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1.
A method of preparation of an urethane emulsion which provides thermosetting film is described here. By reacting a urethane prepolymer containing terminal isocyanate groups with diethylenetriamine in the presence of ketones, poly(urethane-urea-amine) was prepared. In other organic solvents, however, gelation occurred immediately and preparation of polyurethane-urea-amine was not successful. The function of ketone was ascribed to the tentative formation of a Schiff base between the primary amino group of diethylenetriamine and ketone in situ, and the reaction of primary amine with isocyanate was partly masked to prevent gelation. Then the free amino group is generated when the polymer is treated with epichlorohydrin and the reaction occurs between them. After the solution was neutralized with an aqueous acid, the solvent was removed in vacuo to give a stable self-emulsifiable thermosetting urethane emulsion. Typical mechanical properties of film from this urethane emulsion are also given here.  相似文献   

2.
Synthesis and properties of crosslinked waterborne polyurethane   总被引:3,自引:1,他引:2  
Waterborne polyurethane prepolymer was prepared by the reaction of isophorone isocyanate(IPDI), polyether polyol(PTMG), dimethylol propionic acid(DMPA) and trimethylol propane(TMP), which was modified by silicane coupling agent(APTES) to form highly crosslinked polyurethane emulsion. The films of the waterborne polyurethane were prepared. The structure of the polyurethane was characterized by Fourier transform infared spectrometer (FTIR), X-ray diffraction (XRD) and differential scanning calorimeter (DSC). The mechanical properties and water absorption of the films were measured. FT-IR indicates that APTES reacted with -NCO of polyurethane. XRD and DSC shows that crystallinity of polyurethane decreased with the increase of w(APTES). Tensile strength increases as the NCO/OH ratio increases. Tensile strength of films increases with increase of w(DMPA) and elongation at break decreases. The water absorption decreases with the increase of w(TMP) when w(TMP) is lower than 1.8%. As the mass fraction of APTES increases from 0% to 10%, the tensile strength of PU films increased from 18 MPa to 28 MPa, water absorption and ethanol absorption decreased.  相似文献   

3.
A series of polyurethane microcapsules containing a phase change material (PCM) of n‐octadecane was successfully synthesized by an interfacial polymerization in aqueous styrene‐maleic anhydride (SMA) dispersion with diethylene triamine (DETA) as a chain extender reacting with toluene‐2,4‐diisocyanate (TDI). The average diameter of microPCMs is in the range of 5–10 μm under the stirring speed of 3000–4000 rpm. Optical and SEM morphologies of microPCMs had ensured that the shell was regularly fabricated with the influence of SMA. FTIR results confirmed that the shell material was polyurethane and the SMA chains associated on core material reacted with TDI forming a part of shell material. The shell thickness was decreasing in the range of 0.31–0.55 μm with the molar ratio of DETA/TDI from 0.84 to 1.35 and the weight of core material increasing from 40 to 80% (wt %). By controlling the weight ratio of PCM as 40, 50, 60, 70, and 80% in microPCMs, it was found using DSC that the Tm and Tc of microPCMs were in the range of 29.8–31.0oC and 21.1–22.0°C and an obvious phase change had been achieved nearly the same temperature range of that of PCM. The results from release curves of microPCM samples prepared by 1.4, 1.7, and 2.0 g of SMA indicated the release properties were affected by the amount of the dispersant, which attributed to the emulsion effect and shell polymerization structure. The above results suggest that the shell structure of microPCMs can be controlled and the properties of microPCMs determined by shell will perform proper practical usage. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4996–5006, 2006  相似文献   

