Synthesis and properties of waterborne poly(urethane urea)s containing polydimethylsiloxane

To obtain flexible waterborne poly(urethane urea) (WBPU) coatings with functionalities such as shape recovery and water resistance, we synthesized a series of WBPUs by a prepolymer mixing process from hexamethylene diisocyanate, polyol, 2,2‐bis(hydroxymethyl) propionic acid, ethylenediamine, and triethylamine with polyol blends [hydroxyl‐terminated polydimethylsiloxane (PDMS) with a number‐average molecular weight of ≈ 550 and poly(tetramethylene oxide) glycol (PTMG) with a number‐average molecular weight of 650] of different molar ratios. The effects of the PDMS content in PDMS/PTMG on the dynamic thermal and mechanical properties, hardness, tensile properties, water resistance (water absorption, contact angle, and surface energy), and shape‐memory properties of WBPU films were investigated. As the molar percentage of PDMS in WBPUs increased, the storage modulus, tensile strength and modulus, elongation at break, hardness, and shape‐retention rate (30–15%) decreased; however, the water resistance and shape‐recovery rate (80–90%) increased. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Properties of Waterborne Polyurethane Adhesives: Effect of Chain Extender and Polyol Content

A series of waterborne polyurethane (WBPU) adhesives were prepared with various ratios of polyol, poly(tetramethylene oxide glycol) (PTMG), and chain extender, ethylene diamine (EDA), at a fixed content of diisocyanate, 4,4-dicyclohexylmethane diisocyanate (H₁₂MDI) and hydrophilic agent, 2,2-dimethylol propionic acid (DMPA). WBPU adhesives were characterized by IR and ¹H-NMR spectroscopies, X-ray diffraction (XRD) and gel permeation chromatography (GPC). It was found that the extent of hydrogen bonds between hard–hard segment (i.e., hydrogen bonds between the NH and carbonyl groups) increased with increasing chain extender content (decreasing polyol content). Moreover, the disordered hydrogen bond of carbonyl group (hydrogen bond of urethane groups in the interfacial region) increased with increasing chain extender content (decreasing polyol content). The cyclic urea and allophanate group, which are attributed to the side reaction and cross-linking reaction, respectively, were found above a molar ratio 0.17 of chain extender to diisocyanate. The adhesive strength was maximum with 0.95 wt% and 63.10 wt% chain extender and soft segment (PTMG), respectively (H2 sample) at room temperature for the WBPU adhesive. However, with increasing application temperature the adhesive strength decreased for all samples.     

预聚体法制备聚醚聚氨酯胶粘剂

以四氢呋喃-环氧丙烷共聚醚三醇、甲苯二异氰酸酯、1，4-丁二醇、白炭黑为原料，合成了聚醚预聚体，以四氢呋喃-环氧丙烷共聚醚三醇为固化剂，制备了双组分无溶剂聚氨酯胶粘剂。研究了硬段比例，NCO质量分数、白炭黑用量、预聚体贮存时间等因素对预聚体和胶粘剂性能的影响，测试了预聚体的粘度和NCO质量分数，以及胶粘剂固化物的力学性能，粘接强度。测试结果表明，将1，4-丁二醇（BG）和四氢呋喃-环氧丙烷共聚醚三醇（JF）的羟基摩尔比值控制在1.5，NCO质量分数控制在5.6%左右，白炭黑用量为10g，可以获得工艺性能和贮存性能良好的聚醚预聚体，与聚醚固化剂配制，可以获得比较高而且稳定的力学性能和粘接强度。     

PCL–PEG–PCL triblock ester–ether copolydiol-based waterborne polyurethane. II. Effect of NCO/OH mole ratio and DMPA content on the physical properties

This article was focused on the effects of the NCO/OH molar ratio and 2,2-bis(hydroxyl methyl) propionic acid (DMPA) content during prepolymerization on the physical properties of synthesized waterborne polyurethane (WBPU) by using the polycaprolactone–poly(ethyl glycol)–polycaprolactone triblock copolydiol (PCL–PEG–PCL) as the soft segment. The results showed that the particle size of the WBPUs' dispersion decreased with a decreasing NCO/OH molar ratio or increasing DMPA content. Regarding thermal and mechanical properties, the WBPUs had a higher T_g's and lower T_m's and a higher breaking stress and a lower breaking strain of film with the NCO/OH molar ratio or DMPA content increase. The increasing NCO/OH molar ratio was advantageous to the water vapor permeability (WVP)-breaking stress balance, but the effect of the DMPA content on the WVP was not significant. The WBPU with PCL–PEG–PCL as the soft segment had a smaller particle size in dispersion and a better WVP-breaking stress balance than those of WBPU with the blending PCL and PEG as the soft segment. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1301–1311, 1998     

