聚氨酯微交联弹性丙烯酸酯乳液的制备与研究

通过丙烯酸-β-羟乙酯与端异氰酸酯基聚氨酯预聚物的反应,制备了可参与聚合的聚氨酯大单体,并作为交联剂,采用乳液聚合的方法,对丙烯酸酯乳液进行改性,制备弹性乳液。考察了聚氨酯、乳化剂的用量以及温度对乳液的影响。对乳液涂膜进行了FT-IR和DSC的表征。研究表明:改性乳液具有较好的成膜性,其涂膜具有较好的弹性和机械性能。     

聚脲交联改性丙烯酸酯弹性乳液的制备与性能研究

为了在性能上对聚脲交联改性后的丙烯酸酯乳液(PUA)和纯丙乳液(以)进行比较,文章以丙酮为溶剂,通过端氨基聚醚和甲苯二异氰酸酯的缩合反应合成了端异氰酸酯基聚脲预聚物,由于丙酮与胺基的可逆缩合反应,降低了胺基与异氰酸酯基反应的活性,从而可以更好地控制反应速度,降低副反应的发生几率.聚脲预聚体经丙烯酸羟乙基酯双键封端制备了含有2个双键的聚氨酯脲大单体,以其为外交联剂,通过与甲基丙烯酸甲酯、丙烯酸丁酯的乳液共聚反应制备了聚氨酯脲改性的纯丙弹性乳液,对乳液涂膜进行了FT-IR,DSC和TGA的表征.研究表明:PUA涂膜比PA涂膜具有更好的热稳定性、机械性能、耐低温性以及耐溶剂性.     

涂料和涂膜的检验、分析及评价

PVDTiAIB涂料的纳米结构研究;掺杂萘并吡喃的涂料光致变色性能研究;钝化底漆的铬渗出．第1部分．渗出特性;分散温度和溶剂对不同异氰酸酯封端的水性聚氨酯性能的影响;光透射法测定阴极电泳漆乳液粒径……     

胶粘剂新专利

异氰酸酯基封端的聚氨酯预聚物及其制备方法。以及含有该预聚物的胶粘剂 US7906607B22011-03-15 本发明提供一种熔化时具有低黏度、异氰酸酯基封端的聚氨酯预聚物及其制备方法,以及包含该预聚物的胶粘剂。介绍了一种生产异氰酸酯基封端的聚氯酯预聚物的方法,该方法包括多元醇与聚异氰酸酯化合物的反应。     

自增稠丙烯酸乳液在塑料件用双组分水性金属闪光涂料中的应用

采用自增稠丙烯酸乳液、聚氨酯水分散体、水性铝粉、助溶剂和亲水的聚异氰酸酯固化剂,制备了用于汽车塑料件的双组分水性金属闪光涂料。研究了p H值对自增稠丙烯酸乳液黏度和触变性的影响、自增稠触变效果的持续性,乳液、聚氨酯水分散体配比对涂膜的影响,并对所制备的双组分水性金属闪光涂料进行了涂膜性能测试。     

乳化条件及扩链方式对阴离子脂肪族水性聚氨酯乳液及其涂膜性能影响

以聚酯多元醇、4，4’-二环己基甲烷二异氰酸酯和二羟甲基丙酸为原料，采用预聚物混合工艺合成水性聚氨酯分散体，研究了中和方式、乳化条件和扩链方式对乳液及其涂膜性能的影响，确定了最佳乳化条件、中和工艺和扩链方式。     

丙烯酸改性水性聚氨酯合成方法

介绍了聚氨酯预聚物分散制各水性聚氨酯的方法，讨论了丙烯酸酯改性对水性聚氨酯涂膜的性能影响。分析了亲水性物质、交联剂、扩链剂、引发剂、中和剂、有机溶剂等对水性聚氨酯涂膜外观及性能的影响。     

