Mechanical properties and fractography of block copolymers based on NR and MDI-based polyurethanes

Five series of block copolymers were synthesized from hydroxyl-terminated liquid natural rubber (HTNR) and polyurethane (PU) oligomers, from various diols and diphenyl methane-4,4′-diisocyanate (MDI). They were characterized by mechanical testing and fracture studies (SEM analysis). The block copoly...

Full description

Saved in:
Bibliographic Details
Published in:Polymer bulletin (Berlin, Germany) Germany), 2010-06, Vol.65 (1), p.83-96
Main Authors: Nair, M. N. Radhakrishnan, Sukumar, Prema, Jayashree, V., Nair, M. R. Gopinathan
Format: Article
Language:English
Subjects:
Applied sciences
Aromatic compounds
Bisphenol A
Block copolymers
Characterization and Evaluation of Materials
Chemistry
Chemistry and Materials Science
Complex Fluids and Microfluidics
Composition
Copolymers
Diisocyanates
Diols
Diphenyl methane diisocyanate
Ductile fracture
Ductile-brittle transition
Elastomers
Electron microscopes
Exact sciences and technology
Fractography
Fracture mechanics
Mechanical properties
Mechanical tests
Molecular weight
Morphology
Natural polymers
Natural rubber
Organic Chemistry
Original Paper
Physical Chemistry
Physicochemistry of polymers
Polymer Sciences
Polymers
Polyurethane
Polyurethane resins
Rubber
Scanning electron microscopy
Segments
Soft and Granular Matter
Tensile properties
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Five series of block copolymers were synthesized from hydroxyl-terminated liquid natural rubber (HTNR) and polyurethane (PU) oligomers, from various diols and diphenyl methane-4,4′-diisocyanate (MDI). They were characterized by mechanical testing and fracture studies (SEM analysis). The block copolymer characteristics were assessed on the basis of the composition and the type of extender diols. Mechanical properties were found to be strongly dependent on the copolymer composition in all the series. Tensile properties were found to improve with the hard segment content. At low hard segment content samples resemble flexible elastomers whereas at high hard segment content they behave as rigid plastics. Where bisphenol A (BPA) is used as the extender diol sample rigidity was higher compared to the samples with aliphatic diols which is attributed to the presence of aromatic ring system in the former samples. Fracture mechanism was found to vary from ductile fracture to rigid and brittle fracture as the hard segment content increased. Fractography also shows the presence of some beads disposed on the sample surface which could be the uncombined polyurethane homopolymer fractions.
ISSN:0170-0839
1436-2449
DOI:10.1007/s00289-010-0251-8