Abstract
The main aim of this work was to obtain poly(ether-urethane)s using tri-functional polyoxyalkylene polyol (Rokopol G1000), which introducing the chemical cross-links into the structure of polyurethanes. Poly(ether-urethane)s were prepared using two-step method, called prepolymer method, which involves in the first step the reaction of 4,4′-diphenylmethane diisocyanate (MDI) and tri-functional polypropylene glycol glycerol triether polyol. In the second step, prepolymer chains were extended by using: 1,6-hexanediol, 1,4-butanediol in the mixture with poly(ethylene glycol) and poly(ethylene glycol). The prepolymer chains extending was realized at three different molar ratios of NCO groups (presented in prepolymer) to OH groups (presented in chain extender), i.e., 0.95, 1.00 or 1.05. The influence of chain extender type on the chemical structure, selected mechanical properties and thermomechanical properties of the obtained poly(ether-urethane)s was investigated. The results showed that applying different types of chain extenders results in obtaining materials with diversified mechanical properties, but very similar thermal stability. The performance of obtained poly(ether-urethane)s is mostly affected by the chemical cross-links, which were introduced into soft segments by tri-functional polyetherol.
Highlights
Polyurethanes are synthesized through the reaction of di- or poly-isocyanates, high molecular weight polyols and low molecular weight chains extenders [1, 2], but it is possible to synthesis of PUs by non-isocyanate route [3, 4]
The results showed that applying different types of chain extenders results in obtaining materials with diversified mechanical properties, but very similar thermal stability
The performance of obtained poly(etherurethane)s is mostly affected by the chemical cross-links, which were introduced into soft segments by tri-functional polyetherol
Summary
Polyurethanes are synthesized through the reaction of di- or poly-isocyanates, high molecular weight polyols and low molecular weight chains extenders [1, 2], but it is possible to synthesis of PUs by non-isocyanate route [3, 4]. The bio-based components, which can be used as a polyols in the synthesis of polyurethanes, are, for example, castor oil [14], polyricinoleate diol [15], hydroxylated soybean oil [6, 16], hydroxylated hemp seed oil [17] and polyglycerols [18]. The chemical cross-links can be introduced into the structure of polyurethanes through hard segments or soft segments [20,21,22]. Mentioned earlier bio-based substances (especially polyglycerol or vegetable oil-based polyols) introducing generally chemical cross-links into the structure of polyurethanes
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