4.
Anionic polyurethane prepolymers end‐capped with isocyanate groups were dispersed and chain‐extended in aqueous media using three different extension agents: hydrazine, 1,2‐ethylene diamine (EDA) and 1,2‐propylene diamine (PDA). Two types of prepolymer were used. The first was prepared from isophorone diisocyanate (IPDI), α,α‐dimethylol propionic acid (DMPA) and poly(propylene oxide) diol (PPO) and the second from α,α,α′,α′‐tetramethyl‐1,3‐xylylene diisocyanate (m‐TMXDI), poly(caprolactone) diol (PCL) and DMPA. The colloidal particles which formed in the dispersion process and the constituent poly(urethane–urea) chains were characterised by a combination of dynamic and static light scattering, gel permeation chromatography and FTIR spectroscopy. Using EDA as the extender, a study was made of how the degree of extension depended on the molar ratio of amine to isocyanate groups, [NH2]/[NCO] (= RA, I). It was found that using a stoichiometric balance of isocyanate and amine groups did not lead to high degree of extension, and better chain extension was obtained at lower RA, I values. In a comparative study using stoichiometric balances of isocyanate and amine groups, the degrees of extension obtained using PDA and EDA were approximately the same, while hydrazine was the least effective. Force–extension studies were carried out on samples prepared from films cast from the aqueous poly(urethane–urea) dispersions in order to assess the influence of chain‐extender type and stoichiometry on bulk properties; values of Young's modulus, tensile strength and maximum extension are reported. Copyright © 2003 Society of Chemical Industry  相似文献   

5.
An epoxy resin was used to prepare crosslinked polyurethane hybrid emulsion through the blocked NCO prepolymer mixing process. Due to their hydrophobicity, the amine chain extender, blocked –NCO, and epoxy are located inside the emulsion particles. Thus, the crosslinking reaction occurs mostly in the interior of the particles. In this way, the crosslinking density of the resin is increased without the use of solidifying agents or heating during film formation, and the stability of the emulsions remains uninfluenced. The effects of the type of amine chain extender and the type, dosage, and addition mode of the epoxy resin were studied in terms of mechanical properties and swelling properties in water and toluene of the cast films. Additionally, the stability of the single-pack hybrid emulsion was studied. The results showed that the sample prepared with diethylene triamine had good stability, chemical resistance, and high mechanical strength. The modulus and water resistance of the films increased with the epoxy resin content, which could reach 20 wt%. The type of amine chain extender affected the stability of the emulsions significantly. The molar ratio of NH/NCO at 1:1 led to the best film performance. The optimal temperature of the chain-extension reaction was approximately 80°C. The hybrid emulsions could be stored for at least 6 months without apparent performance changes.  相似文献   

6.
A series of water dispersion polyurethanes dispersions (PUDs) were prepared by polyaddition reaction using isophorone diisocyanate (IPDI), toluene diisocyanate (TDI), poly(oxytetramethylene) glycol (PTMG), dimethylol propionic acid (DMPA), and triol (trade name FA‐703). Various formulations were designed to investigate the effects of process variables such as TDI and FA‐703 on the physico‐mechanical properties of PUD. IR spectroscopy was used to check the end of polymerization reaction and characterization of polymer. Evolution of the particle size distribution, contact angle, Tg, molecular weight, viscosity, and mechanical properties of the emulsion‐cast films were significantly affected by variable content of TDI and FA‐703. Average particle size of the prepared polyurethane emulsions and contact angle decrease with increase of content of FA‐703 and TDI. Molecular weight, Tg, tensile strength, tear strength, hardness, viscosity and elongation at break increase with increase of content of FA‐703 and TDI. The increase of molecular weight, tensile strength, tear strength and elongation at break properties are interpreted in terms of increasing hard segments, chain flexibility, and phase separation in high content of FA‐703 and TDI‐based polyurethane. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

