Isocyanate Component Research Articles

Bio-Based Polyurethane Networks Containing Sunflower Oil Based Polyols.

This work focused on the preparation and investigation of polyurethane (SO-PU)-containing sunflower oil glycerides. By transesterification of sunflower oil with glycerol, we synthesized a glyceride mixture with an equilibrium composition, which was used as a new diol component in polyurethanes in addition to poly(ε-caprolactone)diol (PCLD2000). The structure of the glyceride mixture was characterized by physicochemical methods, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), nuclear magnetic resonance spectroscopy (NMR), and size exclusion chromatography (SEC) measurements. The synthesis of polyurethanes was performed in two steps: first the prepolymer with the isocyanate end was synthesized, followed by crosslinking with an additional amount of diisocyanate. For the synthesis of the prepolymer, 4,4'-methylene diphenyl diisocyanate (MDI) or 1,6-hexamethylene diisocyanate (HDI) were used as isocyanate components, while the crosslinking was carried out using an additional amount of MDI or HDI. The obtained SO-PU flexible polymer films were characterized by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The so-obtained flexible SO-PU films were proved to be suitable for the preparation of potentially biocompatible and/or biodegradable scaffolds. In addition, the stress versus strain curves for the SO-PU polymers were interpreted in terms of a mechanical model, taking into account the yield and the strain hardening.

Efficient recycling pathway of bio-based composite polyurethane foams via sustainable diamine

Aminolysis is widely recognized as a valuable chemical route for depolymerizing polymeric materials containing ester, amide, or urethane functional groups, including polyurethane foams. Bio-based polyurethane foams, pristine and reinforced with 40 wt% of sustainable fillers, were depolymerized in the presence of bio-derived butane-1,4-diamine, BDA. A process comparison was made using fossil-derived ethane-1,2-diamine, EDA, by varying amine/polyurethane ratio (F/A, 1:1 and 1:0.6). The obtained depolymerized systems were analyzed by FTIR and NMR characterizations to understand the effect of both diamines on the degradation pathway. The use of bio-based BDA seemed to be more effective with respect to conventional EDA, owing to its stronger basicity (and thus higher nucleophilicity), corresponding to faster depolymerization rates. BDA-based depolymerized systems were then employed to prepare second-generation bio-based composite polyurethane foams by partial replacement of isocyanate components (20 wt%). The morphological, mechanical, and thermal conductivity properties of the second-generation polyurethane foams were evaluated. The best performances (σ10 %=71 ± 9 kPa, λ = 0.042 ± 0.015 W∙ m-1 ∙K-1) were attained by employing the lowest F/A ratio (1:0.6); this demonstrates their potential application in different sectors such as packaging or construction, fulfilling the paradigm of the circular economy.

Biorenewable Oxypropylated Pentane-1,2,5-triol as a Source for Incorporation in Rigid Polyurethane Foams.

In this study, as a product from the efficient Achmatowicz rearrangement and mild subsequent hydrogenation-reduction reactions of biorenewable C5 alcohols derived from lignocellulose, pentane-1,2,5-triol was successfully used after oxypropylation in the preparation of rigid polyurethane foams-one of the most important classes of polymeric materials. Despite the broad range of applications, the production of polyurethanes is still highly dependent on petrochemical materials considering the need of renewable raw materials and new process technologies for the production of polyol or isocyanate components as a key point for the sustainable development of polyurethane foams. The synthesized oxypropylated pentane-1,2,5-triol was analyzed using proton NMR spectroscopy, hydroxyl number, and viscosity, whereas the newly obtained foams incorporated with up to 30% biorenewable polyol were characterized using compressive stress, thermogravimetry, dynamic mechanical analysis, and scanning electron microscopy. The modified rigid polyurethanes showed better compressive strength (>400.0 kPa), a comparable thermal degradation range at 325-450 °C, and similar morphological properties to those of commercial polyurethane formulations.

