2 edition of Strained polycarbonate-polyurethanes with linear and branched diisocyanates found in the catalog.
Strained polycarbonate-polyurethanes with linear and branched diisocyanates
Laura Ruth Kuhn
Written in English
This thesis investigates linear (hexane diisocyanate, HDI) versus branched (lysine diisocyanate, LDI) hard segments, and strain effects on hydrogen bonding (HB) and biodegradation in two 14C-materials. One contained pure HDI hard-segments (100%HDI) and the other (75%HDI) was a 3:1 blend of two polymers: 100%HDI and 100%LDI (polymer containing only LDI hard-segments). HB was determined using infrared spectroscopy (under strain, 0-15%). Biodegradation was conducted by exposing polymer films at the above strains to a macrophage-like cell line and 14C-release monitored. With higher molecular weight materials (>105 polystyrene equiv.), 75%HDI degraded < 100%HDI (p < 0.05). With lower molecular weight materials than the above, 75%HDI degraded six times > 100%HDI (p < 0.05). No statistical differences in degradation were found for the strain levels despite their evident differences in HB. Mathematical modeling of intramolecular interactions suggested that chain rearrangements for hard and soft segments accounted for the observations in the degradation studies.
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USA US09/, USA USA US A US A US A US A US A US A US A US A US A Authority US United States Prior art keywords polymer mixture tde stirred oxidation Prior art date Legal status (The legal status is an assumption and is not a legal conclusion. Polyurethanes (PU) are produced through a complex synthesis between isocyanates (with at least 2 -N=C=O groups in the molecule) and polyols (with 2 or more hydroxyl groups, -OH, in the molecule), in the presence of suitable catalysts (systems based on aliphatic amines and/or organic tin salts).
Markets & Applications Add value to your polyurethane material coatings, adhesives or polymers by using ETERNACOLL ® polycarbonate diols and ETERNATHANE ® polycarbonate-based urethane prepolymers!. The customizable nature of these products gives you the best of the outstanding properties required to meet your business needs for high performance and durability across your Polyurethane. Because a variety of diisocyanates and a wide range of polyols can be used to produce polyurethane, a broad spectrum of materials can be produced to meet the needs of specific applications. It does not matter where you look, you are likely to find polyurethanes. Polyurethanes can be a found in mattresses, couches, insulation, liquid coatings.
2. diisocyanates 3. short-chain diols The polyols and the short-chain diols react with the diisocyanates through polyaddition to form linear polyurethane. Flexible segments are created by the reaction of the polyol with the diisocyanate. The combination of diisocyanate with short-chain diol produces the rigid component (rigid segment). The key difference between polyurethane and polycarbonate is that polyurethane has urethane linkages whereas polycarbonate has carbonate groups.. Both polyurethane and polycarbonates are polymer compounds having a complex structure containing a large number monomers. Most of the times, we name the polymer material depending on the type of monomer(s) used in the production.
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"Linear Polyurethanes - Synthesis Methods, Chemical Structures, Properties and Applications presents exhaustive information on linear polyurethanes.
The book contains over references and is useful for experts involved in detail process issues as well as for researchers in Format: Hardcover. Accompanied by over references, the author presents synthesis methods, physicochemical properties of linear polyurethanes (analyzed with DCS, TG, DMTA, Rtg, AFM microscopy methods) as semiproducts for foams, elastomers, lacquers and coatings.
Research results concerning free surface energy of the polyurethane coatings are also presented. The study was conducted on linear and branched polyurethanes prepared from oligoetherol, urea, phenolsulfonic acid, 2-hydroxynaphthalenesulfonic acid and various amounts of formaldehyde.
The tensile strength, pH, emulsification and protein concentration were determined during the biodegradation of the prepared by: 1.
Polyurethanes are plasticizer-free, segmented polymers comprised of alternating soft and hard segments. In life science applications, the soft segments are typically formed from polyester, polyether, or polycarbonate diols with low glass transition Size: 1MB.
A linear isotactic polypropylene and two branched polypropylenes were considered. The uniaxial extensional viscosity was quantified and the foam characterized based on bulk density, cell size, and cell concentration.
The linear polymer exhibits no strain hardening, while both branched polymers show pronounced strain by: Introduction. Isocyanates are comparatively reactive materials due to the strained bonding of the N C O group. This leads to a variety of reactions with different, so-called active hydrogen-containing reactants, including alcohols, amines, water, carboxylic acids, ureas, and urethanes; isocyanates will also most important reaction commercially is that of an isocyanate with.
synthesis and reactivity of new organosilicon compounds applications in materials and polymer science trends in silicone chemistry summary of the latest (!) knowledge in this area Keep up-to-date in this steadily developing field with the latest issue of "Organosilicon Chemistry".
