DMPA Content Research Articles

The missing piece: Effect of dangling chains on the synthesis and properties of bio‐based waterborne polyurethane

AbstractBio‐based polyols derived from vegetable oils generally contain the dangling chains, which have recently attracted significant attention due to their influence on the preparation and performance of the waterborne polyurethane. Herein, a novel undecylenic‐based primary glycol (UPG) without dangling chains synthesized and the oleic‐based primary glycol (OPG) with dangling chains reported by our previous work were used to prepare straight‐chain and dangling‐chain bio‐based waterborne polyurethane (BWPU), respectively, to study the difference between the two diols and the effects of dangling chains on the synthesis and performance of BWPU. First, the UPG without dangling chains displayed higher activation energy (Ea/Eo = 77.72/80.56 kJ mol−1) and longer reaction end point of prepolymer (240 min), indicating relatively lower reactivity to isocyanate. In addition, the dangling chains were found to influence the dispersion stability of BWPU, and the minimum dosage of DMPA for maintaining dispersion stability was 6.5 wt% for OPG but 5.5 wt% for UPG. The average particle size of BWPU is greater for OPG than for UPG with the same DMPA content. Finally, performance studies revealed that dangling‐chain BWPU showed higher hydrophobicity, extensibility, and low temperature resistance, but lower thermal stability (Td5%) and tensile strength. This work comprehensively clarified the effects of linear and branched bio‐based polyols on the synthesis and properties of BWPU, and provided guidance for the development and application of bio‐based polyols and BWPU coatings.

PH-Responsive Pickering high internal phase emulsions stabilized by Waterborne polyurethane

HypothesisWaterborne polyurethane (WPU) is a common colloidal dispersion that can aggregate in the aqueous phase to form nanoparticles with hydrophobic polyurethane chains as the core and hydrophilic ionic groups as the shell. Considering their structure and pH-responsive functional groups, WPU nanoparticles could be ideal particulate emulsifiers for preparing pH-responsive Pickering high internal phase emulsions (HIPEs). ExperimentsA series of anionic WPU with different content of 2,2-bis(hydroxymethyl)propionic acid (DMPA) side chains were synthesized via a polyaddition reaction. The DMPA content, size, ζ-potential, and interfacial behaviors of WPU were then investigated. Furthermore, the effects of particle concentration, internal phase fraction (ϕ), oil type, and pH values on the Pickering HIPEs’ morphology, stability, and rheological behaviors were systematically studied. Finally, we demonstrated the emulsification–demulsification process of WPU-stabilized Pickering HIPEs and discussed its mechanism. FindingsOil-in-water (O/W) Pickering HIPEs with tailored morphology and excellent pH-responsiveness were prepared from anionic WPU nanoparticles. The WPU concentration, ϕ, and oil type had a large impact on the formation and mean droplet size of the WPU-stabilized emulsions. Rheology analysis demonstrated that the strictly limited movement of droplets endowed the WPU-stabilized HIPEs with high stability, shear sensitivity, and excellent thixotropic recovery. By simply changing the aqueous-phase pH value, the WPU-stabilized HIPEs could undergo more than ten emulsification-demulsification cycles, as the physical and interfacial properties of WPU nanoparticles were pH-dependent. The excellent performance of the WPU-stabilized pH-responsive Pickering HIPEs exhibited their potential practical applications, such as for oil transportation and recovery, emulsion polymerization, and heterogeneous catalysis.

A novel UV-curable waterborne polyurethane-acrylate coating based on green polyol from hydroxyl telechelic natural rubber

A novel UV-curable waterborne polyurethane-acrylate (WPUA) was firstly prepared based on hydroxyl telechelic natural rubber (HTNR) via sequential emulsion polymerization. The WPUA was composed of HTNR, Hexamethylene diisocyanate (HDI), 2-hydroxyethyl acrylate (HEA), and the content of hydroxymethyl propionic acid (DMPA) was studied for effects on particle size, stability, and morphology of the new series of WPUA dispersions. The WPUA had a good stability at a total solids content of about 20%. Particle size and dispersion stability slightly decreased with DMPA content. The WPUA gave a good film formation and can provide good wettability with high surface free energy. The mechanical and thermal properties of WPUA film were improved by UV-curing. The effects of photoinitiator (Darocur1173) content were investigated. The UV-cured WPUA films showed better mechanical properties and less water absorption than the not cured WPUA film. Also, the surface wetting was the improvement in the water resistance of the coating on the substrate. In addition, the thermal properties by TGA and the dynamic properties by DMTA slightly increased with photoinitiator dose level due to the higher crosslink density and decreasing the molecular weight between crosslink (Mc) caused the Tg shift to a higher temperature.

