Polyurethanes Made with Blends of Polycarbonates with Different Molecular Weights Showing Adequate Mechanical and Adhesion Properties and Fast Self-Healing at Room Temperature.

Dynamic non-covalent interactions between polycarbonate soft segments have been proposed for explaining the intrinsic self-healing of polyurethanes synthesized with polycarbonate polyols (PUs) at 20 °C. However, these self-healing PUs showed insufficient mechanical properties, and their adhesion properties have not been explored yet. Different PUs with self-healing at 20 °C, acceptable mechanical properties, and high shear strengths (similar to the highest ones reported in the literature) were synthesized by using blends of polycarbonate polyols of molecular weights 1000 and 2000 Da (CD1000 + CD2000).

Polyurethanes Synthesized with Blends of Polyester and Polycarbonate Polyols-New Evidence Supporting the Dynamic Non-Covalent Exchange Mechanism of Intrinsic Self-Healing at 20 °C.

Polyurethanes (PUs) synthesized with blends of polycarbonate and polyester polyols (CD+PEs) showed intrinsic self-healing at 20 °C. The decrease in the polycarbonate soft segments content increased the self-healing time and reduced the kinetics of self-healing of the PUs. The percentage of C-O species decreased and the ones of C-N and C=O species increased by increasing the polyester soft segments in the PUs, due to higher micro-phase separation.

Influence of the Molecular Weight of the Polycarbonate Polyol on the Intrinsic Self-Healing at 20 °C of Polyurethanes.

Different polyurethanes (PUs) were synthesized with polycarbonate polyols of molecular weights of 500, 1000, and 2000 Da. Their self-healing abilities at 20 °C were tested, and their structural, thermal, and mechanical properties were analyzed. The PUs made with polycarbonates of molecular weights 500 (YC500) and 1000 Da (YC1000) exhibited self-healing at 20 °C, and the self-healing time of YC1000 was the shortest.

Dynamic Non-Covalent Exchange Intrinsic Self-Healing at 20 °C Mechanism of Polyurethane Induced by Interactions among Polycarbonate Soft Segments.

Two polyurethanes (PUs) were similarly synthesized by reacting a cycloaliphatic isocyanate with 1,4-butanediol and two polyols of different nature (polyester, polycarbonate diol) with molecular weights of 1000 Da. Only the PU synthesized with polycarbonate diol polyol (YCD) showed intrinsic self-healing at 20 °C. For assessing the mechanism of intrinsic self-healing of YCD, a structural characterization by molecular weights determination, infrared and X-ray photoelectronic spectroscopies, differential scanning calorimetry, X-ray diffraction, thermal gravimetric analysis, and dynamic mechanical thermal analysis was carried out.

Understanding the Interactions between Soft Segments in Polyurethanes: Structural Synergies in Blends of Polyester and Polycarbonate Diol Polyols.

There are no previous studies on the interactions between polyols of different nature as a model for understanding the interactions between soft segments in PUs. In this study, different blends of two polyols of different natures (polyester-PE, and polycarbonate diol-CD) and similar molecular weights were prepared and their structural, thermal, surface, viscoelastic, and self-adhesion properties were assessed. Different experimental techniques were used: infrared spectroscopy (ATR-IR), differential scanning calorimetry (DSC), X-ray diffraction, thermal gravimetric analysis (TGA), and plate-plate rheology.

Innovative Device and Procedure for In Situ Quantification of the Self-Healing Ability and Kinetics of Self-Healing of Polymeric Materials.

A new device and procedure for the in situ quantification of the extent of the self-healing and the kinetics of self-healing of polymeric materials were proposed. The device consisted of flowing an inert gas below the sample placed in a hermetically closed chamber. When the sample was perforated/damaged, the gas passed through the hole made in the polymeric material and the gas flow rate declined as the self-healing was produced.

Efficient Physical Mixing of Small Amounts of Nanosilica Dispersion and Waterborne Polyurethane by Using Mild Stirring Conditions.

Good dispersion of nanosilica particles in waterborne polyurethane was obtained by mild mechanical stirring when 0.1-0.5 wt.

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

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.

Influence of the Surface Chemistry of Graphene Oxide on the Structure-Property Relationship of Waterborne Poly(urethane urea) Adhesive.

Small amounts-0.04 wt.%-graphene oxide derivatives with different surface chemistry (graphene oxide-GO-, amine-functionalized GO-A-GO-, reduced GO-r-GO) were added during prepolymer formation in the synthesis of waterborne poly(urethane urea) dispersions (PUDs).

Structure-Properties Relationship in Waterborne Poly(Urethane-Urea)s Synthesized with Dimethylolpropionic Acid (DMPA) Internal Emulsifier Added before, during and after Prepolymer Formation.

Dimethylolpropionic acid (DMPA) internal emulsifier has been added before, during and after prepolymer formation in the synthesis of waterborne poly(urethane-urea)s (PUDs) and their structure-properties relationships have been assessed. PUDs were characterized by pH, viscosity and particle size measurements, and the structure of the poly(urethane-urea) (PU) films was assessed by infra-red spectroscopy, differential scanning calorimetry, X-ray diffraction, thermal gravimetric analysis, plate-plate rheology and dynamic mechanical thermal analysis. The adhesion properties of the PUDs were measured by cross-hatch adhesion and T-peel test.

