Hyperbranched Polyurethane Urea Research Articles

Thermal Stability Enhancement of Cotton and Cotton Polyester Blend Fabrics by Hyperbranched Poly Urethane-Urea Treatment

Despite the importance of cotton fabrics and its blends in our lives, the lack of their thermal stability is one of the most important point to be studied. The ability of hyperbranched poly urethane-urea (HBPU) to improve the thermal stability of cotton and cotton polyester (C/PET) fabrics was investigated. Different concentrations of HBPU were used for treatment of both cotton and C/PET fabrics. No significant effect on tensile strength properties was observed with cotton fabrics, while tensile strength of treated C/PET fabrics was affected by treatment with different concentrations of HBPU. TGA analysis shows enhanced char residue values with both treated cotton and C/PET fabrics. Polymer deposition on the surface of treated fabrics and structure changes were followed by SEM and FT-IR spectroscopy, respectively.

Surface functionalized zinc oxide (ZnO) nanoparticle filled organic–inorganic hybrid materials with enhanced thermo-mechanical properties

Abstract The aim of this work is to use surface modified ZnO nanoparticles in combination with hyperbranched reactive polymer network to prepare moisture cure eco-friendly hybrid coatings and study their structure property relationship. The surface of the ZnO nanoparticles has been modified with silane coupling agent to get organo functional modified ZnO nanoparticles and were used for coatings formulation. The structure–properties of HBPUU (hyperbranched polyurethane urea)-modified nano ZnO hybrid materials were compared with HBPUU–nano-ZnO hybrid coatings. The viscoelastic, thermal and surface morphology of these coatings were characterized by Dynamic Mechanical and Thermal Analyzer (DMTA), Thermogravimetric Analyzer (TGA), Atomic Force Microscope (AFM), High Resolution Transmission Electron Microscopy (HR-TEM) and Contact Angle Instrument. TGA and DMTA data suggest higher thermal stability and glass transition temperature ( T g ) for the coatings prepared using modified nano ZnO (5%) as compared to nano ZnO (5%) hybrids. The contact angle data suggest better hydrophobic character of the hybrid coatings prepared using modified ZnO. The AFM result suggests that the surface roughness value of modified nano ZnO hybrid coatings is less when compared to their corresponding nano ZnO based hybrid coatings.

Click Chemistry Engineered Hyperbranched Polyurethane–Urea for Functional Coating Applications

This article reports a facile route for the synthesis of different generations of 1,2,3-triazole-rich hyperbranched polyether polyols using click chemistry and extends their application for the development of moisture-cured polyurethane–urea coatings. Initially, three generations of chlorinated hyperbranched polyether polyols were synthesized by ring-opening polymerization of epichlorohydrin with trimethylolpropane in different mole ratios. These chlorinated polyols on continuous treatments with sodium azide and propargyl alcohol result in three generations of 1,2,3-triazole-rich hyperbranched polyether polyols. Furthermore, these different generations of polyols were reacted with 1-isocyanato-4-[(4-isocyanatocyclohexyl) methyl] cyclohexane (H12MDI) at OH:NCO ratio of 1:1.2 to obtain −NCO-terminated triazole-rich hyperbranched polyurethanes, which were subjected to curing under atmospheric moisture to obtain hyperbranched polyurethane–urea coatings. The coatings showed considerable enhancement in thermal stability, glass transition temperature, and corrosion resistance properties with an increase in generation number. All three generations of coating films show excellent resistance toward various bacterial and fungal attacks.

Development of moisture cure polyurethane–urea coatings using 1,2,3-triazole core hyperbranched polyesters