聚氨酯水分散液

一、前言国外聚氨酯目前在应用多样化、利用途径合理化的发展过程中,同其他聚合物一样,也是向着省资源、安全化和适应环境保护要求的方向发展。在这种发展中。水性化是一条重要的途径。所谓水性化就是以水为溶剂取代传统的有机溶剂,制备出聚氨酯水分散液。本文所说的聚氨酯水分散液包括聚氨酯水乳液、胶体分散液(即微粒乳液)和水溶液等以水为介质的聚氨酯高聚物或预聚物的安定体系,或异氰酸酯及其改性物的水乳液,等暂时安定体系。     

高固体分硅氧烷改性聚氨酯弹性体的研制

采用异氰酸酯TDI和二元、三元聚醚多元醇合成高固体分的端异氰酸根的聚氨酯预聚物,选用不同结构的硅烷偶联剂和异氰酸根反应,制备部分或完全硅烷封端的湿固化聚氨酯弹性体。试验考察了不同的硅氧烷偶联剂以及用量对改性后聚氨酯弹性体合成及其性能的影响。     

ε-己内酰胺-多异氰酸酯封端反应的研究

本文讨论了温度、溶剂、摩尔比、催化剂、不同聚氨酯单体和聚氨酯预聚体对ε-己内酰胺-多异氰酸酯封端反应速度的影响。     

Synthesis and properties of novel polyurethane‐urea insulating coatings from hydroxyl‐terminated prepolymers and blocked isocyanate curing agent

A novel series of one‐pack solvent borne polyurethane‐urea insulating coatings was prepared from hydroxyl‐terminated prepolymers (HTP) and blocked isocyanate curing agent (BIC). HTP was prepared from poly z(tetramethylene ether)glycol (PTMEG) with excess amount of toluene diisocyanate (TDI) and subsequent reaction of NCO‐terminated polyurethane with tris(hydroxymethyl‐aminomethane) (TRIS). BIC was prepared from the reaction of trimethylol propane, TDI, and N‐methyl aniline. HTP, BIC, and final products were characterized by conventional methods, and the curing condition was optimized via gel content measurements. Crosslink density of samples was determined via equilibrium swelling method, using Flory‐Rehner equations. Thermal, mechanical, and electrical properties as well as the chemical resistance of prepared coatings were evaluated and compared with commercially available formulations. Effects of structural parameters on physical, electrical, mechanical, and dynamic mechanical (DMTA) properties of the polyurethane‐urea coatings were investigated. The investigation of results showed superior electrical and mechanical properties of prepared green coating as a tailor‐made electrical insulator for metals. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

聚氨酯涂料的研究进展

综述了聚氨酯涂料用单体、预聚物和环保聚氨酯涂料的研究进展,介绍了聚氨酯涂料性能与应用,指出了聚氨酯涂料的发展趋势。     

Infrared spectral study on the heat curing reaction of glycerin-terminated urethane prepolymers

Glycerin, toluene diisocyanate (TDI), and polyglycol (PG) were reacted at various molar ratios to produce glycerin-terminated urethane prepolymers of different molecular weights. The prepolymers were mixed with equivalent phenol-blocked trimethylol propane–TDI–urethane triisocyanate in m-cresol to give a coating solution. The solution was coated and baked to give polyurethane crosslinked films. The changes of the functional groups during the crosslinking reaction and the mechanical properties of the polyurethane crosslinked films were studies. Experimental results show that the phenol-blocked urethane triisocyanate will deblock phenol to regenerate free isocyanate groups above 120°C and then react with the hydroxyl groups of urethane prepolymers. At 220°C, the rate of deblocking phenol to regenerate isocyanate groups is faster than that of the reaction of urethane prepolymers with isocyanate groups. The deblocking reaction is contemporaneous with the reaction of isocyanate groups with hydroxyl groups, so that the characteristic absorption peaks of isocyanate groups can be observed from IR spectra during the crosslinking reaction. The absorption peak of isocyanate groups gradually decreased with the crosslinking reaction, but the absorption peak increased after curing for about 50–60 min. This feature is caused by the reactivity of the secondary hydroxyl groups of glycerin which is slower than that of the primary hydroxyl groups of glycerin.     