Introduction of bio-based hard segment as an alternative strategy to environmentally friendly polyurethane coated urea

Improved degradation performance of bio-based polyurethane coatings has become a significant challenge for agricultural applications of controlled-release fertilizers. In this work, petroleum-based isocyanate components were innovatively replaced with lysine diisocyanate (LDI) ingredients in various ratios by the in-situ reaction with castor oil to synthesize high bio-based content polyurethane coating materials. The chemical structure and properties of the coatings were also investigated to propose the mechanism of LDI-mediated coatings controlled release and degradation performance. The experiment results indicate that as the LDI content increased, the coatings’ thermodynamic stability, cross-linking density, and controlled release performance decreased while their hydrophilicity and degradation performance increased. Compared to other coated ureas, the coated urea with the 1:1 replacement ratio of petroleum-based isocyanate performed well and had adjustable controlled release performance. Its release period was regulated by adjusting the coating rate and reached 60 days with the 3 % coating rate. With the increase of the lysine component, the degradation performance of the coating materials was improved till the replacing ratio of petroleum-based isocyanate was higher than 1:1. In all, the introduction of bio-based isocyanate is an alternative way further to enhance the degradation performance of the coating materials, and the coatings were non-toxic to rice seeds. The coordination of the controlled release and degradation performance of the coatings can be achieved by adjusting the content of LDI. This research designed a novel strategy to solve the bottleneck problem of bio-based polyurethane coating degradation in coated fertilizers.

Polyurethane foams co-blown by water and alkylated polyethylenimine-CO2 adducts: An additive or antagonistic effect?

Recently developed CO2 adducts of alkylated polyethylenimines (PEIs) can replace traditional, ozone-depleting, and/or global warming halogen-containing blowing agents of polyurethanes (PUs). Meanwhile, water is the most common chemical blowing agent that is cheap and also environment neutral. Herein, the co-blowing performances of the two types of blowing agents were investigated. For the polyether polyol or castor oil derived polyol foaming systems, which were blended just before foaming, the consequent co-blown foams surprisingly did not possess lower densities than the control foams blown solely by water, showing an antagonistic effect in blowing performance. The relatively large particles (e.g. tens of micrometers) of the hydrophilic PEI-CO2 blowing agents absorbed water from the foaming mixtures, preventing the trapped water from chemically blowing PUs. After the foams were set, the absorbed water gradually diffused out to react with the residual isocyanate groups, which no longer contributed to PU foaming. Differently, after aging the castor oil derived polyol foaming mixtures (without water and isocyanate components that were added before PU foaming), the dispersed PEI-CO2 particles decreased in size down to nanoscale (about 20–180 nm). These nanoparticles were small enough for out-diffusion of the absorbed water, which generated foaming CO2 in time. The densities of the resultant foams could be lowered to the theoretical values. The additive effect with water could enhance the application freedom of the climate-friendly alkylated PEI-CO2 blowing agents.

Enhancing the Raveling Resistance of Polyurethane Mixture: From the Perspective of Polyurethane Adhesive

Polyurethane mixture, made of waste rubber particle, aggregate, and polyurethane adhesive, has low raveling resistance which affects the durability of the mixture. The objective of this study is to enhance the raveling resistance of polyurethane mixture. The content of polyol in the hydroxyl component was determined by Fourier transform infrared spectroscopy. The suitable curing conditions for polyurethane adhesive to enhance the raveling resistance were selected by the orthogonal experiment and mechanical tests. The relationship of the raveling resistance with crosslink density and elastic modulus was tested and calculated through the wear test. The results showed that when the ratios of the isocyanate component to the hydroxyl component were 1:3.2, 1:6.3, and 1:9.5, respectively, the isocyanate component was excessive. The ranking of the significance of the influence factors, from high to low, was first the curing temperature, then curing time, and finally the blending ratio; within the ranges of blending ratio, curing temperature, and curing time selected in this study, the appropriate blending ratio was 10:2, and the curing time was 6 h. For the polyurethane mixture involved in this study to obtain high raveling resistance, if a crosslinking agent or a new polyurethane adhesive is added, the tensile strength and tensile elastic modulus should be in the range of 3.02 to 3.27 MPa and 5.50 to 6.02 MPa, respectively; when using the FS2 polyurethane adhesive directly, the suitable curing conditions for the mixture are 90 °C and 6 h or 80 °C and 6 h. The results from this study could be beneficial for obtaining a high raveling resistance for the polyurethane mixture.