This article reports the development of moisture cure polyurethane–urea coatings. The coating has been developed using different generations of novel 1,2,3-triazole core containing hyperbranched polyester polyols (THBP). For the synthesis of THBP, the core molecule, tetra hydroxyl-terminated di-triazole (THTD), has been synthesized by click reaction involving ethylene diazide and 2-butyne-1,4-diol. The polycondensation reaction between the core THTD and 2,2-bis (hydroxymethyl) propionic acid (Bis-MPA) at different mole ratios has been used to get first (THBPG-1), second (THBPG-2), and third (THBPG-3) generations of triazole core hyperbranched polyesters. The structural investigations of these THBPs have been carried out by 1H NMR, 13C NMR, and FTIR spectroscopy. The different generations of THBPs were further reacted with 1-isocyanato-4-[(4-isocyanatocyclohexyl) methyl] cyclohexane (H12-MDI) at OH:NCO ratio of 1:1.2 to get –NCO terminated triazole core hyperbranched polyurethanes. They were cured under atmospheric moisture to get hyperbranched polyurethane–urea coatings and were named as THBPUG-1, THBPUG-2, and THBPUG-3. FTIR has been used to confirm the formation of polyurethane coatings. The TGA and DMTA have been used to determine the thermal stability and dynamic mechanical properties of the coatings, respectively. The corrosion resistance properties of the coatings have been studied by salt spray and electrochemical test. The coatings were also evaluated for microbial resistance. The results indicate that the thermal stability, glass transition temperature, and corrosion resistance properties increase with an increase in generation number of THBPs used for coating development. All three generations of coating films show excellent antimicrobial activity. Based on overall combined structure–property relationship study, these types of coatings will be useful as multifunctional applications in marine and moist environments.

Synthesis of triazole ring‐containing pentol chain extender and its effect on the properties of hyperbranched polyurethane‐urea coatings

AbstractThis article describes the synthesis and property evaluation of different hyperbranched polyurethane‐urea (HBPUU) coatings based on a newly synthesized triazole ring‐based pentol chain extender. For this initially, the chain extender was synthesized using acetylene azide click reaction and the structure of the intermediate compounds were confirmed by 1H‐, 13C‐NMR, FTIR, and ESI‐mass spectrometry. In the further steps, the required HBPUU coatings were prepared by a systematic three‐step reaction process. In the first step, a isocyanate terminated prepolymer resin was synthesized at NCO/OH ratio of 1.2 : 1, while the second and third step involves the partially chain extension followed by moisture curing. The excess NCO content in the prepolymer was calculated by standard dibutylamine titration method and partially (10, 20, 30, 50, and 70% of the excess NCO content) chain extended with the pentol chain extender and remaining was moisture cured. The structure property relation of different HBPUU coating films were analyzed by FTIR peak deconvulation technique using Gaussian curve fitting procedure while, their viscoelastic and thermo‐mechanical properties were measured by dynamic mechanical thermal analysis, thermo gravimetric analysis, differential scanning calorimetric, and universal testing machine instruments. These results showed that thermal stability, glass transition temperature (Tg), elongation at break increases but the storage and tensile modulus decreases with increasing the percent loading of the triazole chain extender. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Investigation of the effect of ZnO nanoparticles on the thermomechanical and microbial properties of hyperbranched polyurethane‐urea hybrid composites

AbstractHybrid coatings of hyperbranched polyurethane‐urea (HBPUU) containing ZnO nanoparticles were prepared by mixing the hyperbranched polyurethane with the nanoparticles. The films were stored at room temperature and laboratory humidity conditions for one week to yield completely cured hybrid films. The ZnO nanoparticles were found to be well dispersed in the polymer up to 3 wt%. The structure–property relationship of various HBPUU–ZnO hybrid coatings was analysed using a Fourier transform infrared peak deconvolution technique with a Gaussian curve‐fitting procedure, while their viscoelastic, thermomechanical and surface morphology were studied using X‐ray diffraction, dynamic mechanical thermal analysis, thermogravimetric analysis, a universal testing machine, scanning electron microscopy, atomic force microscopy and contact angle instruments. The thermal stability and mechanical properties of the hybrid composite films improved with increasing ZnO content, which was believed to be due to thermal insulation in the presence of nanoparticles. Water contact angle data suggested that the hydrophobic character of the hybrid composites increased with increasing nanoparticle concentration. The antimicrobial property of the HBPUU–ZnO hybrid coatings was studied using the disc diffusion method. HBPUU–ZnO hybrid coatings showed good antimicrobial properties compared to HBPUU. Copyright © 2012 Society of Chemical Industry

Structure–property correlation study of hyperbranched polyurethane–urea (HBPU) coatings

