scholarly journals Transparent sulfur-containing thermoplastic polyurethanes with polyether and polycarbonate soft segments

2017 ◽  
Vol 75 (3) ◽  
pp. 1211-1235 ◽  
Author(s):  
Magdalena Rogulska
Keyword(s):  
Thermoplastic Polyurethanes ◽  
Soft Segments ◽  
Sulfur Containing

scholarly journals Structural and Viscoelastic Properties of Thermoplastic Polyurethanes Containing Mixed Soft Segments with Potential Application as Pressure Sensitive Adhesives

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3097
Author(s):  
Mónica Fuensanta ◽  
José Miguel Martín-Martínez
Keyword(s):  
Phase Separation ◽  
Potential Application ◽  
Viscoelastic Properties ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Adhesion Properties ◽  
Pressure Sensitive Adhesives ◽  
Thermoplastic Polyurethanes ◽  
Pressure Sensitive ◽  
Soft Segments

Thermoplastic polyurethanes (TPUs) were synthetized with blends of poly(propylene glycol) (PPG) and poly(1,4-butylene adipate) (PAd) polyols, diphenylmethane-4,4′-diisocyanate (MDI) and 1,4-butanediol (BD) chain extender; different NCO/OH ratios were used. The structure and viscoelastic properties of the TPUs were assessed by infrared spectroscopy, differential scanning calorimetry, X-ray diffraction, thermal gravimetric analysis and plate-plate rheology, and their pressure sensitive adhesion properties were assessed by probe tack and 180° peel tests. The incompatibility of the PPG and PAd soft segments and the segregation of the hard and soft segments determined the phase separation and the viscoelastic properties of the TPUs. On the other hand, the increase of the NCO/OH ratio improved the miscibility of the PPG and PAd soft segments and decreased the extent of phase separation. The temperatures of the cool crystallization and melting were lower and their enthalpies were higher in the TPU made with NCO/OH ratio of 1.20. The moduli of the TPUs increased by increasing the NCO/OH ratio, and the tack was higher by decreasing the NCO/OH ratio. In general, a good agreement between the predicted and experimental tack and 180° peel strength values was obtained, and the TPUs synthesized with PPG+PAd soft segments had potential application as pressure sensitive adhesives (PSAs).

Improved dynamic properties of thermoplastic polyurethanes made from co‐monomeric polyester polyol soft segments based on azelaic acid

2021 ◽  
pp. 50815
Author(s):  
Tuan Noor Maznee Tuan Ismail ◽  
Nor Azowa Ibrahim ◽  
Kosheela Devi Poo Palam ◽  
Aisa Sendijarevic ◽  
Ibrahim Sendijarevic ◽  
...  
Keyword(s):  
Azelaic Acid ◽  
Dynamic Properties ◽  
Polyester Polyol ◽  
Thermoplastic Polyurethanes ◽  
Soft Segments

Thermoplastic Polyurethanes From Undecylenic Acid-Based Soft Segments: Structural Features and Release Properties

2013 ◽  
Vol 13 (5) ◽  
pp. 614-622 ◽  
Author(s):  
Cristina Lluch ◽  
Gerard Lligadas ◽  
Joan C. Ronda ◽  
Marina Galià ◽  
Virginia Cádiz
Keyword(s):  
Structural Features ◽  
Undecylenic Acid ◽  
Thermoplastic Polyurethanes ◽  
Soft Segments

Morphology and properties of thermoplastic polyurethanes with dangling chains in ricinoleate-based soft segments

Polymer ◽  
2008 ◽  
Vol 49 (19) ◽  
pp. 4248-4258 ◽  
Author(s):  
Yijin Xu ◽  
Zoran Petrovic ◽  
Sudipto Das ◽  
Garth L. Wilkes
Keyword(s):  
Thermoplastic Polyurethanes ◽  
Soft Segments

scholarly journals Structural, thermal and surface characterization of thermoplastic polyurethanes based on poly(dimethylsiloxane)