Polyurethane-Based Gel Electrolyte for Application in Flexible Electrochromic Devices.

For the application in flexible electrochromic devices (ECDs) on plastic substrates, a new polyurethane-based gel electrolyte was manufactured. In this context, the curing behavior and the influence of the proportion of solvent and salt on the ion conductivity as well as the optical and mechanical properties were investigated. Furthermore, the stoichiometric ratio of the polyurethane matrix was varied to influence the ion conductivity. As an isocyanate component, the aliphatic difunctional polyisocyanate prepolymer, synthesized by Hexamethylen-1,6-diisocyanat (HDI), was chosen since the resulting polyurethane is considered to be particularly lightfast, color-stable and temperature-resistant and therefore frequently used for paints and coatings. As polyol a trifunctional polyetherpolyol was selected to form a wide-meshed crosslinked matrix to achieve a mechanically stable but flexible electrolyte, that enables the processing and bending of film-based ECDs. The additives amount and the matrix stoichiometric ratio affected the curing behavior and curability. The salt content had almost no influence on the measured properties in the chosen experimental space. Solvent content had a great influence on ion conductivity and mechanical properties. An understoichiometric ratio of the polyurethane matrix (0.85) increases the ion conductivity and the mechanical flexibility, but also the optical properties in a negative manner. The best specific ion conductivity with 10−5 S/cm was reached with an understoichiometric ratio of 0.85 and a high solvent content (30 wt%). Concluding, due to its high flexibility and transmittance, color neutrality and sufficient ion conductivity, the application of the researched electroyte in ECDs might be suitable. A demonstrator ECD was successfully manufactured and conducted.

Interaction peculiarities of the Rhodamine B dye with polyurethane diisocyanates of different chemical types

Covalent bonding between the Rhodamine B xanthene dye and polyurethanes, containing different isocyanate fragments (hexamethylene diisocyanate and toluene diisocyanate) has been realized and studied. Effects of polyurethane isocyanate components, different by chemical structure, on spectral properties of the Rhodamine B have been studied and discussed. Spectral, photophysical and lasing characteristics of the Rhodamine B dye, incorporated to the polyurethane matrices are presented.

Investigating on polymerization process and interaction mechanism of thermosetting polyurethane modified asphalt

Thermosetting polyurethane (PU) can significantly improve the high-temperature stability, mechanical strength, and low-temperature flexibility of asphalt. To broaden its application, a systematic understanding of how the PU interacts with the asphalt is needed. Currently, limited effort has been focused on the polymerization and modification mechanism of thermosetting polyurethane modified asphalt (TPUA). The interaction mechanism of thermosetting PU with asphalt was revealed from three aspects: molecular structure, microstructure, and surface free energy (SFE). First, the polymerization process of thermosetting PU in asphalt was analyzed based on curing reaction kinetics, that is, reaction order and activation energy. Then, the physical and chemical interactions between modifier and asphalt were investigated quantitatively and qualitatively by infrared spectroscopy and nuclear magnetic resonance spectrometer (1H NMR). Besides, the two-phase structure of PU and asphalt was observed by fluorescence microscope (FM) and scanning electron microscope (SEM). Finally, the effect of thermosetting PU on the SFE of asphalt was revealed by the sessile drop method. The results showed that asphalt did not affect the secondary reaction characteristics of the PU modifier. The relationship between the curing time and the reaction degree and temperature was identified, which well predicted the curing time required to finish the reaction under different temperatures. Moreover, the isocyanate component in PU reacted with the active hydrogen in asphalt to form carbamate (–NHCOO–), and the exact degree of chemical modification was asphalt-source dependent. With the increase of modifier content, the continuous phase in TPUA gradually changed from asphalt to PU, and the phase transition point was near 30 wt%. When the critical content was exceeded, asphalt was dispersed in the PU skeleton as microspheres. In addition, adding PU increased asphalt polarity, and the SFE of TPUA increased gradually as the modifier content increased.