7.
This article concerns the modification of polyurethane using polyamide 6,6 prepolymer to improve the dyeability properties of the polyurethane copolymer with acid dye. First, the carboxyl‐terminated polyamide 6,6 prepolymer was synthesized from adipic acid and 1,6‐diaminohexane. The isocyanate‐terminated polyurethane prepolymer was also synthesized from polytetramethylene glycol and 4,4′‐diphenylmethane diisocyanate in N,N‐dimethylformamide. The polyurethane prepolymer was then extended with a mixture of 1,4‐butanediol and the polyamide 6,6 prepolymer (molar ratios of 1,4‐butanediol to prepolymer being 100%, 75%, 50%, and 25%, respectively). Finally, the poly(urethane–amide) copolymers were dyed with acid dyes. The chemical, physical, and the dyeing properties of the poly(urethane–amide) coploymers are discussed. From the experimental results, it is found that the inherent viscosity of poly(urethane–amide) coploymers is increased with the increasing amount of polyamide content. The structure is proven by infrared spectra, which exhibits the absorption peaks of urethane and amide groups as we expected. From the differential scanning calorimetry measurements, it is found that the poly(urethane–amide) coploymers have two‐phase structures and good phase separation. There are four transition temperatures (Tgs, Tgh, Tms, and Tmh), but only those copolymers in PTMG 2,000 series possess Tms. Moreover, the Tgs is found to change with the length of soft segment, and the Tgh is increased with the increasing amount of polyamide content. Also, the dyed copolymers exhibit higher Tgh than those without dyeing of dye molecule, but the Tgs is not obviously changed. For mechanical properties, it is indicated that both the modulus and the strength of the coploymers are higher than those of unmodified polyurethane, but they are lowered after being dyed with dye molecule due to further separation of intermolecular distance of the dyed polyurethanes. For dye uptake in dyeing properties, it is found to increase with increasing amount of polyamide content. For dye fastness, the dyed copolymers exhibit higher grade of water fastness than that of unmodified polyurethane. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1397–1404, 2003  相似文献   

8.
以四氢呋喃均聚醚和甲苯二异氰酸酯为原料,采用分子蒸馏法合成PU预聚体,以3,3′-二氯-4,4′-二氨基二苯甲烷为扩链剂制备低游离甲苯二异氰酸酯浇注型PU弹性体,并对其性能进行研究。结果表明,与常规PU预聚体与扩链剂的混合体相比,低游离PU预聚体与扩链剂的混合体具有良好的流动性和较快的固化速度;低游离PU弹性体与常规PU弹性体拉伸强度和撕裂强度相差不大,但前者回弹值较大、压缩永久变形较小、动态性能较好。  相似文献   

9.
The temperature dependence of the dynamic viscoelastic behavior of interpenetrating networks (IPN) of polyurethane (PU) prepared from poly(oxypropylenediol) (POP) and toluylene diisocyanate (TDI), and of polyurethane diacrylate (PUA) prepared from POP and TDI by reacting isocyanate groups of the prepolymer with 2-hydroxyethyl acrylate, was measured in the main transition region. The photoelastic behavior of IPN swollen in dimethylformamide (DMF) and methyl ethyl ketone (MEK) was examined in the rubbery region. The temperature dependences of the dynamic Young modulus E* of IPN in the concentration range of PUA ≥ 50 vol.% indicate a pronounced two-phase behavior. The effect of the composition of IPN on the temperature dependence of the modulus E* was quantitatively described by Takayanagi's two-phase model with the conclusion that the PU network is the continuous phase of IPN at ≤ 90% PUA. While in the range of high concentrations of PUA (≥50%) the contributions of phases to E* are additive within the whole range of temperatures, the thermomechanical behavior at low PUA concentrations (≤40%) is more complex. This finding is interpreted by the existence of an interfacial layer which leads to the loss of the distinct two-phase character of IPN. The higher number of elastically active network chains (EANC) of the PUA network compared with the PU network corresponds to different molecular weights of POP used in the preparation of both components. The nonadditive dependence both of the concentration of EANC and of the stress-optical coefficient on composition confirms the heterogeneous character of the IPN structure.  相似文献   

10.
以甲苯二异氰酸酯(TDI)、端羟基聚丁二烯-丙烯腈共聚物(HTBN)、聚四氢呋喃醚二醇(PTMG)为主要原料,3,5-二甲硫基甲苯二胺(DMTDA)为扩连剂,采用浇铸法制备了聚氨酯弹性体。研究了聚氨酯预聚体中NCO含量、HTBN/PTMG质量比、PTMG相对分子质量和改变扩链剂用量以及热处理时间对聚氨酯弹性体力学性能的影响。结果表明,低相对分子质量PTMG和高热处理温度有利于提高聚氨酯弹性体的力学性能,当聚氨酯预聚体中HTBN/PTMG的质量比为50∶50、NCO质量分数为5.98%、NCO/NH2摩尔比为1.20、115℃下热处理2 h时,聚氨酯弹性体的力学性能最佳。  相似文献   