Preparation and properties of MDI/H12MDI‐based water‐borne poly(urethane‐urea)s—Effects of MDI content and radiant exposure

Water‐borne poly(urethane‐urea)s (WBPUs) were prepared by a prepolymer mixing process using aromatic diisocyanate (MDI, 4,4′‐diphenylmethane diisocyanate)/aliphatic diisocyanate (H₁₂MDI, 4,4′‐methylenebis cyclohexyl isocyanate), polypropylene glycol (PPG, M_n = 1000), dimethylol propionic acid, and ethylene diamine as a chain extender, and triethylamine as a neutralizing agent. The effect of MDI on the molecular weight, chemical structure, dynamic thermo, and tensile properties of WBPUs was investigated. The yellowness index (YI, photo‐oxidation behavior) change of WBPUs under accelerated weathering exposure was also investigated. The WBPUs containing higher MDI content showed lower molecular weight, which verified the participation of some high reactive isocyanate groups of MDI into side reaction instead of chain growing reaction. As the MDI content increased, the storage modulus and tensile modulus/strength of WBPUs film increased, and their glass transitions of soft segments (T_gs) and hard segments (T_gh) were shifted to higher temperature. The intensity of tan δ peak of all three samples increased with increasing radiant exposure. The YI of H₁₂MDI‐based WBPU sample (WBPU‐0) was not occurred. The YI of WBPUs containing MDI increased with increasing MDI content and radiant exposure. However, the YI of sample WBPU‐25 containing 25 mol % of MDI at 11.3 MJ/m² (radiant exposure) was 6.6 which is a permissible level for exterior applications. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation and properties of polydimethylsiloxane (PDMS)/polytetramethyleneadipate glycol (PTAd)-based waterborne polyurethane adhesives: Effect of PDMS molecular weight and content

Waterborne polyurethane (WBPU) dispersions were prepared by pre-polymer process using siloxane polyol, namely polydimethylsiloxane (PDMS), and polyester polyol, namely poly(tetramethyleneadipate glycol) (PTAd), as a soft segment. Three different molecular weights (M_n = 550, 6000, 110,000) of PDMS and one fixed molecular weight of PTAd (M_n = 2000) was used during preparation of WBPU dispersions. This research aims to explore the potential use of PDMS in complementing WBPU by boosting flexibility, water resistance, and adhesive strength. The water swelling (%), tensile strength, and adhesive strength of WBPUs were investigated with respect to PDMS molecular weight and PDMS content (PDMS mol %). The water swelling (%) and tensile strength decreased with increasing PDMS molecular weight at a fixed PDMS content (mol %) in mixed polyol of WBPU films. By contrast, the peel adhesive strength peaked at 6.64 mol % and 4.43 mol % with molecular weight of PDMS at 550 and 6000, respectively, while it only decreased when the molecular weight of PDMS stood at 110,000. The adhesive strength was almost unaffected with optimum content (6.64 mol %) of lower PDMS molecular weight (M_n = 550) in mixed polyol-based WBPU after immersing the adhesive bonded nylon fabrics in water for 48 h among all of the samples. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

复合膜用双组份聚氨酯胶粘剂的研究

本文确定了复合膜用双组份聚氨酯胶粘剂的组成成份，合成方法和工艺条件。讨论了聚酯多元醇分子是对胶膜力学性能的影响，NCO／OH（摩尔比值）对剥离强度的影响，多异氰酸酯组份的选择等。     

Phase segregation and viscoelastic behavior of poly(ether urethane urea)s

Two poly(ether urethane urea)s were synthesized, one based on poly(propylene glycol) and another one on poly(tetramethylene glycol). Hydrogenated MDI was used as the diisocyanate and propylenediamine as the chain extender. The diisocyanate : polyol : diamine molar ratio was 2 : 1 : 1 for both copolymers. Data from stress-relaxation tests were adjusted to a power law and to the Kohlraush-William-Watts equation. Phase separation and viscoelastic behavior were correlated through the calculation of the time-relaxation spectrum, the steady-state tensile compliance, and the tensile viscosity. The results indicated that the material based on poly(tetramethylene glycol) was the more effectively phase-segregated block copolymer. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 2227–2236, 1997     

