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Janusz Datta - One of the best experts on this subject based on the ideXlab platform.
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Investigation of Thermoplastic Polyurethanes Synthesized via Two Different Prepolymers
Journal of Polymers and the Environment, 2019Co-Authors: Paulina Kasprzyk, Ewelina Sadowska, Janusz DattaAbstract:The man aim of this work was to investigate the effect of the molecular weight of polyols, mixture of Prepolymers, and [NCO]/[OH] molar ratio used during the prepolymer chain extending step on the chemical structure, thermomechanical and mechanical properties, and thermal stability of thermoplastic poly(ether-urethane)s In this work thermoplastic poly(ether-urethane)s were synthesized by using polyols with a various molecular weight, 4,4′-diphenylmethane diisocyanate and bio-based glycol. Materials were obtained by a two-step method. The tests were carried out for polyurethanes obtained from a mixture of Prepolymers and for reference samples. In the case of materials obtained with using mixture of Prepolymers, the ratio of both Prepolymers was determined on 50/50 weight percent. Soft segments of materials prepared with using mixture consist of two different polyols. The chemical structure was analyzed using FTIR spectroscopy. The Gaussian deconvolution technique was used to study the hydrogen bonding as well as to decompose carbonyl region of three peaks in various TPUs. The thermal degradation behavior was investigated by using thermogravimetric analysis at heating rates of 10 °C/min. It was confirmed that the mixture of Prepolymers has an effect of the degree of phase separation, thermal stability and selected properties of synthesized thermoplastic poly(ether-urethane)s.
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novel bio based thermoplastic poly ether urethane s correlations between the structure processing and properties
Polymer, 2019Co-Authors: Paulina Kasprzyk, Janusz DattaAbstract:Abstract The main purpose of this work was to analyze the effect of the number of unreacted isocyanate groups and the [NCO]/[OH] molar ratio during the chain extension of a prepolymer during the polymerization process on the structure, processing and selected properties of thermoplastic poly(ether-urethane)s. Three series of novel thermoplastic polyurethanes were obtained via a prepolymer route. Three Prepolymers were synthesized from diisocyanate and bio-based polyol, which contained 6, 7 and 8% of unreacted isocyanate groups. The prepolymer chains were extended by using bio-based 1,4-butanediol with four different [NCO]/[OH] molar ratios. It was confirmed that the concentration of unreacted isocyanate groups in the prepolymer has an effect on the degree of the hard segment phase separation of poly(ether-urethane)s. It was also found that the melt flow index has a significant impact on the processing of polyurethanes which can be correlated to the chemical structure and dynamic mechanical properties of the polyurethanes.
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effect of hydroxylated soybean oil and bio based propanediol on the structure and thermal properties of synthesized bio polyurethanes
Industrial Crops and Products, 2014Co-Authors: Janusz Datta, Ewa GlowinskaAbstract:The aim of this work was to obtain bio-polyurethanes using synthetic compounds and bio-components, i.e. bio-glycols. Bio-polyurethanes were prepared by means of the prepolymer method. Prepolymers were synthesized from 4,4′-diphenylmethane diisocyanate (MDI) and a polyol mixture containing 75% by weight of commercial polyether and 25% by weight of hydroxylated soybean oils (H2 or H3), the latter being obtained in the reaction with bio-glycol during the hydroxylation process. Bio-components were also used as chain extenders of prepolymer, i.e. bio-based 1,2- or bio-based 1,3-propanediol (1,2bioPDO or 1,3bioPDO). The reaction was catalyzed by 1,4-diazabicyclo[2.2.2]octane (DABCO). The influence of the content of low molecular chain extenders on the structure and thermomechanical properties of the obtained bio-polyurethanes was investigated. The FTIR analysis demonstrated that different types of bio-propanediol change the chemical structure of the obtained bio-polyether urethanes. The results of thermomechanical analysis showed that the application of 1,2-bio-propanediol as a chain extender was advantageous in comparison to bio-based 1,3-propanediol; the polyurethanes produced with 1,2-bio-propanediol exhibited higher storage modulus and lower loss modulus.