11.
Two series of thermoplastic polyurethane elastomers [poly(propylene glycol) (PPG) based PP samples and poly(oxytetramethylene)glycol (PTMG) based PT samples] were synthesized from isophorone diisocyanate (IPDI)/1,4-butanediol (BD)/PPG and IPDI/BD/PTMG. The IPDI/BD based hard segments contents of polyurethane prepared in this study were 40–73 wt %. These polyurethane elastomers had a constant soft segment molecular weight (average Mn, 2000) but a variable hard segment block length (n, 3.5–17.5; average Mn, 1318–5544). Studies were made on the effects of the hard segment content on the dynamic mechanical thermal properties and elastic behaviors of polyurethane elastomers. These properties of PPG based PP and PTMG based PT samples were compared. As the hard segment contents of PP and PT samples increased, dynamic tensile modulus and α-type glass transition temperature (Tg) increased; however, the β-type Tg decreased. The permanent set (%) increased with increasing hard segment content and successive maximum elongation. The permanent set of the PT sample was lower than that of the PP sample at the same hard segment content. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1349–1355, 1998  相似文献   

12.
Polyurethane (PU) prepolymer was first prepared via introducing double bonds on‐to the PU chains, and then polyurethane–poly (butyl methacrylate) (PU–PBMA) hybrid latex was prepared via miniemulsion polymerization. Transmission electron microscopy, Differential scanning calorimeter (DSC), Fourier transform infrared, and dynamic mechanical analysis were adopted to characterize the hybrid latex and its coating film. Both the coating property and the miscibility of PU–PBMA emulsion have been greatly improved through introducing double bonds into PU prepolymer. With an increase in the molecule weight of PU (MPU), the increase in the particle size of PU–PBMA emulsion was observed plus decreases in the stability of the hybrid latex and conversion of methacrylate. Besides, as MPU increased, the final dried coating film of the hybrid latex showed decreased water resistance, weakened miscibility, and improved mechanical properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

13.
Polyurethane prepolymers are widely used in reactive hot melt adhesives and moisture‐cured coatings. The segmented moisture‐cured formulations, based on polytetramethylene glycol (PTMG‐1000)/trimethylol propane (TMP)/isophorone diisocyanate (IPDI) and PTMG/TMP/toluene diisocyanate (TDI), were prepared with NCO/OH ratio of 1.6 : 1.0. The excess isocyanate groups of the prepolymers were chain extended in the ratio of 2 : 1 (NCO/OH) with different aliphatic diols and 4 : 1 with different aromatic diamines. The surplus isocyanate groups of the formulations were completely reacted with atmospheric moisture, and the thermal stability of the postcured materials obtained as cast films were evaluated by thermogravimetric (TG) analysis. It was observed that initial degradation temperatures were above 270°C, with two‐ or three‐step degradation profiles. The degradation parameters were evaluated using the Broido and Coats–Redfern methods. The thermal resistance of moisture‐cured formulations using diisocyanates with the cycloaliphatic structures (IPDI) and the aromatic TDI, at the same NCO/OH ratio (1.6), and TMP content were compared from the isothermal TG experiments at different temperatures and dynamic TG experiments at different heating rates in nitrogen and oxygen environments. The observation suggests that polyurethane‐containing sulfone groups and straight‐chain diol chain extenders were more stable. It was also observed that at lower temperature polyurethane, prepared from aliphatic diisocyanates (IPDI), was more stable than the aromatic diisocyanate (TDI) containing polyurethanes. At high temperature, the stability order follows the reverse trend. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1509–1518, 2005  相似文献   

