 270 C. and 400 C. to create a cured mixture; consolidating the cured mixture in a pressure range between 0.1 MPa and 20 MPa; and sintering the cured mixture and metal plates together; and wherein the ATSP oligomer powders consist of pairs of carboxylic acid-capped and acetoxy-capped oligomers, and wherein fillers consist of discontinuous fillers and continuous fillers, and wherein the discontinuous fillers consist of milled carbon fiber, chopped carbon fiber, chopped glass fiber, milled glass fiber, ceramic powder, graphite, carbon nanotubes, graphenic platelets, and polytetrafluorethylene (PTFE) powder, and wherein the continuous fillers consist of continuous carbon fiber and continuous glass fiber, in the formats of weave sheet, unidirectional fabric sheet, unidirectional tow.

13. The method of claim 12, wherein the step of preparing mixtures of ATSP oligomer powders and fillers are achieved by adding of ATSP oligomer powders and discontinuous fillers in a predetermined weight ratios and then blending together in a blender.

14. The method of claim 12, wherein the metal plates are prepared by surface treatment, and wherein the surface treatment is achieved with one of the following: particle blast roughening, dovetail shape machining, and particle (bronze) sintering.

15. The method of claim 12, wherein the step of curing the mixture of ATSP oligomer powders includes a temperature between 270 C. and 400 C. and wherein the ATSP oligomer powders are formed by crosslinking the carboxylic acid-capped oligomer and the acetoxy-capped oligomer.

16. The method of claim 12, wherein the step of preparing mixtures of ATSP oligomer powders and fillers are achieved by depositing of ATSP oligomer powders on continuous fillers with a solvent free method, and wherein the solvent free method consist of one of the following: dry powder bath, dry powder spray, and wet slurry.

17. The method of claim 12, wherein the consolidation of cured mixture is achieved by setting a pressure of between 0.1 MPa and 20 MPa during a temperature range of between 270 C. and 400 C.

18. The method of claim 12, wherein the sintering of the cured plates and metal plates together is achieved by setting a pressure 0.1 MPa and 20 MPa during a temperature range of 270 C. and 400 C.

19. A method of producing crosslinkable polymer-based composite, comprising: preparing mixtures of oligomers, and fillers, ranged between 100 C. and 400 C. to create a cured mixture, and wherein the oligomers are configured to cure by a condensation mechanism and which possess moieties that are labile at an elevated temperature, consolidating the cured mixture in a high pressure, ranged between 0.1 MPa and 20 MPa; and wherein the crosslinkable oligomers have matched functional end-caps such that a condensation by-product is released as a consequence of their cure reaction; and wherein the fillers consist of discontinuous fillers and continuous fillers; and wherein the discontinuous fillers consist of milled carbon fiber, chopped carbon fiber, chopped glass fiber, milled glass fiber, ceramic powder, graphite, carbon nano tubes, graphene, and polytetrafluorethylene (PTFE) powder; and wherein the continuous fillers consist of continuous carbon fiber and continuous glass fiber, in the formats of weave sheet, unidirectional fabric sheet, unidirectional tow.

20. A method of producing crosslinkable polymer-based composite based composites attached on metal substrate, comprising: preparing mixtures of crosslinkable oligomers and fillers; preparing a metal substrate; curing the mixture of crosslinkable oligomers and fillers between a temperature range of 100 C. and 400 C. with the metal substrate as a backing plate to create a cured mixture; consolidating the cured mixture in a pressure range between 0.1 MPa and 20 MPa; and wherein the crosslinkable oligomers have matched functional end-caps such that a condensation by-product is released as a consequence of their cure reaction; and wherein the fillers consist of discontinuous fillers and continuous fillers; and wherein the discontinuous fillers consist of milled carbon fiber, chopped carbon fiber, chopped glass fiber, milled glass fiber, ceramic powder, graphite, carbon nano tubes, graphene, and polytetrafluorethylene (PTFE) powder; and wherein the continuous fillers consist of continuous carbon fiber and continuous glass fiber, in the formats of weave sheet, unidirectional fabric sheet, unidirectional tow.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0006] The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fees.

