Enhanced polyurethanes based on different polycarbonatediols

Lee

J of Applied Polymer Sci

et al. 2016

The condensation of a mixture of dimethyl carbonate and phthalate derivatives with 1,4‐butanediol (BD), catalyzed by sodium alkoxide, generated high‐molecular weight poly(1,4‐butylene carbonate‐co‐aromatic ester)s with molecular weights (Mn) of 50–120 kDa. The subsequent addition of polyols [BD, glycerol propoxylate, 1,1,1‐tris(hydroxymethyl)ethane, or pentaerythritol] chopped these high‐molecular weight polymers to afford macrodiols or macropolyols with facile control of their molecular weights (Mn, 2000–3000 Da) and unique chain topological compositions. Macropolyols prepared by chopping poly(1,4‐butylene carbonate‐co‐terephthalate) were waxy in nature, whereas those containing isophthalate and phthalate units were oily. The macropolyols synthesized by this chopping method may have potential applications in the polyurethane industry. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43754.

Section: Introductionmentioning

confidence: 99%

Chopping high‐molecular weight poly(1,4‐butylene carbonate‐co‐aromatic ester)s for macropolyol synthesis

Lee

J of Applied Polymer Sci

et al. 2016

J of Applied Polymer Sci

“…The soft segment is a polyol of molecular mass between 500 and 3000 g mol −1 that provides high flexibility at room temperature. The hard segment is formed by a diisocyanate and a low‐molecular‐weight diol which providing physical crosslink sites through strong intermolecular hydrogen bonding . The morphological, physical, chemical, and mechanical properties of TPUs range in a wide spectrum depends on the hard segment formulation and content, molecular structure of soft segment, and manufacturing conditions.…”

Section: Introductionmentioning

confidence: 99%

“…In contrast, polycarbonatediol (PCD) derived TPUs depict improved water and organic solvent resistance, high mechanical strength, and high heat‐resistance, at the expense of an increase in the price . In the last years, we have been working in the identification and functional characterization of improved efficiency of PCD based TPUs since few studies have been published.…”

Section: Introductionmentioning

confidence: 99%

Thermal and dielectric properties of polycarbonatediol polyurethane

Ortiz-Serna

Carsí

Redondo-Foj

et al. 2015

Ortiz Serna, MP.; Carsí Rosique, M.; Redondo Foj, MB.; Sanchis Sánchez, MJ.; Culebras, M.; Gomez, CM.; Cantarero, A. (2015). Thermal and dielectric properties of polycarbonatediol polyurethane. Journal of Applied Polymer Science. 132 (22) ABSTRACTThe dielectric relaxation behaviour of a segmented polyurethane has been studied using Broad-Band Dielectric Spectroscopy in the frequency domain, 10 -2 -10 9 Hz, and in the temperature range of -120 to 140 ºC. The spectra show three secondary processes (,  and β) followed by the  relaxation and conductive processes. The Havriliak-Negami (HN) phenomenological equation was used in order to characterize all the processes. The ,  and  relaxations are probably associated with (i) local motions of the main chain (ii) motions of the carbonate group in the soft phase and (iii) reorientational motions of the water molecules. The microphase-separated morphology associated with soft and hard domains is reflected in the dielectric spectra, at high temperatures, by the presence of the Maxwell-Wagner-Sillars (MWS) interfacial polarization process.

“…Polyurethane solutions were obtained by a standard polymerization method based on the two−step process in DMAc (Costa, et al, 2012). In the first step one equivalent of polycarbonatediol PH was inserted in the reactor, previously dried for 24 h at 373 K, with three equivalents of MDI.…”

Section: Synthesis Of Vp/ba Copolymersmentioning

confidence: 99%

“…The soft segment is a polyol of molecular mass between 500 and 3000 g·mol -1 that provides high flexibility at room temperature. The hard segment is formed by a diisocyanate and a low-molecular-weight diol which provides physical crosslink sites through strong intermolecular hydrogen bonding (Strawhecker, et al, 2013;Costa, et al, 2012). The morphological, physical, chemical and mechanical properties of TPUs range in a wide spectrum, which depends on the hard segment formulation and content, molecular structure of soft segment and manufacturing conditions.…”

Section: Introductionmentioning

confidence: 99%

A contribution to the study of the molecular mobility in polymeric materials by Thermal and Dielectric Analysis

Foj¹,

Belén²

T h e s i s S u p e r v i s o r : P R O F . D r . M a r í a J e s ú s S a n c h i s S á n c h e z t o o b t a i n t h e d e g r e e o f D o c t o r o f P h i l o s o p h y a t t h e U n i v e r s i t a t P o l i t è c n i c a d e V a l è n c i a Prof. Dr. María Jesús Sanchis SánchezThe work presented in this thesis was carried out at the Universitat Politècnica de València and was financially supported by the Spanish Ministry of Economy and Competitiveness (Projects Nos. MAT2008-06725-C03-03 and MAT2012-33483)."Cuando quieres algo, todo el Universo conspira para que ACKNOWLEDGEMENTSTras estos años de trabajo, llega el momento de mostrar mi agradecimiento a todas las personas que me han acompañado y apoyado durante el desarrollo de mi tesis doctoral.En primer lugar, me gustaría expresar mi gratitud a mi directora de tesis María J.Sanchis por su inestimable ayuda durante todos estos años. Muchas gracias por confiar en mí, por darme esta oportunidad y por las incalculables horas invertidas tanto para el desarrollo de esta tesis como al mío propio.También me gustaría agradecer a mis estimadas compañeras Marta Carsí y Pilar Ortiz su ayuda y amistad en este largo recorrido que suponer realizar una tesis doctoral. He aprendido mucho de vosotras tanto científica como personalmente. En este punto, no puedo olvidarme de mi querida Aurora Alonso, que pese a no formar parte de nuestro grupo de investigación, me ha apoyado, aconsejado y dado su amistad durante todos estos años.Quiero mostrar mi agradecimiento a los profesores José M. García y Félix C. García ABSTRACTThe development of new and more complex polymeric materials involves challenging problems to basic sciences. The relationship between structure and molecular dynamics assumes great importance for the future development of novel technologies based on such polymers. Thus, the understanding of how small changes in the chemical structure affect the properties of the material is essential to progress in the technological and scientific area. An in-depth analysis of the molecular mobility leads to establish the structure-properties relationships. On this basis, the main aim of the present work is to study the molecular mobility of two different families of polymeric materials. For this purpose, the experimental techniques mainly used were Differential Scanning Calorimetry (DSC) and Dielectric Relaxation Spectroscopy (DRS) (Chapter 3).The first family of polymers characterized was a series of chemically cross-linked copolymers composed by Vinylpyrrolidone (VP) and Butyl Acrylate (BA) monomers. The study was divided in two parts, which are collected in Chapter 4 and 5.In the first place, Chapter 4 contains the influence of the monomer molar ratio (XVP/YBA) on the copolymer properties. Thus, a Fourier Transform Infrared Spectroscopy (FTIR) analysis verified dipole-dipole interactions between amide groups. The influence of these interactions on several parameters related to the molecular mobility was evidenced by the DSC, DRS and Dynamic Mechanical Analysis (DMA) techni...