Synthesis and Characterization of Epoxy Resins-Modified Waterborne Polyurethane Emulsion

Aqueous polyurethane emulsion was prepared with diphenylmethane diisocyanate (MDI), polybutylene adipate diol (PBA-1000) as main raw materials and 2, 2-dihydroxymethyl propionic acid (DMPA) as hydrophilic chain extender. On this basis, epoxy resin E-44 was introduced to modify the polyurethane prepolymer, and epoxy resin modified waterborne polyurethane emulsion was obtained. In order to obtain better performance waterborne polyurethane, the effect of DMPA content、the amount of epoxy resin added and modification method on the properties of polyurethane was discussed. The results show that when the DMPA content is 4wt%, the overall performance of the emulsion and the film is the best. And the addition of epoxy resin significantly improves the water resistance, solvent resistance and tensile strength of the waterborne polyurethane film, and its hardness and thermal stability are also improved to a certain extent. When the amount of epoxy resin added is 8wt%, the storage stability decreases significantly, the suitable amount of epoxy resin added is 6wt%. The overall performance of the film obtained by chemical modification is better than that of physical modification.

Tailoring the properties of waterborne polyurethanes by incorporating different content of poly(dimethylsiloxane)

A series of novel waterborne polyurethanes (WBPUs) was synthesized using α,ω-dihydroxypropyl poly(dimethylsiloxane) (PDMS), isophorone diisocyanate (IPDI), 2,2-bis-(hydroxymethyl) propionic acid (DMPA) and triethylamine (TEA). Different DMPA/PDMS molar ratio (from 0.2 to 0.7) and fixed –NCO/–OH molar ratio of 1.7, has been applied for the synthesis of six different WBPU films, without utilization of chain extension step during the synthesis. The structure of the prepared WBPUs was examined and confirmed by FTIR and NMR spectroscopy. The particle size of the prepared WBPU dispersions and molecular weight of WBPU films decrease with increasing DMPA content. In order to investigate the effect of the DMPA/PDMS ratio on thermal, mechanical and morphological properties, as well as the water resistance of the prepared WBPUs, diverse experimental techniques, such as thermogravimetric analysis, dynamic mechanical analysis, tensile tests, X-ray diffraction analysis (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM) and water contact angle measurements have been carried out. This research has shown that the incorporation of PDMS in WBPUs led to the appearance of microphase separation and provided surface hydrophobicity, good thermal and mechanical properties, which allow application of these WBPUs as coatings for various purposes.

Synthesis and Characterization of Photocrosslinked Biobased Polyester Membrane

A series of bio-based photocrosslinked polyester membranes, poly(1,8-octanediol-itaconate-citrate-dodecandioate), (POSCI) were synthesized through polycondensation followed by photocrosslinking under UV irradiation in the presence of 2,2-dimethoxy-2-phenylacetophenone (DMPA) as photoinitiator (PI). Upon varied UV exposure time and DMPA content, the corresponding changes in chemical, structural, and mechanical properties of the polymer were studied. The transmission peak of FTIR spectrum centred at 1725 cm-1 indicates the formation of ester structure. Contact angle results suggested all of the synthesized POSCI membranes had hydrophilic properties as their contact angle is less than 90 °. Sol-gel analysis shows that the swelling ratio of POSCI decreases while the gel fraction increases with increasing in photocrosslinking time. The tensile strength of POSCI, thus, increased correspondingly with longer UV exposure. Excess DMPA, however, proved otherwise.