Effects of NCO:OH ratio on the mechanical properties and chemical structure of Kraft lignin–based polyurethane adhesive

ABSTRACT

This work aimed to evaluate the influence of the aliphatic and aromatic hydroxyl level on the polyurethane adhesive property and chemical structure. This adhesive was obtained through the reaction of technical Kraft lignin (TKL) as polyol with diphenylmethane diisocyanate (MDI). Thus, lignopolyurethane adhesives were obtained with NCO:OH ratios of 0.8:1.0, 0.9:1.0, 1.0:1.0, 1.1:1.0, and 1.2:1.0. Initially only the TKL aliphatic hydroxyl level was taken into consideration in the stoichiometry in order to define the mass ratio between MDI and polyol. Subsequently, lignopolyurethane adhesive was obtained using the same NCO:OH ratios considering TKL total hydroxyls’ level, and aromatic and aliphatic hydroxyls. The chemical structures of the synthesized adhesives were analyzed by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (¹³C NMR). The mechanical property of the adhesively bonded joints, comprising wood substrates and synthesized adhesives, was measured using single lap shear tests. Results illustrated that by increasing the NCO:OH ratio, there is an increase in the free isocyanate content leading to higher shear strength values. Higher free isocyanate content leads to MDI dimer formation in the lignopolyurethane structure.     

Synthesis and characterization of linear and crosslinked poly(urethane urea) elastomers with triazine moieties in the main chain

A series of new poly(urethane urea) is synthesized via a two-step poly-addition process from polyether, 1,6-hexamethylene diisocyanate, 2,4-diamino-6-phenyl-1,3,5-triazine and different crosslinkers: glycerin or castor oil. The hard to soft segment ratio (OH_polyol/NCO/NH_{2chain extender}) was varied systematically from 1/2/1 to 1/4/3. Poly(tetramethylene glycol) of molecular weight 1,400 was used as the soft segment. The structural behavioral characterization of these polymers was performed through FTIR spectroscopy, thermogravimetric analysis, dynamic mechanical and thermal analysis, stress–strain measurements, and water contact angle measurements. The resulting linear polyurethane urea elastomers exhibit good mechanical properties with breaking strains of 300–890% and tensile strengths of 8–13.5 MPa. Thermogravimetric analysis indicated that the thermal degradation of poly(urethane urea) started at about 280–300 °C, higher than the degradation temperature of conventional polyurethane. The improvement of properties was influenced by the hard segment content and the nature of the crosslinker, but most of all by the structure and amount of the urea introduced through 2,4-diamino-6-phenyl-1,3,5-triazine into the polymer backbone chain.     

Effects of a soft segment component on the physical properties of synthesized waterborne polyurethanes by using triblock ester-ether copolydiol as the soft segment

This paper examines the effect of an ester-ether soft segment structure on the physical properties of synthesized WBPUs. The CET series, CPT series, and CMT series anionic waterborne polyurethane (WBPU) were prepared with PCL-PEG-PCL, PCL-PPG-PCL, and PCL-PTMG-PCL triblock copolydiol as the soft segment. These copolydiols were synthesized from polyethylene glycol (PEG), polypropylene glycol (PPG), or polytetramethylene glycol (PTMG), respectively, by end capping with caprolactone (CL). Particle size and its distribution, solvent absorption, thermal properties, and the mechanical properties of the WBPUs were studied. The particle size of WBPU dispersion was in the sequence of CET > CPT > CMT series. The CET series WBPU had better phase mixing between the soft and hard segment, whereas the CMT series WBPU had good phase separation and better mechanical properties. In addition, both the phase mixing and mechanical properties increased with PCL content, except for the CMT series WBPU.     

Synthesis and properties of waterborne polyurethane adhesives: effect of chain extender of ethylene diamine,butanediol, and fluoro-butanediol

Waterborne polyurethane (WBPU) adhesives were prepared using poly(tetramethylene oxide glycol), 4,4’-dicyclohexylmethane diisocyanate (H₁₂MDI), hydrophilic agent dimethylol propionic acid and chain extender of 2,2,3,3-tetrafluoro-1,4-butanediol (TFBD), ethylene diamine (EDA), and 1,4-butanediol. All three chain extenders have been used as single and mixed (different ratio) content during synthesis, and the effect of chain extender and their content to the properties of tensile strength, Young’s modulus, water swelling (%), and adhesive strength was investigated. The adhesive strength value was higher using EDA as a single-chain extender; however, the potentiality of adhesive strength under water was improved using mixed-chain extenders of EDA and TFBD in WBPU adhesives. The maxima potentiality was observed with 6.31 mole% TFBD and 2.10 mole% EDA in WBPU adhesives.     

