A comparative study of new linear and hyperbranched polyurethanes built up from a synthesized isocyanate-terminated polyester/urethane

Morsi, Samir M. M.; Mohamed, Heba A.

doi:10.1007/s00289-017-1996-0

Cited by 18 publications

(7 citation statements)

References 30 publications

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“…The presence of C–O and C–O–C bending are observed at 1226 and 1157 cm −1 , which confirms the formation of pre-polymer. The absence of a peak at 2276–240 cm −1 indicates the total consumption of isocyanate groups in the reaction (Morsi and Mohamed, 2017).…”

Section: Resultsmentioning

confidence: 99%

“…The TGA studies indicate the mass loss due to urethane link breakage from 285°C ( T i ) to 456°C (T s ). The second and third successive steps are ascribed to the ester group decomposition at 451°C–505°C ( T f ) (Morsi and Mohamed, 2017). The percentage ratio of urethane and ester loss is 81.1% and 11.54%, respectively, where the high percentage of urethane indicates large amounts of urethane linkage formed during polymerisation (Trovati et al, 2010).…”

Section: Resultsmentioning

confidence: 99%

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Mechanically strong and resilient shape memory polyurethane with hexamethylene diisocyanate as mixing segment

Mohanty

Garg

Gupta

et al. 2020

Journal of Intelligent Material Systems and Structures

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Mechanical robustness and flexibility of shape memory polyurethane (SMPU) make them a prominent candidate in various field. However, the shape memory characteristics are hampered due to the lower breaking stress and strain originating from the slippage of hard segments during deformation and entropic elasticity of the segments. Herein, SMPU is synthesised by modification of Polycaprolactone diol (PCL) based soft segment by introducing a linear chain diisocyante, that is hexamethylene diisocyanate (HDI) as the mixing segment and rigid MDI (4,4′-methylene bis-phenyl diisocyanate) as the hard segment. The HDI based soft segment is expected to improve the chain flexibility, and MDI will retain the strength factor. The SMPU is characterised by chemical, structural and thermal analysis. The stress relaxation behaviour of the film was analysed w.r.t time and correlated with recovery studies using the Maxwell model. The thermomechanical conditions are optimised to attain higher shape fixity (SF) and shape recovery (SR) and the SMPU shows maximum SF (60.8%) and SR (97%) at 70°C temperature and 50% strain condition. Also, SMPU shows the tensile strength of 23.4 MPa with elongation at break of nearly 1270%. Thus, the combination of both diisocyanate and soft segments imparts strength and ductility to the SMPU.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Mechanically strong and resilient shape memory polyurethane with hexamethylene diisocyanate as mixing segment

Mohanty

Garg

Gupta

et al. 2020

Journal of Intelligent Material Systems and Structures

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show abstract

“…This general increase in Tg of the films after each uploading of PANI chains in the styrene-acrylate matrix could be attributed to the physical interactions generated between PANI chains and poly(styrene-co-butyl acrylate) chains [19]. Such physical interactions, including H-bonds, CH-π, polar-π, π-π, and Ar-Ar interactions, restrict the segmental motions of the polymeric chains and rose the Tg of the film [20,21].…”

Section: Analytical Testsmentioning

confidence: 99%

Polyaniline emulsion as a passivator in styrene-acrylate waterborne coatings for the protection of carbon steel against corrosion

Morsi¹,

Khorshed

Samaan³

et al. 2019

Egypt. J. Chem.

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T HE passivation effect of polyaniline (PANI) was utilized to enhance the protection efficiency of styrene-acrylate waterborne coatings against corrosion of carbon steel (CS). Styrene-acrylate emulsion (SACE) based on poly (styrene-co-butyl acrylate) was synthesized via a semi-batch emulsion polymerization while the PANI emulsion (PANE) was prepared by chemical oxidative polymerization of aniline in the micelles of sodium dodecyl benzene sulfonate. The coating formulations (Fs) were prepared by adding PANE to SACE at different weight solid ratios. The viscosity, density, solid content, particle size distribution, the shape of the particles, and stability of the blended emulsions were studied. The properties of the coatedfilms were evaluated such as hardness, impact resistance, flexibility, adhesion to the steel, glass transition temperature (Tg), and surface morphology. The effect of PANE in enhancing the protection efficiency of SACE film against corrosion of CS was estimated by visual corrosion test, weight loss measurements, and electrochemical Tafel polarization. The results showed an increase in the Tg from 23 o C for pure SACE film up to 36 o C for the film containing the maximum PANI content. SACE film loaded with 0.75% and 1% PANI exhibited the least corrosion current density of 0.07 and 0.11 µA/cm 2 , respectively. The formation of a passive layer on the coated-CS was recorded by the shift of corrosion potential for steel to the anodic direction.

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“…Until now, studies on the solid content of waterborne polyurethane have been mainly divided into two aspects: formula and particle size. In the formulation aspect, various factors have been researched such as new hydrophilic monomers, different isocyanates, special chain extenders, and polyol [9][10][11][12][13]. Vilas [14] chose a new type of small molecule sulfonate, acrylamide-tert-butane sulfonate, as a chain extender, which greatly improved sticking time, peel strength, and hardness.…”

Section: Introductionmentioning

confidence: 99%

The Relationship between Solid Content and Particle Size Ratio of Waterborne Polyurethane

Hou

Zhang

et al. 2019

Coatings

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A series of high solid content carboxylic acid/sulfonic acid waterborne polyurethanes was prepared by the emulsion dispersion method. The particle size and solid content were measured. By changing the particle size of the large particles to achieve different particle size ratios, high solid content waterborne polyurethanes were obtained at specific particle size ratios. When the particle size ratio was >7, 4–5 or 2–3, the aqueous polyurethane could reach a higher solid content (more than 56%). This indicated that solid content is related to particle size distribution in high solid content waterborne polyurethane. Moreover, the corresponding three-dimensional stacked models (simple cubic accumulation, face-centered cubic accumulation, cubic close packing and hexagonal closest packing) were established.

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A comparative study of new linear and hyperbranched polyurethanes built up from a synthesized isocyanate-terminated polyester/urethane

Cited by 18 publications

References 30 publications

Mechanically strong and resilient shape memory polyurethane with hexamethylene diisocyanate as mixing segment

Mechanically strong and resilient shape memory polyurethane with hexamethylene diisocyanate as mixing segment

Polyaniline emulsion as a passivator in styrene-acrylate waterborne coatings for the protection of carbon steel against corrosion

The Relationship between Solid Content and Particle Size Ratio of Waterborne Polyurethane

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