The polyurethane/polyacrylate soap-free emulsion formation: effects of hydrophilic polyurethane

The vinyl group terminated water-borne polyurethanes (WPU) with different DMPA content were prepared. Subsequently the core-shell polyurethane/polyacrylate (PUA) composite emulsions were synthesized by soap-free emulsion copolymerization. The WPU as sole surfactant was used in copolymerization, and the lowest surface tension could be achieved to 38.8 mN m−1. Furthermore, the final conversion of acrylic monomer was reached to 98% in the case of WPU reactive seed. The FTIR-ATR indirectly confirmed the core-shell structure of PUA, simultaneously combined with DSC results found that the compatibility of WPU and PA was enhanced by growing grafting efficiency. The TEM results further indicated that the amount of DMPA in WPU had a great significant role in polymerization and final morphology structure. The PUA composite particles changed from scattered structure, core-shell structure to multi-core structure with increasing DMPA content. Correspondingly, the reinforcing and toughening effects were also found in PUA films with the increase content of DMPA by tensile testing.

Preparation and research of waterborne polyurethane phase change material 2

ABSTRACTIn this paper, the researcher first designed molecular structure of water-soluble polyurethane phase change material. Then, by taking HDI, PEG, chain extender (DMPA, BDO, EDA), catalyst (DBTDL) and neutralizing agent (TEA) as the main raw material, the author prepared waterborne polyurethane phase change material (WPUPC), which is available for wet spinning. The orthogonal design determined the optimal ratio of raw materials, namely, DMPA content is 7 wt%, R equals 6, emulsifying temperature is 30°C, the reaction temperature is 60°C and the reaction time is 180 min. What's more, WPUPCM was characterized utilizing FTIR, DSC-TG and TG-FTIR. A series of tests indicated that this experiment successfully prepared WPUPCM, which has the following advantages: reversible phase change process, high thermal stability, excellent thermal cycling stability, safety and environmental protection. It is foreseeable that this material has broad application prospects in the field of functional textiles.

Water‐compatible, pH‐sensitive, colour‐changing polyurethane with low‐temperature flexibility

A pH indicator (Bromocresol Green, Bromocresol Purple, or Thymol Blue) is grafted onto polyurethane (PU) using 2,2‐dimethylolpropanoic acid (DMPA) to enhance water compatibility. The indicator‐grafted, water‐compatible PU is analysed for soft‐segment thermal, tensile, and shape recovery properties, fast colour change depending on various pH conditions, and low‐temperature flexibility. The PU surface becomes water compatible as DMPA content increases, and the characteristic UV‐vis absorbance is observed for each grafted indicator. The PU series exhibits a sharp increase in tensile stress and crosslink density at low DMPA content, but a decrease with increased DMPA content. The glass transition temperature increases significantly with increased DMPA content. Shape recovery remains high, but shape retention sharply decreases after an indicator is grafted. The grafting of pH indicator onto PU improves the low‐temperature flexibility and imparts an immediate colour change according to the solution pH and grafted indicator.

Improvements of antimicrobial and barrier properties of waterborne polyurethane containing hydroxyapatite-silver nanoparticles

Three series of waterborne polyurethane (WBPU)/hydroxyapatite (HA) nanocomposite dispersions were prepared with varying HA and 2,2-dimethylol propionic acid (DMPA) content. It was found that the homogeneous distributed HA was highly dependent on the HA and DMPA content, with homogeneous HA found with up to 0.56, 0.95, and 1.33 mol% HA content with respect to 17.03, 22.05, and 24.02 mol% DMPA content, respectively. The hydrogen bonding increased with increased HA content in each series. The tensile strength, Young’s modulus, glass transition temperature, and water vapor permeability (WVP) resistance all increased up to the optimum HA content. The maximum tensile strength, Young’s modulus, glass transition temperature, and WVP resistance were found with 1.33 mol% HA and 24.02 mol% DMPA content, the concentrations at which the maximum homogeneous dispersed HA was observed in the WBPU/HA nanocomposites. A strong antibacterial property was also recorded when 1.33 mol% HA and 24.02 mol% DMPA content in hydroxyapatite-silver polyurethane (WBPU-C/HA3-Ag) coatings were tested against Escherichia coli and Staphylococcus aureus.

