TY - JOUR
T1 - An overview on 12-polyurethane
T2 - Synthesis, structure and crystallization
AU - Fernández, C. E.
AU - Bermúdez, M.
AU - Versteegen, R. M.
AU - Meijer, E. W.
AU - Vancso, G. J.
AU - Muñoz-Guerra, S.
PY - 2010/11/1
Y1 - 2010/11/1
N2 - The knowledge on linear aliphatic polyurethanes n-PUR has increased significantly due to a series of works made in these last years and published in recent literature. An overview of 12-polyurethane (12-PUR) embracing its synthesis, thermal properties, crystal structure and crystallization is given in this paper. The purpose is to provide a representative example able to reflect comprehensively the state of the art reached for the whole family. The synthesis of 12-PUR was accomplished in good yield and with acceptable molecular weight from 12-amino-1-dodecanol by applying a two-step method without isolation of the isocyanate alcohol precursor. 12-PUR is a semicrystalline polymer with an equilibrium melting temperature of 157 °C. It adopts a layered crystal structure similar to the α-form of nylons with chains in fully-extended conformation and arranged in hydrogen-bonded sheets in the antiparallel mode. This structure is thermally stable up to melting and is unable to undergo Brill transition. 12-PUR crystallized from dilute solution affording well-shaped lamellar crystals with a thickness of 8-9 nm and from the melt yielding either banded or fibrillar spherulitic textures displaying negative birefringence. Isothermal crystallization of 12-PUR from the melt took place with heterogeneous nucleation, while both crystallization rate and the finally attained crystallinity degree were highly depending on crystallization temperature.
AB - The knowledge on linear aliphatic polyurethanes n-PUR has increased significantly due to a series of works made in these last years and published in recent literature. An overview of 12-polyurethane (12-PUR) embracing its synthesis, thermal properties, crystal structure and crystallization is given in this paper. The purpose is to provide a representative example able to reflect comprehensively the state of the art reached for the whole family. The synthesis of 12-PUR was accomplished in good yield and with acceptable molecular weight from 12-amino-1-dodecanol by applying a two-step method without isolation of the isocyanate alcohol precursor. 12-PUR is a semicrystalline polymer with an equilibrium melting temperature of 157 °C. It adopts a layered crystal structure similar to the α-form of nylons with chains in fully-extended conformation and arranged in hydrogen-bonded sheets in the antiparallel mode. This structure is thermally stable up to melting and is unable to undergo Brill transition. 12-PUR crystallized from dilute solution affording well-shaped lamellar crystals with a thickness of 8-9 nm and from the melt yielding either banded or fibrillar spherulitic textures displaying negative birefringence. Isothermal crystallization of 12-PUR from the melt took place with heterogeneous nucleation, while both crystallization rate and the finally attained crystallinity degree were highly depending on crystallization temperature.
KW - Polymer crystal morphology
KW - Polymer crystal structure
KW - Polyurethanes
KW - Structure-properties relationship
UR - http://www.scopus.com/inward/record.url?scp=78149285465&partnerID=8YFLogxK
U2 - 10.1016/j.eurpolymj.2010.09.018
DO - 10.1016/j.eurpolymj.2010.09.018
M3 - Article
AN - SCOPUS:78149285465
VL - 46
SP - 2089
EP - 2098
JO - European Polymer Journal
JF - European Polymer Journal
SN - 0014-3057
IS - 11
ER -