Preparation and properties of novel polyurethane insulating coatings based on glycerin‐terminated urethane prepolymers and blocked isocyanate

Novel polyurethane insulating coatings were prepared from the reaction of glycerin‐terminated polyurethane prepolymers (GPUPs) and a blocked isocyanate curing agent (BIC). The GPUPs were prepared from the reaction of one equivalent of polycaprolactone polyol (CAPA 210) with an excess amount of 4,4′‐methylene bis(phenyl isocyanate) (MDI) and subsequent reaction of the NCO‐terminated polyurethane with glycerin. The BIC was prepared from the reaction of trimethylol propane (TMP), toluene diisocyanate (TDI) and N‐methylaniline (NMA). The polyols and curing agent were characterized by conventional methods while the curing condition was optimized via gel content measurements. The curing kinetics of the polyurethane coating were investigated and the kinetic parameters derived. The crosslink densities of the samples were determined via the equilibrium swelling method, using the Flory–Rehner equation. The relationships between the crosslink density and the electrical, physical, mechanical and dynamic mechanical properties of the coatings were also studied. Copyright © 2005 Society of Chemical Industry     

Novel method for preparation of polyurethane elastomers with improved thermal stability and electrical insulating properties

A novel method was developed for the preparation of polyurethane with enhanced thermal stability and electrical insulation properties via the reaction of epoxy‐terminated polyurethane prepolymer (EPU) and poly(amic acid) (PAA). EPUs were synthesized from the reaction of glycidol with NCO‐terminated polyurethane prepolymers, which were prepared from the reaction of polycaprolactone‐based polyol (CAPA) of different molecular weights and some commercially available diisocyanates including hexamethylene diisocyante, toluene diisocyanate, and 4,4′‐methylene bis(phenyl isocyanate). PAA was prepared from the reaction of equimolar amounts of pyromellitic dianhydride and oxydianiline. The effects of PAA content, the nature of diisocyanate, and the molecular weight of CAPA on the mechanical, thermal, thermomechanical, and electrical properties of the final networks were investigated. The crosslink density of the samples was determined according to an equilibrium swelling method using the Flory–Rehner equation and was correlated to the structure of the final polymers. Gel content and activation energy of network formation in the absence and the presence of a tertiary amine catalyst were also studied. The results showed considerable improvement in the thermal, electrical, and mechanical properties compared to those of other common polyurethanes. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1776–1785, 2007     

Modification of unsaturated polyester resin by polyurethane prepolymers

Unsaturated polyester resins (UPRs) are extensively used by the fiber‐reinforced plastic (FRPs) industry. These resins have the disadvantages of brittleness and poor resistance to crack propagation. In this study, UPRs were chemically modified by reactive blending with polyurethane prepolymers having terminal isocyanate groups. Hybrid networks were formed by copolymerisation of unsaturated polyesters with styrene and simultaneous reaction between terminal hydroxyl groups of unsaturated polyester and isocyanate groups of polyurethane prepolymer. The prepolymers were based on toluene diisocyanate (TDI) and each of hydroxy‐terminated natural rubber (HTNR), hydroxy‐terminated polybutadiene (HTPB), polyethylene glycol (PEG), and castor oil. Properties like tensile strength, toughness, impact resistance, and elongation‐at‐break of the modified UPRs show considerable improvement by this modification. The thermal stability of the copolymer is also marginally better. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 449–456, 2006     

聚氨酯预聚体增韧改性酚醛泡沫塑料

采用异氰酸酯封端且不含游离异氰酸酯单体的聚氨酯预聚体作为酚醛泡沫的增韧改性剂,并在后期混合发泡工艺中减少酸性固化剂的用量,制备了不粉化、韧性高的改性酚醛泡沫体,并考察了异氰酸酯基含量对酚醛泡沫体的表观密度、压缩强度、吸水率、阻燃性和导热性能等的影响.结果表明:随着聚氨酯预聚体用量以及异氰酸酯基含量的增加,改性酚醛泡沫体的表观密度、压缩强度增大;当异氰酸酯基含量为8.6%时,抗粉化程度最好;随着聚氨酯预聚体用量的增加,吸水率和热导率变化不大,当聚氨酯用量不超过6%时,临界氧指数仍大于40.     

