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  • 1
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    Composite materials for precision space reflector panels (1992)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: One of the critical technology needs of large precision reflectors for future astrophysical and optical communications satellites lies in the area of structural materials. Results from a materials research and development program at NASA Langley Research Center to provide materials for these reflector applications are discussed. Advanced materials that meet the reflector panel requirements are identified, and thermal, mechanical and durability properties of candidate materials after exposure to simulated space environments are compared. A parabolic, graphite-phenolic honeycomb composite panel having a surface accuracy of 70.8 microinches rms and an areal weight of 1.17 lbm/sq ft was fabricated with T50/ERL1962 facesheets, a PAEI thermoplastic surface film, and Al and SiO(x) coatings.
    Keywords: COMPOSITE MATERIALS
    Type: In: Design of optical instruments; Proceedings of the Meeting, Orlando, FL, Apr. 22-24, 1992 (A93-29781 11-74); p. 250-261.
    Format: text
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    NASA TECHNICAL REPORTS
  • 2
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    Preparing polymeric matrix composites using an aqueous slurry technique (1993)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: An aqueous process was developed to prepare a consolidated composite laminate from an aqueous slurry. An aqueous poly(amic acid) surfactant solution was prepared by dissolving a poly(amic acid) powder in an aqueous ammonia solution. A polymeric powder was added to this solution to form a slurry. The slurry was deposited on carbon fiber to form a prepreg which was dried and stacked to form a composite laminate. The composite laminate was consolidated using pressure and was heated to form the polymeric matrix. The resulting composite laminate exhibited high fracture toughness and excellent consolidation.
    Keywords: NONMETALLIC MATERIALS
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 3
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    Poly(arylene ether imidazole) surfacing films for flat and parabolic structures (1996)
    In:  CASI
    Details
    Publication Date: 2019-08-28
    Description: Films of thermoplastic poly(arylene ether imidazole)s (PAEI)s are used as surface modifiers for neat resin panels and composite resin panels. The PAEI polymer contains imidazole groups along the backbone which co-cure, i.e., react chemically, with epoxies or bismaleimides during processing and thereby provide excellent adhesion between the PAEI film and an epoxy or bismaleimide neat resin or composite resin facesheet. The film provides good adhesion and a smooth surface to the finished part and acts as a release agent from the mold. The as-processed integral structures have very smooth (specular) surfaces, and since the film releases readily from a glass mold, no release agent is necessary. The PAEI film is thermally stable, resistant to electron radiation, and adheres tenaciously to the facesheet. The film maintains good adhesion even after thermal cycling from room temperature to .about. -196.degree. C.
    Keywords: Composite Materials
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 4
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    Polyimide Matrix composites: Polyimidesulfone/LARC-TPI (1:1) blend (1989)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Polyimide matrix composites were fabricated from unidirectional unsized AS-4 carbon fiber and a doped 1:1 blend of two polyimides: benzophenone dianhydride-3,3'-diamino diphenylsulfone (PISO2) and benzophenone dianhydride-3,3'-diamino benzophenone (LARC-TPI). To enhance melt flow properties, the molecular weight of the PISO2 was controlled by end-capping with phthalic anhydride and addition of 5 percent by weight p-phenylene diamine-phthalic anhydride bisamic acid dopant. Prepreg was drum-wound using a diglyme slurry comprised of the soluble polyamideacid of PISO2, the soluble bisamideacid of the dopant, and the insoluble imidized LARC-TPI powder. Melt flow studies with a rotary rheometer and parallel plate plastometer on neat resin and prepreg helped develop an optimum cure cycle. Composite mechanical properties at room and elevated temperatures, dry and moisture-saturated, were evaluated, including short beam shear strength and flexure, tensile, shear, and compression properties. Two 18 in. x 24 in. skin-stringer panels were fabricated, one of which was tested in compression to failure.
    Keywords: COMPOSITE MATERIALS
    Type: NASA-TM-101568 , NAS 1.15:101568 , International SAMPE Symposium and Exhibition; May 08, 1989 - May 11, 1989; Reno, NV; United States
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    NASA TECHNICAL REPORTS
  • 5
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    The development of composite materials for spacecraft precision reflector panels (1990)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: One of the critical technology needs for large precision reflectors required for future astrophysics and optical communications is in the area of structural materials. Therefore, a major area of the Precision Segmented Reflector Program at NASA is to develop lightweight composite reflector panels with durable, space environmentally stable materials which maintain both surface figure and required surface accuracy necessary for space telescope applications. Results from the materials research and development program at NASA Langley Research Center are discussed. Advanced materials that meet the reflector panel requirements are identified. Thermal, mechanical and durability properties of candidate materials after exposure to simulated space environments are compared to the baseline material.
