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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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7 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Polymerizations of 2-(Trimethylsilyl)ethanesulfonyl-activated aziridines

A novel N-sulfonyl aziridine, N-((2-(trimethylsilyl)ethyl)sulfonyl)-2-methyl-aziridine (SES-MeAz) was synthesized, and its controlled anionic ring-opening polymerization to form poly(SES-MeAz) studied. The desulfonylation of poly(SES-MeAz)s can be achieved under mild conditions, with tetrabutylammonium fluoride (TBAF) to form polypropylene imine (PPI), although purification of the PPI was not completely successful. The block copolymer p(pTs-MeAz)-b-p(SES-MeAz), (pTs-MeAz = N-para-tosyl-2-methyl-aziridine) was prepared by a sequential polymerization. The desulfonylation of the block copolymer is the first example of the selective removal of a sulfonyl protecting group from a poly(sulfonylazirdine) block copolymer and this is the first formation of a polysufonylaziridine-block-polypropylene imine copolymer. Three-armed star-shaped poly(SES-MeAz)s were also successfully synthesized and exhibited improved solubility compared with linear poly(SES-MeAz)s.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1988

Feasibility studies of the growth of 3-5 compounds of boron by MOCVD

Boron-arsenic and boron-phosphorus films have been grown on Si sapphire and silicon-on-sapphire (SOS) by pyrolyzing Group 3 alkyls of boron, i.e., trimethylborane (TMB) and triethylborane (TEB), in the presence of AsH3 and PH3, respectively, in an H2 atmosphere. No evidence for reaction between the alkyls and the hydrides on mixing at room temperature was found. However, the films were predominantly amorphous. The film growth rate was found to depend on the concentration of alkyl boron compound and was essentially constant when TEB and AsH3 were pyrolyzed over the temperature range 550 C to 900 C. The films were found to contain mainly carbon impurities (the amount varying with growth temperature), some oxygen, and were highly stressed and bowed on Si substrates, with some crazing evident in thin (2 micron) B-P and thick (5 micron) B-As films. The carbon level was generally higher in films grown using TEB as the boron source. Films grown from PH3 and TMB showed a higher carbon content than those grown from AsH3 and TMB. Based on their B/As and B/P ratios, films with nominal compositions B sub12-16 As2 and B sub1.1-1.3 P were grown using TMB as the boron source.

Manasevit, H. M.↗
NASA NTRS1989

The use of metalorganics in the preparation of semiconductor materials. VIII - Feasibility studies of the growth of Group III-Group V compounds of boron by MOCVD

The MOCVD growth of B-As and B-P films on Si, sapphire, and Si-on-sapphire substrates is described; in this process, trimethylborane (TMB) or triethylborane (TEB) is pyrolyzed in the presence of AsH3 or PH3 in an H2 atmosphere. The procedures employed are outlined, and the results are presented in graphs, tables, and micrographs. It is found that the growth rate of the primarily amorphous films is dependent on the TMB or TEB concentration but approximately constant for TEB and AsH3 at 550-900 C. The nominal compositions of films grown using TMB are given as B(12-16)As2 and B(1-1.3)P. Carbon impurities and significant stress, bowing, and crazing are observed in the films grown on Si substrates, with the highest carbon content in the films grown from TMB and PH3.

Manasevit, H. M.↗
DOE OSTI2020

Materials Data on B13P2 by Materials Project

B13P2 crystallizes in the trigonal R-3m space group. The structure is two-dimensional and consists of three B13P2 sheets oriented in the (0, 0, 1) direction. there are three inequivalent B+0.23- sites. In the first B+0.23- site, B+0.23- is bonded in a cuboctahedral geometry to twelve B+0.23- atoms. There is six shorter (1.76 Å) and six longer (1.83 Å) B–B bond length. In the second B+0.23- site, B+0.23- is bonded in a 1-coordinate geometry to six B+0.23- and one P+1.50+ atom. There are a spread of B–B bond distances ranging from 1.87–1.91 Å. The B–P bond length is 2.03 Å. In the third B+0.23- site, B+0.23- is bonded in a 8-coordinate geometry to eight B+0.23- atoms. All B–B bond lengths are 1.84 Å. P+1.50+ is bonded in a distorted T-shaped geometry to three equivalent B+0.23- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BP by Materials Project

BP is Zincblende, Sphalerite structured and crystallizes in the cubic F-43m space group. The structure is three-dimensional. B3+ is bonded to four equivalent P3- atoms to form corner-sharing BP4 tetrahedra. All B–P bond lengths are 1.97 Å. P3- is bonded to four equivalent B3+ atoms to form corner-sharing PB4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on B6P by Materials Project

B6P is T-50 Boron-derived structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are two inequivalent B sites. In the first B site, B is bonded in a 1-coordinate geometry to five B and one P atom. There are a spread of B–B bond distances ranging from 1.75–1.81 Å. The B–P bond length is 1.92 Å. In the second B site, B is bonded in a 6-coordinate geometry to six B atoms. There is one shorter (1.74 Å) and two longer (1.88 Å) B–B bond length. P is bonded in a distorted tetrahedral geometry to three equivalent B and one P atom. The P–P bond length is 2.25 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BP by Materials Project

BP is Wurtzite structured and crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. B3+ is bonded to four equivalent P3- atoms to form corner-sharing BP4 tetrahedra. There is three shorter (1.96 Å) and one longer (1.98 Å) B–P bond length. P3- is bonded to four equivalent B3+ atoms to form corner-sharing PB4 tetrahedra.

36 MATERIALS SCIENCE↗