POLYURETHANES - SUSTAINABLE MATERIALS THETRIPLE JUMP # The FAO5 estimate that 24 billion tonnes of topsoil are removed each year, while UNFPA1 report that 7 million hectares of crop and grazing land are lost to erosion, desertification and salification each year.
FAO also report that 40% of. At stoichiometric use of diisocyanates and diols (macrodiols and chain extender taken together) linear segmented polyurethanes are created with thermoplastic properties (TPU).
Thus, TPU products are produced from earlier synthesized polymers in the form of granules. Nonisocyanate polyurethanes (NIPU) are a solution for the problem of toxicity, moisture sensitivity and phosgene-based synthesis of diisocyanates and polyisocyanates.
Industrially, polyurethanes are produced by the reaction of diisocyanates, polyols and a low molecular weight chain extender. Transparent thermoplastic polyurethanes based on aliphatic diisocyanates and polycarbonate diol Article in Journal of Elastomers and Plastics 49(1) April with 86 Reads How we measure 'reads'.
Polyurethanes are plastic polymers made by combining diisocyanates (TDI and MDI) and polyols. There are literally hundreds of different types of polyurethanes and each is made in a slightly different way: Carbon dioxide is used as a blowing agent to create the soft, comfortable feel of a mattress or sofa.
10 Polyurethane Basic Products – Isocyanates and polyols for versatile polymers Product Functionality OH number [mgKOH/g] Molecular weight [g/mol] Viscosity at 25°C [mPa*s] Description Lupranol /1 2 55 2, Linear polypropylene glycol.
KOH catalyzed. Lupranol /2 2 55 2, Linear polypropylene glycol. DMC catalyzed. Studies on the morphology, properties and biocompatibility of aliphatic diisocyanate-polycarbonate polyurethanes Article in Polymer Degradation and Stability November with Reads. Linear hydroxyl-bearing medium viscosity polyester resin (solvent-free) 3 ± ∼1, Mondur® TDS/Bayer Materials Science: Toluene diisocyanate (TDI) (mixture of 98% 2,4 and 2% 2,6 isomers) N/A: N/A: Desmophen® /Bayer Materials Science: Slightly branched polyester polyol (solvent-free) 82 + N/A: Mondur® MR/Bayer Materials Science.
An unsaturated terminal diol, 1,octadecendiol (ODEDO), and a saturated terminal diol, 1,9-nonanediol (NDO), were synthesized from oleic acid. The feasibility of utilizing these new diols for the production of thermoplastic polyurethanes (TPUs) was demonstrated by reacting them with a fatty acid-derived diisocyanate, 1,7-heptamethylene diisocyanate (HPMDI), and a commercially available.
Polymers and Composite Resins from Plant Oils. architecture can be controlled to produce linear, branched, or cross-linked polymers. and crosslinked with sulfur or diisocyanates to form. A series of coumarin-containing branched polyurethanes based on polycaprolactones, hexamethylene diiso- cyanate and a monohydroxylated coumarin monomer with 5.
In Polymer Science and Technology. within branch chains produce PUs ranging from linear to branched and flexible to rigid.
elasticity then produces stress–strain isotherms suitable for. Quasi static experiments were conducted at three strain rates: /s, /s, and /s. Figure 2 shows a representative stress strain curve at each rate.
All three stress-strain curves in the figure display similar behaviors. First, stress increases nonlinearly up to a peak strain of ~ mm/mm. It is assumed that this behavior is visco.
AbstractThe correlation between properties and the network structure of hydroxyl terminated polybutadiene (HTPB) based polyurethanes (PUs) was studied through linear and branched structure polymer matrixes formed by toluene diisocyanate (TDI) and an aliphatic polyisocyanate curing agent (N).
The curing reactions were monitored using differential scanning calorimetry (DSC) and .The Benefits of Polyurethanes in Transportation INTRODUCTION This factsheet describes the important and growing role of polyurethanes (PU) in a very wide range of applications in vehicles and transportation.
The main benefits which polyurethanes bring are comfort, safety, weight saving and longevity coupled with design freedom.Polyurethanes are all around us. They are one of the most versatile groups of plastics. They are innovative and durable. This website will help you discover more about polyurethanes.
It will show you how they play a vital role not only in making our lives more comfortable and convenient, but also in conserving our planet's precious natural.