This paper deals with the structure–property relation of different HBPU coatings based on the variation of parameters like, NCO/OH ratio, generation number and type of diisocyanates used. For this, the NCO terminated HBPU prepolymers were synthesized first by reacting the different generation hyperbranched polyesters (HBPs) with excess diisocyanates. In the next step, these HBPU prepolymer coated films were completely moisture cured to get the desired HBPU coatings. The synthesized polymers were confirmed by 1H, 13C NMR and FT-IR spectroscopy methods whereas structure–property relation was drawn from the FT-IR peak deconvolution technique. The degree of branching (DB) and percent composition of different structural units present in the HBPs were calculated from the 1H and 13C NMR data by using Fretch equation. The melt viscosity study of different HBP samples suggests that most polyester sample showed Newtonian behavior. The coating film properties were studied by DMTA, TGA, UTM, and contact angle measurement instruments. DMTA and TGA data shows that the increase of NCO/OH ratio and generation number had a favorable impact on storage modulus (E′), glass transition temperature (Tg), onset degradation temperature (T1ON) and char residue values of the coatings. The contact angle and UTM data suggest that the hydrophobicity and tensile strength increases but flexibility decreases with increasing the NCO/OH ratio.

Effect of NCO/OH ratio and Ce‐Zr nanoparticles on the thermo‐mechanical properties of hyperbranched polyurethane urea coatings

AbstractThe present study describes the effect of NCO/OH ratio and addition of Cerium (Ce)‐Zirconium (Zr) mixed oxide nanoparticles on the properties of Hyperbranched Polyurethane Urea (HBPUU) Coatings. Initially a hydroxyl terminated hyperbranched polymer (HTBP) was synthesized through A3 + CB2 approach. The HTBP and Ce‐Zr nanopowder dispersed HTBP, both were reacted with hexamethylene diisocyanate (HDI) separately; at various NCO/OH eq. ratios to get different NCO terminated HBPU and HBPU/Ce‐Zr hybrid prepolymers. These prepolymers were used for the preparation of HBPUU and HBPUU/Ce‐Zr hybrid coating films through moisture curing. The techniques such as 1H NMR, 13C NMR, FT‐IR, and XRD have been used for structural information while Dynamic mechanical and thermal analyzer (DMTA), Thermogravimetric analysis (TGA) and Universal testing machine (UTM) have been used for evaluation of thermo‐mechanical properties. The combined spectroscopic investigations results indicate the formation of HBPUU network with a degree of branching of 76% while FT‐IR deconvolution results indicates the formation of more hydrogen bonded structure with increasing NCO/OH ratio. The XRD and FT‐IR studies confirm the presence of Ce‐Zr mixed nanoparticles in the HBPUU hybrids. As per TGA and DMTA analysis the thermal stability, char residue, storage modulus (E', material stiffness) and glass transition temperature (Tg), increases with increasing NCO/OH ratio and Ce‐Zr nanoparticle loading in HBPUU coatings. In general, UTM data suggest that the tensile strength increases and per cent elongation at break decreases with increasing the NCO/OH ratio and addition level of nanoparticles in HBPUU coatings. Copyright © 2009 John Wiley & Sons, Ltd.

Synthesis and characterization of hyperbranched polyurethane–urea coatings

A series of hyperbranched polyurethane (HBPU)–urea coatings were synthesized by a systematic two-step reaction process. Initially, isocyanate terminated PU prepolymers were prepared from a hyperbranched polyester polyols with isophorone diisocyanate at NCO/OH ratio of 1.6:1 for 5 h at 70–80 °C. The excess NCO content after the synthesis of NCO terminated HBPU prepolymer was completely reacted with atmospheric moisture. The obtained HBPU–urea networks were characterized with Fourier transform-infrared (FT-IR) spectroscopy for the quantitative evolution of the extent of urethane and urea bonds as well as to study the structure-property relationship. In order to find out the changes and types of intermolecular H-bonding interaction in the HBPU–urea films with the variation in polyester structure, the deconvolution of FT-IR spectra were carried out using Origin 6.0 software through Gaussian curve-fitting method. The viscoelastic properties and thermal stability of the synthesized coatings were determined by dynamic mechanical and thermal analyzer and thermogravimetric analyzer, respectively. For HBPU–urea samples glass transition temperature and thermal stability increased with the generation number from the first to the third. Polyester samples showed single step decomposition profile and HBPU–urea samples showed two-steps decomposition with good thermal stability.