scholarly journals Synthesis and Properties of Novel Polyurethanes Containing Long-Segment Fluorinated Chain Extenders

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1292 ◽  
Author(s):  
Jia-Wun Li ◽  
Hsun-Tsing Lee ◽  
Hui-An Tsai ◽  
Maw-Cherng Suen ◽  
Chih-Wei Chiu
Keyword(s):  
Hard Segment ◽  
Soft Segment ◽  
Mechanical Analysis ◽  
Chain Extender ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Atomic Force ◽  
Chain Extenders ◽  
Relationship Of ◽  
The Relationship

In this study, novel biodegradable long-segment fluorine-containing polyurethane (PU) was synthesized using 4,4′-diphenylmethane diisocyanate (MDI) and 1H,1H,10H,10H-perfluor-1,10-decanediol (PFD) as hard segment, and polycaprolactone diol (PCL) as a biodegradable soft segment. Nuclear magnetic resonance (NMR) was used to perform 1H NMR, 19F NMR, 19F–19F COSY, 1H–19F COSY, and HMBC analyses on the PFD/PU structures. The results, together with those from Fourier transform infrared spectroscopy (FTIR), verified that the PFD/PUs had been successfully synthesized. Additionally, the soft segment and PFD were changed, after which FTIR and XPS peak-differentiation-imitating analyses were employed to examine the relationship of the hydrogen bonding reaction between the PFD chain extender and PU. Subsequently, atomic force microscopy was used to investigate the changes in the microphase structure between the PFD chain extender and PU, after which the effects of the thermal properties between them were investigated through thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis. Finally, the effects of the PFD chain extender on the mechanical properties of the PU were investigated through a tensile strength test.

Effect of cooling induced crystallization upon the properties of segmented thermoplastic polyurethanes

2017 ◽  
Vol 37 (5) ◽  
pp. 471-480 ◽  
Author(s):  
Daniel Ramirez ◽  
Juliana Nanclares ◽  
Marisa Spontón ◽  
Mara Polo ◽  
Diana Estenoz ◽  
...  
Keyword(s):  
Hard Segment ◽  
Chain Extender ◽  
Thermal Transitions ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Thermoplastic Polyurethanes ◽  
Dsc Measurements ◽  
Atomic Force ◽  
Hard Segment Content ◽  
Induced Crystallization

Abstract An investigation on the cooling-induced crystallization in three thermoplastic polyurethanes based on MDI, PTMG, and 1.4-BD as chain extender with different hard segment content is reported. Thermal transitions were determined using differential scanning calorimetry (DSC) measurements at different cooling rates, and thermal stability was studied by thermogravimetric analysis. Changes in Raman spectra were useful to correlate the thermal transitions with changes in the morphology of the polymers. The dissimilarity in the composition gave different rheological behavior in the molten state, indicated by the temperature dependence of the viscosity. The mechanical properties and the crystallinity was influenced not only by the cooling rate but also by the hard segment content. Thermoplastic polyurethanes with more hard segment content formed more crystalline hard domains as evidenced by the DSC and atomic force microscopy results.

scholarly journals Preparation, Thermal, and Thermo-Mechanical Characterization of Polymeric Blends Based on Di(meth)acrylate Monomers

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 878
Author(s):  
Krystyna Wnuczek ◽  
Andrzej Puszka ◽  
Łukasz Klapiszewski ◽  
Beata Podkościelna
Keyword(s):  
Mechanical Analysis ◽  
Attenuated Total Reflection ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Chemical Structures ◽  
Atomic Force ◽  
Polymeric Blends ◽  
Ft Ir ◽  
Acrylate Monomers ◽  
Synthesized Materials