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a mathematical model of rheological behavior of novel bio based isocyanate terminated polyurethane Prepolymers
Industrial Crops and Products, 2014Co-Authors: Ewa Glowinska, Janusz DattaAbstract:In this paper, the results of rheological study on isocyanate-terminated polyurethane Prepolymers, containing modified soybean oil residues incorporated into the chemical structure are described. Isocyanate-terminated Prepolymers were synthesized from 4,4′-diphenylmethane diisocyanate and the mixture of hydroxylated soybean oil and commercial polyether. The measurements were performed by using rotary rheometer R/S-CPS+ (Brookfield, USA), while the rheological parameters were calculated by using Rheo3000 program. Based on rheological measurements, the viscosity curves and flow curves for Prepolymers in the temperature range from 50 to 70 °C were plotted. Prepolymer samples were tested with controlled shear rate (CSR). It was found that a viscosity of bio-based isocyanate-terminated Prepolymers decreases with increasing content of hydroxylated soybean oil in the polyol mixture. The rheological data for bio-based polyurethane Prepolymers were also mathematically modeled. It was found that the synthesized Prepolymers are non-Newtonian fluids that can be described by Ostwald-de Waele and Herschel Bulkley functions as optimal individual models. The conducted investigations showed that the dynamic viscosity and rheological behavior of bioPrepolymers samples could depend on the amount of hydroxylated soybean oil used in the polyol mixture.
João C. Bordado - One of the best experts on this subject based on the ideXlab platform.
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influence of molecular weight and free nco content on the rheological properties of lithium lubricating greases modified with nco terminated Prepolymers
European Polymer Journal, 2008Co-Authors: G Moreno, C Valencia, J M Franco, C Gallegos, Antonio Correia Diogo, João C. BordadoAbstract:In this work, the use of reactive diisocyanate-terminated polymeric materials as rheology modifiers of lubricating greases has been studied. Particularly, the influences that free NCO content, molecular weight and functionality of the reactive Prepolymers exert on the rheological response and microstructure of lubricating greases were analyzed. With this aim, NCO-terminated Prepolymers were prepared from several di and trifunctional polyols and polymeric MDI. Afterwards, the reaction between terminal isocyanate groups and the hydroxy group located in the hydrocarbon chain of the 12-hydroxystearate lithium soap, used as thickener, was promoted during processing of lubricating greases. Polymeric materials used as additives and final lubricating greases were characterized by FTIR, DSC and GPC techniques. The effectiveness of these reactive additives was tested by performing small-amplitude oscillatory shear (SAOS), as well as standardized mechanical stability tests, on final greases. The rheological response was related to the microstructure of these greases, characterized by means of atomic force microscopy (AFM). From the experimental results obtained, it may be concluded that the effectiveness of these polymeric additives to modify the rheology of greases is due to the progress of the reaction between terminal isocyanate groups and the hydroxy group of lithium soap. However, a large dependence on both free NCO content and prepolymer molecular weight was found. Experimental results confirm that a balance between prepolymer molecular weight and NCO content is necessary to reach an optimal rheological modification of lithium greases. Moreover, this balance is a function of grease ageing, due to the progress of the reaction promoted.
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Influence of the storage of reactive urethane quasi-Prepolymers in their composition and adhesion properties
International Journal of Adhesion and Adhesives, 2007Co-Authors: Ana Luísa Daniel Da Silva, José Miguel Martín-martínez, João C. BordadoAbstract:Abstract In an industrial environment, isocyanate-based adhesives are frequently stored for a long period of time before being used. Due to the presence of unreacted isocyanate (NCO) groups, several undesirable by-products may be formed during the storage period and eventually may affect the adhesion properties. In this work, the effect of the storage of several isocyanate-tipped quasi-Prepolymers on their composition and adhesion properties was studied. The functionality of the polyol (2 and 3), the unreacted isocyanate content (14 and 16 wt%), and the concentration of a morpholine-based catalyst (0–7 g/eq polyol) were varied, and two different containers (made from glass and tinplate) were used as storage containers. The influence of the storage conditions on the composition, and properties of the quasi-Prepolymers were assessed by plate–plate rheometry, IR spectroscopy and 1 H-NMR spectroscopy. The adhesion properties of the moisture-cured quasi-Prepolymers have been obtained from single lap shear tests of vulcanized styrene-butadiene rubber/cured quasi-prepolymer joints and of aluminum/cured quasi-prepolymer joints. The properties of the moisture-cured quasi-Prepolymers were studied by thermogravimetric analysis and modulated temperature differential scanning calorimetry (MDSC). The viscosity of the quasi-Prepolymers increased during the storage period and a reduction in the free isocyanate content was observed, probably due to the participation of NCO groups in secondary reactions. The formation of uretdione and isocyanurate was identified by IR spectroscopy while the allophanate linkages were identified by 1 H-NMR. The thermogravimetric analysis and the MDSC results suggest an increase in the crosslink density of the cured quasi-prepolymer after the storage period. Single lap shear strength values of rubber and aluminum/moisture cured quasi-prepolymer joints increased after increasing the storage period of the quasi-prepolymer and was ascribed to the higher cohesion of the higher crosslinked cured quasi-Prepolymers.