2014 ◽  
Vol 79 (7) ◽  
pp. 843-866 ◽  
Author(s):  
Marija Pergal ◽  
Ivan Stefanovic ◽  
Dejan Godjevac ◽  
Vesna Antic ◽  
Vesna Milacic ◽  
...  
Keyword(s):  
Surface Properties ◽  
Surface Characterization ◽  
Soft Segment ◽  
Hydrophobic Surface ◽  
Sem Analysis ◽  
Degree Of Crystallinity ◽  
Water Contact ◽  
Thermoplastic Polyurethanes ◽  
Melting Temperatures ◽  
Soft Segments

In this study, the synthesis, structure and physical properties of two series of thermoplastic polyurethanes based on hydroxypropyl terminated poly(dimethylsiloxane) (HP-PDMS) or hydroxyethoxy propyl terminated poly(dimethylsiloxane) (EO-PDMS) as a soft segment, and 4,4?-methylenediphenyl diisocyanate and 1,4-butanediol as a hard segment were investigated. Each series is composed of samples prepared with a different soft segment. The polyurethanes were synthesized by two-step polyaddition in solution. The effects of the type and content of PDMS segments on the structure, thermal and surface properties of copolymers were studied by 1H NMR, 13C NMR and two-dimensional NMR (HMBC and ROESY) spectroscopy, GPC, DSC, TGA, WAXS, SEM, water contact angle and water absorption measurements. Thermal properties investigated by DSC indicated that the presence of soft PDMS segments lowers the glass transition and melting temperatures of the hard phase as well as the degree of crystallinity. SEM analysis of copolymers with a lower soft segment content confirmed the presence of spherulite superstructures, which arise from the crystallization of the hard segments. When compared with polyurethanes prepared from HP-PDMS, copolymers synthesized from EO-PDMS with the same content of the soft segments have higher degree of crystallinity, better thermal stability and less hydrophobic surface. Our results show that the synthesized polyurethanes have good thermal and surface properties, which could be further modified by changing the type or content of the soft segments.

Methionine-Specific Staining of Collagen

1982 ◽  
Vol 40 ◽  
pp. 294-295
Author(s):  
E.M. Kuhn ◽  
K.D. Marenus ◽  
M. Beer
Keyword(s):  
Amino Acids ◽  
Collagen Fibers ◽  
Type Iii Collagen ◽  
Type I ◽  
Electron Microscopic ◽  
Good Correspondence ◽  
Specific Staining ◽  
Type Iii ◽  
Different Types ◽  
Sulfur Containing

Fibers composed of different types of collagen cannot be differentiated by conventional electron microscopic stains. We are developing staining procedures aimed at identifying collagen fibers of different types.Pt(Gly-L-Met)Cl binds specifically to sulfur-containing amino acids. Different collagens have methionine (met) residues at somewhat different positions. A good correspondence has been reported between known met positions and Pt(GLM) bands in rat Type I SLS (collagen aggregates in which molecules lie adjacent to each other in exact register). We have confirmed this relationship in Type III collagen SLS (Fig. 1).

Signal-regulated oxidation of proteins via MICAL

2020 ◽  
Vol 48 (2) ◽  
pp. 613-620
Author(s):  
Clara Ortegón Salas ◽  
Katharina Schneider ◽  
Christopher Horst Lillig ◽  
Manuela Gellert
Keyword(s):  
Signal Transduction ◽  
Hydrogen Peroxide ◽  
Cell Death ◽  
Redox Regulation ◽  
Signal Transduction Pathways ◽  
Cellular Functions ◽  
Intracellular Signals ◽  
Amino Acid Side Chains ◽  
Specific Receptors ◽  
Sulfur Containing

Processing of and responding to various signals is an essential cellular function that influences survival, homeostasis, development, and cell death. Extra- or intracellular signals are perceived via specific receptors and transduced in a particular signalling pathway that results in a precise response. Reversible post-translational redox modifications of cysteinyl and methionyl residues have been characterised in countless signal transduction pathways. Due to the low reactivity of most sulfur-containing amino acid side chains with hydrogen peroxide, for instance, and also to ensure specificity, redox signalling requires catalysis, just like phosphorylation signalling requires kinases and phosphatases. While reducing enzymes of both cysteinyl- and methionyl-derivates have been characterised in great detail before, the discovery and characterisation of MICAL proteins evinced the first examples of specific oxidases in signal transduction. This article provides an overview of the functions of MICAL proteins in the redox regulation of cellular functions.

Sign in / Sign up

Export Citation Format

Share Document