This study presents the preparation and the thermo-mechanical characteristics of polymeric blends based on di(meth)acrylates monomers. Bisphenol A glycerolate diacrylate (BPA.GDA) or ethylene glycol dimethacrylate (EGDMA) were used as crosslinking monomers. Methyl methacrylate (MMA) was used as an active solvent in both copolymerization approaches. Commercial polycarbonate (PC) was used as a modifying soluble additive. The preparation of blends and method of polymerization by using UV initiator (Irqacure® 651) was proposed. Two parallel sets of MMA-based materials were obtained. The first included more harmless linear hydrocarbons (EGDMA + MMA), whereas the second included the usually used aromatic copolymers (BPA.GDA + MMA). The influence of different amounts of PC on the physicochemical properties was discussed in detail. Chemical structures of the copolymers were confirmed by attenuated total reflection–Fourier transform infrared (ATR/FT-IR) spectroscopy. Thermo-mechanical properties of the synthesized materials were investigated by means of differential scanning calorimetry (DSC), thermogravimetric (TG/DTG) analyses, and dynamic mechanical analysis (DMA). The hardness of the obtained materials was also tested. In order to evaluate the surface of the materials, their images were obtained with the use of atomic force microscopy (AFM).

Effect of Catalysts on the Properties of Fluorinated Polyurethanes

2013 ◽  
Vol 464 ◽  
pp. 9-13 ◽  
Author(s):  
Zan Li ◽  
Xia Wang ◽  
Ying Li ◽  
Wei Chain ◽  
Jiao Jiao Hu
Keyword(s):  
Hard Segment ◽  
Soft Segment ◽  
Force Microscopy ◽  
Atomic Force ◽  
Structure Surface ◽  
Improved Stability ◽  
Ft Ir ◽  
Tin Metal ◽  
Polyether Polyol ◽  
Catalyst Efficiency

Fluorinated polyurethanes (FPU) was prepared using fluorinated polyether polyol (FPO) as the soft segment, 4,4`-diphenylmethane diisocyanate (MDI) as the hard segment, 1,4-butanodiol (BDO) as the chain extender and catalysts. Tin metal catalysts were used to catalyze the polyurethane reaction of polyether polyols and isocyanate. The effect of different catalysts including stannous octoate (T-9) and dibutyltindalautrate (DBTDL) on the structure, surface properties and thermal properties of FPU was studied. The structural elucidation of the synthesized FPU was performed by Fourier transform infrared (FT-IR) and discovered that with decreasing catalyst efficiency or without catalyst, the strength of hydrogen bounds were enhanced. The FPU films surface was characterized by contact angle (CA) and atomic force microscopy (AFM) and it was found that the phase separation was increasing with increasing catalyst efficiency. The thermal property was exhibited by Thermo gravimetric (TG) and showed that joining catalyst improved stability significantly.

scholarly journals New thermoplastic poly(carbonate-urethane) elastomers

2011 ◽  
Vol 13 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Anna Kultys ◽  
Magdalena Rogulska
Keyword(s):  
Soft Segment ◽  
Tensile Tests ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Melt Polymerization ◽  
Atomic Force ◽  
Amorphous Structures ◽  
A Chain ◽  
Poly Carbonate

New thermoplastic poly(carbonate-urethane) elastomersTwo series of novel thermoplastic poly(carbonate-urethane) elastomers, with different hard-segment content (30 - 60 wt %), were synthesized by melt polymerization from poly(hexane-1,6-diyl carbonate) diol of Mn= 2000 as a soft segment, 4,4'-diphenylmethane diisocyanate (MDI) or hexane-1,6-diyl diisocyanate (HDI) and 6,6'-[methylenebis(1,4-phenylenemethylenethio)]dihexan-1-ol as a chain extender. The structure and basic properties of the polymers were examined by Fourier transform infrared spectroscopy, X-ray diffraction analysis, atomic force microscopy, differential scanning calorimetry, thermogravimetric analysis, Shore hardness and tensile tests. The resulting TPUs were colorless polymers, showing almost amorphous structures. The MDI-based TPUs showed higher tensile strengths (up to 21.3 MPa vs. 15.8 MPa) and elongations at break (up to 550% vs. 425%), but poorer low-temperature properties than the HDI-based analogs.