[0007] A fuller understanding of the foregoing may be had by reference to the accompanying drawings, wherein:

[0008] FIG. 1 is a picture of a produced fully dense composite of ATSP with 28 wt. % chopped IM-9 carbon fiber;

[0009] FIG. 2 illustrates TGA curves showing remaining weight percentage vs. temperature for different composites;

[0010] FIG. 3 is a graph illustrating a curve of curing parameters for temperature and pressure;

[0011] FIG. 4 is an illustration of the production process for ATSP composites, mixture of ATSP oligomers (CB and AB) with milled carbon fiber in a 22 mold on the left, and final consolidate 22 ATSP composites;

[0012] FIG. 5 shows SEM image of consolidate ATSP+30% milled carbon fiber composite with different magnifications;

[0013] FIG. 6 is an illustration of a Pin-on-disk tribological experimental configuration;

[0014] FIG. 7 are Tribological experimental results, friction results on the left and wear rate result on the right;

[0015] FIG. 8 is an illustration of a Cylindrical mold for producing ATSP-based tilting pad bearings;

[0016] FIG. 9 is a photo of a Finished ATSP-based tilting pad bearing;

[0017] FIG. 10 shows examples of ATSP based continuous fiber composites, from left to the right: ATSP-carbon fiber vail, ATSP-glass fiber weave, ATSP-glass fiber weave, and ATSP-carbon fiber weave;

[0018] FIG. 11 shows different methods to spread ATSP oligomer powders on the continuous fiber weaves/sheets, dry powder bath (top left), dry powder spray (top right) and wet slurry method (bottom);

[0019] FIG. 12 shows sample of ATSP-glass fiber composite, uncured stack of oligomer powder and glass fiber mixed sheet (left), cured ATSP-glass fiber composite (right);

[0020] FIG. 13 is a graph illustrating a curve of curing parameters for temperature and pressure; and

[0021] FIG. 14 shows the production of multilayer ATSP based composite, ATSP/MF denotes CBAB:milled carbon fiber (70:30), ATSP coating denotes CBAB coating on aluminum sheet, Neat ATSP is neat CBAB, and ATSP/CF denotes CBAB:chopped carbon fiber (70:30).

DESCRIPTION OF THE INVENTION

[0022] Referring now to the figures, a process is described to produce fully dense materials of ATSP in spite of the off-gassing of the acetic acid. Once the oligomer powder mixture is blended with the right concentration of other fillers, such as milled carbon fiber, chopped carbon fiber, continuous fibers, and powders (ceramic powder, graphite, PTFE, etc.), the acetic acid produced at a high curing temperature can leak out through the free space among the fillers. Once the cure finishes, with compressive pressure at high temperature, the cured mixture/blend can consolidate and approach theoretical density. These composites can be used for variety of applications, such as for ablative material, bearing material, structure material, etc. Embodiments of the present invention provide a method for fabricating ATSP based composites and more generally a method for producing composites in cases where a by-product is evolved by the cure reaction but the resin features exchangeable bonds.

[0023] In an embodiment of the present invention, ATSP-chopped carbon fiber composite is produced directly from ATSP oligomers and chopped carbon fiber mixture. In accordance with such embodiments, ATSP oligomers and chopped carbon fiber are added together and then blended well in a blender. Then, the blended mixture is loaded in a mold, goes through a high temperature cure and compression cycle and forms the final ATSP-chopped carbon fiber composite. Different length and different material of chopped fibers are applicable for the same fabrication process.

[0024] In another embodiment of the present invention, ATSP-milled carbon fiber (and other small size fillers) composites are produced directly from ATSP oligomers and small size fillers mixture. In accordance with such embodiments, ATSP oligomers and small size fillers are added together with desired weight ration and then blended well in a blender. Then, the blended mixtures are loaded in a mold, and go through a high temperature cure and compression cycle and form the final ATSP-based composites. Various filler materials, combination of different fillers and different weight ratios are applicable for the same fabrication process with the significant requirement being that they do not melt or significantly thermally degrade as a consequence of the process cycle.