14.
Waterborne polyurethane (WPU) was prepared by the reaction of isophorone isocyanate (IPDI), polyether polyol (PTMG1000), dimethylol propionic acid (DMPA), and trimethylol propane (TMP) and 3-aminopropyltriethoxysilane (APTES) as coupling agent. The films of the WPU were prepared by casting emulsions on Teflon surfaces. The structure of the polyurethane (PU) was characterized by Fourier transform infrared spectrometer (FT-IR), thermogravimetry (TG), X-ray diffraction (XRD), and differential scanning calorimeter (DSC). The mechanical properties and solvent absorption of the cast films were also measured quantificationally. FT-IR indicates that –NH2 of APTES reacted with –NCO of PU prepolymer. TG analysis indicates that APTES can improve thermal stability of PU. XRD and DSC show that crystallinity of PU decreased with the increase of w(APTES). It was found that greater mechanical properties of WPU were obtained when chemical networks were formed between PU and APTES. As the mass fraction of APTES increases from 0% to 10%, water absorption decreased from 17% to 8%, ethanol absorption decreased from 46% to 30%. The particle size increases with increase of w(APTES).  相似文献   

15.
Substituted N‐methylanilines are shown to act as blocking agents for toluenediisocyanate. N‐methylaniline‐, N‐methyl‐p‐anisidine‐ and N‐methyl‐p‐nitroaniline‐blocked toluene diisocyanates have been prepared and characterized by FTIR, 1H NMR and 13C NMR spectroscopies, and nitrogen content analysis. A new method for determining the minimum deblocking temperature of the blocked isocyanate is described. The method has advantages in that it can be used to find the minimum deblocking temperature of even non‐volatile blocking agents. The minimum deblocking temperature of the adducts is found to be in the following order: N‐methyl‐p‐anisidine–TDI adduct < N‐methyaniline–TDI adduct < N‐methyl‐p‐nitroaniline–TDI adduct. The anilines exhibit the same trend when they block a polyurethane prepolymer prepared using polypropylene glycol of molecular weight 2000 g mol?1 and tolylene‐2,6‐diisocyanate. The deblocking temperatures are lower in the case of blocked prepolymers than in the blocked adducts. The blocked adducts and prepolymers are reacted with pyromellitic dianhydride (PMDA) in dimethylpropylene urea (DMPU) and the evolution of carbon dioxide is monitored to study the completion of imidization. The reaction time is in accordance with the deblocking ability of the adducts. The regeneration of the blocking agent is confirmed by gas chromatography. © 2002 Society of Chemical Industry  相似文献   

16.
Trimethylol propane (TMP), polyglycol (PG), and toluene diisocyanate (TDI) were reacted in various molar ratios to produce TMP–TDI–PG–urethane prepolymers and then mixed with equivalent isocyanate generator (Desmodur AP-Stable) in a mixture of m-cresol and naphtha to give polyurethane varnishes which finally became crosslinked films by the casting method. The mechanical properties and viscoelasticities of the PG-modified and PG-free polyurethane crosslinked films and the practicability of magnet wires coated with them were studied in this article. Three different PGs used in this experiment were polyethylene glycol, PEG(#400), polypropylene glycols, PPG(#1000) and PPG(#2000). In the case of adding PEG(#400) for modification, strength at break increased but elongation did not change. Meanwhile, glass transition temperature (Tg) shifted to lower temperature with increasing molar ratio. In the case of adding PPG(#1000) and PPG(#2000) for modification, the samples changed their mechanical properties from hard and brittle to soft and tough. With increasing molar ratios, strength at break initially increased and then decreased gradually, and elongation varied a lot and was consistently contrary to strength at break. Tg occurred at two regions: one at high temperature above 100°C for small molar ratios and the other at low temperature below 100°C for high molar ratios. Besides, for all PG-modified polyurethane crosslinked films, strength at break showed a local maximum at TMP/TDI/PG = 1/1/0.5, which indicated their homogeneous structures. The molar ratios of PG-modified urethane prepolymers, which are suitable for manufacturing practical magnet wires according to testing method JIS-C-3211, are as follows: TMP/TDI/PPG(#100) = 1/1/0.15–0.35 and TMP/TDI/PPG(#2000) = 1/1/0.10. PEG(#400)-modified magnet wires were not accepted on the aging test. The properties of crosslinked films of practical magnet wires are generally as follows: strength at break at 200–700 kg/cm2, elongation less than 41%, and Tg at 100–200°C.  相似文献   