Nanoscale anisotropic Orientation in Shape Memory Random POSS/Polycaprolactone Nanocomposites

2013 ◽  
Vol 1453 ◽  
Author(s):  
Bonifacio Alvarado-Tenorio ◽  
Angel Romo-Uribe ◽  
Patrick T. Mather
Keyword(s):  
Shape Memory ◽  
Mechanical Analysis ◽  
Molar Concentration ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Atomic Force ◽  
Weak Reflection ◽  
One Step ◽  
Crosslinked Networks ◽  
Saxs Analysis

ABSTRACTShape memory nanocomposites were produced following a simple one-step synthesis route initiated by a series of molar mixtures of POSS thiol nanocages and pentaerythritol tetrakis (3mercaptopropionate), and a diacrylate polycaprolactone (PCL) with Mn=3,000 g/mol. Simultaneous wide- and small- angle X ray scattering (WAXS/SAXS), differential scanning calorimetry (DSC) and atomic force microscopy (AFM) experiments were carried out and results were correlated on microstructure. Molecular identification was performed by Fourier transformed infrared (FTIR-ATR). Thermomechanical shape memory cycles revealed that the nanocomposites achieved excellent shape recovery (99%) and shape fixity (100%) parameters. Dynamic mechanical analysis showed that elastomeric modulus decrease in function of the POSS thiol molar concentration and this result is correlated with the decrease in average crosslink density (ν). WAXS studies revealed orthorhombic crystallites for PCL combined with an amorphous POSS phase when the molar concentration of POSS was low (2.5%, 5%, 10%). However, increasing the molar concentration of POSS thiol until 20%, a broad and weak reflection centered around 2θ =7.9° which corresponded to imperfect POSS crystals. At the nanoscale, SAXS analysis showed lamellar nanostructure formation for all POSS/polycaprolactone crosslinked networks. Strikingly, induced anisotropic orientation of polycaprolactone lamellar nanostructure was observed when the concentration of POSS increased to 10 and 20 mol%.

scholarly journals Shape memory polyurethanes based on recycled polyvinyl butyral. I. Synthesis and morphology

2013 ◽  
Vol 11 (12) ◽  
pp. 2058-2065 ◽  
Author(s):  
Tsvetomir Tsonev ◽  
Michael Herzog ◽  
Sanchi Nenkova
Keyword(s):  
Shape Memory ◽  
Hard Segment ◽  
Soft Segment ◽  
Polyvinyl Butyral ◽  
Mechanical Analysis ◽  
Attenuated Total Reflection ◽  
Polypropylene Glycol ◽  
Scanning Calorimetry ◽  
Chemical Crosslinks ◽  
Physical And Chemical

AbstractShape memory polyurethanes (SMPUs) were synthesized by 4,4′-diphenylmethane diisocyanate (MDI), hexane-1,6-diol (HD), polypropylene glycol (PPG), and recycled polyvinyl butyral (PVB). Dynamic mechanical analysis, differential scanning calorimetry and Fourier transformation infrared attenuated total reflection spectroscopy was used to characterize the poly (vinylbutyral-urethanes). Micro-phase domain separation of hard and soft segments and phase inversion were investigated. Increasing the hard segment content, i.e., average hard segment molecular weight, leads to an increase in the degree of micro-phase separation, hard domain order and crystallinity. The crystalline hard segment structures combined with the elastic nature of soft segment matrix provide enough physical and chemical crosslinks to have shape memory effect.

Effect of Process Variables and Dopants on Characteristics of Electrochemically-Deposited Pedot Films

2002 ◽  
Vol 736 ◽  
Author(s):  
Mihir A. Oka ◽  
Stephen S. Hardaker ◽  
Farzad Nazir ◽  
Richard V. Gregory ◽  
Keith R. Brenneman ◽  
...  
Keyword(s):  
Electrode Materials ◽  
Morphological Structure ◽  
Constant Current ◽  
Process Variables ◽  
Residual Solvent ◽  
Force Microscopy ◽  
Atomic Force ◽  
Electrochemically Deposited ◽  
Relationship Of ◽  
The Relationship

