PROGRESS IN ORGANIC COATINGS
·
2021
·
IF 5.161
Man Lu,Chunmei Song,Bo Wan
Hydrophobically Modified Ethoxylated Urethanes (HEURs) were synthesized by a step growth polymerization of polyethylene glycol (PEG, M n = 4000, 6000, 8000) with isophorone diisocyanate (IPDI). The thickeners were produced with different sizes of the hydrophilic section by changing the molar ratios of reactants. The hydrophobic ends, 1-tetradecanol (C14), was constant for all prepared samples. The structure, molecular weight and polymer dispersity index (PDI) of HEUR were characterized by 1 H NMR, IR and GPC respectively. The rheological behavior of the HEUR-thickened latex (Latex/HEUR) was determined by oscillatory and flow experiments. Dramatic increases in viscosity of Latex/HEUR are obtained. Under flow conditions the Latex/HEUR fits the Cross model, showing two regions, a Newtonian and a shear thinning one. Broad thixotropy are observed in hysteresis tests and three interval thixotropy test (3ITT) with decreasing molecular weight of the prepolymer, which was analyzed using a second-order kinetic equation. The results of atomic force microscopy (AFM) and the flow-levelling performance tests for Latex/HEUR films show smoother surface and better levelling with the increase of the hydrophilic component size.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
POLYMER
·
2019
·
IF 3.771
Tao Guan,Zhukang Du,Xueyi Chang,Dongli Zhao,Shurui Yang,Ning Sun,Biye Ren
Hydrophobically modified ethoxylated urethanes (HEURs), as a representative class of associative polymers, are widely used as rheology modifiers in waterborne systems such as coatings, emulsions, inks etc. due to their unique associative network structure and finite relaxation behavior in solution. However, conventional HEURs are non-reactive and generally stay free in final cured films, which may induce some damages to the performance of the coatings. To solve the problem, a new concept of reactive HEUR has been proposed. That is, a reactive HEUR should bear reactive hydrophobic end-groups which can chemically crosslink with matrix resins during the curing process of waterborne coatings. In this work, with the help of the hydrogen abstraction photo-initiating reactivity of benzophenone (BP) group, a reactive HEUR (BPC 11 HEUR) end-functionalized by a photo-initiator BP moiety has been prepared. In aqueous solution, as demonstrated by steady shear measurement, an exponential increment of solution viscosity along with the increasing of polymer concentration ( C ) was found when C surpassed its critical percolation concentration ( C p ≈ 23.6 g/L). Besides, ultraviolet (UV) light induced photolysis in aqueous solution manifested a typical photochemical reaction behavior of BPC 11 HEUR polymer with a final photolysis degree ( D ) of approximate 78% after 300 s of irradiation. In situ 1 H NMR and rheological measurements collectively revealed the efficient photo-initiating reactivity of BPC 11 HEUR for waterborne UV monomers or resins. Further, rheological measurements demonstrated that the emulsion zero/low shear viscosity can be greatly enhanced by ca. 50 folds for a commercially available waterborne UV polyurethane acrylate emulsion when the addition amount of BPC 11 HEUR varied from 0 to 1.0 wt%. These results shown that the reactive BPC 11 HEUR polymer can not only be used to efficiently modify the rheological properties of solutions or emulsions but also can chemically crosslink with waterborne UV acrylic monomers or resins by light irradiation . The work may be of interest for development of reactive HEURs used in waterborne UV coatings, inks, and adhesives, etc.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Coatings Technology and Research
·
2022
·Vol. 20
·期 2
·587-601
·
IF 2.339
Lin Yating,Song Chunmei,Xiao Xiong,Wan Bo
Hydrophobically modified ethoxylated urethane (HEUR) with different structures was synthesized and confirmed by gel permeation chromatography, Fourier transform infrared spectroscopy and nuclear magnetic resonance ( 1 H NMR). We propose the relationship between the temperature insensitivity model and the thickening mechanism of HEUR/latex/Fe 2 O 3 /Zn 3 (PO 4 ) 2 /BaSO 4 suspensions. Meanwhile, the temperature insensitivity of HEUR/C suspensions is the result of two main associations: intermolecular interactions bridging the hydrophobic tails of HEURs and the hydrophobic groups tightly adsorbing onto the latex particle surfaces. A smaller ratio of viscosity (Rv) at 1 s −1 from the steady state condition indicates the better temperature insensitivity of viscosity. The higher degree of crystallinity and rheological activation energy corresponds to a great extent with better temperature insensitivity due to stronger association. The temperature insensitivity is consistent with the longer hydrophobic chain, which was proven by hysteresis tests and oscillatory shear measurements. The storage stability was enhanced in the lockstep with a hydrophobic length of HEUR, which is consistent with the rougher surfaces of HEUR/C films. As an appealing method, the results are meaningful and instructive for coating storage and application. Graphical abstract
An intermolecular network model of HEUR/C is presented, which suggests intermolecular associations in the bridging of hydrophobic tails and the hydrophobic groups adsorbing onto the latex particle surfaces. A temperature insensitivity mechanism model combined with rheology results and AFM is also proposed to clarify the relationship between temperature insensitivity and storage stability and the hydrophobic tail length.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
MACROMOLECULES
·
2016
·
IF 5.554
Zhukang Du,Biye Ren,Xueyi Chang,Renfeng Dong,Jun Peng,Zhen Tong