17.
以异佛尔酮二异氰酸酯(IPDI)、二羟甲基丁酸(DMBA)和聚四氢呋喃醚二醇(PTMG)等为主要原料,制得聚氨酯(PU)预聚体;然后将其与丙烯酸羟乙酯(HEA)反应,制得HEA封端的聚氨酯丙烯酸酯(PUA)预聚体;最后在PUA预聚体中加入中和剂等助剂,制备出阴离子改性PUA紫外光(UV)固化胶粘剂。研究结果表明:当w(DMBA中-COOH)=1.2%(相对于PU预聚体质量而言)、中和度=n(中和剂)∶n(DMBA)=80%、以PTMG为多元醇且偶联剂采用预处理法加入时,相应的阴离子改性PUA型UV固化胶粘剂的耐水性、粘接强度和耐久性俱佳。  相似文献   

18.
李永鑫 《云南化工》2019,(6):117-118
将聚醚多元醇与MOCA制成交联剂,采用甲苯二异氰酸酯(TDI)与聚醚多元醇制成异氰酸酯预聚体,制备双组分无溶剂高强型聚氨酯防水涂料。分析了预聚体的用量、填料类型与聚醚类型、聚醚多元醇的配比、异氰酸根含量(-NCO)对涂膜力学性能的作用。通过此方式所制备的防水涂料效果良好,可以满足高铁专线混凝土桥梁防水层的相关要求。  相似文献   

19.
Waterborne cationic fluorinated polyurethane (WCFPU) micro-emulsion was prepared by the reaction of isophorone diisocyanate (IPDI), polytetramethyleneether glycol (PTMG1000), 1,4-butanediol (BDO), N-methyldiethanolamine (MDEA), trimethylolpropane (TMP) and perfluoroalkylethyl octanol (FEOH), and then the films of the WCFPU were prepared. The influence on the mechanical properties and water absorption of the films, such as the molar ratio of NCO to OH, the dosage of MDEA, TMP and FEOH, was investigated. Their structure, morphology and heat performance were characterized by fourier transform infared spectrometer (FT-IR), dynamic light scattering (DLS), transmission electron microscope (TEM), X-ray diffraction (XRD), differential scanning calorimeter (DSC) and thermogravimetry (TG). The results revealed that the best mechanical properties and water resistance could be obtained under the condition that NCO/OH molar ratio was 1.25, w(TMP) was 1.1%, w(MDEA) was 7.29% and w(FEOH) was 22.3%. In addition, WCFPU was endowed with low surface energy of its film and the membrane surfaces had excellent water and oil repellency. Furthermore, the thermal stability of the waterborne cationic fluorinated polyurethane increased with the incorporation of perfluoroalkyl chain. And XRD, DSC and TG showed that micro-crystallinity of polyurethane increased with the increase of FEOH, which was benefit to the micro-phase seperation.  相似文献   

20.
油脂基聚氨酯改性脂肪胺水性环氧固化剂的合成及性能   总被引:1,自引:0,他引:1  
以高级脂肪醇聚氧乙烯醚(OE-6)、甲苯二异氰酸酯(TDI)为原料,物料比n(TDI)∶n(OE-6)= 1.05∶1、温度45℃、反应2.5 h合成了端异氰酸酯预聚体,再将其与多元胺按照摩尔比n (多元胺)∶n (预聚体)=1.2∶1、温度40℃、反应3 h扩链,得到油脂基聚氨酯改性脂肪胺水性环氧固化剂(UFAWECAOF)。用红外光谱、 13C-NMR表征了UFAWECAOF的结构。粒径分析表明目标产物具有乳化液体环氧树脂的功能,其与环氧树脂EPON828复配制备的双组分水性涂料涂膜固化物,柔韧性达1 mm、铅笔硬度达3 H、耐冲击性达50 kg/cm。  相似文献   

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