Accession Number:

ADA289996

Title:

Polyethylene-Based Polyurethane Copolymers and Block Copolymers.

Descriptive Note:

Final rept.,

Corporate Author:

ARMY RESEARCH LAB WATERTOWN MA MATERIALS DIRECTORATE

Personal Author(s):

• Byme, C. A.
• Desper, C. R.
• Schneider, N. S.
• Chu, B.
• Li, Y. J.

Report Date:

1994-11-01

Pagination or Media Count:

34.0

Abstract:

Low molecular weight hydroxy terminated polyethylene HTPE containing on average an ethyl group every 16-18 carbon atoms, and a hydroxy functionality of 2.6, has been used to prepare polyurethane copolymers and block copolymers which have good solvent resistance. The polymers show somewhat complicated thermal behavior, including T sub g at around -40 deg C due to the HTPE and diffuse endotherms between 40 and 60 deg C. The simple copolymers, containing only the polyol and a diisocyanate, show infrared evidence for two phases in the case where CHDI trans-1,4-diisocyanatocyclohexane, was used, and poorer phase separation where other diisocyanates were used. Dynamic mechanical spectra show very broad tan delta transitions for the copolymers in the range of -9 to -23 deg C. All the polymers exhibit another transition in the G curve above room temperature. For the simple copolymers at 30 deg C, SAXS reveals a microphase separated structure which increases in spacing, then disappears in the 60-70 deg C range. With cooling, the microphase separated structure reappears readily for the CHDI-based copolymer, while its reappearance shows a hysteresis resulting from rate effects for the other copolymers. jg

Descriptors:

• *COPOLYMERS
• *BLOCK COPOLYMERS
• *POLYURETHANE RESINS
• *POLYETHYLENE
• THERMAL PROPERTIES
• MECHANICAL PROPERTIES
• DYNAMICS
• POLYMERS
• RESISTANCE
• ELASTOMERS
• RATES
• CARBON
• COOLING
• PHASE
• ROOM TEMPERATURE
• SPECTRA
• SOLVENTS
• SEPARATION
• DIFFUSION
• INFRARED RADIATION
• HYSTERESIS
• ETHYL RADICALS
• HYDROGENATION
• ISOCYANATES
• ENDOTHERMIC REACTIONS

Subject Categories:

• Polymer Chemistry
• Organic Chemistry
• Physical Chemistry

Distribution Statement:

APPROVED FOR PUBLIC RELEASE