    Keywords: COMPOSITE MATERIALS
    Type: Advances in Optical Structure Systems; Apr 16, 1990 - Apr 19, 1990; Orlando, FL; United States
    Format: text
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    NASA TECHNICAL REPORTS
  • 6
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    Wax Reinforces Honeycomb During Machining (1995)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: Method of machining on conventional metal lathe devised for precise cutting of axisymmetric contours on honeycomb cores made of composite (matrix/fiber) materials. Wax filling reinforces honeycomb walls against bending and tearing while honeycomb being contoured on lathe. Innovative method of machining on lathe involves preparation in which honeycomb is placed in appropriate fixture and the fixture is then filled with molten water-soluble wax. Number of different commercial waxes have been tried.
    Keywords: FABRICATION TECHNOLOGY
    Type: LAR-14927 , NASA Tech Briefs (ISSN 0145-319X); 19; 10; P. 90
    Format: text
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    NASA TECHNICAL REPORTS
  • 7
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    LaRC-TPI 1500 composites fabricated using an aqueous slurry process (1990)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: Unidirectional composites from unsized carbon fiber and LaRC-TPI matrix material were fabricated using 'high flow' and'medium flow' grades of the LaRC-TPI 1500 series of polyimides. Prepreg was drum-wound from a slurry composed of the polyimide powder dispersed in an aqueous solution of LaRC-TPI poly(amide acid). The poly(amide acid) was found to be an effective binding agent in the prepregging process. Composite short beam shear and flexure properties were measured at room and elevated temperatures (to 177 C) with both dry and moisture-saturated specimens. The mechanical properties observed for composites fabricated from the high and medium flow materials were virtually identical. Additionally, double cantilever beam measurements showed nearly equivalent fracture toughness for the two composite materials.
    Keywords: COMPOSITE MATERIALS
    Type: International SAMPE Technical Conference; Nov 06, 1990 - Nov 08, 1990; Boston, MA; United States
    Format: text
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    NASA TECHNICAL REPORTS
  • 8
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    Poly(Arylene Ether Imidazole) Surface Films (1993)
    In:  Other Sources
    Details
    Publication Date: 2019-07-12
    Description: Films adhere well to some substrates, provide smooth surfaces, and facilitate release from molds. Thin films of thermoplastic poly(arylene ether imidazole)s (PAEI's) particularly suitable for use as surface modifiers for graphite/epoxy or graphite/bismaleimide composite panels. Molecule of PAEI includes imidazole groups along its backbone that co-cure with epoxies or bismaleimides during processing. Films thermally stable and resistant to bombardment by energetic electrons.
    Keywords: MATERIALS
    Type: LAR-14812 , NASA Tech Briefs (ISSN 0145-319X); 17; 5; P. 26
    Format: text
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    NASA TECHNICAL REPORTS
  • 9
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    Polyimide matrix composites - Polyimidesulfone/LARC-TPI (1:1) blend (1989)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: Polyimide matrix composites were fabricated from unidirectional unsized AS-4 carbon fiber and a doped 1:1 blend of two polyimides: PISO2 and LARC-TPI. To enhance melt flow properties, the molecular weight of the PISO2 was controlled by end-capping with phthalic anhydride and addition of 5 percent by weight p-phenylenediamine-phthalic anhydride bisamic acid dopant. Prepreg was drum-wound using a diglyme slurry comprised of the soluble polyamideacid of PISO2, the soluble bisamideacid of the dopant, and the insoluble imidized LARC-TPI powder. Melt flow studies with a rotary rheometer and parallel plate plastometer on neat resin and prepreg helped develop an optimum cure cycle. Composite mechanical properties at room and elevated temperatures, dry and moisture-saturated, were evaluated, including short beam shear strength and flexure, tensile, shear, and compression properties. Two 18 x 24-inch skin-stringer panels were fabricated, one of which was tested in compression to failure.
    Keywords: COMPOSITE MATERIALS
    Type: International SAMPE Symposium and Exhibition; May 08, 1989 - May 11, 1989; Reno, NV; United States
    Format: text
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    NASA TECHNICAL REPORTS
  • 10
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    Poly(arylene ether imidazole) surfacing films for flat and parabolic structures (1994)
    In:  CASI
    Details
    Publication Date: 2019-08-15
    Description: Films of thermoplastic poly(arylene ether imidazole)s (PAEIs) are used as surface modifiers for neat resin panels and composite resin panels. The PAEI polymer contains imidazole groups along the backbone which co-cure, i.e., react chemically, with epoxies or bismaleimides during processing and thereby provide excellent adhesion between the PAEI film and an epoxy or bismaleimide neat resin or composite resin facesheet. The film provides good adhesion and a smooth surface to the finished part and acts as a release agent from the mold. The as-processed integral structures have very smooth (specular) surfaces, and since the film releases readily from a glass mold, no release agent is necessary. The PAEI film is thermally stable, resistant to electron radiation, and adheres tenaciously to the facesheet. The film maintains good adhesion even after thermal cycling from room temperature to approximately -196 C.
    Keywords: NONMETALLIC MATERIALS
    Type: NAS 1.71:LAR-14812-1
    Format: application/pdf
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    NASA TECHNICAL REPORTS
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