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Influence of the free isocyanate content in the adhesive properties of reactive trifunctional polyether urethane quasi-Prepolymers
International Journal of Adhesion and Adhesives, 2006Co-Authors: Ana Luísa Daniel Da Silva, José Miguel Martín-martínez, João C. BordadoAbstract:Abstract The effect of the free isocyanate (NCO) content on the adhesive properties of urethane quasi-Prepolymers was studied. Polyether-based isocyanate ended quasi-Prepolymers containing between 13 and 21 wt% NCO were prepared by reacting a trifunctional polypropyleneglycol with polymeric MDI. The quasi-Prepolymers were characterized by infrared spectroscopy (IR), proton nuclear magnetic resonance ( 1 H-NMR) spectroscopy, Brookfield viscosity, and differential scanning calorimetry (DSC). Immediate adhesion of quasi-Prepolymers was studied by means of a probe test performed with a texture analyzer. Adhesion properties of the moisture-cured quasi-Prepolymers have been obtained from single lap shear tests of vulcanized styrene–butadiene (R1) rubber/cured quasi-prepolymer joints. The increase in the free isocyanate content produced quasi-Prepolymers with lower average chain length and less intermolecular interactions between polymer chains. Due to the presence of free isocyanate molecules, lower Brookfield viscosity values and lower glass transition temperatures were obtained by increasing the free isocyanate content in the quasi-Prepolymers. The lower the free NCO content, the higher the cohesion and the immediate adhesion of the quasi-Prepolymers because of the increase in the average molecular weight. During debonding, fibrillation was observed in the quasi-Prepolymers with free NCO content lower than 20 wt%. Single lap shear strength values of R1 rubber/moisture cured quasi-Prepolymers joints showed a particular trend as a function of the increase in the NCO content, which can be ascribed to the opposite trends in the cohesion and adhesion properties of the cured quasi-Prepolymers.
Jeong-ik Lee - One of the best experts on this subject based on the ideXlab platform.
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A variation in wrinkle structures of UV-cured films with chemical structures of Prepolymers
Materials Letters, 2017Co-Authors: Seung Koo Park, Young-je Kwark, Saekwang Nam, Jaehyun Moon, Dong-wook Kim, Suntak Park, Bong Je Park, Sungryul Yun, Jeong-ik LeeAbstract:Abstract Spontaneously wrinkled films can be easily obtained from UV-crosslinkable liquid Prepolymers under special UV-curing conditions. They vary wrinkle structures of the UV-cured films and, however, cannot be precisely controlled. Here, five different UV-crosslinkable Prepolymers are synthesized to study the chemical structure effect of Prepolymers on wrinkle formation and modulation of the UV-cured films irrespective of the UV-curing conditions. Both wavelength and amplitude of the wrinkles are tuned with the different liquid Prepolymers from 4.10 to 5.63 µm and from 1.00 to 1.66 µm, respectively. The wrinkle structures of the UV-cured films are faded by adding a solid prepolymer to a liquid prepolymer due to interference from it in the shrinkage of the liquid prepolymer layer. The wrinkles completely disappear in the UV-cured films fabricated from the formulated Prepolymers containing over 50 wt% of the solid prepolymer.
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Wrinkle structures formed by formulating UV-crosslinkable liquid Prepolymers
Polymer, 2016Co-Authors: Seung Koo Park, Young-je Kwark, Saekwang Nam, Jaehyun Moon, Suntak Park, Bong Je Park, Sungryul Yun, Jeong-ik Lee, Ki-uk KyungAbstract:Abstract Artificial wrinkles have recently been in the spotlight due to their potential use in high-tech applications. A spontaneously wrinkled film can be fabricated from UV-crosslinkable liquid Prepolymers. Here, we controlled the wrinkle formation by simply formulating two UV-crosslinkable liquid Prepolymers, tetraethylene glycol bis(4-ethenyl-2,3,5,6-tetrafluorophenyl) ether (TEGDSt) and tetraethylene glycol diacrylate (TEGDA). The wrinkles were formed from the TEGDSt/TEGDA formulated prepolymer layers containing up to 30 wt% of TEGDA. The wrinkle formation depended upon the rate of photo-crosslinking reaction of the formulated Prepolymers. The first order apparent rate constant, k app , was between ca. 5.7 × 10 −3 and 12.2 × 10 −3 s −1 for the wrinkle formation. The wrinkle structures were modulated within the k app mainly due to variation in the extent of shrinkage of the formulated prepolymer layers with the content of TEGDA.