Hydrophobically modified ethoxylated urethanes (HEURs) belong to an important class of telechelic associative polymers for improving solution rheological properties. We designed and prepared a novel azobenzene end-functionalized HEUR polymer (AzoHEUR), which was used to investigate the effects of hydrophobicity change of end hydrophobes induced by photoisomerization of azobenzene on the solution aggregation and rheological properties. The concentrated AzoHEUR solutions show a reversible rheological property change upon alternative exposure to UV and visible light. We have demonstrated that a reversible change in hydrophilic–lipophilic balance of polymer followed by photoisomerization of azobenzene induces a reversible rearrangement of micellar junctions through loop–bridge or bridge–loop transitions, which reversibly changes not only the network connectivity but also the solution relaxation behavior. Moreover, a structural model is proposed to describe the rearrangement of micellar junctions induced by photoisomerization of azobenzene. The work will not only provide new insights into the effect of hydrophobicity change of stimuli-responsive end groups on the aggregation and rheological behavior of HEUR aqueous solutions but also open a new perspective for development of some special applications of HEURs in fabrication and transmission of soft materials, medicines, cosmetics, inks for inkjet printers, and flow rate controlling systems.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF RHEOLOGY
·
2017
·Vol. 61
·期 1
·107-116
·
IF 3.136
Dong Renfeng,Peng Jun,Chang Xueyi,Zhang Qilu,Hong Liangzhi,Ren Biye
Hydrophobically modified ethoxylated urethanes (HEURs) have been widely used as effective thickeners for improving the solution rheological properties in a variety of applications for over 40 years. We designed and prepared a novel photosensitive spiropyran-functionalized HEUR polymer ( SP-HEUR ), which was used to investigate the influence of hydrophobicity change of hydrophobes induced by photoisomerization of spiropyran (SP) group on the solution aggregation and rheological properties. The concentrated SP-HEUR solutions show an interesting photoresponsive rheological behavior upon alternative exposure to ultraviolet and visible light due to a reversible SP- to merocyanine-form conversion and back. A reversible rearrangement of micellar junctions through loop-bridge or bridge-loop transitions is proposed to interpret the influence of photoisomerozation of spiropyran groups on the associative structure and rheological properties of the polymer solution. This work will not only provide new insights into the influence of hydrophobicity change of hydrophobes on the associative structure and rheological properties of HEUR solutions but also opens a new perspective for the development of some special applications of HEURs in the manufacturing and transmission of soft materials, waterborne coating, inks, medicines, cosmetics, and so on.
研究领域:
材料科学
·
化学工程
·
软物质物理
✓ 已验证
产品关联
DOI
高影响因子
POLYMER ENGINEERING AND SCIENCE
·
2025
·
IF 3.2
Huishan Chen,Xiaoyi Sun,Ning Qing,Liuyan Tang
Hydrophobically modified ethoxylated urethane (HEUR), a typical polymer associative thickener, is extensively applied in aqueous coatings, textile printing, and resin coatings to regulate the rheological properties of the system. However, conventional branched HEURs face two critical limitations: (1) the risk of excessive cross-linking during the chain-expansion stage due to high monomer reactivity; (2) the phase-separation phenomenon in some branched HEUR aqueous solutions upon standing. To overcome these challenges, we designed and synthesized a polyhydroxy hyperbranched structure (PU-OH 3-6 ). This structure features two main advantages: a larger central backbone and a greater spacing between active groups (OH). The hyperbranched HEUR 3-6 synthesized using PU-OH 3-6 as a branched-type chain extender is more controllable and viable in the production process. Moreover, various testing methods were employed to assess the thickening performance, salt resistance, and water retention of HEUR in a pure-water system. The results indicated that the branched structures of HEUR 3-6 have better thickening properties compared with the previously reported HEUR with a linear structure (HEUR L ), and branched HEUR with using gamma-triol (HEUR GI ), pentaerythritol (HEUR P ), and xylitol (HEUR X ) to expand the chain. Among them, HEUR 5 demonstrated the best thickening effect in pure-water systems, while in salt-containing solutions, HEUR 6 with a six-branched degree showed more pronounced anti-electrolyte properties.
研究领域:
高分子科学
·
材料工程
·
化学合成
·
流变学
·
涂料技术
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2016
·
IF 2.76
Feng Wang,Jun Peng,Renfeng Dong,Xueyi Chang,Biye Ren,Zhen Tong
Hydrophobically modified ethoxylated urethanes (HEURs) are an important class of telechelic associative polymers with various industrial applications, in which careful control of the rheology of the solution is required. We report the synthesis of three novel HEUR polymers end-functionalized by dendritic di-substituted benzene alcohol ( HEUR-2Cn , where n is the length of hydrophobic tails) and their rheological properties in aqueous solutions and latex. The concentrated solutions of these HEURs show interesting aggregation and viscoelastic properties dependent of their hydrophobe length: a viscoelastic liquid for HEUR-2C8 , and elastic gels for both HEUR-2C12 and HEUR-2C16 due to their different relaxation behavior. Interestingly, the concentrated solutions of HEUR-2C16 form the strongest transient network with the largest number density of active micellar junctions and slowest relaxation because of its longest hydrophobe. Furthermore, these HEUR polymers have highly efficient thickening performance in latex compared with a conventional HEUR-C16 with −C 16 H 33 end group, because the dendritic two-tail hydrophobes can form more stable absorption on the surface of the latex through bridging between the latex particles than a single hydrophobe. This work opens a new perspective for highly efficient thickeners and also provides new insights into the potential of these HEUR polymers in waterborne coating, cosmetics, dyestuff, medicines and so on.
研究领域:
材料科学
·
化学工程
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）