Properties of isocyanate‐reactive waterborne polyurethane adhesives: Effect of cure reaction with various polyol and chain extender content

Three series of isocyanate‐reactive waterborne polyurethane adhesives were prepared with various contents of chain extender (4.25/8.25/12.50 mol %) and polyol (20.75/16.75/12.50 mol %). Each series had a fixed amount of excess (residual) NCO group (0.50–2.00 mol %). FTIR and ¹H‐NMR spectroscopy identified the formation of urea crosslink structure mainly above 80°C of various cure temperatures (20–120°C) with excess diisocyanate. The molecular weight, tensile strength, Young's modulus, and adhesive strength depend on excess NCO content and cure temperature and also varied with polyol and chain extender content. The optimum cure temperature was 100°C for all the samples. The tensile strength, Young's modulus, and adhesive strength increased with increasing cure temperature above 60°C up to the optimum temperature) (100°C) and then almost leveled off. Among all the samples, the maximum values of tensile strength, Young's modulus, and adhesive strength were found with 63.22 wt % polyol, 0.93 wt % chain extender, and 1.50 mol % excess (residual) NCO content at 100°C optimum cure temperature. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effect of Poly(dimethylsiloxane) Content on the Properties of Water-Borne Poly(urethane-urea)s Containing MDI

Low photo- and water-resistance is often cited as the problem of MDI-based WBPU. This study addressed this problem. Water-borne poly(urethane-urea)s (WBPUs) were synthesized using a pre-polymer mixing process from 4,4'-methylenebis(phenyl isocyanate)(MDI)/4,4-dicyclohexylmethyl diisocyanate (H₁₂MDI) (15/85 mole %)/dimethylol propionic acid (DMPA)/ethylene diamine (EDA)/triethylamine (TEA) with different poly(propylene glycol) (PPG, M _n = 2000)/hydroxyl terminated poly(dimethylsiloxane) (PDMS, M _n = ～550) molar ratios. This study highlights the effect of PDMS content on the inherent viscosity, hydrogen-bonding, storage modulus, tan δ peak intensity, tensile modulus/strength, elongation (%) at break, water swelling (%), contact angle, and the yellowness index of WBPUs containing MDI. The mechanical properties (strength/modulus), water-resistance and photo-resistance of WBPUs containing MDI increased significantly in proportion to the PDMS content. These results indicate the potential for using multi-performance WBPU with PDPS for WBPU coatings.     

双组分聚氨酯纸塑复合胶粘剂的研制

采用溶剂法合成了一种具有较高固含量、低粘度、贮存稳定的纸塑复合用双组分聚氯酯胶粘剂。探讨了扩链剂用量、NCO／OH摩尔比、双组分胶粘剂配比等因素对胶粘剂性能的影响，并用红外光谱仪对双组分聚氨酯胶粘剂的固化过程进行了表征。结果表明，控制NCO／OH摩尔比值在0．97-0．99之间，聚醚／扩链剂／TDI摩尔比为0．64／0．38／1．00时，合成的聚氨酯复合胶的主剂固含量高、粘度较低，贮存稳定。主剂与固化剂的质量比以10：(1-1．5)为宜。     

Properties of Waterborne Polyurethane Adhesives with Aliphatic and Aromatic Diisocyanates

A series of waterborne polyurethane (WBPU) adhesives were prepared with various ratios of aliphatic/aromatic diisocyanates, namely 4,4′-dicyclohexylmethane diisocyanate (H₁₂MDI) as an aliphatic diisocyanate and 4,4′-diphenylmethane diisocyanate (MDI) as an aromatic diisocyanate with poly(tetramethyleneoxideglycol) (PTMG), ethylene diamine (EDA) and dimethylol propionic acid (DMPA). ¹H-NMR spectroscopy was utilized to investigate the side reaction at the dispersion step during synthesis of WBPU dispersions with respect to aliphatic, aromatic and mixed diisocyanates. The tensile strength, Young's modulus, elongation at break (%), storage modulus, glass transition temperature and adhesive strength were measured with respect to aliphatic/aromatic diisocyanate contents. The adhesive strength was maximum using mixed diisocyanates containing 25 mol% MDI in WBPU adhesives.     