[0025] In another embodiment of the present invention, ATSP/milled carbon fiber composite is directly produced from ATSP oligomers and milled carbon fiber mixture; and the composite is attached on a metal surface at the same time. In accordance with such embodiments, ATSP oligomers and milled carbon fiber filler are added together with desired weight ration and then blended well in a blender. The mixture is loaded in a mold such that one side of the mold is mounted with the metal backing plate coated with ATS. Then, the blended mixture goes through a high temperature cure and compression cycle and form the final ATSP-milled carbon fiber composite attached on the coated metal. Various filler materials, combination of different fillers and different weight ratios are applicable for the same fabrication process. And the bonding between ATSP composites and metal can be also supplied by mechanical interlocking, such as dovetail grooves on metal substrate surface and sintered porous metal (e.g. bronze) powder on metal substrate surface.

[0026] In another embodiment of the present invention, ATSP-based multilayer composite was produced by bonding several plates of cured ATSP composites or ATSP-coated aluminum. Cured ATSP-milled carbon fiber and ATSP-chopped carbon fiber composite are directly produced from ATSP oligomers and milled/chopped carbon fiber mixtures. In accordance with such embodiments, ATSP oligomers and milled/chopped carbon fiber filler are added together with desired weight ration and then blended well in a blender. Load the mixtures in a mold that go through a high temperature cure and compression cycle and form the final ATSP-milled/chopped carbon fiber composites. Stack the cured ATSP composites and ATSP coated aluminum sheets in desired order and load the stack in hot press machine for a hot sintering process; and a multilayer composites can be formed. Various filler materials, combination of different fillers and different weight ratios are applicable for the same fabrication process. And the bonding between ATSP composites and metal can be also supplied by mechanical interlocking, such as dovetail grooves on metal substrate surface and sintered porous metal (e.g. bronze) powder on metal substrate surface.

[0027] In another embodiment of the present invention, ATSP based continuous fiber composites are produced directly from ATSP oligomers and continuous fiber weave mixture. In accordance with such embodiments, ATSP oligomers are deposited on the continuous fiber weave with three different ways: dry powder bath, dry powder spray and wet slurry method. Then, the blended mixtures are loaded in a hot press machine, and go through a high temperature cure and compression cycle and form the final ATSP-based continuous fiber composites. Various continuous fiber materials, with different formats (weave sheet, unidirectional fabric, tow, etc.), combination of different fillers and different weight ratios are applicable for the same fabrication process.

Example 1: ATSP-Chopped Carbon Fiber Composite

[0028] This example demonstrates the production of discontinuous ATSP composites filled with chopped carbon fiber (other chopped fibers such as glass fibers work with the same principle). First, mix the two oligomers (CB and AB) with desired weight percentage of chopped carbon fiber. Then the blended components are loaded into a mold and placed in a hot press. The hot press is ramped to 270 C. and held for one hour with no pressure applied to the mold. After one hour, the temperature is ramped to 360 C. At 360 C., the pressure is increased to 27.6 MPa (4000 psi) and the sample is held for 2 hours and then allowed to cool. An example of a fully dense discontinuous composites produced by this method (as seen in FIG. 1) is one where the filler was chopped IM-9 carbon fiber (by Hexcel) was 28 wt. % of the composite. Initial thermal experiments on this are described below.

[0029] Thermal degradation of the composites was performed by a TGA (TA-2950) from room temperature to 800 C. with heating rate of 10 C./min under nitrogen.