Experimental study of polyurea-coated fiber-reinforced cement boards under gas explosions

Five types of polyurea elastomers were synthesized by changing the isocyanate component and the mechanical properties of polyurea materials were measured. Fiber-reinforced cement boards (FRCB) strengthened by polyurea with different formulations were processed, and a series of experiments were carried out on the specimens with gas explosion devices. The results showed that the conventional mechanical properties of different types of polyureas had their own advantages. Based on the gas explosion overpressure criterion, the blast resistances of reinforced plates were quantitatively evaluated, and the best polyurea was selected to guide the formulation design. The three typical failure modes of polyurea-reinforced FRCBs were flexural, shear, and flexural–shear failure. Dynamic thermodynamics and shock wave spectral analysis revealed that the polyurea did not undergo a glass transition in the gas explosion tests but retained its elastic properties, allowing it to effectively wrap the fragments formed by the brittle substrates.

Effect of diacylhydrazine as chain extender on microphase separation and performance of energetic polyurethane elastomer

Abstract It is low cost and feasible to improve the mechanical properties of polyurethane by using the chain extender with hydrogen bonding function to improve the degree of microphase separation. In this article, hydrazine hydrate was used to react with ethylene carbonate and propylene carbonate, respectively, to synthesize diacylhydrazines as the polyurethane chain extender with amide bonds, which were characterized by 1H nuclear magnetic resonance. Polyurethane with different contents of hard segment were prepared from poly-3,3-bis(azidomethyl)oxetane-tetrahydrofuran as the polyol and 4,4′-diphenylmethane diisocyanate as the isocyanate components. Fourier transform infrared spectroscopy showed that with the increase of the hard segment content, the proportion of hydrogen-bonded ordered carbonyl group increased to 94%, proving that diacylhydrazines could improve the degree of ordered hydrogen bonding, which led to clear microphase separation observed by field emission scanning electron microscopy and higher storage modulus of the polyurethane. Differential scanning calorimetry and dynamic mechanical analysis showed that polyurethane with higher hard segment content is likely to exhibit multiple thermal transitions caused by microphase separation. When the hard segment content was 40%, compared with polyurethane with 1,4-butanediol as the chain extender, the tensile strengths of polyurethanes with diacylhydrazines also improved by 30% and 76%, respectively.

Characterization and Properties of Polyurea Elastomer Used as Blast Mitigation Agent

The blast that caused from terrorist activities, explosion and weapons effect on not only the human life, but also the architectural structure. The development of materials used to protect them is needed. Polyurea is a one type of elastomer that derive from the reaction product of an isocyanate component and a synthetic resin blend component through step-growth polymerization. It is revealed that polyurea is a new entrant in the field of elastomer has received enormous attention in view of its excellent blast mitigation properties and ballistic protection. In this work, the microstructure and elemental composition of polyurea samples are studied using scanning electron microscope coupled with energy dispersive X-ray spectrometer (SEM-EDS). The main composition consisted of carbon, oxygen and silica approximately 63-75, 17-29, and 0.15-1.69 wt%, respectively. Sulfur and chlorine present as the chain extender. Titanium is added to modify its structure. Other elements present as the additives, fillers and pigments. Atomic force microscopy (AFM) is conducted to confirm nano-scale composition. Dynamic mechanical, thermal and tensile properties are also studied. It is shown that the modulus and loss factor increase as the increasing of the frequency and temperature. The elongation capacity is greater than 100%. Infrared spectroscopy based on synchrotron radiation (SR IR) shows the various constituents of the composition in the form of the functional groups along with the wave number.

Kinetics of cross-linking processes of fast-curing polyurethane system

This work focuses on the application of thermal analysis and kinetics investigations to analyze chemical processes during cross-linking of the complex fast-curing polyurethane system. Non-isothermal Differential Scanning Calorimetry (DSC) measurements were performed for both stoichiometric mixtures of polyol and isocyanate component and for mixture with large isocyanate excess. Isoconversional methods were used to calculate initial parameters for the multi-step procedure. Data were fitted according to autocatalytic Sestak-Berggren equation and activation energies and reaction orders were obtained. Those investigations led to the successful identification of three main reactions i.e. polyaddition, isocyanate deblocking and formation allophanate groups.

