Effect of soft segment molecular weight on tensile properties of poly(propylene oxide) based polyurethaneureas
Yükleniyor...
Tarih
2012
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Elsevier
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
Influence of soft segment molecular weight and hard segment content on the morphology, thermomechanical and tensile properties of homologous polyurethaneurea copolymers based on narrow molecular weight poly(propylene oxide)glycol (PPG) oligomers were investigated. A series of polyurethaneureas with hard segment contents of 12–45% by weight and PPG number average molecular weights <Mn> of 2000 to 11,800 g/mol were synthesized and characterized structurally by SAXS and mechanically by DMA and stress strain analysis. Bis(4-isocyanatocyclohexyl)methane and 2-methyl-1,5-diaminopentane were used as the diisocyanate and the chain extender respectively. All copolymers displayed microphase separation by SAXS and DMA. The critical entanglement molecular weight (Me) of PPG is reported to be around 7700 g/mol. Our mechanical results suggest that when copolymers possess similar hard segment contents and are compared to those based on soft segments with number average molecular weights (Mn) greater than Me, they generally displayed higher tensile strengths and particularly lower hysteresis and creep than those having soft segment molecular weights below Me. These results imply that soft segment entanglements in thermoplastic polyurethaneureas may provide a critical contribution to the tensile properties of these copolymers – particularly in the range where the soft segment content is dominant.
Açıklama
Anahtar Kelimeler
Polyurethaneurea Elastomer, Hysteresis, Entanglements, Poliüretanüre Elastomer, Histerezis, Polyurethanharnstoff Elastomer, Hysterese
Kaynak
Polymer
WoS Q Değeri
Scopus Q Değeri
Q1
Cilt
53
Sayı
21
Künye
Ertem, S. P., Yılgör, E., Koşak Söz, Ç., Wilkes, G. L., Zhang, M., & Yılgör, İ. (2012). Effect of soft segment molecular weight on tensile properties of poly (propylene oxide) based polyurethaneureas. Polymer, 53(21), 4614-4622.
