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Tri-Block Copolymers of Polyethylene Glycol and Hyperbranched Poly-3-ethyl-3-(hydroxymethyl)oxetane Through Cationic Ring Opening Polymerization
KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry.
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.ORCID iD: 0000-0002-8348-2273
2009 (English)In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 47, no 22, 6191-6200 p.Article in journal (Refereed) Published
Abstract [en]

Tri-block copolymers of linear poly(ethylene glycol) (PEG) and hyperbranched poly-3-ethyl-3-(hydroxymethyl)oxetane (poly-TMPO) are reported. The novel dumb-bell shaped polyethers were synthesized in bulk with cationic ring-opening polymerization utilizing BF3OEt2 as initiator, via drop-wise addition of the oxetane monomer. The thermal properties of the materials were successfully tuned by varying the amount of poly-TMPO attached to the PEG-chains, ranging from a melting point of 54 degrees C and a degree of crystallinity of 76% for pure PEG, to a melting point of 35 degrees C and a degree of crystallinity of 12% for the polyether copolymer having an average of 14 TMPO units per PEG chain. The materials are of relatively low polydispersity, with M-n/M-w ranging from 1.2 to 1.4. The materials have been evaluated for usage with the energetic oxidizer ammonium dinitramide.

Place, publisher, year, edition, pages
2009. Vol. 47, no 22, 6191-6200 p.
Keyword [en]
ADN, ammonium dinitramide, cationic polymerization, oxetane, polymerization, polyether, thermal properties, TMPO, multihydroxyl branched polyethers, aliphatic polyethers, polymers, 3-ethyl-3-(hydroxymethyl)oxetane, dendrimers, analog
National Category
Chemical Sciences
URN: urn:nbn:se:kth:diva-18951DOI: 10.1002/pola.23662ISI: 000271670000025ScopusID: 2-s2.0-70350230133OAI: diva2:336998
QC 20100525Available from: 2010-08-05 Created: 2010-08-05 Last updated: 2011-01-18Bibliographically approved
In thesis
1. Green Propellants
Open this publication in new window or tab >>Green Propellants
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

To enable future environmentally friendly access to space by means of solid rocket propulsion a viable replacement to the hazardous ammonium perchlorate oxidizer is needed. Ammonium dinitramide (ADN) is one of few such compounds currently known. Unfortunately compatibility issues with many polymer binder systems and unexplained solid-state behavior have thus far hampered the development of ADN-based propellants.

Chapters one, two and three offer a general introduction to the thesis, and into relevant aspects of quantum chemistry and polymer chemistry.

Chapter four of this thesis presents extensive quantum chemical and spectroscopic studies that explain much of ADN’s anomalous reactivity, solid-state behavior and thermal stability. Polarization of surface dinitramide anions has been identified as the main reason for the decreased stability of solid ADN, and theoretical models have been developed to explain and predict the solid-state stability of general dinitramide salts. Experimental decomposition characteristics for ADN, such as activation energy and decomposition products, have been explained for different physical conditions. The reactivity of ADN towards many chemical groups is explained by ammonium-mediated conjugate addition reactions. It is predicted that ADN can be stabilized by changing the surface chemistry with additives, for example by using hydrogen bond donors, and by trapping radical intermediates using suitable amine-functionalities.

Chapter five presents several conceptual green energetic materials (GEMs), including different pentazolate derivatives, which have been subjected to thorough theoretical studies. One of these, trinitramide (TNA), has been synthesized and characterized by vibrational and nuclear magnetic resonance spectroscopy.

Finally, chapter six covers the synthesis of several polymeric materials based on polyoxetanes, which have been tested for compatibility with ADN. Successful formation of polymer matrices based on the ADN-compatible polyglycidyl azide polymer (GAP) has been demonstrated using a novel type of macromolecular curing agent. In light of these results further work towards ADN-propellants is strongly encouraged.

Place, publisher, year, edition, pages
Stockholm: KTH, 2010. 77 p.
Trita-CHE-Report, ISSN 1654-1081 ; 2010:43
Quantum chemistry, reaction kinetics, ammonium dinitramide, high energy density materials, rocket propellants, chemical spectroscopy, polymer synthesis
National Category
Theoretical Chemistry Physical Chemistry
urn:nbn:se:kth:diva-25835 (URN)978-91-7415-758-1 (ISBN)
Public defence
2010-11-23, F1, Lindstedtsvägen 22, KTH, Stockholm, 09:30 (English)
QC 20101103Available from: 2010-11-03 Created: 2010-11-02 Last updated: 2011-03-21Bibliographically approved

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Rahm, MartinWestlund, RobertMalmström, Eva
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