Reaction of jute fiber with isocyanate component for the production of plant fiber-reinforced polyurethane composites

It is thought that hydroxyl groups of plant fiber may react with isocyanate groups during the preparation of plant fiber-reinforced polyurethane composite, resulting in good interfacial bonding. In this work, jute fiber was reacted with polymethane polyphenyl isocyanate (pMDI) under different conditions, and the degree of reaction was evaluated using Fourier transform infrared spectroscopy and elemental analysis. The degree of reaction largely depended on the accessibility of the hydroxyl groups of the jute fibers and it increased with the reaction time and temperature. Thus, to obtain good interfacial bonding sufficient reaction time and a proper high temperature should be provided for the reaction of plant fiber with an isocyanate component in the preparation of plant fiber-reinforced polyurethane composites. The activity of catalyst also had a significant effect on the reaction of jute fiber with pMDI. The alkali-treated jute fiber presented clearly lower reactivity to pMDI than the raw fiber for the hydroxyl groups of the former fiber were less assessible. When pMDI reacted with the raw fiber, isocyanate groups primarily reacted with the hydroxyl groups of hemicellulose covering its surface, which might result in interfacial debonding between the hemicellulose molecules bonded to matrix and those adhered by van der Waals forces in raw fiber-reinforced polyurethane composite. When jute fiber reacted with pMDI at room temperature with no catalyst, the reaction rate was extremely low.

In Ukrainian

The purpose of this work was to create оrgano-inorganic composites (ONC) of polyurethane containing sodium silicate and Zn-Al layered double hydroxides (LDH). Macrodiisocyanate (MDI) was selected as an organic matrix on the basis of a simple oligoether - oligooxypropylene glycol (OOPG) M w = 1052. In the synthesis of MDI, an isocyanate component was used as toluene diisocyanate (TDI). Molar ratio of OOPG: TDI was 1: 2. The content of isocyanate groups in MDI was ≈ 3.6 % wt. Synthesis of organo-inorganic composites in the form of films was carried out by introducing a Zn-Al solution of LDH into sodium silicate, followed by addition to the reaction mixture of MDI, at constant stirring at room temperature. The compositions were obtained with a ratio of inorganic component to organic as 40:60 parts by weight. It is found that the Zn-Al LDH are not chemically bound to the components of polymeric hybrides and play the role of the filler. X-ray studies have shown that when a modifier is introduced, a homogeneous amorphous system is formed. The study of the physico-mechanical characteristics of the ONC has shown that the introducing of Zn-Al LDH leads to a reduction in the tensile straight, which is accompanied by a simultaneous increase in elongation at break of organic inorganic specimens. An obvious explanation for the changes in the physical and mechanical characteristics of created nanohybrides is that the introduction of Zn-Al LDH leads to a change in the phase interaction of sodium silicate with a polymer matrix, which determines the structure of these composites, and hence mechanical characteristics. An increase in the absorption capacity of the water for obtained composite materials was found. The development of nanomaterials for use as a polyurethane filler is a promising area of research, since these composites can be used as protective coatings for reinforced concrete structures.

Testing of Disposable Protective Garments Against Isocyanate Permeation From Spray Polyurethane Foam Insulation.

