Dynamic mechanical and thermal properties of seven polyurethane adhesives
Seven polyurethane adhesives have been developed at Lawrence Livermore National Laboratory (LLNL). These adhesives, designated Halthanes were synthesized because of OSHA restrictions on the use of the curing agent methylene bis(2-chloroaniline). Four of the Halthanes were made from LLNL-developed 4,4'-methylene bis(phenylisocyanate) terminated prepolymers cured with a blend of polyols; three were made from an LLNL-developed prepolymer terminated with Hylene W and cured with aromatic diamines. In this paper the dynamic mechanical and thermal behavior of these seven segmented polyurethanes are discussed. The chemical structure of the hard and soft segments, the concentrations of each block, and the presence of tetrafunctional crosslinker determined the dynamic mechanical and thermal properties of the three types of polyurethane adhesives, 73-, 87-, and 88-series Halthanes studied. Aromatic-aliphatic MDI- butanediol urethane hard segments produce lower modulus (10/sup 6/ Pa) materials in the rubbery region than cyclic unsaturated-aromatic urea hard segments. Incorporation of chemical crosslinks in the hard segments extended the rubbery plateau beyond the hard segment transitions up to temperatures where the polymer begins to degrade. Concentration of hard and soft segments can also be used to control the modulus between the glass transition temperatures of the two blocks.
- Research Organization:
- Lawrence Livermore National Lab., CA (USA)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6608539
- Report Number(s):
- UCRL-82694(Rev.1); CONF-810308-7
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360403* -- Materials-- Polymers & Plastics-- Mechanical Properties-- (-1987)
360405 -- Materials-- Polymers & Plastics-- Degradation & Erosion-- (-1987)
ADHESIVES
ALCOHOLS
AMINES
AROMATICS
BUTANEDIOLS
CHEMICAL REACTIONS
CROSS-LINKING
FLUID FLOW
GLASS
GLYCOLS
HALTHANE
HYDROXY COMPOUNDS
ISOCYANATES
MECHANICAL PROPERTIES
MELTING
ORGANIC COMPOUNDS
ORGANIC POLYMERS
PETROCHEMICALS
PETROLEUM PRODUCTS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
PLASTICS
POLYAMIDES
POLYMERIZATION
POLYMERS
POLYURETHANES
RELAXATION
THERMAL DEGRADATION
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE
VISCOUS FLOW