Synthesis and characterization of triazole rich polyether polyols using click chemistry for highly branched polyurethanes

The present work describes development of moisture cured polyurethane–urea coatings based on 1,2,3-triazole rich polyether polyols. In this paper, two polyether polyols were synthesized by using 1,3-dipolar azide–alkyne cycloaddition reaction and they were named as PL-1 and PL-2 where PL-1 is 9 terminal hydroxyl groups and PL-2 is 6 terminal hydroxyl groups. These polyols were reacted with 4, 4′-diisocyanatodicyclohexylmethane (H₁₂MDI) at OH:NCO ratio of 1:1.2 in order to obtain isocyanate terminated polyurethane prepolymers. The resulted prepolymers were casted on tin foil and cured under atmospheric moisture in order to get completely cured polyurethane–urea free films. The free films were characterized by using Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and dynamic mechanical thermal analysis (DMTA) techniques. The TGA and DMTA results showed that these films have good thermal and mechanical stability. Anti-microbial studies proved that these polyurethane films show good resistance towards different bacterial and fungal attacks. These polymers were also coated on mild steel panels in order to evaluate corrosion resistance properties by using salt spray and electro chemical polarization studies.     

Thermal and dynamic mechanical characterization of polyurethane–urea–imide coatings

A series of NCO terminated polyurethane (PU)–imide copolymers were synthesized by a systematic three‐step process and were chain extended with different diol/diamine chain extenders. In the first step, isocyanate terminated PU prepolymers were prepared by reacting soft segments such as polyester (PE) polyols and polyether polyols such as polypropylene glycol (PPG‐1000) with hard segments like 2,4‐tolylene‐diisocyanate (TDI) or isophorone‐diisocyanate (IPDI) with NCO/OH ratio 2:1. In the second step, thermally stable heterocyclic imide ring was incorporated using isocyanate terminated PU prepolymers by reacting with pyromellitic dianhydride (PMDA) in a excess‐NCO:anhydride ratio of 1:0.5. The surplus NCO content after imidization was both moisture cured or partially reacted with chain extender and moisture cured. The films were characterized by thermogravimetric (TG), differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) instruments. The adhesion strength of these coatings on mild steel (MS), copper (Cu), and aluminum (Al) is dependent on the nature of the substrate. The TGA analysis show good thermal stability. The DMTA results show the microphase separation between the different hard and soft segments. Finally, a structure to property correlation was drawn based on the structure of the soft, hard, and chain extender and the observed properties are useful for understanding and design of intelligent coatings. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3158–3167, 2006     

Polyurethane ionomers. I. Structure–properties relationships of polyurethane ionomers

The influence of chemical structure on mechanical properties of polyurethane ionomers (PU ionomers) has been examined. NCO-terminated prepolymers prepared from primarily 4,4-methylene bis(phenyl isocyanate) (MDI) and poly(oxytetramethylene) glycol (PTMO) were chain extended with tertiary amine-containing diols and the ionomers obtained by quaternization of the prepolymers. The N-methyldiethanolamine chain extender gave the best physical properties. The mechanical properties of the PU ionomers were improved with decreasing chain length of PTMO and with increasing concentration of quaternary ammonium centers (or NCO/OH ratio of PU prepolymers). A lower degree of quaternization resulted in a decrease in the mechanical properties of the resulting PU ionomers, but their properties could be improved by post-quaternization. The adhesion of the PU ionomers to aluminum and the glass transition temperature increased with increasing concentration of quaternizing centers.