Diisocyanates (isocyanates), including methylene diphenyl diisocyanate (MDI), are the primary reactive components of spray polyurethane foam (SPF) insulation. They are potent immune sensitizers and a leading cause of occupational asthma. Skin exposure to isocyanates may lead to both irritant and allergic contact dermatitis and possibly contribute to systemic sensitization. More than sufficient evidence exists to justify the use of protective garments to minimize skin contact with aerosolized and raw isocyanate containing materials during SPF applications. Studies evaluating the permeation of protective garments following exposure to SPF insulation do not currently exist. To conduct permeation testing under controlled conditions to assess the effectiveness of common protective gloves and coveralls during SPF applications using realistic SPF product formulations. Five common disposable garment materials [disposable latex gloves (0.07 mm thickness), nitrile gloves (0.07 mm), vinyl gloves (0.07 mm), polypropylene coveralls (0.13 mm) and Tyvek coveralls (0.13 mm)] were selected for testing. These materials were cut into small pieces and assembled into a permeation test cell system and coated with a two-part slow-rise spray polyurethane foam insulation. Glass fiber filters (GFF) pretreated with 1-(9-anthracenylmethyl)piperazine) (MAP) were used underneath the garment to collect permeating isocyanates. GFF filters were collected at predetermined test intervals between 0.75 and 20.00 min and subsequently analyzed using liquid chromatography-tandem mass spectrometry. For each garment material, we assessed (i) the cumulative concentration of total isocyanate, including phenyl isocyanate and three MDI isomers, that effectively permeated the material over the test time; (ii) estimated breakthrough detection time, average permeation rate, and standardized breakthrough time; from which (iii) recommendations were developed for the use of similar protective garments following contamination by two-component spray polyurethane foam systems and the limitations of such protective garments were identified. Each type of protective garment material demonstrated an average permeation rate well below the ASTM method F-739 standardized breakthrough rate threshold of 100.0 ng/cm2 min-1. Disposable latex gloves displayed the greatest total isocyanate permeation rate (4.11 ng/cm2 min-1), followed by the vinyl and nitrile gloves, respectively. The Tyvek coverall demonstrated a greater average rate of isocyanate permeation than the polypropylene coveralls. Typical isocyanate loading was in the range of 900 to 15,000 ng MDI/cm2. Permeation test data collected during this study indicated that each type of protective garment evaluated, provided a considerable level of protection (i.e. 10-110-fold reduction from the level of direct exposure) against the isocyanate component of the SPF insulation mixture. Nitrile gloves and polypropylene coveralls demonstrated the lowest rate of permeation and the lowest cumulative permeation of total isocyanate for each garment type.

Exposure to organophosphate flame retardants in spray polyurethane foam applicators: Role of dermal exposure

BackgroundSpray polyurethane foam (SPF) is a highly effective thermal insulation material that has seen considerable market growth in the past decade. Organophosphate flame retardants (PFRs) are added to SPF formulations to meet fire code requirements. A common flame retardant used in SPF formulations is tris 1-chloro 2-propyl phosphate (TCIPP), a suspected endocrine disruptor. Exposure monitoring efforts during SPF applications have focused primarily on the isocyanate component, a potent respiratory and dermal sensitizer. However, to our knowledge, there is no monitoring data for TCIPP. ObjectiveTo characterize occupational exposures to TCIPP and other flame retardants during SPF insulation. MethodsWorkers at four SPF insulation sites and one foam removal site (total n = 14) were recruited as part of this pilot study. Personal inhalation exposure to TCIPP was monitored with a CIP-10MI inhalable sampler and potential dermal exposure was assessed through the use of a glove dosimeter. Biomarkers of TCIPP and three other PFRs were measured in urine collected from workers pre-and post-shift. Linear mixed effect models were used to analyze associations of urinary biomarkers with inhalation and dermal exposures and paired t-tests were used to examine the difference on the means of urinary biomarkers pre-and post-shift. Chemical analysis of all species was performed with liquid chromatography-electrospray ionization tandem mass spectrometry. ResultsGeometric mean (GM) concentrations of TCIPP in personal air monitors and glove dosimeters collected from SPF applicators, 294.7 μg/m3 and 18.8 mg/pair respectively. Overall, GM concentrations of the two TCIPP urinary biomarkers BCIPP and BCIPHIPP and (6.2 and 88.8 μg/mL) were 26–35 times higher than reported in the general population. Post-shift levels of TCIPP biomarkers were higher than pre-shift even though workers at insulation sites wore supplied air respirators, gloves and coveralls. The urinary biomarkers for the other PFRs were not elevated post shift. Concentrations of TCIPP on glove dosimeters were positively associated with post-shift urinary TCIPP biomarkers (p < 0.05) whereas concentrations in personal air samples were not. ConclusionsHigh levels of urinary biomarkers for TCIPP among SPF applicators, including post-shift, points to absorption of TCIPP during the work shift, in spite of the use of best industry exposure control practices. Dermal exposure appears to be an important, if not the primary exposure pathway for TCIPP, although inhalation or incidental ingestion of foam particles post-SPF application cannot be ruled out in this pilot study.