Paulina Kasprzyk - One of the best experts on this subject based on the ideXlab platform.
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Investigation of Thermoplastic Polyurethanes Synthesized via Two Different Prepolymers
Journal of Polymers and the Environment, 2019Co-Authors: Paulina Kasprzyk, Ewelina Sadowska, Janusz DattaAbstract:The man aim of this work was to investigate the effect of the molecular weight of polyols, mixture of Prepolymers, and [NCO]/[OH] molar ratio used during the prepolymer chain extending step on the chemical structure, thermomechanical and mechanical properties, and thermal stability of thermoplastic poly(ether-urethane)s In this work thermoplastic poly(ether-urethane)s were synthesized by using polyols with a various molecular weight, 4,4′-diphenylmethane diisocyanate and bio-based glycol. Materials were obtained by a two-step method. The tests were carried out for polyurethanes obtained from a mixture of Prepolymers and for reference samples. In the case of materials obtained with using mixture of Prepolymers, the ratio of both Prepolymers was determined on 50/50 weight percent. Soft segments of materials prepared with using mixture consist of two different polyols. The chemical structure was analyzed using FTIR spectroscopy. The Gaussian deconvolution technique was used to study the hydrogen bonding as well as to decompose carbonyl region of three peaks in various TPUs. The thermal degradation behavior was investigated by using thermogravimetric analysis at heating rates of 10 °C/min. It was confirmed that the mixture of Prepolymers has an effect of the degree of phase separation, thermal stability and selected properties of synthesized thermoplastic poly(ether-urethane)s.
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novel bio based thermoplastic poly ether urethane s correlations between the structure processing and properties
Polymer, 2019Co-Authors: Paulina Kasprzyk, Janusz DattaAbstract:Abstract The main purpose of this work was to analyze the effect of the number of unreacted isocyanate groups and the [NCO]/[OH] molar ratio during the chain extension of a prepolymer during the polymerization process on the structure, processing and selected properties of thermoplastic poly(ether-urethane)s. Three series of novel thermoplastic polyurethanes were obtained via a prepolymer route. Three Prepolymers were synthesized from diisocyanate and bio-based polyol, which contained 6, 7 and 8% of unreacted isocyanate groups. The prepolymer chains were extended by using bio-based 1,4-butanediol with four different [NCO]/[OH] molar ratios. It was confirmed that the concentration of unreacted isocyanate groups in the prepolymer has an effect on the degree of the hard segment phase separation of poly(ether-urethane)s. It was also found that the melt flow index has a significant impact on the processing of polyurethanes which can be correlated to the chemical structure and dynamic mechanical properties of the polyurethanes.
Ketut Hariyawati - One of the best experts on this subject based on the ideXlab platform.
