Synthesis and swelling behavior of polyurethane networks based on hyperbranched polymer

A series of six polyurethane (PU) networks was synthesized from BoltornR hydroxy-functional hyperbranched polyester (HBP) of the second pseudo generation as a crosslinking agent, ?,?- dihydroxy-(ethylene oxide-poly(dimethylsiloxane)-ethylene oxide) (EO-PDMS-EO) and 4,4?- methylenediphenyl diisocyana...

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Bibliographic Details
Published inHemijska industrija Vol. 65; no. 6; pp. 637 - 644
Main Authors Dzunuzovic, Jasna, Pergal, Marija, Jovanovic, Slobodan, Vodnik, Vesna
Format Journal Article
LanguageEnglish
Serbian
Published Belgrade Hemijska Industrija 01.01.2011
Association of Chemical Engineers of Serbia
Subjects
Chemical synthesis
Corrosion resistance
Crosslinking
Ethylene oxide
Fourier transforms
Hydroxyl groups
hyperbranched polyester
Networks
NMR
Nuclear magnetic resonance
poly(dimethylsiloxane)
Polydimethylsiloxane
Polymerization
polyurethane
Polyurethane resins
Silicone resins
Swelling
swelling behavior
Toluene
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Summary:A series of six polyurethane (PU) networks was synthesized from BoltornR hydroxy-functional hyperbranched polyester (HBP) of the second pseudo generation as a crosslinking agent, ?,?- dihydroxy-(ethylene oxide-poly(dimethylsiloxane)-ethylene oxide) (EO-PDMS-EO) and 4,4?- methylenediphenyl diisocyanate, by a two-step polymerization in solution. Each sample of the prepared PUs had different EO-PDMS-EO content. The chemical structure of the synthesized networks was analyzed by FTIR spectroscopy. The influence of the EO-PDMS-EO content and type of the solvent on the swelling behavior of the PUs in 2-propanol and toluene was investigated. During the swelling measurements certain amount of sol fractions was extracted from the PUs by solvents. According to the 1H NMR results, sol fractions are mainly composed of the soluble hyperbranched PU, formed during the polymerization by partial modification of the end hydroxyl groups of HBP with NCO-terminated prepolymer synthesized in the first step of the reaction. Chains of the so reacted prepolymer can then fold back and form cyclic products by reaction of the free -NCO group from the NCO-terminated prepolymer with free -OH group of HBP. As the EO-PDMS-EO content increases the amount of the sol fractions and swelling degree also increased, indicating that networks with lower EO-PDMS-EO content are more crosslinked and have higher solvent resistance. nema
ISSN:2217-7426
0367-598X
2217-7426
DOI:10.2298/hemind110902071d