Relationship between reagents molar ratio and dispersion stability and film properties of waterborne polyurethanes

Environmentally-friendly waterborne polyurethanes showing a broad range of properties have been synthesized by the prepolymer method. A macrodiol based on poly(ϵ-caprolactone) diol (PCL) was used as soft segment (SS) and isophorone diisocyanate (IPDI), 2-bis(hydroxymethyl) propionic acid (DMPA) and 1,4-butanediol (BD) as hard segment (HS). The IPDI/(PCL + DMPA) and PCL/DMPA molar ratio were varied in order to determine the influence of these variables in particle size and stability of dispersions and also in final properties of polymer films. Particle size of the obtained dispersions, determined by means of dynamic light scattering, showed a narrow distribution with small particle diameters. Isocyanate content increase leads to bigger particles due to urethane linkages which restrict chain mobility, whereas DMPA content increase promotes small particles due to higher density of ionic groups. The stable dispersions have been used for films preparation, which have been characterized from the view point of their physicochemical, thermal and mechanical properties, as well as morphology. The increase of IPDI/(PCL + DMPA) molar ratio leads to higher yield stress, stress at break and modulus, maintaining high elongation at break values. Nevertheless, the increase of DMPA content promotes less crystalline soft domains achieving soft segment strain induced crystallization under stress and thus, obtaining higher stress at break and improving elongation at break. Films surface hydrophilicity is predominantly affected by IPDI/(PCL + DMPA) molar ratio, whereas water diffusion depends on DMPA content.

Synthesis and stability research of reproducible aqueous polyurethane micelles with low de‐blocking temperature

ABSTRACTAqueous polyurethane micelles from 2,4,6‐trichlorphenol blocking terminal‐isocynate pre‐polymer were prepared which could be de‐blocked at low temperature. The prepared aqueous blocked polyurethane micelles (BPUMs) were uniform and spherical micro‐particles. The particle size was decreased with increase of the DMPA content, while it was enlarged at first and then gradually decreased by increasing R‐value. The stability of the micelles was affected by the R value, blocked efficiency and DMPA content. HDI‐BPUMs were more stable than HDI‐BPUMs at the same condition. The stability was further researched by the zeta potential combining with technique and viscosity tracking method, and the initial zeta potential be used as the stability criterion. In addition, a stabilization mechanism of the micelles was proposed. TCP‐blocked TDI‐BPUMs could be initially de‐blocked at about 75°C and TCP‐blocked HDI‐BPUMs was de‐blocked at about 80°C. The de‐blocking temperature could be further reduced in the presence of catalyst, but it was scarcely affected by the change of R‐value and DMPA content. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41908

Novel temperature‐sensitive and pH‐sensitive polyurethane membranes: preparation and characterization

AbstractThe polyurethane (PU) membranes with temperature and pH double sensitivities for water permeation were designed and prepared from a two‐step solution polymerization from the crystalline polycaprolactone diols (PCL), 4,4′‐diphenylmethane diisocyanate (MDI) and pH‐sensitive 2,2‐dimethylol propionic acid (DMPA), etc. The structure and properties of PU membranes were characterized by differential scanning calorimetry meter, contact angle tester, mechanical tester, porosity tests, water flux tests, water absorption tests, etc. Results showed that all PU membranes had a similar crystalline melting transition in their soft segments. With increasing DMPA content, or −COOH group content, the mechanical property of PU membranes was decreased, but the surface wettability and porosity of PU membranes were increased, which were expected to improve the water flux and water absorption of PU membranes. When the environment temperature was raised above the temperature of crystal‐melting transition (Tm) of the soft segments, the water fluxes across these PU membranes changed markedly, showing the temperature sensitivity. When pH varied around the dissociation constant (pKa) of DMPA contained in PU(2), PU(3) and PU(4) macromolecules, their water fluxes and water absorption were also obviously changed, showing the pH sensitivity. © 2014 Curtin University of Technology and John Wiley & Sons, Ltd.