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The effect of the soft segment of Prepolymers on properties of poly(urethane-ester) and its biodegradability
Polymer International, 2011Co-Authors: I Made Arcana, Bunbun Bundjali, Muhamad Ali Zulfikar, Muhammad Hasan, Ketut HariyawatiAbstract:The influence of soft-segment Prepolymers prepared through the polymerization of δ-valerolactone (VL) and 2,2-dimethyl-1,3-propandiol (DP) monomers on the structure and properties of poly(urethane-ester) as well as its biodegradability were investigated. Poly(urethane-ester) was prepared in two steps. The first step was the preparation of Prepolymers with various chain lengths by polymerizing VL and DP monomers in the presence of a distannoxane catalyst at 100 °C under nitrogen atmosphere. The second step was the preparation of poly(urethane-ester) by polymerizing 4,4′-methylene-bis(phenyl isocyanate) (MDI) and Prepolymers with various chain lengths in the absence of catalysts. The poly(urethane-ester) was characterized through an analysis of functional groups (FTIR), thermal properties (differential thermal analysis/TGA), mechanical properties (tensile tester), crystallinity (XRD) and biodegradability. An increased chain length of the prepolymer used in polymerization with MDI leads to an increase in the thermal properties and crystallinity of poly(urethane-ester). However, the maximum biodegradability in the activated sludge was observed in the poly(urethane-ester) prepared by polymerizing MDI and Prepolymers with a molar VL/DP ratio of 20/1. The amorphous parts of polymers were more easily decomposed by microorganism enzymes than were the crystalline parts after an incubation period of 30 days. Copyright © 2011 Society of Chemical Industry
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Study on Properties of Poly(urethane-ester) Synthesized from Prepolymers of ε-Caprolactone and 2,2-Dimethyl-1,3-Propanediol Monomers and Their Biodegradability
Journal of Polymers and the Environment, 2010Co-Authors: I Made Arcana, Bunbun Bundjali, Ketut Hariyawati, Helen Mariani, Shinta Dewi Anggraini, Muhammad Hasan, Aditya ArdanaAbstract:Poly(urethane-ester) was prepared by polymerization of 4,4′-methylenebis(phenyl isocyanate) (MDI) and Prepolymers of ε-caprolactone and 2,2-dimethyl-1,3-propanediol monomers P(CL-DP) with various chain lengths as polyol sources. Characterizations of poly(urethane-ester) were carried out by analysis of functional groups (FTIR), thermal properties (DTA/TGA), mechanical properties (Tensile tester), crystallinity (XRD), and biodegradability. The chain length of Prepolymers used in polymerization has a significant effect in properties of poly(urethane-ester) as well as their biodegradability. The formation of poly(urethane-ester) was indicated by the presence of new absorption peaks at wave number of 3,348.2 and 1,596.9 cm^−1 for urethane (–NH–) and aromatic groups in chain of polymers, respectively. The increase chain length of prepolymer used in polymerization with 4,4′-methylenebis(phenyl isocyanate) was observed the increase thermal property and crystallinity of poly(urethane-ester). However, the maximum mechanical property and also biodegradability in activated sludge were observed in poly(urethane-ester) prepared by polymerization of 4,4′-methylenebis(phenyl isocyanate) (MDI) and P(CL-DP) Prepolymers with DP/CL ratio of 1/20. Apparently, the amorphous parts of polymers are rapidly decomposed by enzymes of microorganisms, so the crystallinity on the whole of poly(urethane-ester) increases after incubation time of 30 days.
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Study on Properties of Poly(urethane-ester) Synthesized from Prepolymers of ε-Caprolactone and 2,2-Dimethyl-1,3-Propanediol Monomers and Their Biodegradability
Journal of Polymers and The Environment, 2010Co-Authors: I Made Arcana, Bunbun Bundjali, Ketut Hariyawati, Helen Mariani, Shinta Dewi Anggraini, Muhammad Hasan, Aditya ArdanaAbstract:Poly(urethane-ester) was prepared by poly- merization of 4,4 0 -methylenebis(phenyl isocyanate) (MDI) and Prepolymers of e-caprolactone and 2,2-dimethyl-1,3- propanediol monomers P(CL-DP) with various chain lengths as polyol sources. Characterizations of poly(ure- thane-ester) were carried out by analysis of functional groups (FTIR), thermal properties (DTA/TGA), mechani- cal properties (Tensile tester), crystallinity (XRD), and biodegradability. The chain length of Prepolymers used in polymerization has a significant effect in properties of poly(urethane-ester) as well as their biodegradability. The formation of poly(urethane-ester) was indicated by the presence of new absorption peaks at wave number of 3,348.2 and 1,596.9 cm -1 for urethane (-NH-) and aro- matic groups in chain of polymers, respectively. The increase chain length of prepolymer used in polymerization with 4,4 0 -methylenebis(phenyl isocyanate) was observed the increase thermal property and crystallinity of poly(urethane- ester). However, the maximum mechanical property and also biodegradability in activated sludge were observed in poly(urethane-ester) prepared by polymerization of 4,4 0 - methylenebis(phenyl isocyanate) (MDI) and P(CL-DP) Prepolymers with DP/CL ratio of 1/20. Apparently, the amorphous parts of polymers are rapidly decomposed by enzymes of microorganisms, so the crystallinity on the whole of poly(urethane-ester) increases after incubation time of 30 days.