Addition of Graphene Oxide in Different Stages of the Synthesis of Waterborne Polyurethane-Urea Adhesives and Its Influence On Their Structure, Thermal, Viscoelastic and Adhesion Properties.

In this study, 0.04 wt % graphene oxide (GO) was added in different stages (before and after prepolymer formation, and during water addition) of the synthesis of waterborne polyurethane-urea dispersions (PUDs) prepared by using the acetone method. The structural, thermal, mechanical, viscoelastic, surface and adhesion properties of the polyurethane-ureas (PUUs) containing 0.

New Waterborne Polyurethane-Urea Synthesized with Ether-Carbonate Copolymer and Amino-Alcohol Chain Extenders with Tailored Pressure-Sensitive Adhesion Properties.

New waterborne polyurethane-urea dispersions with adequate adhesion and cohesion properties have been synthesized by reacting isophorone diisocyanate, copolymer of ether and carbonate diol polyol and three amino-alcohols with different number of OH groups chain extenders using the prepolymer method. The waterborne polyurethane-urea dispersions were characterized by pH, particle-size distribution, and viscosity, and the polyurethane-urea films were characterized by attenuated total reflectance infrared (ATR-IR) spectroscopy, differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), and plate-plate rheology (temperature and frequency sweeps). Polyurethane-urea pressure-sensitive adhesives (PUU PSAs) were prepared by placing the waterborne polyurethane dispersions on polyethylene terephthalate (PET) films and they were characterized at 25 °C by creep test, tack and 180° peel test.

Balanced Viscoelastic Properties of Pressure Sensitive Adhesives Made with Thermoplastic Polyurethanes Blends.

Pressure sensitive adhesives made with blends of thermoplastic polyurethanes (TPUs PSAs) with satisfactory tack, cohesion, and adhesion have been developed. A simple procedure consisting of the physical blending of methyl ethyl ketone (MEK) solutions of two thermoplastic polyurethanes (TPUs) with very different properties-TPU1 and TPU2-was used, and two different blending procedures have been employed. The TPUs were characterized by infra-red spectroscopy in attenuated total reflectance mode (ATR-IR spectroscopy), differential scanning calorimetry, thermal gravimetric analysis, and plate-plate rheology (temperature and frequency sweeps).

Comparative Adhesion, Ageing Resistance, and Surface Properties of Wood Plastic Composite Treated with Low Pressure Plasma and Atmospheric Pressure Plasma Jet.

Wood plastic composites (WPCs) have poor adhesion properties due to their high surface concentration in non-polar polymers. In this work, two different plasma surface treatments, low pressure plasma (LPP) and atmospheric pressure plasma jet (APPJ), are proposed to increase the surface energy and adhesion property of WPC made with polyethylene (PE-WPC). After optimizing the conditions for each plasma surface treatment, the surface modifications and adhesion of PE-WPC treated with LPP and APPJ were compared.

New Binary Blends of Ethylene-co-n-butyl Acrylate (EBA) Copolymer and Low Molecular Weight Rosin Ester Resin with Potential as Pressure Sensitive Adhesives.

For improving the adhesion property of ethylene-co-n-butyl acrylate copolymer (EBA) at ambient temperature, binary blends of EBA with 27 wt% n-butyl acrylate and different amounts (20⁻62 wt%) of low molecular weight hydrogenated glycerol rosin ester (ECH) resin have been prepared. The addition of glycerol rosin ester resin decreased the crystallinity and size of the ethylene domains of the EBA copolymer. The addition of up to 50 wt% (100 phr) ECH resin improved the compatibility with the EBA copolymer, whereas when more than 50 wt% (100 phr) ECH resin was added, the compatibility of the blends did not change but the viscoelastic properties were noticeably decreased.

Ethanol-induced symptoms in patients receiving gemcitabine diluted from a concentrate for solution for infusion containing ethanol.

Purpose Ethanol as an excipient is used to enhance the solubility of gemcitabine, but, sometimes, the dose of ethanol a patient may be given is much higher than the dose considered to be toxic. We aimed to assess ethanol-related symptoms and signs in patients receiving two formulations of gemcitabine, with and without ethanol. Methods A randomized double blind cross-over study was conducted.

Estimation of polyurethane-carbon black interactions by means of inverse gas chromatography.

The properties of composites depend mainly on the interfacial interactions between filler and matrix that can be related to the adhesion between filler and polymer matrix. In this study the work of cohesion between the carbon black particles - Wcoh - and the thermodynamic work of adhesion - Wa - between four carbon blacks of different specific surface area and surface chemistry (nature and content of carbon-oxygen functional groups) and thermoplastic polyurethane were calculated by means of inverse gas chromatography (IGC) at infinite dilution. IGC derived data indicated that the work of adhesion increased by increasing the surface area of the carbon black, but the opposite trend was found in Wa/Wcoh and work of cohesion.