[0030] Table 1 and FIG. 2 show the TGA results, it is clear that ATSP-CBAB and its carbon composite have much better thermal stability, both the neat ATSP and its composite have 186 C. to 210 C. higher temperature compared with Phenolic+50 wt. % glass fiber composite with respect to their degree of thermal degradation at 5%, 10% and 25% of weight loss. Compared with neat ATSP, the neat Phenolic resol in also showed worse thermal stability even with a faster beating rate of 20 C./min. As for MXBE-350, its thermal stability is also worse than neat ATSP; for MXB-360, compared with neat ATSP, it has a lower temperature at 5 wt. % loss but higher temperature at 10 wt. % loss, while the higher temperature is strongly determined by its high percentage (73.5%) of fillers. Thus, if we design ATSP composites with different fillers or complex structures, ATSP will have promising and favorable thermal performance.

TABLE-US-00001 TABLE 1 Materials used in the proof-of-concept TGA and results at several mass loss points as well as residual mass after 800 C. (char yield) Filler Density T_5 wt % T_10 wt % T_25 wt % Residual mass Materials (%) (g/cm.sup.3) loss loss loss at 800 C. 1. ATSP-CBAB 0 1.3 478 C. 496 C. 518 C. 45.3% 2. ATSP-CBAB + 28 1.42 476 C. 498 C. 532 C. 57.6% chopped carbon fiber 3. G10 Phenolic 50 1.94 282 C. 310 C. 322 C. 61.9% glass fiber composite Phenolic resol 0 1.3 260 C. 310 C. 480 C. .sup.52% MXB-360 73.5 1.8 383 C. 527 C. N/A .sup.85% MXBE-350 56.5 1.72 322 C. 383 C. 485 C. .sup.68%

Example 2: ATSP-with Different Fillers

[0031] As for Tribological applications, polymers in pure form as unfilled polymers may have high COF, high wear rate and poor mechanical properties, so they typically do not satisfy the tribological application needs. Thus, it is of great interest in producing composites or blended polymers by adding different fillers and reinforcements in the polymers, improving significantly their mechanical, thermal or tribological properties. In this example, we produced ATSP bearing grade composites by mixing ATSP oligomers with different fillers such as milled carbon fiber (Zoltek PX35MF0150), graphite powder, PTFE powder, carbon black, carbon nanotubes, and graphene nanoplatelets with different weight percentages. Examples of mixing ratio between ATSP and fillers that have been tried is listed in

[0032] Table 2.

TABLE-US-00002 TABLE 2 Examples of mixing ratio between ATSP and fillers Composition of the mixture No. (CBAB is mixed of CB and AB oligomers with 50:50 weight ratio) 1 CBAB:milled carbon fiber (70:30) 2 CBAB:milled carbon fiber:Teflon PTFE 7A X (60:30:10) 3 CBAB:Teflon PTFE 7A X (70:30) 4 CBAB:carbon nanotubes (90:10) 5 CBAB:graphite (60:40) 6 CBAB:graphite:Teflon PTFE 7A X (50:40:10) 7 CBAB:graphene (90:10) 8 CBAB:graphite:Teflon PTFE 7A X:milled carbon fiber (55:15:15:15)

[0033] The parameter curve for curing of the mixture of ATSP oligomers and the fillers is shown in FIG. 3: the mixture composition was loaded into the mold (as in FIG. 4 on the left) followed by the mold anvil. Loaded mold was placed into a vacuum-enclosed hot press. A temperature cycle consisting of a 5 C./min ramp to 330 C. followed by a 150 min hold followed by a 1 C./min ramp to 360 C. with a 2 hours hold and then cool down naturally. After 1 hour hold at 360 C., applied the pressure of 6.9 MPa (1000 psi) for the mold and hold till the sample cooled down. ATSP composites were removed from the mold and can be seen in FIG. 4 on the right. These 22 plates were produced with thickness of about 0.4. As shown in FIG. 5 of the SEM analysis of ATSP+30% milled carbon fiber composite, the sample was fully condensed and the milled carbon fiber filler are uniformly distributed in the composite.