자동차 내장재용 열가소성 폴리프로필렌에 적용되는 선처리제용 친환경 수분산 폴리우레탄-우레아의 제조 및 성질

The significance of thermoplastic polyolefin polypropylene (PP) lies in its potential to replace polyvinyl chloride (PVC), the most widely used material for automobile interiors (door trim, dash board), which discharges harmful compounds in certain conditions. Another benefit of PP (0.855 amorphous 0.946 crystalline g/cm) is its low density compared to that of PVC (1.1-1.45 g/cm), which reduces vehicle weight. Market demand for eco-friendly water-based adhesive/coating material is rising significantly as a substitute for solvent-based adhesive/coating material which emits VOC and causes harmful working conditions. 232 * To whom correspondence should be addressed. E-mail: kimhd@pusan.ac.kr http://cleantech.or.kr/ct/ doi: 10.7464/ksct.2014.20.3.232 pISSN 1598-9721 eISSN 2288-0690 This is an Open-Access article distributed under the therms of the Ceative Commens Attribution Non-Commercial License (http://creativecommons.org/licences/ by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is property cited.. 자동차 내장재용 열가소성 폴리프로필렌에 적용되는 선처리제용 친환경 수분산 폴리우레탄-우레아의 제조 및 성질 233 Under such context, in this study, a series of eco-friendly waterborne polyurethane-urea primer (a paint product that allows finishing paint to adhere much better than if it were used alone) for hydrophobic PP were prepared from different mix of DMPA content, NCO/OH molar ratio, various wt% of silicone diol and various soft segment content, among which DMPA of 21 mole %, NCO/OH molar ratio of 1.2, modified silicone diol of 5 wt% and soft segment content of 73 wt% led to good adhesion strength. Additionally, the incorporation of optimum content of additives (0.5 wt% dispersing agent, 0.5 wt% levelling agent, 1.5 wt% antifoaming agent, 3.0 wt% matting agent) into the optimum waterborne polyurethane-urea also enabled good stability, levelling, antifoaming and non-glossy.

Synthesis of high solid content waterborne polyurethanes with controllable bimodal particle size distribution

ABSTRACTA series of waterborne polyurethane dispersions were synthesized by one‐pot reaction and step‐wise reaction, respectively. The effects of synthetic methods and DMPA content on the particle size distribution (PSD), solid contents and viscosity were studied by laser particle size analyzer, Brookfield viscometer and TEM analysis. High solid content and low viscosity waterborne polyurethanes (WPUs) with controllable bimodal PSD were prepared by one‐pot reaction using 2,2‐dimethylol propionic acid (DMPA) as the only self‐emulsifier. Meanwhile, 40% solid content WPUs with unimodal PSD were obtained by step‐wise reaction at the same formula. With the increment of DMPA content, the ratio of large particles to small particles decreased and two peaks of the particle size finally became one peak by one‐pot reaction while the PSD remained unimodal by step‐wise reaction. The reason leading to the difference of PSD between one‐pot reaction and step‐wise reaction was analyzed and the relationships among PSD, viscosity and solid content were discussed. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40420.

Synthesis and adhesion property of waterborne polyurethanes with different ionic group contents

In this study, a series of waterborne polyurethanes (WPUs) with different ionic group contents were synthesized by varying the amount of the internal emulsifier 2,2-dimethylolpropionic acid (DMPA). The effects of the ionic group content on the stability and adhesion behavior of WPUs were investigated in terms of particle size, viscosity, surface tension, interfacial tension, contact angle, and adhesion performance. It was found that stable WPUs could be obtained when the DMPA content was larger than 3.5 wt% (with respect to the total solid content). Adhesion performance of WPUs to substrates was mainly affected by the wetting of WPUs on the substrates and the molecular interactions between them. With the increase of DMPA content, the surface tension of WPUs as well as the interfacial tension and contact angle between WPUs and polyethylene terephthalate (PET) films increased. Moreover, the adhesion strength of the WPUs firstly increased and then gradually decreased. The type of debonding failure of all the synthesized WPUs on PET films was cohesion failure due to their lower cohesion strength, which was theoretically testified by the comparison between the adhesion energy and cohesion energy.