ABSTRACTPoly(3,4-ethlyenedioxythiophene), PEDOT, has found wide use in applications such as electrostatic coatings, antistatic layers and electrode materials in electronic devices. Electrochemical deposition of PEDOT is a prominent means of obtaining thin, uniform films. However, the relationship of these films' properties to their morphological structure is still poorly understood. We have prepared PEDOT films by electrochemical oxidation of monomer (3,4-ethylenedioxythiophene), EDOT, under constant current conditions, employing a variety of electrolytes, and processing conditions. We report the effect of using different dopants, deposition time, deposition temperature and current density on the observed conductivity of PEDOT films. Atomic force microscopy studies were carried out to determine the possible effect of the process variables on the resulting film morphology. Also, the effect of residual solvent on the conductivity of the films was studied by thermogravimetric analysis (TGA).

Photochemical Reactivity of Sr2Nb2O7 and Sr2Ta2O7 as a Function of Surface Orientation

2002 ◽  
Vol 755 ◽  
Author(s):  
Jennifer L. Giocondi ◽  
Ariana M. Zimbouski ◽  
Gregory S. Rohrer
Keyword(s):  
Perovskite Structure ◽  
Orientation Dependence ◽  
Layered Perovskite ◽  
Reaction Products ◽  
Force Microscopy ◽  
Atomic Force ◽  
Wide Range ◽  
Layered Perovskite Structure ◽  
Relationship Of ◽  
The Relationship

ABSTRACTSr2Nb2O7 and Sr2Ta2O7 have a (110) layered perovskite structure and are efficient photolysis catalysts. Aqueous silver and lead cations were photochemically reduced and oxidized, respectively, on the surfaces of Sr2Nb2O7 and Sr2Ta2O7 crystals with a wide range of orientations. Atomic force microscopy has been used to observe the distribution of photochemically reduced and oxidized products and determine the orientation dependence of the reactivity. On surfaces with the same orientation, reaction products frequently had a non-uniform distribution. The reactivity of both compounds proved to be only weakly anisotropic, with the highest relative reactivity for both oxidation and reduction occurring for surfaces oriented between (010), (110), and (011). These low index orientations have structures similar to the ideal {110} and {100} planes in the perovskite structure, respectively. The relationship of the perovskite structure to the reactivity is discussed.

HIV infection changes glomerular podocyte cytoskeletal composition and results in distinct cellular mechanical properties

2007 ◽  
Vol 292 (2) ◽  
pp. F701-F710 ◽  
Author(s):  
R. Tandon ◽  
I. Levental ◽  
C. Huang ◽  
F. J. Byfield ◽  
J. Ziembicki ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Characteristics ◽  
Stress Fibers ◽  
Wild Type ◽  
Force Microscopy ◽  
Hemodynamic Forces ◽  
Filtration Barrier ◽  
Atomic Force ◽  
Relationship Of ◽  
The Relationship

In addition to forming the selective filtration barrier for the renal glomerulus, podocytes maintain glomerular capillary architecture by opposing distending hemodynamic forces. To understand the relationship of cytoskeletal properties and the mechanical characteristics of podocytes, we studied filamin expression and distribution and measured cell membrane deformability in conditionally immortalized wild-type (WT) mouse podocytes, and in podocytes derived from a mouse model of HIV-associated nephropathy (HIVAN). In the WT cells, filamin and F-actin were localized at the periphery and in prominent stress fibers. In the HIVAN cells, filamin expression was reduced, and stress fibers were sparse. In a microaspiration assay, HIVAN cells ruptured under minimal negative pressure. Atomic force microscopy demonstrated that the WT cells had a stiffness of 17 kPa, whereas the value for the HIVAN cells was 4 kPa. These results demonstrate that the mechanical properties of WT and HIVAN podocytes are markedly different in a manner that is consistent with differences in the composition and arrangement of their cytoskeletons. The mechanical properties of the WT podocytes suggest that these cells can better maintain capillary integrity than the HIVAN podocytes and implicate pathological assembly of the cytoskeleton as a mechanism of HIVAN.

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