[0034] The composites showed excellent machinability and they were made into cylindrical pins for tribological performance evaluation by a pin-on-disk experimental configuration, as shown in FIG. 6. The tribological experiments were performed by a tribometer allowing to do experiment with different conditions such as load, speed and temperature. The counterpart of the composite pin was a 2 diameter disk made from 416 stainless steel, with root mean square roughness of 0.1 m. The experimental conditions were: dry sliding, temperature of 25 C., sliding speed of 0.5 m/s and contact pressure of 4 MPa. Both normal and friction forces were recorded and used for calculation of coefficient of friction (COF), which is the ratio of friction force and normal force. The wear rate, with unit of mm.sup.3/Nm, was calculated by dividing wear volume by the product of normal force and the sliding distance. The friction and wear rate results are shown in FIG. 7. For comparison, two commercial bearing grade polymer composites were selected: DuPont Vespel SP-21 and Ketron@ HPV PEEK. Among the 6 different composites that were tested, ATSP+30% PTFE showed lowest COF of 0.270.01, corresponding with a very low wear rate of 3.210-7 mm.sup.3/Nm; and ATSP+40% Graphite+10% PTFE had lowest wear rate of 2.710.sup.7 mm.sup.3/Nm, corresponding with COF of 0.290.01. Both these two ATSP composites had better tribological performance compared with the two commercial composites, where Vespel SP21 had COF 0.500.06 with wear rate of 4910-7 mm/Nm and HPV PEEK had COF 0.380.06 with wear rate of 10710-7 mm.sup.3/Nm with the same experimental conditions. These tribological results show the utility of ATSP composites as high performance bearing materials.

Example 3: ATSP BasedMetal Composite

[0035] Tilting pad bearings (for use in e.g. electrical submersible pumps) were fabricated using a filled composition of ATSP. A 304 stainless steel base was roughened by grit blast and subsequently cleaned via ultrasonication in isopropanol and then dried at 70 C. A mixed layer of CB and AB ground oligomeric powders (50:50 mass ratio, mesh size <90 um) were deposited via electrostatic powder deposition. The deposited coating was melted and cured via convection oven at 270 C.

[0036] The coated 304 base was inserted into a cylindrical mold as shown in FIG. 8. A blend of CB:AB oligomers (at 50:50 mass ratio) was mixed with milled carbon fiber (Zoltek PX35MF0150) and PTFE at mass proportions of 70:25:5 and thoroughly blended in a laboratory blender. Blended composition was loaded into the mold followed by the mold anvil. Loaded mold was inserted into a vacuum-enclosed hot press. A temperature cycle consisting of a 2 C./min ramp to 270 C. followed by a 30 minute hold followed by a 2 C./min ramp to 340 C. with a one hour hold followed by a 2 C./min ramp to 370 C. with a hold for 2 hours. At the start of the 370 C. hold, the applied pressure on the mold is increased to 4000 psi. Sample is allowed to cool naturally. Specimen was removed from the mold and then machined into correct dimensions, as seen in FIG. 9. The bonding between ATSP composite and the 304 ss substrate was created by the electrostatic powder coating, in addition to this coating method, the bonding could also be supplied by mechanical interlocking, such as dovetail grooves on metal substrate surface and sintered porous metal (eg. bronze) powder on metal substrate surface. The ATSP composite can thereby achieve mechanical interlocking and occupy the free space on the metal substrate and then ensure the ATSP composite on the metal substrate is well-attached.

Example 4: ATSP Based Synthetic Multilayer Composites

[0037] To produce the ATSP based synthetic multilayer (5 layers) composite as shown in FIG. 14 on the right, 3 different fully condensed ATSP composites, namely CBAB:milled carbon fiber (70:30), neat CBAB, and CBAB:chopped carbon fiber (70:30), and two aluminum plates deposited with CBAB coating need to be produced, as in FIG. 14 on the left. ATSP/milled carbon fiber composite plate was produced with same method as in Example 2 and ATSP/chopped carbon fiber composite plate was produced with same method as in Example 1.