Synthesis of polyurethane dispersion from polyesteramide polyol

Purpose The study aims to synthesise polyurethane dispersion from polyesteramide polyol. The polyesteramide polyol is a novel polyol for the synthesis of polyurethane dispersion. Design/methodology/approach Polyesteramide polyol has been synthesised from phthalic anhydride and fatty amide of mustard oil. Aminolysis of mustard oil had been carried out with diethanolamine. The novel polyurethane dispersion had been synthesised using a polyesteramide polyol as a precursor. Isophorone diisocyanate was used as an isocyanate component and polyurethane dispersion (PUDs) had been synthesised by an anionic method where DMPA was introduced to introduce –COOH groups as via grafting to the resin backbone. Triethylamine was used for neutralisation and, hence, for further dispersion in water. Hydroxyl ethyl methacrylate was used for the synthesis to introduce unsaturation in the backbone of PUDs. The coating was made by an UV curing process. The coating was characterised for mechanical properties, chemical properties, thermal properties as well as stain resistance. Findings The polyurethane dispersion formed through it has ester and amide linkage present in it. The acetone process is used for its synthesis. The nuclear magnetic resonance spectroscopy confirms the successful formation of polyesteramide polyol and PUDs. Even though long aliphatic chains present in polyol which may impart hydrophobicity the synthesis PUDs well dispersed in water. It is observed as the coating made from it have hardness and scratch resistance properties. The coating also exhibits good stain resistance properties. Practical implications The method is an easy one to synthesise polyurethane dispersion from polyesteramide polyol, which is based on ester and amide linkage. Originality/value To the best of the authors’ knowledge, this is the first report on synthesised polyurethane dispersion from polyesteramide polyol. The polyesteramide resin already proves its excellence and upcoming technology in the coating industry. Here, they are incorporated into the synthesis of polyurethane dispersion.

Coupling of poly(lactic acid) with a polyurethane elastomer by reactive processing

A segmented polyurethane elastomer (PU) was synthesized in poly(lactic acid) (PLA) melt by reactive processing. The isocyanate component was anticipated to react with the end-groups of PLA resulting in the formation of block-copolymers. The stoichiometry of the functional groups was optimized in the preliminary experiments. Two different processing methods were compared in the further experiments: conventional mixing of PU with PLA (PLA/PU), and reactive blending (PLA-b-PU). The comparison of the structure and properties of compatibilized reactive blends and conventional physical blends clearly shows the benefits of reactive processing. Coupling resulted in a finer dispersion of the particles in the matrix leading to better mechanical properties in the reactive blend. The successful synthesis of PLA-b-PU block copolymers was confirmed by NMR spectroscopy. The isocyanate component was found to react only with the hydroxyl end-groups of PLA, while the formation of amide and acylurea groups was not detected on the carboxyl end.

THE INFLUENCE OF BIO-BASED CHAIN EXTENDER ON THE POLYURETHANE PROPERTIES

The development of polymers obtained from renewable raw materials is important because it is known that the fossil sources will be depleted in the future. Due to this fact, the possibilities for the synthesis of polyurethanes based on renewable resources increases. This work analyzes the properties of polyurethane materials obtained from the renewable resources. Polyurethane elastomers were prepared by a two stage process in solution, which involved the synthesis of the pre-polymer and synthesis of the polyurethane elastomer. As a polyol component, poly (propylene glycol) was used. Isophorone-diisocyanate and hexamethylene diisocyanate were employed as isocyanate components. For some samples, petrochemically obtained chain extender, butanediol, was replaced by biobased product isosorbide. Characterization of polyurethane materials was carried out by infrared spectroscopy with Fourier transformation, thermogravimetric analysis and differential scanning calorimetry. The properties of synthesized polyurethane materials were improved by adding the nanoparticles in various proportions.