Properties of waterborne polyurethane (WBPU) coatings: Effect of alkyl chain length of tertiary amines of carboxylic acid salt groups

Waterborne polyurethane (WBPU) dispersions were prepared via a pre-polymer process using 4,4-dicyclohexylmethane diisocyanate (H12MDI), poly(tetramethyleneoxideglycol) (PTMG), 2,2-dimethylol propionic acid (DMPA), ethylene diamine (EDA), and tertiary amines (TAs) with varying amounts of DMPA and TAs. Three TAs with different alkyl chain lengths were used to neutralize the DMPA carboxylic group: N,N-dimethylbutylamine (DMBA, C4), N,N-dimethylhexylamine (DMHA, C6), and N,N-dimethyloctylamine (DMOA, C8). The structures of the synthesized WBPUs were determined via FT-IR and 1H NMR spectroscopic techniques. The effects of DMPA and TA content and the TA alkyl chain length on stability of dispersions and properties such as water swelling (%), glass transition temperature (Tg), tensile strength, binding energy and adhesive strength were investigated. The initial adhesive strength of the intact coatings increased with increasing DMPA and TA content and increasing alkyl chain length of TA. However, after immersion of the coatings in water, the adhesive strength decreased. The maximum adhesive strength under water was observed at a DMPA content of 20.20 mol% with 5.30 wt% DMOA, which has the longest alkyl chain.

Preparation and Properties of Epoxy Resin Modified Waterborne Polyurethane

The 4,4-diphenyl methane diisocyanate (MDI), polyethylene glycol (PEG) and epoxy resin (EP-44 and EP-51) were selected to prepare series of water polyurethane modified by epoxy resin (EWPU) by using chain extender, catalyst, and neutralizer. The influence of such factors as the R (NCO/OH), the contents of DMPA and epoxy resin on the performance of emulsion and film were discussed in details. The results shows that when R was 1.7, DMPA content was 7%, epoxy resin content was 8%, the EWPU emulsion appears brilliantly and shows great stability, it was measured that the water absorption, tensile strength and breaking elongation of the film are respectively 8.41%, 15.52MPa and 318%. Moreover, the comprehensive performance of the WPU modified by E-44 is better than that modified by E-51. According to the FTIR analysis, the EP has been successfully introduced to the waterborne polyurethane molecular chain.

Synthesis, characteristic, and properties of waterborne polyurethane based on natural rubber

AbstractA series of new waterborne polyurethanes (WPUs) was successfully prepared by prepolymer process from renewable source, hydroxytelechelic natural rubber (HTNR), with different amounts of DMPA (1.6–8.4 wt %), different molecular weights (1000–4000 g mol−1), and different levels of epoxide (0%–20%) of HTNR. It was found that the urethane conversions of prepolymer were over 80% as calculated by FTIR technique. The resulting HTNR2000‐based WPUs exhibit a uniform particle size, which decreases from 420‐ to 83‐nm diameters with an increase in the amount of DMPA from 2.9 to 6.6 wt %. The particle size also decreases with an increase of soft segment or with an increase of epoxide content. They are well stable more over 6 months and without a significant difference in particle size compared with starting of them. Chemical structure of WPU films was confirmed by FTIR, 1H‐NMR, and 13C‐NMR. Molecular weight and polydispersity were determined by SEC. In addition, thermal and water uptake properties were investigated. The experimental results reveal that the DMPA content, molecular weight of HTNR, and epoxide content play an important key role in water uptake and thermal properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Synthesis and Properties of Waterborne UV Polyurethane

Toluene diisocyanate(TDI), polyethylene glycol(PEG), double-propionic acid(DMPA), hydroxyethyl methacrylate(HEMA) and other raw materials were used to synthesis UV-curable waterborne polyurethane, and the effect of the synthesis condition on the particle size of the emulsion was investigated in this paper. The structure of the polyurethane was identified by infrared spectroscopy (IR), thermal decomposition properties was measured through the thermogravimetric(TG). The results showed that, the target product is expected waterborne UV polyurethane by IR. With DMPA content increasing, the particle size decrease, stability and appearance of the emulsion turn better. With the mole ration of PEG/DMPA decreasing, adhesion and water absorption of the film increase. TG analysis indicates that the thermal decomposition performance of the Waterborne UV Polyurethane （WPUA） is excellent.