[0038] Neat CBAB plate was produced as below: cured CBAB powders were produced by first crosslinking the CB and AB oligomers. CB and AB oligomers were mixed at a 1:1 weight ratio were mixed and cured via an imposed thermal cycle of 200 C. for 1 h, 270 C. for 2 h followed by 330 C. for 3 h under vacuum. This produces a foam material with a typical density of 0.36-0.53 g/cm.sup.3. ATSP foamed structures were then ground to produce powders which pass through a <90 m mesh. The cured ATSP powder was then loaded into the mold was compressed with 6.7 MPa (1000 psi) normal pressure in a vacuumed hot press machine with heating elements installed in the top and the bottom press plates. The temperature increased to 340 C. and held for 2 h for hot sintering of ATSP powders in to bulk plate.

[0039] To produce the CBAB coating on aluminum, the aluminum substrate was roughened by grit blast and subsequently cleaned via ultrasonication in isopropanol and then dried at 70 C. A mixed layer of CB and AB ground oligomeric powders (50:50 mass ratio, mesh size <90 um) were deposited via electrostatic powder deposition. The deposited coating was melted and cured via convection oven at 270 C.

[0040] With the 5 plates as in FIG. 14 on the left, they were stacked together in the mold in order: 1) CBAB:milled carbon fiber, 2) ATSP coating, 3) neat CB AB, 4) ATSP coating, and 5) CBAB:chopped carbon fiber, followed by the mold anvil. Loaded mold was inserted into a vacuum-enclosed hot press. A temperature cycle consisting of a 2 C./imin ramp to 340 C. followed by a 2 hours hold. At the start of the 340 C. hold, the applied pressure on the mold is increased to 13.8 MPa (2000 psi). The sample is allowed to cool naturally. Specimen was removed from the mold and then machined into correct dimensions, as seen in FIG. 14 on the right.

Example 5: ATSP-Continuous Glass Fiber (and Carbon Fiber, Etc.) Composites

[0041] To produce the ATSP-continuous glass fiber (and carbon fiber, etc.) composites as shown in FIG. 10, the continuous fiber weaves/sheets need to be covered by the ATSP oligomer powders (CB and AB powders for this patent). In this patent, as shown in FIG. 11, we demonstrate three different methods to spread ATSP oligomer powders on the continuous fiber weaves/sheets, namely, dry powder bath, dry powder spray and wet slurry method. As for the dry powder bath method, place the fiber sheet on the top of the powder in the glass tray, and then press the all the fiber sheet area lightly with a sponge that is fulfilled with oligomer powder. By this way the fiber sheet will be fully covered by the oligomer powder. Following this, the oligomer saturated fiber sheets are arranged in a stack, as in FIG. 12 (left), and then the stack of sheets is placed in a hot press machine. As shown in FIG. 13, the curve of curing parameters for temperature and pressure. For temperature cycle: the temperature is ramped to 220 C. and held for one hour, then the temperature is ramped to 270 C. and held for one hour, the temperature is then ramped to 360 C. and kept for one hour. For pressure cycle, the pressure is increased to 0.1 MPa (15 psi) after 30 min hold at 220 C., and then the pressure is increased to 6.9 MPa (1000 psi) and held till the sample cools down. At 220 C., with low pressure, the oligomers melt and can wet through the fiber bundles; at 330 C. for 1 hour, ATSP oligomers can finish the reaction; at 360 C. for 1 hour, with help of high pressure, the cured ATSP resin in the composite softens and form a consolidated ATSP based continuous fiber composite with density approaching theoretical. After the curing cycle, the finished ATSP-glass fiber composite is shown in FIG. 12 (right).

[0042] While particular elements, embodiments, and applications of the present invention have been shown and described, it is understood that the invention is not limited thereto because modifications may be made by those skilled in the art, particularly in light of the foregoing teaching. It is therefore contemplated by the appended claims to cover such modifications and incorporate those features which come within the sprint and scope of the invention.