透明聚氨酯胶粘剂及其在透明防弹材料上应用研究

介绍了以聚醚、异氰酸酯、交联剂等为主要原料 ,制备用于生产透明防弹材料的透明聚氨酯胶粘剂 ,讨论了原材料配比、NCO/OH的配比、水含量对胶粘剂的性能的影响 ,确定制备工艺     

Synthesis and properties of highly hydrophilic waterborne polyurethane‐ureas containing various hardener content for waterproof breathable fabrics

As part of an ongoing search for highly hydrophilic waterborne polyurethanes for waterproof breathable fabrics, a waterborne polyurethane [waterborne polyurethane‐ureas (WBPU): P70, the number indicates the poly(ethylene glycol) (PEG) content] dispersion was synthesized from PEG (70 wt %) and dimethylol propionic acid (14 mol %) as the hydrophilic/ionic components, 4,4′‐diisocyanato dicyclohexylmethane as a diisocyanate, ethylenediamine as a chain extender, and aliphatic tri‐isocyanate as a hardener. To determine the best highly hydrophilic WBPU coatings for waterproof breathable fabrics, this study focused on the effect of the hardener content(0–1.2 wt %) in the WBPU P70 sample on the dynamic thermal mechanical properties, contact angle/surface energy, water swelling, water insolubility, and water vapor transmission rate (WVTR). The contact angle, water swelling, glass transition temperature, modulus, and strength increased with increasing hardener content, whereas the surface energy, water insolubility, and WVTR decreased. Sample P70/0.5 (cured sample containing 0.5 wt % of hardener) showed relatively good dimensional stability in water (high water insolubility), strong hydrophilicity (low‐water contact angle/high‐surface energy/high water absorption), and a high WVTR, highlighting its promising applications in waterproof breathable fabrics. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Properties of waterborne polyurethane‐fluorinated marine coatings: The effect of different types of diisocyanates and tetrafluorobutanediol chain extender content

Three series of waterborne polyurethane‐ (WBPU) fluorinated coatings were prepared with single aliphatic (4,4′‐dicyclohexylmethane diisocyanate, H₁₂MDI), aromatic (4,4′‐diphenylmethane, MDI) and a mixture of aliphatic and aromatic diisocyanates (1 : 1). Different contents of 2,2,3,3‐tetrafluoro1,4‐butanediol (TFBD) as a chain extender were used in the WBPU coatings. The fluoro‐enriched surface of the WBPU coatings was obtained with a combination of a high TFBD content (8.77 mol %) as well as the aliphatic or mixed diisocyanates. The tensile strength, Young's modulus, elongation at break (%) and adhesive strength were characterized with respect to the TFBD contents. The mechanical strength and adhesive strength increased with increasing TFBD content in the three series. In artificial salt water, the maximum adhesive strength of WBPU was observed for this coating, which was achieved by TFBD bonded H₁₂MDI of mixed diisocyanates with a higher TFBD content (8.77 mol %). © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39905.     

The influence of the NCO/OH ratio and the 1,6-hexanediol/ dimethylol propionic acid molar ratio on the properties of waterborne polyurethane dispersions based on 1,5-pentamethylene diisocyanate

1,5-Pentamethylene diisocyanate, a novel aliphatic diisocyanate formed from bio-based 1,5-pentamethylenediamine, has been used as a hard segmented material to synthesize polyurethane. In this study, several waterborne polyurethane (WPU) dispersions have been successfully prepared by a prepolymer process from 1,5-pentamethylene diisocyanate poly(polyether) with different NCO/OH ratios and 1,6-hexanediol (HDO)/dimethylol propionic acid (DMPA) molar ratios. The Fourier transfonn infrared (FTIR) spectra, thermogravimetric analysis, differential scanning calorimetry, X-ray diffiraction, and a mechanical tensile test were used to investigate the structures, thermal stability, phase separation, crystallinity, mechanical properties, and adhesive performance of the WPU dispersions. The FTIR results indicate that the degree of hydrogen bonding and the numbers of urea groups increase as the NCO/OH ratio and HDO/DMPA molar ratio increase. Furthermore, the phase separation increases and the thermal stability decreases as the NCO/OH ratio increases or the HDO/DMPA molar ratio decreases. Finally, WPU3.0-2.4 (NCO/OH = 3, HDO/DMPA = 2.4) exhibits a maximum tensile strength and shear strength, pointing to its possible use as an adhesive. These results could provide a very valuable reference for industrial applications of WPU.